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Senousy HH, El-Sheekh MM, Khairy HM, El-Sayed HS, Mahmoud GAE, Hamed AA. Biodiesel Production from the Marine Alga Nannochloropsis oceanica Grown on Yeast Wastewater and the Effect on Its Biochemical Composition and Gene Expression. PLANTS (BASEL, SWITZERLAND) 2023; 12:2898. [PMID: 37631110 PMCID: PMC10459201 DOI: 10.3390/plants12162898] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/13/2023] [Revised: 07/24/2023] [Accepted: 08/05/2023] [Indexed: 08/27/2023]
Abstract
Microalgae-based biodiesel synthesis is currently not commercially viable due to the high costs of culture realizations and low lipid yields. The main objective of the current study was to determine the possibility of growing Nannochloropsis oceanica on Saccharomyces cerevisiae yeast wastewater for biodiesel generation at an economical rate. N. oceanica was grown in Guillard F/2 synthetic medium and three dilutions of yeast wastewater (1, 1.25, and 1.5%). Biodiesel properties, in addition to carbohydrate, protein, lipid, dry weight, biomass, lipid productivity, amino acids, and fatty acid methyl ester (FAMEs) content, were analyzed and the quality of the produced biodiesel is assessed. The data revealed the response of N. oceanica to nitrogen-deficiency in the three dilutions of yeast wastewater. N. oceanica in Y2 (1.25%) yeast wastewater dilution exhibited the highest total carbohydrate and lipid percentages (21.19% and 41.97%, respectively), and the highest lipid productivity (52.46 mg L-1 day -1) under nitrogen deficiency in yeast wastewater. The fatty acids profile shows that N. oceanica cultivated in Y2 (1.25%) wastewater dilution provides a significant level of TSFA (47.42%) and can be used as a feedstock for biodiesel synthesis. In addition, N. oceanica responded to nitrogen shortage in wastewater dilutions by upregulating the gene encoding delta-9 fatty acid desaturase (Δ9FAD). As a result, the oleic and palmitoleic acid levels increased in the fatty acid profile of Y2 yeast wastewater dilution, highlighting the increased activity of Δ9FAD enzyme in transforming stearic acid and palmitic acid into oleic acid and palmitoleic acid. This study proved that the Y2 (1.25%) yeast wastewater dilution can be utilized as a growth medium for improving the quantity of specific fatty acids and lipid productivity in N. oceanica that affect biodiesel quality to satisfy global biodiesel requirements.
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Affiliation(s)
- Hoda H. Senousy
- Botany and Microbiology Department, Faculty of Science, Cairo University, Giza 12613, Egypt;
| | | | - Hanan M. Khairy
- National Institute of Oceanography and Fisheries (NIOF), Cairo 11516, Egypt; (H.M.K.); (H.S.E.-S.)
| | - Heba S. El-Sayed
- National Institute of Oceanography and Fisheries (NIOF), Cairo 11516, Egypt; (H.M.K.); (H.S.E.-S.)
| | | | - Amal A. Hamed
- Botany and Microbiology Department, Faculty of Science, Cairo University, Giza 12613, Egypt;
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Fierli D, Barone ME, Graceffa V, Touzet N. Cold stress combined with salt or abscisic acid supplementation enhances lipogenesis and carotenogenesis in Phaeodactylum tricornutum (Bacillariophyceae). Bioprocess Biosyst Eng 2022; 45:1967-1977. [PMID: 36264371 DOI: 10.1007/s00449-022-02800-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Accepted: 10/07/2022] [Indexed: 11/02/2022]
Abstract
Compounds from microalgae such as ω3-fatty acids or carotenoid are commercially exploited within the pharmacology, nutraceutical, or cosmetic sectors. The co-stimulation of several compounds of interest may improve the cost-effectiveness of microalgal biorefinery pipelines. This study focussed on Phaeodactylum tricornutum to investigate the effects on lipogenesis and carotenogenesis of combined stressors, here cold temperature and addition of NaCl salt or the phytohormone abscisic acid, using a two-stage cultivation strategy. Cold stress with NaCl or phytohormone addition increased the neutral lipid content of the biomass (20 to 35%). These treatments also enhanced the proportions of EPA (22% greater than control) in the fatty acid profile. Also, these treatments had a stimulatory effect on carotenogenesis, especially the combination of cold stress with NaCl addition, which returned the highest production of fucoxanthin (33% increase). The gene expression of diacylglycerol acyltransferase (DGAT) and the ω-3 desaturase precursor (PTD15) were enhanced 4- and 16-fold relative to the control, respectively. In addition, zeaxanthin epoxidase 3 (ZEP3), was downregulated at low temperature when combined with abscisic acid. These results highlight the benefits of applying a combination of low temperature and salinity stress, to simultaneously enhance the yields of the valuable metabolites EPA and fucoxanthin in Phaeodactylum tricornutum.
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Affiliation(s)
- David Fierli
- School of Science, Department of Environmental Science, Centre for Environmental Research, Sustainability and Innovation, Atlantic Technological University, Ash Ln, Ballytivnan, Sligo, F91 YW50, Ireland.
| | - Maria Elena Barone
- School of Science, Department of Environmental Science, Centre for Environmental Research, Sustainability and Innovation, Atlantic Technological University, Ash Ln, Ballytivnan, Sligo, F91 YW50, Ireland
| | - Valeria Graceffa
- School of Science, Department of Life Sciences, Cellular Health and Toxicology Research Group (CHAT), Atlantic Technological University, Ash Ln, Ballytivnan, Sligo, F91 YW50, Ireland
| | - Nicolas Touzet
- School of Science, Department of Environmental Science, Centre for Environmental Research, Sustainability and Innovation, Atlantic Technological University, Ash Ln, Ballytivnan, Sligo, F91 YW50, Ireland
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3
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Aburai N, Onda T, Fujii K. Carotenogenesis and carotenoid esterification in biofilms of the microalga Coelastrella rubescens KGU-Y002 in the aerial phase. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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Wang Z, Wang Y, Shang P, Yang C, Yang M, Huang J, Ren B, Zuo Z, Zhang Q, Li W, Song B. Overexpression of Soybean GmWRI1a Stably Increases the Seed Oil Content in Soybean. Int J Mol Sci 2022; 23:5084. [PMID: 35563472 PMCID: PMC9102168 DOI: 10.3390/ijms23095084] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2022] [Revised: 04/27/2022] [Accepted: 04/29/2022] [Indexed: 02/04/2023] Open
Abstract
WRINKLED1 (WRI1), an APETALA2/ethylene-responsive-element-binding protein (AP2/EREBP) subfamily transcription factor, plays a crucial role in the transcriptional regulation of plant fatty acid biosynthesis. In this study, GmWRI1a was overexpressed in the soybean cultivar 'Dongnong 50' using Agrobacterium-mediated transformation to generate three transgenic lines with high seed oil contents. PCR and Southern blotting analysis showed that the T-DNA was inserted into the genome at precise insertion sites and was stably inherited by the progeny. Expression analysis using qRT-PCR and Western blotting indicated that GmWRI1a and bar driven by the CaMV 35S promoter were significantly upregulated in the transgenic plants at different developmental stages. Transcriptome sequencing results showed there were obvious differences in gene expression between transgenic line and transgenic receptor during seed developmental stages. KEGG analysis found that the differentially expressed genes mainly annotated to metabolic pathways, such as carbohydrated metabolism and lipid metabolism. A 2-year single-location field trial revealed that three transgenic lines overexpressing GmWRI1a (GmWRI1a-OE) showed a stable increase in seed oil content of 4.97-10.35%. Importantly, no significant effect on protein content and yield was observed. Overexpression of GmWRI1a changed the fatty acid composition by increasing the linoleic acid (C18:2) content and decreasing the palmitic acid (C16:0) content in the seed. The three GmWRI1a-OE lines showed no significant changes in agronomic traits. The results demonstrated that the three GmWRI1a overexpression lines exhibited consistent increases in seed oil content compared with that of the wild type and did not significantly affect the seed yield and agronomic traits. The genetic engineering of GmWRI1a will be an effective strategy for the improvement of seed oil content and value in soybean.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | - Wenbin Li
- Key Laboratory of Soybean Biology of Ministry of Education China, Key Laboratory of Soybean Biology and Breeding (Genetics) of Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin 150030, China; (Z.W.); (Y.W.); (P.S.); (C.Y.); (M.Y.); (J.H.); (B.R.); (Z.Z.); (Q.Z.)
| | - Bo Song
- Key Laboratory of Soybean Biology of Ministry of Education China, Key Laboratory of Soybean Biology and Breeding (Genetics) of Ministry of Agriculture and Rural Affairs, Northeast Agricultural University, Harbin 150030, China; (Z.W.); (Y.W.); (P.S.); (C.Y.); (M.Y.); (J.H.); (B.R.); (Z.Z.); (Q.Z.)
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Rau EM, Bartosova Z, Kristiansen KA, Aasen IM, Bruheim P, Ertesvåg H. Overexpression of Two New Acyl-CoA:Diacylglycerol Acyltransferase 2-Like Acyl-CoA:Sterol Acyltransferases Enhanced Squalene Accumulation in Aurantiochytrium limacinum. Front Microbiol 2022; 13:822254. [PMID: 35145505 PMCID: PMC8821962 DOI: 10.3389/fmicb.2022.822254] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 01/10/2022] [Indexed: 11/13/2022] Open
Abstract
Thraustochytrids are heterotrophic marine eukaryotes known to accumulate large amounts of triacylglycerols, and they also synthesize terpenoids like carotenoids and squalene, which all have an increasing market demand. However, a more extensive knowledge of the lipid metabolism is needed to develop thraustochytrids for profitable biomanufacturing. In this study, two putative type-2 Acyl-CoA:diacylglycerol acyltransferases (DGAT2) genes of Aurantiochytrium sp. T66, T66ASATa, and T66ASATb, and their homologs in Aurantiochytrium limacinum SR21, AlASATa and AlASATb, were characterized. In A. limacinum SR21, genomic knockout of AlASATb reduced the amount of the steryl esters of palmitic acid, SE (16:0), and docosahexaenoic acid, SE (22:6). The double mutant of AlASATa and AlASATb produced even less of these steryl esters. The expression and overexpression of T66ASATb and AlASATb, respectively, enhanced SE (16:0) and SE (22:6) production more significantly than those of T66ASATa and AlASATa. In contrast, these mutations did not significantly change the level of triacylglycerols or other lipid classes. The results suggest that the four genes encoded proteins possessing acyl-CoA:sterol acyltransferase (ASAT) activity synthesizing both SE (16:0) and SE (22:6), but with the contribution from AlASATb and T66ASATb being more important than that of AlASATa and T66ASATa. Furthermore, the expression and overexpression of T66ASATb and AlASATb enhanced squalene accumulation in SR21 by up to 88%. The discovery highlights the functional diversity of DGAT2-like proteins and provides valuable information on steryl ester and squalene synthesis in thraustochytrids, paving the way to enhance squalene production through metabolic engineering.
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Affiliation(s)
- E-Ming Rau
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Zdenka Bartosova
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Kåre Andre Kristiansen
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Inga Marie Aasen
- Department of Biotechnology and Nanomedicine, SINTEF Industry, Trondheim, Norway
| | - Per Bruheim
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
| | - Helga Ertesvåg
- Department of Biotechnology and Food Science, NTNU Norwegian University of Science and Technology, Trondheim, Norway
- *Correspondence: Helga Ertesvåg,
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7
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Lan C, Wang S, Zhang H, Wang Z, Wan W, Liu H, Hu Y, Cui Q, Song X. Cocktail biosynthesis of triacylglycerol by rational modulation of diacylglycerol acyltransferases in industrial oleaginous Aurantiochytrium. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:246. [PMID: 34961557 PMCID: PMC8714446 DOI: 10.1186/s13068-021-02096-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 12/18/2021] [Indexed: 06/14/2023]
Abstract
BACKGROUND Triacylglycerol (TAG) is an important storage lipid in organisms, depending on the degree of unsaturation of fatty acid molecules attached to glycerol; it is usually used as the feedstock for nutrition or biodiesel. However, the mechanism of assembly of saturated fatty acids (SFAs) or polyunsaturated fatty acids (PUFAs) into TAGs remains unclear for industrial oleaginous microorganism. RESULTS Diacylglycerol acyltransferase (DGAT) is a key enzyme for TAG synthesis. Hence, ex vivo (in yeast), and in vivo functions of four DGAT2s (DGAT2A, DGAT2B, DGAT2C, and DGAT2D) in industrial oleaginous thraustochytrid Aurantiochytrium sp. SD116 were analyzed. Results revealed that DGAT2C was mainly responsible for connecting PUFA to the sn-3 position of TAG molecules. However, DGAT2A and DGAT2D target SFA and/or MUFA. CONCLUSIONS There are two specific TAG assembly routes in Aurantiochytrium. The "saturated fatty acid (SFA) TAG lane" primarily produces SFA-TAGs mainly mediated by DGAT2D whose function is complemented by DGAT2A. And, the "polyunsaturated fatty acid (PUFA) TAG lane" primarily produces PUFA-TAGs via DGAT2C. In this study, we demonstrated the functional distribution pattern of four DGAT2s in oleaginous thraustochytrid Aurantiochytrium, and provided a promising target to rationally design TAG molecular with the desired characteristics.
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Affiliation(s)
- Chuanzeng Lan
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Sen Wang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China
| | - Huidan Zhang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China
| | - Zhuojun Wang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Weijian Wan
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
| | - Huan Liu
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China
| | - Yang Hu
- Faculty of Science, University of Calgary, Calgary, AB, T2N 1N4, Canada
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China.
- Shandong Energy Institute, Qingdao, 266101, Shandong, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
| | - Xiaojin Song
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China.
- Shandong Energy Institute, Qingdao, 266101, Shandong, China.
- Qingdao New Energy Shandong Laboratory, Qingdao, 266101, Shandong, China.
- Center for Ocean Mega-Science, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China.
- University of Chinese Academy of Sciences, Beijing, 100049, China.
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Wang Z, Wang S, Feng Y, Wan W, Zhang H, Bai X, Cui Q, Song X. Obtaining High-Purity Docosahexaenoic Acid Oil in Thraustochytrid Aurantiochytrium through a Combined Metabolic Engineering Strategy. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:10215-10222. [PMID: 34415758 DOI: 10.1021/acs.jafc.1c03781] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
High-purity docosahexaenoic acid (DHA) resources are insufficient in the pharmaceutical and food industries. Although many efforts have attempted to obtain the high-purity DHA production, few reports have been successful. Here, a combined metabolic engineering strategy was employed to increase the DHA purity in the oleaginous thraustochytrid Aurantiochytrium. The strategy includes both partial deactivation of the competing pathway of DHA biosynthesis, by disrupting one copy of the fatty acid synthase gene, and strengthening of substrate supply and triacylglycerol synthesis, by the overexpression of acetyl-CoA carboxylase and diacylglycerol acyltransferase. With this strategy, a final mutant was obtained with a DHA purity of 61% in total fatty acids and a content of 331 mg/g dry cell weight. This study provides an advanced strategy for sustainable high-purity DHA production and highlights the strategy for producing designer oils in industrial oleaginous microorganisms.
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Affiliation(s)
- Zhuojun Wang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Sen Wang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Yingang Feng
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Weijian Wan
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Huidan Zhang
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
| | - Xinfeng Bai
- Biology Institute, Qilu University of Technology, Jinan 250013, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xiaojin Song
- CAS Key Laboratory of Biofuels, Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- Shandong Energy Institute, Qingdao, Shandong 266101, China
- Qingdao New Energy Shandong Laboratory, Qingdao, Shandong 266101, China
- Center for Ocean Mega-science, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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9
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Fatty Acid Production and Direct Acyl Transfer through Polar Lipids Control TAG Biosynthesis during Nitrogen Deprivation in the Halotolerant Alga Dunaliella tertiolecta. Mar Drugs 2021; 19:md19070368. [PMID: 34202376 PMCID: PMC8304655 DOI: 10.3390/md19070368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 12/31/2022] Open
Abstract
The aims of this work were to evaluate the contribution of the free fatty acid (FA) pool to triacylglyceride (TAG) biosynthesis and to try to characterize the mechanism by which FA are assimilated into TAG in the green alga Dunaliella tertiolecta. A time-resolved lipidomic analysis showed that nitrogen (N) deprivation induces a redistribution of total lipidome, particularly of free FA and major polar lipid (PL), in parallel to enhanced accumulation of polyunsaturated TAG. The steady-state concentration of the FA pool, measured by prolonged 14C-bicarbonate pre-labeling, showed that N deprivation induced a 50% decrease in total FA level within the first 24 h and up to 85% after 96 h. The abundance of oleic acid increased from 50 to 70% of total free FA while polyunsaturated FA (PUFA) disappeared under N deprivation. The FA flux, measured by the rate of incorporation of 14C-palmitic acid (PlA), suggests partial suppression of phosphatidylcholine (PC) acyl editing and an enhanced turnover of the FA pool and of total digalactosyl-diacylglycerol (DGDG) during N deprivation. Taken together, these results imply that FA biosynthesis is a major rate-controlling stage in TAG biosynthesis in D. tertiolecta and that acyl transfer through PL such as PC and DGDG is the major FA assimilation pathway into TAG in that alga and possibly in other green microalgae. Increasing the availability of FA could lead to enhanced TAG biosynthesis and to improved production of high-value products from microalgae.
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10
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Guéguen N, Le Moigne D, Amato A, Salvaing J, Maréchal E. Lipid Droplets in Unicellular Photosynthetic Stramenopiles. FRONTIERS IN PLANT SCIENCE 2021; 12:639276. [PMID: 33968100 PMCID: PMC8100218 DOI: 10.3389/fpls.2021.639276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The Heterokonta or Stramenopile phylum comprises clades of unicellular photosynthetic species, which are promising for a broad range of biotechnological applications, based on their capacity to capture atmospheric CO2 via photosynthesis and produce biomolecules of interest. These molecules include triacylglycerol (TAG) loaded inside specific cytosolic bodies, called the lipid droplets (LDs). Understanding TAG production and LD biogenesis and function in photosynthetic stramenopiles is therefore essential, and is mostly based on the study of a few emerging models, such as the pennate diatom Phaeodactylum tricornutum and eustigmatophytes, such as Nannochloropsis and Microchloropsis species. The biogenesis of cytosolic LD usually occurs at the level of the endoplasmic reticulum. However, stramenopile cells contain a complex plastid deriving from a secondary endosymbiosis, limited by four membranes, the outermost one being connected to the endomembrane system. Recent cell imaging and proteomic studies suggest that at least some cytosolic LDs might be associated to the surface of the complex plastid, via still uncharacterized contact sites. The carbon length and number of double bonds of the acyl groups contained in the TAG molecules depend on their origin. De novo synthesis produces long-chain saturated or monounsaturated fatty acids (SFA, MUFA), whereas subsequent maturation processes lead to very long-chain polyunsaturated FA (VLC-PUFA). TAG composition in SFA, MUFA, and VLC-PUFA reflects therefore the metabolic context that gave rise to the formation of the LD, either via an early partitioning of carbon following FA de novo synthesis and/or a recycling of FA from membrane lipids, e.g., plastid galactolipids or endomembrane phosphor- or betaine lipids. In this review, we address the relationship between cytosolic LDs and the complex membrane compartmentalization within stramenopile cells, the metabolic routes leading to TAG accumulation, and the physiological conditions that trigger LD production, in response to various environmental factors.
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Ma H, Wu X, Wei Z, Zhao L, Li Z, Liang Q, Zheng J, Wang Y, Li Y, Huang L, Hu Q, Han D. Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:510-524. [PMID: 33005924 PMCID: PMC7853605 DOI: 10.1093/jxb/eraa451] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 10/05/2020] [Indexed: 05/03/2023]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final committed step in triacylglycerol biosynthesis in eukaryotes. In microalgae, the copy number of DGAT genes is extraordinarily expanded, yet the functions of many DGATs remain largely unknown. This study revealed that microalgal DGAT can function as a lysophosphatidic acyltransferase (LPAAT) both in vitro and in vivo while losing its original function as DGAT. Among the five DGAT-encoding genes identified and cloned from the green microalga Haematococcus pluvialis, four encoded HpDGATs that showed triacylglycerol synthase activities in yeast functional complementation analyses; the exception was one of the type II DGAT encoding genes, HpDGTT2. The hydrophobic recombinant HpDGTT2 protein was purified in soluble form and was found to function as a LPAAT via enzymatic assay. Introducing this gene into the green microalga Chlamydomonas reinhardtii led to retarded cellular growth, enlarged cell size, and enhanced triacylglycerol accumulation, identical to the phenotypes of transgenic strains overexpressing CrLPAAT. This study provides a framework for dissecting uncharacterized DGATs, and could pave the way to decrypting the structure-function relationship of this large group of enzymes that are critical to lipid biosynthesis.
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Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoying Wu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Ziwang Wei
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhongze Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qing Liang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jie Zheng
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu Wang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Linfei Huang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Algae Biomass, SDIC Biotech Investment Corporation, Beijing, China
- Correspondence: or
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Correspondence: or
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Gao B, Wang F, Huang L, Liu H, Zhong Y, Zhang C. Biomass, lipid accumulation kinetics, and the transcriptome of heterotrophic oleaginous microalga Tetradesmus bernardii under different carbon and nitrogen sources. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:4. [PMID: 33407769 PMCID: PMC7789750 DOI: 10.1186/s13068-020-01868-9] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/03/2020] [Accepted: 12/24/2020] [Indexed: 06/12/2023]
Abstract
BACKGROUND Heterotrophic cultivation of microalgae has been proposed as a viable alternative method for novel high-value biomolecules, enriched biomass, and biofuel production because of their allowance of high cell density levels, as well as simple production technology. Tetradesmus bernardii, a newly isolated high-yielding oleaginous microalga under photoautotrophic conditions, is able to grow heterotrophically, meaning that it can consume organic carbon sources in dark condition. We investigated the effect of different carbon/nitrogen (C/N) ratios on the growth and lipid accumulation of T. bernardii in heterotrophic batch culture under two nitrogen sources (NaNO3 and CO(NH2)2). In addition, we conducted time-resolved transcriptome analysis to reveal the metabolic mechanism of T. bernardii in heterotrophic culture. RESULTS T. bernardii can accumulate high biomass concentrations in heterotrophic batch culture where the highest biomass of 46.09 g/L was achieved at 100 g/L glucose concentration. The rate of glucose to biomass exceeded 55% when the glucose concentration was less than 80 g/L, and the C/N ratio was 44 at urea treatment. The culture was beneficial to lipid accumulation at a C/N ratio between 110 and 130. NaNO3 used as a nitrogen source enhanced the lipid content more than urea, and the highest lipid content was 45% of dry weight. We performed RNA-seq to analyze the time-resolved transcriptome of T. bernardii. As the nitrogen was consumed in the medium, nitrogen metabolism-related genes were significantly up-regulated to speed up the N metabolic cycle. As chloroplasts were destroyed in the dark, the metabolism of cells was transferred from chloroplasts to cytoplasm. However, storage of carbohydrate in chloroplast remained active, mainly the synthesis of starch, and the precursor of starch synthesis in heterotrophic culture may largely come from the absorption of organic carbon source (glucose). With regard to lipid metabolism, the related genes of fatty acid synthesis in low nitrogen concentration increased gradually with the extension of cultivation time. CONCLUSION T. bernardii exhibited rapid growth and high lipid accumulation in heterotrophic culture. It may be a potential candidate for biomass and biofuel production. Transcriptome analysis showed that multilevel regulation ensured the conversion from carbon to the synthesis of carbohydrate and lipid.
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Affiliation(s)
- Baoyan Gao
- Department of Ecology, Research Center for Hydrobiology, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Feifei Wang
- Department of Ecology, Research Center for Hydrobiology, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Luodong Huang
- Department of Ecology, Research Center for Hydrobiology, Jinan University, Guangzhou, 510632, People's Republic of China
| | - Hui Liu
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Yuming Zhong
- College of Resources and Environment, Zhongkai University of Agriculture and Engineering, Guangzhou, 510225, China
| | - Chengwu Zhang
- Department of Ecology, Research Center for Hydrobiology, Jinan University, Guangzhou, 510632, People's Republic of China.
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Cui H, Zhao C, Xu W, Zhang H, Hang W, Zhu X, Ji C, Xue J, Zhang C, Li R. Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis. BMC PLANT BIOLOGY 2021; 21:20. [PMID: 33407140 PMCID: PMC7788937 DOI: 10.1186/s12870-020-02794-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/09/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. RESULTS Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. CONCLUSIONS Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Hongjiang Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wei Hang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Xiaoli Zhu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
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Chungjatupornchai W, Fa-Aroonsawat S. Enhanced triacylglycerol production in oleaginous microalga Neochloris oleoabundans by co-overexpression of lipogenic genes: Plastidial LPAAT1 and ER-located DGAT2. J Biosci Bioeng 2020; 131:124-130. [PMID: 33069576 DOI: 10.1016/j.jbiosc.2020.09.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 09/18/2020] [Accepted: 09/18/2020] [Indexed: 12/29/2022]
Abstract
Microalgae accumulate lipid triacylglycerol (TAG), a promising feedstock for production of natural edible oils and biofuels. To make products derived from microalgal TAG economically viable, increasing TAG content and productivity are of high importance. To increase TAG content, two endogenous key enzymes of TAG biosynthesis: plastidial lysophosphatidic acid acyltransferase (NeoLPAAT1) and endoplasmic reticulum-located diacylglycerol acyltransferase 2 (NeoDGAT2) were co-overexpressed in oleaginous microalga Neochloris oleoabundans. The neutral lipid content in NeoLPAAT1-NeoDGAT2 co-overexpressing transformant detected by Nile red staining increased 2-fold without compromising cell growth. The transcriptional levels of NeoLPAAT1 and NeoDGAT2 levels were 1.9-fold higher in the transformant than wild type. Considerably higher lipid accumulation was found in the transformant than wild type: total lipid content (73.72 ± 4.17 % DCW) increased 1.6-fold, TAG content (50.63 ± 6.15 % DCW) increased 2.1-fold, total lipid productivity (16.84 ± 0.66 mg/L/day) increased 1.9-fold, and TAG productivity (11.68 ± 0.90 mg/L/day) increased 2.1-fold. Fatty acid composition was slightly altered in the transformant compared to wild type; saturated fatty acid C16:0 increased to 26% from 20%, whereas C18:0 was reduced to 7% from 14%. Long-term stability of NeoLPAAT1-NeoDGAT2 co-overexpression was observed in the transformant continuously maintained on solid medium in a period of 4 years. The results suggested that targeted engineering of genes in pathway located at different organelles should be possible in microalgal lipid metabolism.
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Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom 73170, Thailand.
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15
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Falarz LJ, Xu Y, Caldo KMP, Garroway CJ, Singer SD, Chen G. Characterization of the diversification of phospholipid:diacylglycerol acyltransferases in the green lineage. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 103:2025-2038. [PMID: 32538516 DOI: 10.1111/tpj.14880] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/28/2020] [Accepted: 06/02/2020] [Indexed: 05/03/2023]
Abstract
Triacylglycerols have important physiological roles in photosynthetic organisms, and are widely used as food, feed and industrial materials in our daily life. Phospholipid:diacylglycerol acyltransferase (PDAT) is the pivotal enzyme catalyzing the acyl-CoA-independent biosynthesis of triacylglycerols, which is unique in plants, algae and fungi, but not in animals, and has essential functions in plant and algal growth, development and stress responses. Currently, this enzyme has yet to be examined in an evolutionary context at the level of the green lineage. Some fundamental questions remain unanswered, such as how PDATs evolved in photosynthetic organisms and whether the evolution of terrestrial plant PDATs from a lineage of charophyte green algae diverges in enzyme function. As such, we used molecular evolutionary analysis and biochemical assays to address these questions. Our results indicated that PDAT underwent divergent evolution in the green lineage: PDATs exist in a wide range of plants and algae, but not in cyanobacteria. Although PDATs exhibit the conservation of several features, phylogenetic and selection-pressure analyses revealed that overall they evolved to be highly divergent, driven by different selection constraints. Positive selection, as one major driving force, may have resulted in enzymes with a higher functional importance in land plants than green algae. Further structural and mutagenesis analyses demonstrated that some amino acid sites under positive selection are critically important to PDAT structure and function, and may be central in lecithin:cholesterol acyltransferase family enzymes in general.
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Affiliation(s)
- Lucas J Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| | - Colin J Garroway
- Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Stacy D Singer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, T1J 4B1, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
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16
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Wang X, Xin Y, Ren L, Sun Z, Zhu P, Ji Y, Li C, Xu J, Ma B. Positive dielectrophoresis-based Raman-activated droplet sorting for culture-free and label-free screening of enzyme function in vivo. SCIENCE ADVANCES 2020; 6:eabb3521. [PMID: 32821836 PMCID: PMC7413728 DOI: 10.1126/sciadv.abb3521] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/18/2020] [Accepted: 06/26/2020] [Indexed: 05/19/2023]
Abstract
The potential of Raman-activated cell sorting (RACS) is inherently limited by conflicting demands for signal quality and sorting throughput. Here, we present positive dielectrophoresis-based Raman-activated droplet sorting (pDEP-RADS), where a periodical pDEP force was exerted to trap fast-moving cells, followed by simultaneous microdroplet encapsulation and sorting. Screening of yeasts for triacylglycerol (TAG) content demonstrated near-theoretical-limit accuracy, ~120 cells min-1 throughput and full-vitality preservation, while sorting fatty acid degree of unsaturation (FA-DU) featured ~82% accuracy at ~40 cells min-1. From a yeast library expressing algal diacylglycerol acyltransferases (DGATs), a pDEP-RADS run revealed all reported TAG-synthetic variants and distinguished FA-DUs of enzyme products. Furthermore, two previously unknown DGATs producing low levels of monounsaturated fatty acid-rich TAG were discovered. This first demonstration of RACS for enzyme discovery represents hundred-fold saving in time consumables and labor versus culture-based approaches. The ability to automatically flow-sort resonance Raman-independent phenotypes greatly expands RACS' application.
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Affiliation(s)
- Xixian Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Lihui Ren
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Zheng Sun
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Pengfei Zhu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yuetong Ji
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
- Qingdao Single-cell Biotechnology Co., Ltd., Qingdao, Shandong, China
| | - Chunyu Li
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
- Corresponding author. (B.M.); (J.X.)
| | - Bo Ma
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics and Shandong Institute of Energy Research, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, China
- Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong, China
- University of Chinese Academy of Sciences, Beijing, China
- Corresponding author. (B.M.); (J.X.)
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You W, Wei L, Gong Y, Hajjami ME, Xu J, Poetsch A. Integration of proteome and transcriptome refines key molecular processes underlying oil production in Nannochloropsis oceanica. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:109. [PMID: 32565907 PMCID: PMC7302151 DOI: 10.1186/s13068-020-01748-2] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/08/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Under nitrogen deficiency situation, Nannochloropsis spp. accumulate large amounts of lipids in the form of triacylglycerides (TAG). Mechanisms of this process from the perspective of transcriptome and metabolome have been obtained previously, yet proteome analysis is still sparse which hinders the analysis of dynamic adaption to nitrogen deficiency. Here, proteomes for 3 h, 6 h, 12 h, 24 h, 48 h and 10th day of nitrogen deplete (N-) and replete (N+) conditions were obtained and integrated with previous transcriptome data for N. oceanica. RESULTS Physiological adaptations to N- not apparent from transcriptome data were unveiled: (a) abundance of proteins related to photosynthesis only slightly decreased in the first 48 h, indicating that photosynthesis is still working efficiently, and protein amounts adjust gradually with reduction in chloroplast size. (b) Most proteins related to the TCA cycle were strongly upregulated after 48 h under N-, suggesting that respiration is enhanced after 48 h and that TCA cycle efflux supports the carbon required for lipid synthesis. (c) Proteins related to lipid accumulation via the Kennedy pathway increased their abundance at 48 h, synchronous with the previously reported diversification of fatty acids after 48 h. CONCLUSIONS This study adds a proteome perspective on the major pathways for TAG accumulation in Nannochloropsis spp. Temporal changes of proteome exhibited distinct adaptation phases that are usually delayed relative to transcriptomic responses. Notably, proteome data revealed that photosynthesis and carbon fixation are still ongoing even after 48 h of N-. Moreover, sometimes completely opposite trends in proteome and transcriptome demonstrate the relevance of underexplored post-transcriptional regulation for N- adaptation.
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Affiliation(s)
- Wuxin You
- Single-Cell Center CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong China
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Li Wei
- Single-Cell Center CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong China
- University of Chinese Academy of Science, Beijing, China
| | - Yanhai Gong
- Single-Cell Center CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong China
- University of Chinese Academy of Science, Beijing, China
| | - Mohamed El Hajjami
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - Jian Xu
- Single-Cell Center CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong China
- University of Chinese Academy of Science, Beijing, China
| | - Ansgar Poetsch
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003 China
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18
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Sahoo S, Mahapatra SR, Das N, Parida BK, Rath S, Misra N, Suar M. Functional elucidation of hypothetical proteins associated with lipid accumulation: Prioritizing genetic engineering targets for improved algal biofuel production. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101887] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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19
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Xu Y, Caldo KMP, Falarz L, Jayawardhane K, Chen G. Kinetic improvement of an algal diacylglycerol acyltransferase 1 via fusion with an acyl-CoA binding protein. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:856-871. [PMID: 31991039 DOI: 10.1111/tpj.14708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/26/2019] [Accepted: 01/21/2020] [Indexed: 05/03/2023]
Abstract
Microalgal oils in the form of triacylglycerols (TAGs) are broadly used as nutritional supplements and biofuels. Diacylglycerol acyltransferase (DGAT) catalyzes the final step of acyl-CoA-dependent biosynthesis of TAG, and is considered a key target for manipulating oil production. Although a growing number of DGAT1s have been identified and over-expressed in some algal species, the detailed structure-function relationship, as well as the improvement of DGAT1 performance via protein engineering, remain largely untapped. Here, we explored the structure-function features of the hydrophilic N-terminal domain of DGAT1 from the green microalga Chromochloris zofingiensis (CzDGAT1). The results indicated that the N-terminal domain of CzDGAT1 was less disordered than those of the higher eukaryotic enzymes and its partial truncation or complete removal could substantially decrease enzyme activity, suggesting its possible role in maintaining enzyme performance. Although the N-terminal domains of animal and plant DGAT1s were previously found to bind acyl-CoAs, replacement of CzDGAT1 N-terminus by an acyl-CoA binding protein (ACBP) could not restore enzyme activity. Interestingly, the fusion of ACBP to the N-terminus of the full-length CzDGAT1 could enhance the enzyme affinity for acyl-CoAs and augment protein accumulation levels, which ultimately drove oil accumulation in yeast cells and tobacco leaves to higher levels than the full-length CzDGAT1. Overall, our findings unravel the distinct features of the N-terminus of algal DGAT1 and provide a strategy to engineer enhanced performance in DGAT1 via protein fusion, which may open a vista in generating improved membrane-bound acyl-CoA-dependent enzymes and boosting oil biosynthesis in plants and oleaginous microorganisms.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Kethmi Jayawardhane
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
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20
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Jang S, Kong F, Lee J, Choi BY, Wang P, Gao P, Yamano T, Fukuzawa H, Kang BH, Lee Y. CrABCA2 Facilitates Triacylglycerol Accumulation in Chlamydomonas reinhardtii under Nitrogen Starvation. Mol Cells 2020; 43:48-57. [PMID: 31910336 PMCID: PMC6999713 DOI: 10.14348/molcells.2019.0262] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 11/30/2019] [Accepted: 12/02/2019] [Indexed: 11/27/2022] Open
Abstract
The microalga Chlamydomonas reinhardtii accumulates triacylglycerols (TAGs) in lipid droplets under stress conditions, such as nitrogen starvation. TAG biosynthesis occurs mainly at the endoplasmic reticulum (ER) and requires fatty acid (FA) substrates supplied from chloroplasts. How FAs are transferred from chloroplast to ER in microalgae was unknown. We previously reported that an Arabidopsis thaliana ATP-binding cassette (ABC) transporter, AtABCA9, facilitates FA transport at the ER during seed development. Here we identified a gene homologous to AtABCA9 in the C. reinhardtii genome, which we named CrABCA2. Under nitrogen deprivation conditions, CrABCA2 expression was upregulated, and the CrABCA2 protein level also increased. CrABCA2 knockdown lines accumulated less TAGs and CrABCA2 overexpression lines accumulated more TAGs than their untransformed parental lines. Transmission electron microscopy showed that CrABCA2 was localized in swollen ER. These results suggest that CrABCA2 transports substrates for TAG biosynthesis to the ER during nitrogen starvation . Our study provides a potential tool for increasing lipid production in microalgae.
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Affiliation(s)
- Sunghoon Jang
- Department of Life Sciences, Pohang University of Science and Technology, Pohang 37673,
Korea
| | - Fantao Kong
- School of Bioengineering, Dalian University of Technology, Dalian 116024,
China
| | - Jihyeon Lee
- Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673,
Korea
| | - Bae Young Choi
- Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673,
Korea
| | - Pengfei Wang
- Cellular and Molecular Biology Program, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong 999077,
China
| | - Peng Gao
- Cellular and Molecular Biology Program, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong 999077,
China
| | - Takashi Yamano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,
Japan
| | - Hideya Fukuzawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8502,
Japan
| | - Byung-Ho Kang
- Cellular and Molecular Biology Program, State Key Laboratory of Agrobiotechnology, School of Life Sciences, The Chinese University of Hong Kong, New Territories, Hong Kong 999077,
China
| | - Youngsook Lee
- Integrative Biosciences and Biotechnology, Pohang University of Science and Technology, Pohang 37673,
Korea
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21
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Nguyen T, Xu Y, Abdel-Hameed M, Sorensen JL, Singer SD, Chen G. Characterization of a Type-2 Diacylglycerol Acyltransferase from Haematococcus pluvialis Reveals Possible Allostery of the Recombinant Enzyme. Lipids 2019; 55:425-433. [PMID: 31879987 DOI: 10.1002/lipd.12210] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2019] [Revised: 12/09/2019] [Accepted: 12/13/2019] [Indexed: 12/24/2022]
Abstract
Haematococcus pluvialis is a green microalga used in the algal biotechnology industry that can accumulate considerable amounts of storage triacylglycerol (TAG) and astaxanthin, which is a high-value carotenoid with strong antioxidant activity, under stress conditions. Diacylglycerol acyltransferase (DGAT) catalyzes the last step of the acyl-CoA-dependent TAG biosynthesis and appears to represent a bottleneck in algal TAG formation. In this study, putative H. pluvialis DGAT2 cDNA (HpDGAT2A, B, D and E) were identified from a transcriptome database and were subjected to sequence-based in silico analyses. The coding sequences of HpDGAT2B, D, and E were then isolated and characterized through heterologous expression in a TAG-deficient Saccharomyces cerevisiae strain H1246. The expression of HpDGAT2D allowed the recovery of TAG biosynthesis in this yeast mutant, and further in vitro enzymatic assays confirmed that the recombinant HpDGAT2D possessed strong DGAT activity. Interestingly, the recombinant HpDGAT2D displayed sigmoidal kinetics in response to increasing acyl-CoA concentrations, which has not been reported in plant or algal DGAT2 in previous studies.
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Affiliation(s)
- Trinh Nguyen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada
| | - Mona Abdel-Hameed
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - John L Sorensen
- Department of Chemistry, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
| | - Stacy D Singer
- Agriculture and Agri-Food Canada, Lethbridge Research and Development Centre, Lethbridge, AB, T1J 4B1, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, AB, T6G 2P5, Canada.,Department of Biological Sciences, University of Manitoba, Winnipeg, MB, R3T 2N2, Canada
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22
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Singh N, Roy K, Goyal A, Moholkar VS. Investigations in ultrasonic enhancement of β-carotene production by isolated microalgal strain Tetradesmus obliquus SGM19. ULTRASONICS SONOCHEMISTRY 2019; 58:104697. [PMID: 31450379 DOI: 10.1016/j.ultsonch.2019.104697] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Revised: 07/11/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Microalgae constitute relatively novel source of lipids for biodiesel production. The economy of this process can be enhanced by the recovery of β-carotenes present in the microalgal cells. The present study has addressed matter of enhancement of lipids and β-carotene production by microalgal species of Tetradesmus obliquus SGM19 with the application of sonication. As first step, the growth cycle of Tetradesmus obliquus SGM19 was optimized using statistical experimental design. Optimum parameters influencing microalgal growth were: Sodium nitrate = 1.5 g/L, ethylene diamine tetraacetic acid = 0.001 g/L, temperature = 28.5 °C, pH = 7.5, light intensity = 5120 lux, β-carotene yield = 0.67 mg/g DCW. Application of 33 kHz and 1.4 bar ultrasound at 10% duty cycle was revealed to enhance the lipid and β-carotene yields by 34.5% and 31.5%, respectively. Kinetic analysis of substrate and product profiles in control and test experiments revealed both lipid and β-carotene to be growth-associated products. The intracellular NAD(H) content during late log phase was monitored in control and test experiments as a measure of relative kinetics of intracellular metabolism. Consistently higher NAD(H) concentrations were observed for test experiments; indicating faster metabolism. Finally, the viability of ultrasound-exposed microalgal cells (assessed with flow cytometry) was >80%.
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Affiliation(s)
- Neha Singh
- Centre for Energy, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India
| | - Kuldeep Roy
- Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India
| | - Arun Goyal
- Centre for Energy, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India; Department of Biosciences and Bioengineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India
| | - Vijayanand S Moholkar
- Centre for Energy, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India; Department of Chemical Engineering, Indian Institute of Technology Guwahati, Guwahati 781 039, Assam, India.
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23
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Xin Y, Shen C, She Y, Chen H, Wang C, Wei L, Yoon K, Han D, Hu Q, Xu J. Biosynthesis of Triacylglycerol Molecules with a Tailored PUFA Profile in Industrial Microalgae. MOLECULAR PLANT 2019; 12:474-488. [PMID: 30580039 DOI: 10.1016/j.molp.2018.12.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/29/2018] [Accepted: 12/13/2018] [Indexed: 05/06/2023]
Abstract
The composition of polyunsaturated fatty acids (PUFAs) in triacylglycerols (TAGs) is key to health benefits and for oil applications, yet the underlying genetic mechanism remains poorly understood. In this study, by in silico, ex vivo, and in vivo profiling of type-2 diacylglycerol acyltransferases (DGAT2s) in Nannochloropsis oceanica we revealed two novel PUFA-preferring enzymes that discriminate individual PUFA species in TAG assembly, with NoDGAT2J for linoleic acid (LA) and NoDGAT2K for eicosapentaenoic acid (EPA). The LA and EPA composition of TAG molecules is mediated in vivo via the functional partitioning between NoDGAT2J and 2K, both of which are localized in the chloroplast envelope. By modulating transcript abundance of the DGAT2s, an N. oceanica strain bank was created, where proportions of LA and EPA in TAG vary by 18.7-fold (between 0.21% and 3.92% dry weight) and 34.7-fold (between 0.09% and 3.12% dry weight), respectively. These findings lay the foundation for producing designer TAG molecules with tailored health benefits or for biofuel applications in industrial microalgae and higher-plant crops.
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Affiliation(s)
- Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Shen
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiting She
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Chen
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Cong Wang
- Core Laboratory, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kangsup Yoon
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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24
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Chungjatupornchai W, Areerat K, Fa-Aroonsawat S. Increased triacylglycerol production in oleaginous microalga Neochloris oleoabundans by overexpression of plastidial lysophosphatidic acid acyltransferase. Microb Cell Fact 2019; 18:53. [PMID: 30866936 PMCID: PMC6415348 DOI: 10.1186/s12934-019-1104-2] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 03/08/2019] [Indexed: 11/17/2022] Open
Abstract
Background Microalgae are promising sources of lipid triacylglycerol (TAG) for sustainable production of natural edible oils and biofuels. Nevertheless, products derived from microalgal TAG are not yet economically feasible; increasing TAG content via targeted genetic engineering of genes in TAG biosynthesis pathway are important to achieve economic viability. To increase TAG content, oleaginous microalga Neochloris oleoabundans was genetically engineered with the endogenous enzyme lysophosphatidic acid acyltransferase (NeoLPAAT1) responsible for plastidial TAG biosynthesis Results NeoLPAAT1 was found to contain all canonical motifs attributed to LPAAT proteins, two hypothetical membrane-spanning domains and a putative chloroplast transit peptide, indicating as a member of plastidial LPAAT type 1 subfamily. The NeoLPAAT1-expression cassette integrated in N. oleoabundans transformant was confirmed by PCR. The neutral lipid content in the transformant detected by Nile red staining was 1.6-fold higher than in wild type. The NeoLPAAT1 transcript was twofold higher in the transformant than wild type. Considerably higher lipid quantity was found in the transformant than wild type: total lipid content increased 1.8- to 1.9-fold up to 78.99 ± 1.75% dry cell weight (DCW) and total lipid productivity increased 1.8- to 2.4-fold up to 16.06 ± 2.68 mg/L/day; while TAG content increased 2.1- to 2.2-fold up to 55.40 ± 5.56% DCW and TAG productivity increased 1.9- to 2.8-fold up to 10.67 ± 2.37 mg/L/day. A slightly altered fatty acid composition was detected in the transformant compared to wild type; polyunsaturated fatty acid (C18:2) increased to 19% from 11%. NeoLPAAT1-overexpression stability was observed in the transformant continuously maintained in solid medium over 150 generations in a period of about 6 years. Conclusions Our results demonstrate the considerably increased TAG content and productivity in N. oleoabundans by overexpression of plastidial NeoLPAAT1 that are important for products derived from microalgal TAG to achieve economic viability. Plastidial LPAAT1 can be a candidate for target genetic manipulation to increase TAG content in other microalgal species with desired characteristics for production of natural edible oils and biofuels.
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Affiliation(s)
- Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom, 73170, Thailand.
| | - Kanchanaporn Areerat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom, 73170, Thailand
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Phutthamonthon, Nakhon Pathom, 73170, Thailand
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25
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Li-Beisson Y, Thelen JJ, Fedosejevs E, Harwood JL. The lipid biochemistry of eukaryotic algae. Prog Lipid Res 2019; 74:31-68. [PMID: 30703388 DOI: 10.1016/j.plipres.2019.01.003] [Citation(s) in RCA: 175] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2018] [Revised: 01/22/2019] [Accepted: 01/23/2019] [Indexed: 02/06/2023]
Abstract
Algal lipid metabolism fascinates both scientists and entrepreneurs due to the large diversity of fatty acyl structures that algae produce. Algae have therefore long been studied as sources of genes for novel fatty acids; and, due to their superior biomass productivity, algae are also considered a potential feedstock for biofuels. However, a major issue in a commercially viable "algal oil-to-biofuel" industry is the high production cost, because most algal species only produce large amounts of oils after being exposed to stress conditions. Recent studies have therefore focused on the identification of factors involved in TAG metabolism, on the subcellular organization of lipid pathways, and on interactions between organelles. This has been accompanied by the development of genetic/genomic and synthetic biological tools not only for the reference green alga Chlamydomonas reinhardtii but also for Nannochloropsis spp. and Phaeodactylum tricornutum. Advances in our understanding of enzymes and regulatory proteins of acyl lipid biosynthesis and turnover are described herein with a focus on carbon and energetic aspects. We also summarize how changes in environmental factors can impact lipid metabolism and describe present and potential industrial uses of algal lipids.
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Affiliation(s)
- Yonghua Li-Beisson
- Aix-Marseille Univ, CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F-13108, France.
| | - Jay J Thelen
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - Eric Fedosejevs
- Department of Biochemistry, University of Missouri, Christopher S. Bond Life Sciences Center, Columbia, MO 65211, United States.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK.
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26
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Xu Y, Falarz L, Chen G. Characterization of Type-2 Diacylglycerol Acyltransferases in the Green Microalga Chromochloris zofingiensis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:291-298. [PMID: 30543104 DOI: 10.1021/acs.jafc.8b05755] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step of the acyl-CoA-dependent TAG biosynthesis and thus is a key target for manipulating oil production in microalgae. The microalga Chromochloris zofingiensis can accumulate substantial amounts of triacylglycerol (TAG) and represents a promising source of algal lipids. In this study, C. zofingiensis DGAT2s (CzDGAT2s) were characterized with in silico, in vivo (yeast), and in vitro assays. Putative CzDGAT2s were identified, and their functional motifs and evolutionary relationship with other DGAT2s were analyzed. When CzDGAT2s were individually expressed in a TAG-deficient Saccharomyces cerevisiae strain, only CzDGAT2C could restore the TAG biosynthesis. Further in vitro assays indicated that CzDGAT2C displayed typical DGAT activity, which was fitted to the Michaelis-Menten equation, and N- and C-terminals were important for the enzyme activity. In addition, membrane yeast two-hybrid assay revealed a possible DGAT2 activity modulation via the formation of homodimer/heterodimer among different DGAT2 isoforms.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
- Department of Biological Sciences , University of Manitoba , Winnipeg , Manitoba , Canada R3T 2N2
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science , University of Alberta , Edmonton , Alberta , Canada T6G 2P5
- Department of Biological Sciences , University of Manitoba , Winnipeg , Manitoba , Canada R3T 2N2
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27
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Becker KW, Collins JR, Durham BP, Groussman RD, White AE, Fredricks HF, Ossolinski JE, Repeta DJ, Carini P, Armbrust EV, Van Mooy BAS. Daily changes in phytoplankton lipidomes reveal mechanisms of energy storage in the open ocean. Nat Commun 2018; 9:5179. [PMID: 30518752 PMCID: PMC6281602 DOI: 10.1038/s41467-018-07346-z] [Citation(s) in RCA: 42] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2018] [Accepted: 10/25/2018] [Indexed: 12/31/2022] Open
Abstract
Sunlight is the dominant control on phytoplankton biosynthetic activity, and darkness deprives them of their primary external energy source. Changes in the biochemical composition of phytoplankton communities over diel light cycles and attendant consequences for carbon and energy flux in environments remain poorly elucidated. Here we use lipidomic data from the North Pacific subtropical gyre to show that biosynthesis of energy-rich triacylglycerols (TAGs) by eukaryotic nanophytoplankton during the day and their subsequent consumption at night drives a large and previously uncharacterized daily carbon cycle. Diel oscillations in TAG concentration comprise 23 ± 11% of primary production by eukaryotic nanophytoplankton representing a global flux of about 2.4 Pg C yr−1. Metatranscriptomic analyses of genes required for TAG biosynthesis indicate that haptophytes and dinoflagellates are active members in TAG production. Estimates suggest that these organisms could contain as much as 40% more calories at sunset than at sunrise due to TAG production. Day-night cycles in the biochemical composition of phytoplankton remain poorly understood. Here, Becker et al. use lipidomic and transcriptomic data from the North Pacific subtropical gyre to describe a daily cycle of production and consumption of energy-rich lipids by eukaryotic phytoplankton.
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Affiliation(s)
- Kevin W Becker
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - James R Collins
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.,Massachusetts Institute of Technology/Woods Hole Oceanographic Institution Joint Program in Oceanography, Woods Hole, MA, 02543, USA.,School of Oceanography and eScience Institute, University of Washington, Seattle, WA, 98195, USA
| | - Bryndan P Durham
- School of Oceanography, University of Washington, Seattle, WA, 98195, USA
| | - Ryan D Groussman
- School of Oceanography, University of Washington, Seattle, WA, 98195, USA
| | - Angelicque E White
- College of Earth, Ocean, and Atmospheric Sciences, Oregon State University, Corvallis, OR, 97331, USA
| | - Helen F Fredricks
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Justin E Ossolinski
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Daniel J Repeta
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA
| | - Paul Carini
- Department of Microbiology, Oregon State University, Corvallis, OR, 97331, USA.,Department of Soil, Water and Environmental Science, University of Arizona, Tucson, AZ, 85721, USA
| | | | - Benjamin A S Van Mooy
- Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, 02543, USA.
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28
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Zienkiewicz K, Benning U, Siegler H, Feussner I. The type 2 acyl-CoA:diacylglycerol acyltransferase family of the oleaginous microalga Lobosphaera incisa. BMC PLANT BIOLOGY 2018; 18:298. [PMID: 30477429 PMCID: PMC6257963 DOI: 10.1186/s12870-018-1510-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Accepted: 10/29/2018] [Indexed: 05/05/2023]
Abstract
BACKGROUND Oleaginous microalgae are promising sources of energy-rich triacylglycerols (TAGs) for direct use for food, feed and industrial applications. Lobosphaera incisa is a fresh water unicellular alga, which in response to nutrient stress accumulates a high amount of TAGs with a high proportion of arachidonic acid (ARA). The final committed step of de novo TAG biosynthesis is catalyzed by acyl-CoA:diacylglycerol acyltransferases (DGATs), which add a fatty acid (FA) to the final sn-3 position of diacylglycerol (DAG). RESULTS Genome analysis revealed the presence of five putative DGAT isoforms in L. incisa, including one DGAT of type 1, three DGATs of type 2 and a single isoform of a type 3 DGAT. For LiDGAT1, LiDGAT2.1, LiDGAT2.2 and LiDGAT2.3 enzyme activity was confirmed by expressing them in the TAG-deficient yeast strain H1246. Feeding experiments of yeast transformants with fatty acids suggest a broad substrate specificity spectrum for LiDGAT1. A significant TAG production in response to exogenous ARA was found for LiDGAT2.2. Cellular localization of the four type 1 and type 2 DGATs expressed in yeast revealed that they all localize to distinct ER domains. A prominent association of LiDGAT1 with ER domains in close proximity to forming lipid droplets (LDs) was also observed. CONCLUSIONS The data revealed a distinct molecular, functional and cellular nature of type 1 and type 2 DGATs from L. incisa, with LiDGAT1 being a major contributor to the TAG pool. LiDGATs of type 2 might be in turn involved in the incorporation of unusual fatty acids into TAG and thus regulate the composition of TAG. This report provides a valuable resource for the further research of microalgae DGATs oriented towards production of fresh-water strains with higher oil content of valuable composition, not only for oil industry but also for human and animal nutrition.
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Affiliation(s)
- Krzysztof Zienkiewicz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Urs Benning
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Heike Siegler
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
- Department of Plant Biochemistry, Goettingen Center for Molecular Biosciences (GZMB), University of Goettingen, 37077 Goettingen, Germany
- Department of Plant Biochemistry, International Center for Advanced Studies of Energy Conversion (ICASEC), University of Goettingen, 37077 Goettingen, Germany
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Middepogu A, Hou J, Gao X, Lin D. Effect and mechanism of TiO 2 nanoparticles on the photosynthesis of Chlorella pyrenoidosa. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2018; 161:497-506. [PMID: 29913418 DOI: 10.1016/j.ecoenv.2018.06.027] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/01/2018] [Revised: 06/07/2018] [Accepted: 06/09/2018] [Indexed: 05/15/2023]
Abstract
Titanium dioxide nanoparticles (n-TiO2) have been used in numerous applications, which results in their release into aquatic ecosystems and impact algal populations. A possible toxic mechanism of n-TiO2 on algae is via the disruption of the photosynthetic biochemical pathways, which yet remains to be demonstrated. In this study, Chlorella pyrenoidosa was exposed to different concentrations (0, 0.1, 1, 5, 10, and 20 mg/L) of a type of anatase n-TiO2, and the physiological, biochemical, and molecular responses involved in photosynthesis were investigated. The 96 h half growth inhibition concentration (IC50) of the n-TiO2 to algae was determined to be 9.1 mg/L. A variety of cellular and sub-cellular damages were observed, especially the blurry lamellar structure of thylakoids, indicating the n-TiO2 impaired the photosynthetic function of chloroplasts. Malondialdehyde (MDA) and glutathione disulfide (GSSG) significantly increased while the glutathione (GSH) content decreased. This implies the increased consumption of GSH by the increased intracellular oxidative stress upon n-TiO2 was insufficient to eliminate the lipid peroxidation. The contents of photosynthetic pigments, including chlorophyll a (Chl a) and phycobiliproteins (PBPs) in the exposed algal cells increased along with the up-regulation of genes encoding Chl a and photosystem II (PS II), which could be explained by a compensatory effect to overcome the toxicity induced by the n-TiO2. On the other hand, the photosynthetic activity was significantly inhibited, indicating the impairment on the photosynthesis via damaging the reaction center of PS II. In addition, lower productions of adenosine triphosphate (ATP) and glucose, together with the change of gene expressions suggested that the n-TiO2 disrupted the material and energy metabolisms in the photosynthesis. These findings support a paradigm shift of the toxic mechanism of n-TiO2 from physical and oxidative damages to metabolic disturbances, and emphasize the threat to the photosynthesis of algae in contaminated areas.
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Affiliation(s)
- Ayyaraju Middepogu
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Jie Hou
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Xuan Gao
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China
| | - Daohui Lin
- Department of Environmental Science, Zhejiang University, Hangzhou 310058, China; Zhejiang Provincial Key Laboratory of Organic Pollution Process and Control, Zhejiang University, Hangzhou 310058, China.
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30
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Rosli R, Chan PL, Chan KL, Amiruddin N, Low ETL, Singh R, Harwood JL, Murphy DJ. In silico characterization and expression profiling of the diacylglycerol acyltransferase gene family (DGAT1, DGAT2, DGAT3 and WS/DGAT) from oil palm, Elaeis guineensis. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2018; 275:84-96. [PMID: 30107884 DOI: 10.1016/j.plantsci.2018.07.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2018] [Revised: 07/05/2018] [Accepted: 07/25/2018] [Indexed: 05/14/2023]
Abstract
The diacylglycerol acyltransferases (DGAT) (diacylglycerol:acyl-CoA acyltransferase, EC 2.3.1.20) are a key group of enzymes that catalyse the final and usually the most important rate-limiting step of triacylglycerol biosynthesis in plants and other organisms. Genes encoding four distinct functional families of DGAT enzymes have been characterised in the genome of the African oil palm, Elaeis guineensis. The contrasting features of the various isoforms within the four families of DGAT genes, namely DGAT1, DGAT2, DGAT3 and WS/DGAT are presented both in the oil palm itself and, for comparative purposes, in 12 other oil crop or model/related plants, namely Arabidopsis thaliana, Brachypodium distachyon, Brassica napus, Elaeis oleifera, Glycine max, Gossypium hirsutum, Helianthus annuus, Musa acuminata, Oryza sativa, Phoenix dactylifera, Sorghum bicolor, and Zea mays. The oil palm genome contains respectively three, two, two and two distinctly expressed functional copies of the DGAT1, DGAT2, DGAT3 and WS/DGAT genes. Phylogenetic analyses of the four DGAT families showed that the E. guineensis genes tend to cluster with sequences from P. dactylifera and M. acuminata rather than with other members of the Commelinid monocots group, such as the Poales which include the major cereal crops such as rice and maize. Comparison of the predicted DGAT protein sequences with other animal and plant DGATs was consistent with the E. guineensis DGAT1 being ER located with its active site facing the lumen while DGAT2, although also ER located, had a predicted cytosol-facing active site. In contrast, DGAT3 and some (but not all) WS/DGAT in E. guineensis are predicted to be soluble, cytosolic enzymes. Evaluation of E. guineensis DGAT gene expression in different tissues and developmental stages suggests that the four DGAT groups have distinctive physiological roles and are particularly prominent in developmental processes relating to reproduction, such as flowering, and in fruit/seed formation especially in the mesocarp and endosperm tissues.
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Affiliation(s)
- Rozana Rosli
- Genomics and Computational Biology Research Group, University of South Wales, Pontypridd, CF37 1DL, United Kingdom; Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
| | - Pek-Lan Chan
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
| | - Kuang-Lim Chan
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
| | - Nadzirah Amiruddin
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
| | - Eng-Ti Leslie Low
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
| | - Rajinder Singh
- Advanced Biotechnology and Breeding Centre, Malaysian Palm Oil Board, No 6, Persiaran Institusi, Bandar Baru Bangi, 43000 Kajang, Selangor, Malaysia
| | - John L Harwood
- School of Biosciences, University of Cardiff, Cardiff, CF10 3AX, United Kingdom
| | - Denis J Murphy
- Genomics and Computational Biology Research Group, University of South Wales, Pontypridd, CF37 1DL, United Kingdom.
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31
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Xu Y, Caldo KMP, Pal-Nath D, Ozga J, Lemieux MJ, Weselake RJ, Chen G. Properties and Biotechnological Applications of Acyl-CoA:diacylglycerol Acyltransferase and Phospholipid:diacylglycerol Acyltransferase from Terrestrial Plants and Microalgae. Lipids 2018; 53:663-688. [PMID: 30252128 DOI: 10.1002/lipd.12081] [Citation(s) in RCA: 60] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Revised: 07/23/2018] [Accepted: 07/24/2018] [Indexed: 12/14/2022]
Abstract
Triacylglycerol (TAG) is the major storage lipid in most terrestrial plants and microalgae, and has great nutritional and industrial value. Since the demand for vegetable oil is consistently increasing, numerous studies have been focused on improving the TAG content and modifying the fatty-acid compositions of plant seed oils. In addition, there is a strong research interest in establishing plant vegetative tissues and microalgae as platforms for lipid production. In higher plants and microalgae, TAG biosynthesis occurs via acyl-CoA-dependent or acyl-CoA-independent pathways. Diacylglycerol acyltransferase (DGAT) catalyzes the last and committed step in the acyl-CoA-dependent biosynthesis of TAG, which appears to represent a bottleneck in oil accumulation in some oilseed species. Membrane-bound and soluble forms of DGAT have been identified with very different amino-acid sequences and biochemical properties. Alternatively, TAG can be formed through acyl-CoA-independent pathways via the catalytic action of membrane-bound phospholipid:diacylglycerol acyltransferase (PDAT). As the enzymes catalyzing the terminal steps of TAG formation, DGAT and PDAT play crucial roles in determining the flux of carbon into seed TAG and thus have been considered as the key targets for engineering oil production. Here, we summarize the most recent knowledge on DGAT and PDAT in higher plants and microalgae, with the emphasis on their physiological roles, structural features, and regulation. The development of various metabolic engineering strategies to enhance the TAG content and alter the fatty-acid composition of TAG is also discussed.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biochemistry, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2H7, Canada
| | - Dipasmita Pal-Nath
- French Associates Institute for Agriculture and Biotechnology of Drylands, The Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, Midreshet Ben-Gurion, 8499000, Israel
| | - Jocelyn Ozga
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2H7, Canada
| | - Randall J Weselake
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, 116 Street and 85 Avenue, Edmonton, Alberta, T6G 2P5, Canada
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Yan B, Xu X, Gu Y, Zhao Y, Zhao X, He L, Zhao C, Li Z, Xu J. Genome-wide characterization and expression profiling of diacylglycerol acyltransferase genes from maize. Genome 2018; 61:735-743. [PMID: 30092654 DOI: 10.1139/gen-2018-0029] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Diacylglycerol acyltransferase (DGAT) catalyzes the only rate-limiting step in the pathway of plant oil (TAG) biosynthesis and is involved in plant development. In this study, five DGAT family members were identified from maize genome database. Phylogenetic analysis classified the ZmDGATs into type-I, II, and III clusters. Conserved functional domain analysis revealed that the proteins encoded by ZmDGAT1 contained conserved MBOAT domains, while two ZmDGAT2-encoding proteins harbored LPLAT domains. qRT-PCR analysis showed that ZmDGAT genes exhibited very high relative expression in developing seeds, especially at the early stage of seed development. Under various abiotic stress conditions, differential responses of ZmDGAT genes were observed. An overall significant induction of ZmDGAT genes under cold stress in leaves and a quick and strong response to osmotic stresses in roots were highlighted. This study provides useful information for understanding the roles of DGATs in oil accumulation and stress responses in higher plants.
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Affiliation(s)
- Bowei Yan
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China.,b Institute for Comprehensive Utilization of Agricultural and Animal Husbandry, Heilongjiang Academy of Land Reclamation sciences, Harbin, 150000, Heilongjiang, China
| | - Xiaoxuan Xu
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Yingnan Gu
- c Remote Sensing Technology Center, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, Heilongjiang, China
| | - Ying Zhao
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Xunchao Zhao
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Lin He
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Changjiang Zhao
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Zuotong Li
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
| | - Jingyu Xu
- a Key Lab of Modern Agricultural Cultivation and Crop Germplasm Improvement of Heilongjiang Province, College of Agriculture, Heilongjiang Bayi Agricultural University, Daqing, 163319, Heilongjiang, China
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Arora N, Pienkos PT, Pruthi V, Poluri KM, Guarnieri MT. Leveraging algal omics to reveal potential targets for augmenting TAG accumulation. Biotechnol Adv 2018; 36:1274-1292. [PMID: 29678388 DOI: 10.1016/j.biotechadv.2018.04.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 04/11/2018] [Accepted: 04/15/2018] [Indexed: 02/08/2023]
Abstract
Ongoing global efforts to commercialize microalgal biofuels have expedited the use of multi-omics techniques to gain insights into lipid biosynthetic pathways. Functional genomics analyses have recently been employed to complement existing sequence-level omics studies, shedding light on the dynamics of lipid synthesis and its interplay with other cellular metabolic pathways, thus revealing possible targets for metabolic engineering. Here, we review the current status of algal omics studies to reveal potential targets to augment TAG accumulation in various microalgae. This review specifically aims to examine and catalog systems level data related to stress-induced TAG accumulation in oleaginous microalgae and inform future metabolic engineering strategies to develop strains with enhanced bioproductivity, which could pave a path for sustainable green energy.
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Affiliation(s)
- Neha Arora
- Department of Biotechnology, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Philip T Pienkos
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Vikas Pruthi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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Chen L, Zheng Y, Dong Z, Meng F, Sun X, Fan X, Zhang Y, Wang M, Wang S. Soybean (Glycine max) WRINKLED1 transcription factor, GmWRI1a, positively regulates seed oil accumulation. Mol Genet Genomics 2018; 293:401-415. [PMID: 29138932 DOI: 10.1007/s00438-017-1393-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Accepted: 11/02/2017] [Indexed: 12/21/2022]
Abstract
Soybean is the world's most important leguminous crop producing high-quality protein and oil. Elevating oil accumulation in soybean seed is always many researchers' goal. WRINKLED1 (WRI1) encodes a transcription factor of the APETALA2/ethylene responsive element-binding protein (AP2/EREBP) family that plays important roles during plant seed oil accumulation. In this study, we isolated and characterized three distinct orthologues of WRI1 in soybean (Glycine max) that display different organ-specific expression patterns, among which GmWRI1a was highly expressed in maturing soybean seed. Electrophoretic mobility shift assays and yeast one-hybrid experiments demonstrated that the GmWRI1a protein was capable of binding to AW-box, a conserved sequence in the proximal upstream regions of many genes involved in various steps of oil biosynthesis. Transgenic soybean seeds overexpressing GmWRI1a under the control of the seed-specific napin promoter showed the increased total oil and fatty acid content and the changed fatty acid composition. Furthermore, basing on the activated expressions in transgenic soybean seeds and existence of AW-box element in the promoter regions, direct downstream genes of GmWRI1a were identified, and their products were responsible for fatty acid production, elongation, desaturation and export from plastid. We conclude that GmWRI1a transcription factor can positively regulate oil accumulation in soybean seed by a complex gene expression network related to fatty acid biosynthesis.
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Affiliation(s)
- Liang Chen
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China
| | - Yuhong Zheng
- Key Laboratory of Soybean Biology in Chinese Ministry of Education, Northeast Agricultural University, Harbin, 150030, People's Republic of China
| | - Zhimin Dong
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China.
| | - Fanfan Meng
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China
| | - Xingmiao Sun
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China
| | - Xuhong Fan
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China
| | - Yunfeng Zhang
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China
| | - Mingliang Wang
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China
| | - Shuming Wang
- Soybean Research Institute, Jilin Academy of Agricultural Sciences/National Engineering Research Center for Soybean, Changchun, 130033, People's Republic of China.
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35
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Ma R, Thomas-Hall SR, Chua ET, Alsenani F, Eltanahy E, Netzel ME, Netzel G, Lu Y, Schenk PM. Gene expression profiling of astaxanthin and fatty acid pathways in Haematococcus pluvialis in response to different LED lighting conditions. BIORESOURCE TECHNOLOGY 2018; 250:591-602. [PMID: 29216572 DOI: 10.1016/j.biortech.2017.11.094] [Citation(s) in RCA: 54] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 11/23/2017] [Accepted: 11/27/2017] [Indexed: 05/06/2023]
Abstract
Haematococcus pluvialis is a green microalga of major interest to industry based on its ability to produce large amounts of astaxanthin. Biosynthesis of astaxanthin and its mono- and di-esters was significantly stimulated under 150 μmol m-2 s-1 of white LED (W-150) compared with lower light intensities, but the highest astaxanthin amounts were produced under 70 μmol m-2 s-1 of blue LED (B-70). Transcripts of astaxanthin biosynthesis genes psy, crtO, and bkt2 were upregulated under W-150, while psy, lcy, crtO, and crtR-B were upregulated by B-70. Total fatty acid content and biosynthesis genes fata and all dgat genes were induced under W-150, while C18:3n6 biosynthesis and dgat2a expression were specifically stimulated by B-70 which was correlated to astaxanthin ester biosynthesis. Nitrogen starvation, various LEDs and the identified upregulated genes may provide useful tools for future metabolic engineering to significantly increase free astaxanthin, its esters and fatty acid precursors in H. pluvialis.
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Affiliation(s)
- Ruijuan Ma
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Skye R Thomas-Hall
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Elvis T Chua
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Faisal Alsenani
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Eladl Eltanahy
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia; Phycology Laboratory, Botany Department, Faculty of Science, Mansoura University, Egypt
| | - Michael E Netzel
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, PO Box 156, Archerfield, QLD 4108, Australia
| | - Gabriele Netzel
- Queensland Alliance for Agriculture and Food Innovation, The University of Queensland, PO Box 156, Archerfield, QLD 4108, Australia
| | - Yinghua Lu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China
| | - Peer M Schenk
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia.
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Cui Y, Zhao J, Wang Y, Qin S, Lu Y. Characterization and engineering of a dual-function diacylglycerol acyltransferase in the oleaginous marine diatom Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2018; 11:32. [PMID: 29449880 PMCID: PMC5806285 DOI: 10.1186/s13068-018-1029-8] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2017] [Accepted: 01/23/2018] [Indexed: 05/03/2023]
Abstract
BACKGROUND Photosynthetic oleaginous microalgae are promising feedstocks for biofuels. Acyl-CoA:diacylglycerol acyltransferases (DGATs) represent rich sources for engineering microalgal lipid production. The principal activity of DGATs has been defined as a single-function enzyme catalyzing the esterification of diacylglycerol with acyl-CoA. RESULTS A dual-function PtWS/DGAT associated with diatom Phaeodactylum tricornutum is discovered in the current study. Distinctive to documented microalgal DGAT types, PtWS/DGAT exhibits activities of both a wax ester synthase (WS) and a DGAT. WS/DGATs are broadly distributed in microalgae, with different topology and phylogeny from those of DGAT1s, DGAT2s, and DGAT3s. In vitro and in vivo assays revealed that PtWS/DGAT, functioning as either a WS or a DGAT, exhibited a preference on saturated FA substrate. Endogenous overexpression of PtWS/DGAT demonstrated that the DGAT activity was dominant, whereas the WS activity was condition dependent and relatively minor. Compared with the wild type (WT), overexpression of PtWS/DGAT in the diatom resulted in increased levels of total lipids (TL) and triacylglycerol (TAG) regardless of nitrogen availability. The stability and scalability of the introduced traits were further investigated at a 10-L photobioreactor, where the mutant growth resembled WT, with moderately increased productivity of TL and TAG. Furthermore, the production of wax esters increased considerably (from undetectable levels to 2.83%) under nitrogen-deplete conditions. CONCLUSIONS PtWS/DGAT is a bifunctional enzyme and may serve as a promising target for the engineering of microalga-based oils and waxes for future industrial use.
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Affiliation(s)
- Yulin Cui
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003 Shandong China
| | - Jialin Zhao
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003 Shandong China
- University of Chinese Academy of Sciences, Beijing, 101408 China
| | - Yinchu Wang
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003 Shandong China
| | - Song Qin
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, 264003 Shandong China
| | - Yandu Lu
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Oceanology, Hainan University, Haikou, Hainan 570228 China
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37
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Karpagam R, Jawaharraj K, Ashokkumar B, Sridhar J, Varalakshmi P. Unraveling the lipid and pigment biosynthesis in Coelastrella sp. M-60: Genomics-enabled transcript profiling. ALGAL RES 2018. [DOI: 10.1016/j.algal.2017.11.031] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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38
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Sayanova O, Mimouni V, Ulmann L, Morant-Manceau A, Pasquet V, Schoefs B, Napier JA. Modulation of lipid biosynthesis by stress in diatoms. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160407. [PMID: 28717017 PMCID: PMC5516116 DOI: 10.1098/rstb.2016.0407] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/14/2017] [Indexed: 12/19/2022] Open
Abstract
Diatoms are responsible for up to 40% of the carbon fixation in our oceans. The fixed carbon is moved through carbon metabolism towards the synthesis of organic molecules that are consumed through interlocking foodwebs, and this process is strongly impacted by the abiotic environment. However, it has become evident that diatoms can be used as 'platform' organisms for the production of high valuable bio-products such as lipids, pigments and carbohydrates where stress conditions can be used to direct carbon metabolism towards the commercial production of these compounds. In the first section of this review, some aspects of carbon metabolism in diatoms and how it is impacted by environmental factors are briefly described. The second section is focused on the biosynthesis of lipids and in particular omega-3 long-chain polyunsaturated fatty acids and how low temperature stress impacts on the production of these compounds. In a third section, we review the recent advances in bioengineering for lipid production. Finally, we discuss new perspectives for designing strains for the sustainable production of high-value lipids.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- Olga Sayanova
- Department of Plant Sciences, Rothamsted Research, Harpenden AL5 2JQ, UK
| | - Virginie Mimouni
- Metabolism, Bioengineering of Microalgal Molecules and Applications, Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, Le Mans-Laval, France
| | - Lionel Ulmann
- Metabolism, Bioengineering of Microalgal Molecules and Applications, Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, Le Mans-Laval, France
| | - Annick Morant-Manceau
- Metabolism, Bioengineering of Microalgal Molecules and Applications, Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, Le Mans-Laval, France
| | - Virginie Pasquet
- Metabolism, Bioengineering of Microalgal Molecules and Applications, Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, Le Mans-Laval, France
| | - Benoît Schoefs
- Metabolism, Bioengineering of Microalgal Molecules and Applications, Mer Molécules Santé, UBL, IUML-FR 3473 CNRS, University of Le Mans, Le Mans-Laval, France
| | - Johnathan A Napier
- Department of Plant Sciences, Rothamsted Research, Harpenden AL5 2JQ, UK
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Brodie J, Chan CX, De Clerck O, Cock JM, Coelho SM, Gachon C, Grossman AR, Mock T, Raven JA, Smith AG, Yoon HS, Bhattacharya D. The Algal Revolution. TRENDS IN PLANT SCIENCE 2017; 22:726-738. [PMID: 28610890 DOI: 10.1016/j.tplants.2017.05.005] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2017] [Revised: 05/04/2017] [Accepted: 05/16/2017] [Indexed: 05/28/2023]
Abstract
Algae are (mostly) photosynthetic eukaryotes that occupy multiple branches of the tree of life, and are vital for planet function and health. In this review, we highlight a transformative period in studies of the evolution and functioning of this extraordinary group of organisms and their potential for novel applications, wrought by high-throughput 'omic' and reverse genetic methods. We cover the origin and diversification of algal groups, explore advances in understanding the link between phenotype and genotype, consider algal sex determination, and review progress in understanding the roots of algal multicellularity. Experimental evolution studies to determine how algae evolve in changing environments are highlighted, as is their potential as production platforms for compounds of commercial interest, such as biofuel precursors, nutraceuticals, or therapeutics.
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Affiliation(s)
- Juliet Brodie
- Natural History Museum, Department of Life Sciences, London SW7 5BD, UK
| | - Cheong Xin Chan
- Institute for Molecular Bioscience, The University of Queensland, Brisbane, QLD 4072, Australia
| | - Olivier De Clerck
- Research Group Phycology, Ghent University, Krijgslaan 281, S8, 9000 Ghent, Belgium
| | - J Mark Cock
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Susana M Coelho
- CNRS, Sorbonne Université, UPMC University Paris 06, Algal Genetics Group, UMR 8227, Integrative Biology of Marine Models, Station Biologique de Roscoff, CS 90074, Roscoff F-29688, France
| | - Claire Gachon
- Scottish Association for Marine Science, Scottish Marine Institute, Oban, PA37 1QA, UK
| | - Arthur R Grossman
- Department of Plant Biology, The Carnegie Institution, Stanford, CA 94305, USA
| | - Thomas Mock
- School of Environmental Sciences, University of East Anglia, Norwich Research Park, Norwich, NR4 7TJ, UK
| | - John A Raven
- Permanent address: Division of Plant Sciences, University of Dundee at the James Hutton Institute, Dundee DD2 5DA, UK; School of Plant Biology, University of Western Australia, Crawley, WA 6009, Australia
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Cambridge, CB2 3EA, UK
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon 16419, Korea
| | - Debashish Bhattacharya
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ 08901, USA.
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Klaitong P, Fa-Aroonsawat S, Chungjatupornchai W. Accelerated triacylglycerol production and altered fatty acid composition in oleaginous microalga Neochloris oleoabundans by overexpression of diacylglycerol acyltransferase 2. Microb Cell Fact 2017; 16:61. [PMID: 28403867 PMCID: PMC5389083 DOI: 10.1186/s12934-017-0677-x] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Accepted: 04/05/2017] [Indexed: 11/25/2022] Open
Abstract
Background Microalgae are promising sources of lipid triacylglycerol (TAG) for biodiesel production. However, to date, microalgal biodiesel is technically feasible, but not yet economically viable. Increasing TAG content and productivity are important to achieve economic viability of microalgal biodiesel. To increase TAG content, oleaginous microalga Neochloris oleoabundans was genetically engineered with an endogenous key enzyme diacylglycerol acyltransferase 2 (NeoDGAT2) responsible for TAG biosynthesis. Results The integration of NeoDGAT2 expression cassettes in N. oleoabundans transformant was confirmed by PCR. The neutral lipid accumulation in the transformant detected by Nile red staining was accelerated and 1.9-fold higher than in wild type; the lipid bodies in the transformant visualized under fluorescence microscope were also larger. The NeoDGAT2 transcript was two-fold higher in the transformant than wild type. Remarkably higher lipid accumulation was found in the transformant than wild type: total lipid content increased 1.6-to 2.3-fold up to 74.5 ± 4.0% dry cell weight (DCW) and total lipid productivity increased 1.6- to 3.2-fold up to 14.6 ± 2.0 mg/L/day; while TAG content increased 1.8- to 3.2-fold up to 46.1 ± 1.6% DCW and TAG productivity increased 1.6- to 4.3-fold up to 8.9 ± 1.3 mg/L/day. A significantly altered fatty acid composition was detected in the transformant compared to wild type; the levels of saturated fatty acid C16:0 increased double to 49%, whereas C18:0 was reduced triple to 6%. Long-term stability was observed in the transformant continuously maintained in solid medium over 100 generations in a period of about 4 years. Conclusions Our results demonstrate the increased TAG content and productivity in N. oleoabundans by NeoDGAT2 overexpression that may offer the first step towards making microalgae an economically feasible source for biodiesel production. The strategy for genetically improved microalga presented in this study can be applied to other microalgal species possessing desired characteristics for industrial biofuel production.
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Affiliation(s)
- Paeka Klaitong
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom, 73170, Thailand
| | - Sirirat Fa-Aroonsawat
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom, 73170, Thailand
| | - Wipa Chungjatupornchai
- Institute of Molecular Biosciences, Mahidol University, Salaya Campus, Nakhon Pathom, 73170, Thailand.
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Dinamarca J, Levitan O, Kumaraswamy GK, Lun DS, Falkowski PG. Overexpression of a diacylglycerol acyltransferase gene in Phaeodactylum tricornutum directs carbon towards lipid biosynthesis. JOURNAL OF PHYCOLOGY 2017; 53:405-414. [PMID: 28078675 DOI: 10.1111/jpy.12513] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2016] [Accepted: 11/17/2016] [Indexed: 05/03/2023]
Abstract
Under nutrient deplete conditions, diatoms accumulate between 15% to 25% of their dry weight as lipids, primarily as triacylglycerols (TAGs). As in most eukaryotes, these organisms produce TAGs via the acyl-CoA dependent Kennedy pathway. The last step in this pathway is catalyzed by diacylglycerol acyltransferase (DGAT) that acylates diacylglycerol (DAG) to produce TAG. To test our hypothesis that DGAT plays a major role in controlling the flux of carbon towards lipids, we overexpressed a specific type II DGAT gene, DGAT2D, in the model diatom Phaeodactylum tricornutum. The transformants had 50- to 100-fold higher DGAT2D mRNA levels and the abundance of the enzyme increased 30- to 50-fold. More important, these cells had a 2-fold higher total lipid content and incorporated carbon into lipids more efficiently than the wild type (WT) while growing only 15% slower at light saturation. Based on a flux analysis using 13 C as a tracer, we found that the increase in lipids was achieved via increased fluxes through pyruvate and acetyl-CoA. Our results reveal overexpression of DAGT2D increases the flux of photosynthetically fixed carbon towards lipids, and leads to a higher lipid content than exponentially grown WT cells.
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Affiliation(s)
- Jorge Dinamarca
- Environmental Biophysics and Molecular Ecology Laboratory, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - Orly Levitan
- Environmental Biophysics and Molecular Ecology Laboratory, Departments of Marine and Coastal Sciences and Plant Biology and Pathology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - G Kenchappa Kumaraswamy
- Waksman Institute and Department of Chemistry & Chemical Biology, Rutgers University, Piscataway, New Jersey, 08854, USA
| | - Desmond S Lun
- Center for Computational and Integrative Biology and Department of Computer Science, Rutgers University, Camden, New Jersey, 08102, USA
- Department of Plant Biology, Rutgers University, New Brunswick, New Jersey, 08901, USA
| | - Paul G Falkowski
- Environmental Biophysics and Molecular Ecology Laboratory, Departments of Marine and Coastal Sciences and Earth and Planetary Sciences, Rutgers University, Piscataway, New Jersey, 0885, USA
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Bagnato C, Prados MB, Franchini GR, Scaglia N, Miranda SE, Beligni MV. Analysis of triglyceride synthesis unveils a green algal soluble diacylglycerol acyltransferase and provides clues to potential enzymatic components of the chloroplast pathway. BMC Genomics 2017; 18:223. [PMID: 28274201 PMCID: PMC5343412 DOI: 10.1186/s12864-017-3602-0] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2016] [Accepted: 02/24/2017] [Indexed: 12/26/2022] Open
Abstract
Background Microalgal triglyceride (TAG) synthesis has attracted considerable attention. Particular emphasis has been put towards characterizing the algal homologs of the canonical rate-limiting enzymes, diacylglycerol acyltransferase (DGAT) and phospholipid:diacylglycerol acyltransferase (PDAT). Less work has been done to analyze homologs from a phylogenetic perspective. In this work, we used HMMER iterative profiling and phylogenetic and functional analyses to determine the number and sequence characteristics of algal DGAT and PDAT, as well as related sequences that constitute their corresponding superfamilies. We included most algae with available genomes, as well as representative eukaryotic and prokaryotic species. Results Amongst our main findings, we identified a novel clade of DGAT1-like proteins exclusive to red algae and glaucophyta and a previously uncharacterized subclade of DGAT2 proteins with an unusual number of transmembrane segments. Our analysis also revealed the existence of a novel DGAT exclusive to green algae with moderate similarity to plant soluble DGAT3. The DGAT3 clade shares a most recent ancestor with a group of uncharacterized proteins from cyanobacteria. Subcellular targeting prediction suggests that most green algal DGAT3 proteins are imported to the chloroplast, evidencing that the green algal chloroplast might have a soluble pathway for the de novo synthesis of TAGs. Heterologous expression of C. reinhardtii DGAT3 produces an increase in the accumulation of TAG, as evidenced by thin layer chromatography. Conclusions Our analysis contributes to advance in the knowledge of complex superfamilies involved in lipid metabolism and provides clues to possible enzymatic players of chloroplast TAG synthesis. Electronic supplementary material The online version of this article (doi:10.1186/s12864-017-3602-0) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Carolina Bagnato
- Instituto de Energía y Desarrollo Sustentable, Comisión Nacional de Energía Atómica, Centro Atómico Bariloche, Av. Bustillo 9500, 8400S. C. de Bariloche, Río Negro, Argentina
| | - María B Prados
- Instituto de Energía y Desarrollo Sustentable, Comisión Nacional de Energía Atómica, Centro Atómico Bariloche, Av. Bustillo 9500, 8400S. C. de Bariloche, Río Negro, Argentina
| | - Gisela R Franchini
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP-CONICET-UNLP), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120 s/n, 1900, La Plata, Argentina
| | - Natalia Scaglia
- Instituto de Investigaciones Bioquímicas de La Plata (INIBIOLP-CONICET-UNLP), Facultad de Ciencias Médicas, Universidad Nacional de La Plata, Calle 60 y 120 s/n, 1900, La Plata, Argentina
| | - Silvia E Miranda
- Universidad de Buenos Aires. CONICET Instituto de Investigaciones Cardiológicas (ININCA), - Laboratorio de Glico-Inmuno-Biología, Marcelo T. de Alvear 2270, C1122AAJ, Buenos Aires, Argentina
| | - María V Beligni
- Instituto de Investigaciones Biológicas (IIB-CONICET-UNMdP), Facultad de Ciencias Exactas y Naturales, Universidad Nacional de Mar del Plata, CC 1245, 7600, Mar del Plata, Argentina.
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Tan KWM, Lee YK. Expression of the heterologous Dunaliella tertiolecta fatty acyl-ACP thioesterase leads to increased lipid production in Chlamydomonas reinhardtii. J Biotechnol 2017; 247:60-67. [PMID: 28279815 DOI: 10.1016/j.jbiotec.2017.03.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2016] [Revised: 03/03/2017] [Accepted: 03/04/2017] [Indexed: 12/22/2022]
Abstract
Biofuel production from genetically-engineered microalgae is currently among the most widely studied strategies in generating renewable energy. However, microalgae currently suffer from low oil yields which limit the commercial feasibility of industrial-scale production. A major bottleneck in cost-efficient biofuel production from microalgae is the dilemma between biomass productivity and lipid accumulation. When grown under stressful culture conditions such as nitrogen depletion, microalgae accumulate large amounts of neutral lipids, but it comes at the expense of growth which negatively impacts overall lipid productivity. Overexpression of acyl-ACP thioesterases (TE) had been successful in increasing the production of fatty acids (FA) in prokaryotes such as E. coli and cyanobacteria, but has not been effectively tested in microalgae. In this study, we introduced a TE from D. tertiolecta (DtTE) into C. reinhardtii to investigate its effects on FA production without compromising growth. The results indicate that C. reinhardtii transformants were able to produce 63 and 94% more neutral lipids than the wild-type, which translates to an approximately 56% improvement in total lipids, without compromising growth. These findings demonstrate the cross-species functionality of TE, and provide a platform for further studies into using TE as a strategy to increase biofuel production from microalgae.
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Affiliation(s)
- Kenneth Wei Min Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545
| | - Yuan Kun Lee
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117545.
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Che R, Huang L, Xu JW, Zhao P, Li T, Ma H, Yu X. Effect of fulvic acid induction on the physiology, metabolism, and lipid biosynthesis-related gene transcription of Monoraphidium sp. FXY-10. BIORESOURCE TECHNOLOGY 2017; 227:324-334. [PMID: 28042988 DOI: 10.1016/j.biortech.2016.12.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2016] [Revised: 12/02/2016] [Accepted: 12/03/2016] [Indexed: 05/03/2023]
Abstract
Fulvic acid (FA) triggers lipid accumulation in Monoraphidium sp. FXY-10, which can produce biofuels. Therefore, the metabolism shift and gene expression changes influenced by fulvic acid should be investigated. In this study, lipid and protein contents increased rapidly from 44.6% to 54.3% and from 31.4% to 39.7% under FA treatment, respectively. By contrast, carbohydrate content sharply declined from 49.5% to 32.5%. The correlation between lipid content and gene expression was also analyzed. Results revealed that accD, ME, and GPAT genes were significantly correlated with lipid accumulation. These genes could likely influence lipid accumulation and could be selected as modification candidates. These results demonstrated that FA significantly increased microalgal lipid accumulation by changing the intracellular reactive oxygen species, gene expression, and enzyme activities of acetyl-CoA carboxylase, malic enzyme, and phosphoenolpyruvate carboxylase.
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Affiliation(s)
- Raoqiong Che
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Li Huang
- Institute of Chemical Industry, Kunming Metallurgy College, Kunming, China
| | - Jun-Wei Xu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Peng Zhao
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Tao Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China
| | - Huixian Ma
- School of Foreign Languages, Kunming University, Kunming 650200, China
| | - Xuya Yu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming, China.
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Guo X, Fan C, Chen Y, Wang J, Yin W, Wang RRC, Hu Z. Identification and characterization of an efficient acyl-CoA: diacylglycerol acyltransferase 1 (DGAT1) gene from the microalga Chlorella ellipsoidea. BMC PLANT BIOLOGY 2017; 17:48. [PMID: 28222675 PMCID: PMC5319178 DOI: 10.1186/s12870-017-0995-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/04/2016] [Accepted: 02/02/2017] [Indexed: 05/06/2023]
Abstract
BACKGROUND Oil in the form of triacylglycerols (TAGs) is quantitatively the most important storage form of energy for eukaryotic cells. Diacylglycerol acyltransferase (DGAT) is considered the rate-limiting enzyme for TAG accumulation. Chlorella, a unicellular eukaryotic green alga, has attracted much attention as a potential feedstock for renewable energy production. However, the function of DGAT1 in Chlorella has not been reported. RESULTS A full-length cDNA encoding a putative diacylglycerol acyltransferase 1 (DGAT1, EC 2.3.1.20) was obtained from Chlorella ellipsoidea. The 2,142 bp open reading frame of this cDNA, designated CeDGAT1, encodes a protein of 713 amino acids showing no more than 40% identity with DGAT1s of higher plants. Transcript analysis showed that the expression level of CeDGAT1 markedly increased under nitrogen starvation, which led to significant triacylglycerol (TAG) accumulation. CeDGAT1 activity was confirmed in the yeast quadruple mutant strain H1246 by restoring its ability to produce TAG. Upon expression of CeDGAT1, the total fatty acid content in wild-type yeast (INVSc1) increased by 142%, significantly higher than that transformed with DGAT1s from higher plants, including even the oil crop soybean. The over-expression of CeDGAT1 under the NOS promoter in wild-type Arabidopsis thaliana and Brassica napus var. Westar significantly increased the oil content by 8-37% and 12-18% and the average 1,000-seed weight by 9-15% and 6-29%, respectively, but did not alter the fatty acid composition of the seed oil. The net increase in the 1,000-seed total lipid content was up to 25-50% in both transgenic Arabidopsis and B. napus. CONCLUSIONS We identified a gene encoding DGAT1 in C. ellipsoidea and confirmed that it plays an important role in TAG accumulation. This is the first functional analysis of DGAT1 in Chlorella. This information is important for understanding lipid synthesis and accumulation in Chlorella and for genetic engineering to enhance oil production in microalgae and oil plants.
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Affiliation(s)
- Xuejie Guo
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
| | - Chengming Fan
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yuhong Chen
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Jingqiao Wang
- Institute of Economical Crops, Yunnan Agricultural Academy, Kunming, 65023 China
| | - Weibo Yin
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
| | - Richard R. C. Wang
- United States Department of Agriculture, Agricultural Research Service, Forage and Range Research Laboratory, Utah State University, Logan, UT 84322-6300 USA
| | - Zanmin Hu
- Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101 China
- University of Chinese Academy of Sciences, Beijing, 100049 China
- Present address: Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Datun Road, Chaoyang District, Beijing, 100101 China
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Zienkiewicz K, Zienkiewicz A, Poliner E, Du ZY, Vollheyde K, Herrfurth C, Marmon S, Farré EM, Feussner I, Benning C. Nannochloropsis, a rich source of diacylglycerol acyltransferases for engineering of triacylglycerol content in different hosts. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:8. [PMID: 28070221 PMCID: PMC5210179 DOI: 10.1186/s13068-016-0686-8] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 12/10/2016] [Indexed: 05/03/2023]
Abstract
BACKGROUND Photosynthetic microalgae are considered a viable and sustainable resource for biofuel feedstocks, because they can produce higher biomass per land area than plants and can be grown on non-arable land. Among many microalgae considered for biofuel production, Nannochloropsis oceanica (CCMP1779) is particularly promising, because following nutrient deprivation it produces very high amounts of triacylglycerols (TAG). The committed step in TAG synthesis is catalyzed by acyl-CoA:diacylglycerol acyltransferase (DGAT). Remarkably, a total of 13 putative DGAT-encoding genes have been previously identified in CCMP1779 but most have not yet been studied in detail. RESULTS Based on their expression profile, six out of 12 type-2 DGAT-encoding genes (NoDGTT1-NoDGTT6) were chosen for their possible role in TAG biosynthesis and the respective cDNAs were expressed in a TAG synthesis-deficient mutant of yeast. Yeast expressing NoDGTT5 accumulated TAG to the highest level. Over-expression of NoDGTT5 in CCMP1779 grown in N-replete medium resulted in levels of TAG normally observed only after N deprivation. Reduced growth rates accompanied NoDGTT5 over-expression in CCMP1779. Constitutive expression of NoDGTT5 in Arabidopsis thaliana was accompanied by increased TAG content in seeds and leaves. A broad substrate specificity for NoDGTT5 was revealed, with preference for unsaturated acyl groups. Furthermore, NoDGTT5 was able to successfully rescue the Arabidopsis tag1-1 mutant by restoring the TAG content in seeds. CONCLUSIONS Taken together, our results identified NoDGTT5 as the most promising gene for the engineering of TAG synthesis in multiple hosts among the 13 DGAT-encoding genes of N. oceanica CCMP1779. Consequently, this study demonstrates the potential of NoDGTT5 as a tool for enhancing the energy density in biomass by increasing TAG content in transgenic crops used for biofuel production.
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Affiliation(s)
- Krzysztof Zienkiewicz
- Michigan State University-US Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37073 Göttingen, Germany
| | - Agnieszka Zienkiewicz
- Michigan State University-US Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37073 Göttingen, Germany
- Great Lakes Bioenergy Center, Michigan State University, East Lansing, MI 48824 USA
| | - Eric Poliner
- Cell and Molecular Biology Program, Michigan State University, East Lansing, MI 48824 USA
| | - Zhi-Yan Du
- Michigan State University-US Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
| | - Katharina Vollheyde
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37073 Göttingen, Germany
| | - Cornelia Herrfurth
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37073 Göttingen, Germany
| | - Sofia Marmon
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37073 Göttingen, Germany
- Dept. of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Eva M. Farré
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
| | - Ivo Feussner
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, Georg-August-University, 37073 Göttingen, Germany
- Department of Plant Biochemistry, Göttingen Center for Molecular Biosciences (GZMB), Georg-August-University, 37073 Göttingen, Germany
- Department of Plant Biochemistry, International Center for Advanced Studies of Energy Conversion (ICASEC), Georg-August-University, 37073 Göttingen, Germany
| | - Christoph Benning
- Michigan State University-US Department of Energy Plant Research Laboratory, Michigan State University, East Lansing, MI 48824 USA
- Great Lakes Bioenergy Center, Michigan State University, East Lansing, MI 48824 USA
- Department of Plant Biology, Michigan State University, East Lansing, MI 48824 USA
- Department Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI 48824 USA
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Tan KWM, Lee YK. The dilemma for lipid productivity in green microalgae: importance of substrate provision in improving oil yield without sacrificing growth. BIOTECHNOLOGY FOR BIOFUELS 2016; 9:255. [PMID: 27895709 PMCID: PMC5120525 DOI: 10.1186/s13068-016-0671-2] [Citation(s) in RCA: 73] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 11/16/2016] [Indexed: 05/02/2023]
Abstract
Rising oil prices and concerns over climate change have resulted in more emphasis on research into renewable biofuels from microalgae. Unlike plants, green microalgae have higher biomass productivity, will not compete with food and agriculture, and do not require fertile land for cultivation. However, microalgae biofuels currently suffer from high capital and operating costs due to low yields and costly extraction methods. Microalgae grown under optimal conditions produce large amounts of biomass but with low neutral lipid content, while microalgae grown in nutrient starvation accumulate high levels of neutral lipids but are slow growing. Producing lipids while maintaining high growth rates is vital for biofuel production because high biomass productivity increases yield per harvest volume while high lipid content decreases the cost of extraction per unit product. Therefore, there is a need for metabolic engineering of microalgae to constitutively produce high amounts of lipids without sacrificing growth. Substrate availability is a rate-limiting step in balancing growth and fatty acid (FA) production because both biomass and FA synthesis pathways compete for the same substrates, namely acetyl-CoA and NADPH. In this review, we discuss the efforts made for improving biofuel production in plants and microorganisms, the challenges faced in achieving lipid productivity, and the important role of precursor supply for FA synthesis. The main focus is placed on the enzymes which catalyzed the reactions supplying acetyl-CoA and NADPH.
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Affiliation(s)
- Kenneth Wei Min Tan
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545 Singapore
| | - Yuan Kun Lee
- Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117545 Singapore
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Metabolic pathways for lipid synthesis under nitrogen stress in Chlamydomonas and Nannochloropsis. Biotechnol Lett 2016; 39:1-11. [DOI: 10.1007/s10529-016-2216-y] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2016] [Accepted: 09/13/2016] [Indexed: 12/13/2022]
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49
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Li DW, Cen SY, Liu YH, Balamurugan S, Zheng XY, Alimujiang A, Yang WD, Liu JS, Li HY. A type 2 diacylglycerol acyltransferase accelerates the triacylglycerol biosynthesis in heterokont oleaginous microalga Nannochloropsis oceanica. J Biotechnol 2016; 229:65-71. [DOI: 10.1016/j.jbiotec.2016.05.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Revised: 05/02/2016] [Accepted: 05/03/2016] [Indexed: 11/15/2022]
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50
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Proteomic analyses bring new insights into the effect of a dark stress on lipid biosynthesis in Phaeodactylum tricornutum. Sci Rep 2016; 6:25494. [PMID: 27147218 PMCID: PMC4857112 DOI: 10.1038/srep25494] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/19/2016] [Indexed: 01/24/2023] Open
Abstract
Microalgae biosynthesize high amount of lipids and show high potential for renewable biodiesel production. However, the production cost of microalgae-derived biodiesel hampers large-scale biodiesel commercialization and new strategies for increasing lipid production efficiency from algae are urgently needed. Here we submitted the marine algae Phaeodactylum tricornutum to a 4-day dark stress, a condition increasing by 2.3-fold the total lipid cell quotas, and studied the cellular mechanisms leading to lipid accumulation using a combination of physiological, proteomic (iTRAQ) and genomic (qRT-PCR) approaches. Our results show that the expression of proteins in the biochemical pathways of glycolysis and the synthesis of fatty acids were induced in the dark, potentially using excess carbon and nitrogen produced from protein breakdown. Treatment of algae in the dark, which increased algal lipid cell quotas at low cost, combined with optimal growth treatment could help optimizing biodiesel production.
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