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Song Y, Yang X, Li S, Luo Y, Chang JS, Hu Z. Thraustochytrids as a promising source of fatty acids, carotenoids, and sterols: bioactive compound biosynthesis, and modern biotechnology. Crit Rev Biotechnol 2024; 44:618-640. [PMID: 37158096 DOI: 10.1080/07388551.2023.2196373] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 02/20/2023] [Indexed: 05/10/2023]
Abstract
Thraustochytrids are eukaryotes and obligate marine protists. They are increasingly considered to be a promising feed additive because of their superior and sustainable application in the production of health-benefiting bioactive compounds, such as fatty acids, carotenoids, and sterols. Moreover, the increasing demand makes it critical to rationally design the targeted products by engineering industrial strains. In this review, bioactive compounds accumulated in thraustochytrids were comprehensively evaluated according to their chemical structure, properties, and physiological function. Metabolic networks and biosynthetic pathways of fatty acids, carotenoids, and sterols were methodically summarized. Further, stress-based strategies used in thraustochytrids were reviewed to explore the potential methodologies for enhancing specific product yields. There are internal relationships between the biosynthesis of fatty acids, carotenoids, and sterols in thraustochytrids since they share some branches of the synthetic routes with some intermediate substrates in common. Although there are classic synthesis pathways presented in the previous research, the metabolic flow of how these compounds are being synthesized in thraustochytrids still remains uncovered. Further, combined with omics technologies to deeply understand the mechanism and effects of different stresses is necessary, which could provide guidance for genetic engineering. While gene-editing technology has allowed targeted gene knock-in and knock-outs in thraustochytrids, efficient gene editing is still required. This critical review will provide comprehensive information to benefit boosting the commercial productivity of specific bioactive substances by thraustochytrids.
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Affiliation(s)
- Yingjie Song
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
- College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen, P.R. China
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
| | - Xuewei Yang
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
| | - Shuangfei Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
| | - Yanqing Luo
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
| | - Jo-Shu Chang
- Department of Chemical and Materials Engineering, Tunghai University, Taichung, Taiwan
- Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung, Taiwan
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Zhangli Hu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen, P.R. China
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Zhang H, Wang Z, Sun C, Zhang C, Liu H, Cui Q, Song X, Wang S. A phospholipid:diacylglycerol acyltransferase is involved in the regulation of phospholipids homeostasis in oleaginous Aurantiochytrium sp. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:142. [PMID: 37752571 PMCID: PMC10523756 DOI: 10.1186/s13068-023-02396-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Accepted: 09/18/2023] [Indexed: 09/28/2023]
Abstract
BACKGROUND Thraustochytrids have gained attention as a potential source for the production of docosahexaenoic acid (DHA), where DHA is predominantly stored in the form of triacylglycerol (TAG). The TAG biosynthesis pathways, including the acyl-CoA-dependent Kennedy pathway and the acyl-CoA-independent pathway, have been predicted in thraustochytrids, while the specific details regarding their roles are currently uncertain. RESULTS Phospholipid:diacylglycerol acyltransferase (PDAT) plays a key role in the acyl-CoA-independent pathway by transferring acyl-group from phospholipids (PL) to diacylglycerol (DAG) to from TAG. In thraustochytrid Aurantiochytrium sp. SD116, an active AuPDAT was confirmed by heterologous expression in a TAG-deficient yeast strain H1246. Analysis of AuPDAT function in vivo revealed that deletion of AuPDAT led to slow growth and a significant decrease in cell number, but improved PL content in the single cell during the cell growth and lipid accumulation phases. Interestingly, deletion of AuPDAT did not affect total lipid and TAG content, but both were significantly increased within a single cell. Moreover, overexpression of AuPDAT also resulted in a decrease in cell number, while the total lipid and cell diameter of a single cell were markedly increased. Altogether, both up-regulation and down-regulation of AuPDAT expression affected the cell number, which further associated with the total lipid and TAG content in a single cell. CONCLUSIONS Our study demonstrates that AuPDAT-mediated pathway play a minor role in TAG synthesis, and that the function of AuPDAT may be involved in regulating PL homeostasis by converting PL to TAG in a controlled manner. These findings expand our understanding of lipid biosynthesis in Aurantiochytrium sp. and open new avenues for developing "customized cell factory" for lipid production.
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Affiliation(s)
- Huidan Zhang
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China
| | - Zhuojun Wang
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China
| | - Caili Sun
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China
| | - Chuchu Zhang
- Key Laboratory of Marine Drugs, Ministry of Education, School of Medicine and Pharmacy, Ocean University of China, Qingdao, 266003, China
| | - Huan Liu
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China
| | - Qiu Cui
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China
| | - Xiaojin Song
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China.
- Academy of Plateau Science and Sustainability, Qinghai Normal University, Xining, 810016, Qinghai, China.
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China.
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China.
| | - Sen Wang
- CAS Key Laboratory of Biofuels, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, No.189 Songling Road, Laoshan District, Qingdao, 266101, Shandong, China.
- Shandong Provincial Key Laboratory of Energy Genetics, Shandong Engineering Laboratory of Single Cell Oil, Shandong Energy Institute, Qingdao, 266101, Shandong, China.
- Qingdao New Energy Shandong Laboratory, Qingdao Engineering Laboratory of Single Cell Oil, Qingdao, 266101, Shandong, China.
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Chen L, Liu X, Li C, Li H, Chen W, Li D. Transcriptome analyses reveal the DHA enhancement mechanism in Schizochytrium limacinum LD11 mutant. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hien HTM, Thom LT, Pham QH, Hong DD. Genome analysis of the heterotrophic microalga Thraustochytrium sp. TN22 to identify genes involved in exopolysaccharide and carotenoid biosynthesis pathways. Mar Genomics 2022; 61:100918. [DOI: 10.1016/j.margen.2021.100918] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2021] [Revised: 12/11/2021] [Accepted: 12/13/2021] [Indexed: 10/19/2022]
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Chi G, Xu Y, Cao X, Li Z, Cao M, Chisti Y, He N. Production of polyunsaturated fatty acids by Schizochytrium (Aurantiochytrium) spp. Biotechnol Adv 2021; 55:107897. [PMID: 34974158 DOI: 10.1016/j.biotechadv.2021.107897] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2021] [Revised: 12/05/2021] [Accepted: 12/20/2021] [Indexed: 12/28/2022]
Abstract
Diverse health benefits are associated with dietary consumption of omega-3 long-chain polyunsaturated fatty acids (ω-3 LC-PUFA), particularly docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA). Traditionally, these fatty acids have been obtained from fish oil, but limited supply, variably quality, and an inability to sustainably increase production for a rapidly growing market, are driving the quest for alternative sources. DHA derived from certain marine protists (heterotrophic thraustochytrids) already has an established history of commercial production for high-value dietary use, but is too expensive for use in aquaculture feeds, a much larger potential market for ω-3 LC-PUFA. Sustainable expansion of aquaculture is prevented by its current dependence on wild-caught fish oil as the source of ω-3 LC-PUFA nutrients required in the diet of aquacultured animals. Although several thraustochytrids have been shown to produce DHA and EPA, there is a particular interest in Schizochytrium spp. (now Aurantiochytrium spp.), as some of the better producers. The need for larger scale production has resulted in development of many strategies for improving productivity and production economics of ω-3 PUFA in Schizochytrium spp. Developments in fermentation technology and metabolic engineering for enhancing LC-PUFA production in Schizochytrium spp. are reviewed.
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Affiliation(s)
- Guoxiang Chi
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Yiyuan Xu
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Xingyu Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China
| | - Zhipeng Li
- College of Food and Biological Engineering, Jimei University, Xiamen 361000, China
| | - Mingfeng Cao
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
| | - Yusuf Chisti
- School of Engineering, Massey University, Private Bag 11 222, Palmerston North, New Zealand.
| | - Ning He
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen 361005, China; The Key Laboratory for Synthetic Biotechnology of Xiamen City, Xiamen University, Xiamen 361005, China.
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Antarctic Thraustochytrids as Sources of Carotenoids and High-Value Fatty Acids. Mar Drugs 2021; 19:md19070386. [PMID: 34356811 PMCID: PMC8303828 DOI: 10.3390/md19070386] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/17/2021] [Accepted: 06/29/2021] [Indexed: 01/20/2023] Open
Abstract
Eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), and carotenoids are needed as human dietary supplements and are essential components in commercial feeds for the production of aquacultured seafood. Microorganisms such as thraustochytrids are potential natural sources of these compounds. This research reports on the lipid and carotenoid production capacity of thraustochytrids that were isolated from coastal waters of Antarctica. Of the 22 isolates, 21 produced lipids containing EPA+DHA, and the amount of these fatty acids exceeded 20% of the total fatty acids in 12 isolates. Ten isolates were shown to produce carotenoids (27.4-63.9 μg/g dry biomass). The isolate RT2316-16, identified as Thraustochytrium sp., was the best producer of biomass (7.2 g/L in five days) rich in carotenoids (63.9 μg/g) and, therefore, became the focus of this investigation. The main carotenoids in RT2316-16 were β-carotene and canthaxanthin. The content of EPA+DHA in the total lipids (34 ± 3% w/w in dry biomass) depended on the stage of growth of RT2316-16. Lipid and carotenoid content of the biomass and its concentration could be enhanced by modifying the composition of the culture medium. The estimated genome size of RT2316-16 was 44 Mb. Of the 5656 genes predicted from the genome, 4559 were annotated. These included genes of most of the enzymes in the elongation and desaturation pathway of synthesis of ω-3 polyunsaturated fatty acids. Carotenoid precursors in RT2316-16 were synthesized through the mevalonate pathway. A β-carotene synthase gene, with a different domain organization compared to the gene in other thraustochytrids, explained the carotenoid profile of RT2316-16.
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Functional Analysis of an Acyltransferase-Like Domain from Polyunsaturated Fatty Acid Synthase in Thraustochytrium. Microorganisms 2021; 9:microorganisms9030626. [PMID: 33803061 PMCID: PMC8003026 DOI: 10.3390/microorganisms9030626] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 03/15/2021] [Accepted: 03/15/2021] [Indexed: 12/19/2022] Open
Abstract
Biosynthesis of very long chain polyunsaturated fatty acids (VLCPUFA) such as docosahexaenoic acid (DHA, 22:6-4,7,10,13,16,19) and docosapentaenoic acid (DPA, 22:5-4,7,10,13,16) in protist Thraustochytrium is catalyzed by a polyunsaturated fatty acids (PUFA) synthase comprising three large subunits, each with multiple catalytic domains. This study used complementation test, in vitro assays, and functional expression to characterize an acyltransferase (AT)-like domain in Subunit-B of a PUFA synthase from Thraustochytrium. Complementation test in Escherichia coli showed that the AT-like domain could not restore the growth phenotype of a temperature-sensitive mutant (∆fabDts) defective in malonyl-CoA:ACP transacylase activity. In vitro assays showed that the AT-like domain possessed thioesterase activity towards a few acyl-CoAs tested where docosahexaenoyl-CoA (DHA-CoA) was the preferred substrate. Expression of this domain in an E. coli mutant (∆fadD) defective in acyl-CoA synthetase activity resulted in the increased accumulation of free fatty acids. Site-directed mutagenesis showed that the substitution of two putative active site residues, serine at 96 (S96) and histidine at 220 (H220), in the AT-like domain significantly reduced its activity towards DHA-CoA and accumulation of free fatty acids in the ∆fadD mutant. These results indicate that the AT-like domain of the PUFA synthase does not function as a malonyl-CoA:ACP transacylase, rather it functions as a thioesterase. It might catalyze the last step of the VLCPUFA biosynthesis by releasing freshly synthesized VLCPUFAs attached to ACP domains of the PUFA synthase in Thraustochytrium.
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Hu F, Clevenger AL, Zheng P, Huang Q, Wang Z. Low-temperature effects on docosahexaenoic acid biosynthesis in Schizochytrium sp. TIO01 and its proposed underlying mechanism. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:172. [PMID: 33088342 PMCID: PMC7565746 DOI: 10.1186/s13068-020-01811-y] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2020] [Accepted: 10/06/2020] [Indexed: 05/25/2023]
Abstract
BACKGROUND Schizochytrium species are known for their abundant production of docosahexaenoic acid (DHA). Low temperatures can promote the biosynthesis of polyunsaturated fatty acids (PUFAs) in many species. This study investigates low-temperature effects on DHA biosynthesis in Schizochytrium sp. TIO01 and its underlying mechanism. RESULTS The Schizochytrium fatty acid biosynthesis pathway was evaluated based on de novo genome assembly (contig N50 = 2.86 Mb) and iTRAQ-based protein identification. Our findings revealed that desaturases, involved in DHA synthesis via the fatty acid synthase (FAS) pathway, were completely absent. The polyketide synthase (PKS) pathway and the FAS pathway are, respectively, responsible for DHA and saturated fatty acid synthesis in Schizochytrium. Analysis of fatty acid composition profiles indicates that low temperature has a significant impact on the production of DHA in Schizochytrium, increasing the DHA content from 43 to 65% of total fatty acids. However, the expression levels of PKS pathway genes were not significantly regulated as the DHA content increased. Further, gene expression analysis showed that pathways related to the production of substrates (acetyl-CoA and NADPH) for fatty acid synthesis (the branched-chain amino acid degradation pathway and the pentose phosphate pathway) and genes related to saturated fatty acid biosynthesis (the FAS pathway genes and malic enzyme) were, respectively, upregulated and downregulated. These results indicate that low temperatures increase the DHA content by likely promoting the entry of relatively large amounts of substrates into the PKS pathway. CONCLUSIONS In this study, we provide genomic, proteomic, and transcriptomic evidence for the fatty acid synthesis pathway in Schizochytrium and propose a mechanism by which low temperatures promote the accumulation of DHA in Schizochytrium. The high-quality and nearly complete genome sequence of Schizochytrium provides a valuable reference for investigating the regulation of polyunsaturated fatty acid biosynthesis and the evolutionary characteristics of Thraustochytriidae species.
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Affiliation(s)
- Fan Hu
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005 China
| | - April L. Clevenger
- Department of Chemistry and Biochemistry, University of Oklahoma, Norman, OK USA
| | - Peng Zheng
- College of Life Science and Health, Wuhan University of Science and Technology, Wuhan, 430065 China
| | - Qiongye Huang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005 China
| | - Zhaokai Wang
- Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, 361005 China
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Molecular mechanisms for biosynthesis and assembly of nutritionally important very long chain polyunsaturated fatty acids in microorganisms. Prog Lipid Res 2020; 79:101047. [DOI: 10.1016/j.plipres.2020.101047] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/29/2020] [Accepted: 06/09/2020] [Indexed: 12/23/2022]
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Zhu X, Li S, Liu L, Li S, Luo Y, Lv C, Wang B, Cheng CHK, Chen H, Yang X. Genome Sequencing and Analysis of Thraustochytriidae sp. SZU445 Provides Novel Insights into the Polyunsaturated Fatty Acid Biosynthesis Pathway. Mar Drugs 2020; 18:md18020118. [PMID: 32085426 PMCID: PMC7073664 DOI: 10.3390/md18020118] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 02/06/2020] [Accepted: 02/14/2020] [Indexed: 12/18/2022] Open
Abstract
Thraustochytriidae sp. have broadly gained attention as a prospective resource for the production of omega-3 fatty acids production in significant quantities. In this study, the whole genome of Thraustochytriidae sp. SZU445, which produces high levels of docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA), was sequenced and subjected to protein annotation. The obtained clean reads (63.55 Mb in total) were assembled into 54 contigs and 25 scaffolds, with maximum and minimum lengths of 400 and 0.0054 Mb, respectively. A total of 3513 genes (24.84%) were identified, which could be classified into six pathways and 44 pathway groups, of which 68 genes (1.93%) were involved in lipid metabolism. In the Gene Ontology database, 22,436 genes were annotated as cellular component (8579 genes, 38.24%), molecular function (5236 genes, 23.34%), and biological process (8621 genes, 38.42%). Four enzymes corresponding to the classic fatty acid synthase (FAS) pathway and three enzymes corresponding to the classic polyketide synthase (PKS) pathway were identified in Thraustochytriidae sp. SZU445. Although PKS pathway-associated dehydratase and isomerase enzymes were not detected in Thraustochytriidae sp. SZU445, a putative DHA- and DPA-specific fatty acid pathway was identified.
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Affiliation(s)
- Xingyu Zhu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Shuangfei Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Longhua Innovation Institute for Biotechnology, Shenzhen University, Shenzhen 518060, China
| | - Liangxu Liu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Siting Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Yanqing Luo
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Chuhan Lv
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
| | - Boyu Wang
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Longhua Innovation Institute for Biotechnology, Shenzhen University, Shenzhen 518060, China
| | - Christopher H. K. Cheng
- School of Biomedical Sciences, The Chinese University of Hong Kong, Hong Kong 999077, China;
| | - Huapu Chen
- Guangdong Research Center on Reproductive Control and Breeding Technology of Indigenous Valuable Fish Species, Fisheries College, Guangdong Ocean University, Zhanjiang 524088, China;
| | - Xuewei Yang
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Key Laboratory of Plant Epigenetics, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; (X.Z.); (S.L.); (L.L.); (S.L.); (Y.L.); (C.L.); (B.W.)
- Shenzhen Key Laboratory of Marine Biological Resources and Ecology Environment, Shenzhen Key Laboratory of Microbial Genetic Engineering, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518055, China
- Longhua Innovation Institute for Biotechnology, Shenzhen University, Shenzhen 518060, China
- Correspondence:
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Han X, Zhao Z, Wen Y, Chen Z. Enhancement of docosahexaenoic acid production by overexpression of ATP-citrate lyase and acetyl-CoA carboxylase in Schizochytrium sp. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:131. [PMID: 32699554 PMCID: PMC7372839 DOI: 10.1186/s13068-020-01767-z] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2019] [Accepted: 07/11/2020] [Indexed: 05/18/2023]
Abstract
BACKGROUND Docosahexaenoic acid (DHA) is an important omega-3 long-chain polyunsaturated fatty acid that has a variety of physiological functions for infant development and human health. Although metabolic engineering was previously demonstrated to be a highly efficient way to rapidly increase lipid production, metabolic engineering has seldom been previously used to increase DHA accumulation in Schizochytrium spp. RESULTS Here, a sensitive β-galactosidase reporter system was established to screen for strong promoters in Schizochytrium sp. Four constitutive promoters (EF-1α p , TEF-1 p , ccg1 p , and ubiquitin p ) and one methanol-induced AOX1 promoter were characterized by the reporter system with the promoter activity ccg1 p > TEF-1 p > AOX1 p (induced) > EF-1α p > ubiquitin p . With the strong constitutive promoter ccg1 p , Schizochytrium ATP-citrate lyase (ACL) and acetyl-CoA carboxylase (ACC) were overexpressed in Schizochytrium sp. ATCC 20888. The cells were cultivated at 28 °C and 250 rpm for 120 h with glucose as the carbon source. Shake-flask fermentation results showed that the overexpression strains exhibited growth curves and biomass similar to those of the wild-type strain. The lipid contents of the wild-type strain and of the OACL, OACC, and OACL-ACC strains were 53.8, 68.8, 69.8, and 73.0%, respectively, and the lipid yields of the overexpression strains were increased by 21.9, 30.5, and 38.3%, respectively. DHA yields of the wild-type strain and of the corresponding overexpression strains were 4.3, 5.3, 6.1, and 6.4 g/L, i.e., DHA yields of the overexpression strains were increased by 23.3, 41.9, and 48.8%, respectively. CONCLUSIONS Acetyl-CoA and malonyl-CoA are precursors for fatty acid synthesis. ACL catalyzes the conversion of citrate in the cytoplasm into acetyl-CoA, and ACC catalyzes the synthesis of malonyl-CoA from acetyl-CoA. The results demonstrate that overexpression of ACL and ACC enhances lipid accumulation and DHA production in Schizochytrium sp.
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Affiliation(s)
- Xiao Han
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Zhunan Zhao
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Ying Wen
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
| | - Zhi Chen
- State Key Laboratory of Agrobiotechnology and Key Laboratory of Soil Microbiology, Ministry of Agriculture, College of Biological Sciences, China Agricultural University, Beijing, 100193 China
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Yue XH, Chen WC, Wang ZM, Liu PY, Li XY, Lin CB, Lu SH, Huang FH, Wan X. Lipid Distribution Pattern and Transcriptomic Insights Revealed the Potential Mechanism of Docosahexaenoic Acid Traffics in Schizochytrium sp. A-2. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9683-9693. [PMID: 31379160 DOI: 10.1021/acs.jafc.9b03536] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Schizochytrium sp. A-2 is a heterotrophic marine fungus used for the commercial production of docosahexaenoic acid (DHA). However, the pattern of the distribution of DHA and how DHA is channeled into phospholipid (PL) and triacylglycerol (TAG) are unknown. In this study, we systematically analyzed the distribution of DHA in TAG and PL during the growth of the cell. The migration of DHA from PL to TAG was presumed during the fermentation cycle. DHA and docosapentaenoic acid were accumulated in both TAG and phosphatidylcholine (PC), whereas eicosapentaenoic acid was mainly deposited in PC. RNA seq revealed that malic enzyme may provide lipogenic NADPH. In addition, long-chain acyl-CoA synthase and acyl-CoA:lysophosphatidylcholine acyltransferase may participate in the accumulation of DHA in PL. No phosphatidylcholine:diacylglycerol cholinephosphotransferase was identified from the genome sequence. In contrast, phospholipid:diacylglycerol acyltransferase-mediated acyl-CoA-independent TAG synthesis pathway and phospholipase C may contribute to the channeling of DHA from PC to TAG.
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Affiliation(s)
- Xiu-Hong Yue
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences , Wuhan 430062 , P. R. China
| | - Wen-Chao Chen
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences , Wuhan 430062 , P. R. China
- Key Laboratory of Biology and Genetic Improvement of Oil Crops , Ministry of Agriculture , Wuhan 430062 , P. R. China
- Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory , Wuhan 430062 , P. R. China
- Hubei Key Laboratory of Lipid Chemistry and Nutrition , Wuhan 430062 , P. R. China
| | - Zhi-Ming Wang
- CABIO Biotech (Wuhan) Co., Ltd , Wuhan 430223 , P. R. China
| | - Peng-Yang Liu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences , Wuhan 430062 , P. R. China
| | - Xiang-Yu Li
- CABIO Biotech (Wuhan) Co., Ltd , Wuhan 430223 , P. R. China
| | - Chu-Bin Lin
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences , Wuhan 430062 , P. R. China
| | - Shu-Huan Lu
- CABIO Biotech (Wuhan) Co., Ltd , Wuhan 430223 , P. R. China
| | - Feng-Hong Huang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences , Wuhan 430062 , P. R. China
- Key Laboratory of Biology and Genetic Improvement of Oil Crops , Ministry of Agriculture , Wuhan 430062 , P. R. China
- Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory , Wuhan 430062 , P. R. China
- Hubei Key Laboratory of Lipid Chemistry and Nutrition , Wuhan 430062 , P. R. China
| | - Xia Wan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences , Wuhan 430062 , P. R. China
- Key Laboratory of Biology and Genetic Improvement of Oil Crops , Ministry of Agriculture , Wuhan 430062 , P. R. China
- Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory , Wuhan 430062 , P. R. China
- Hubei Key Laboratory of Lipid Chemistry and Nutrition , Wuhan 430062 , P. R. China
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Xie X, Meesapyodsuk D, Qiu X. Enhancing oil production in Arabidopsis through expression of a ketoacyl-ACP synthase domain of the PUFA synthase from Thraustochytrium. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:172. [PMID: 31297160 PMCID: PMC6599236 DOI: 10.1186/s13068-019-1514-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Accepted: 06/21/2019] [Indexed: 06/01/2023]
Abstract
BACKGROUND Plant seed oil is an important bioresource for human food and animal feed, as well as industrial bioproducts. Therefore, increasing oil content in seeds has been one of the primary targets in the breeding programs of oilseed crops. Thraustochytrium is a marine protist that can produce a high level of very long-chain polyunsaturated fatty acids (VLCPUFAs) using a PUFA synthase, a polyketide synthase-like fatty acid synthase with multiple catalytic domains. Our previous study showed that a KS domain from the synthase could complement an Escherichia coli mutant defective in β-ketoacyl-ACP synthase I (FabB) and increase the total fatty acid production. In this study, this KS domain from the PUFA synthase was further functionally analyzed in Arabidopsis thaliana for the capacity of oil production. RESULTS The plastidial expression of the KS domain could complement the defective phenotypes of a KASI knockout mutant generated by CRISPR/Cas9. Seed-specific expression of the domain in wild-type Arabidopsis significantly increased seed weight and seed oil, and altered the unsaturation level of fatty acids in seeds, as well as promoted seed germination and early seedling growth. CONCLUSIONS The condensation process of fatty acid biosynthesis in plants is a limiting step, and overexpression of the KS domain from a PUFA synthase of microbial origin offers a new strategy to increase oil production in oilseed plants.
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Affiliation(s)
- Xi Xie
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Dauenpen Meesapyodsuk
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
| | - Xiao Qiu
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK S7N 5A8 Canada
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Zhao X, Qiu X. Very Long Chain Polyunsaturated Fatty Acids Accumulated in Triacylglycerol Are Channeled From Phosphatidylcholine in Thraustochytrium. Front Microbiol 2019; 10:645. [PMID: 30972054 PMCID: PMC6446058 DOI: 10.3389/fmicb.2019.00645] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2019] [Accepted: 03/14/2019] [Indexed: 11/13/2022] Open
Abstract
Thraustochytrium is a marine protist that can accumulate a large amount of very long chain polyunsaturated fatty acids (VLCPUFA) in triacylglycerols (TAG). How these freshly synthesized VLCPUFAs are channeled into TAG remains unknown. In this study, the glycerolipid profile of Thraustochytrium at log and stationary growth stages was first analyzed by lipidomic tools, and then 14C-acetate and 14C-glycerol were used to trace the flux of fatty acids and backbone in glycerolipids. Lipidomic analysis showed that VLCPUFAs were mostly allocated to phosphatidylcholine (PC) and TAG. PC possessed a relatively stable profile of VLCPUFAs, whereas TAG carrying VLCPUFAs were significantly increased at the stationary phase. 14C-acetate labeled VLCPUFAs were predominately incorporated into PC initially but were mostly found in TAG at later time of labeling. Positional analysis showed that PC had either one VLCPUFA at its sn-2 position (PC1) or two VLCPUFAs (PC2), while TAG incorporated VLCPUFAs almost exclusively at the sn-2 position. Similarly, 14C-glycerol was more efficiently incorporated into PC1 than TAG initially but was mostly found in TAG at later time of labeling, and diacylglycerol and PC1 shared a similar incorporation pattern. These results indicate that VLCPUFAs in TAG are mainly channeled from PC likely through diacylglycerol as the intermediate.
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Affiliation(s)
| | - Xiao Qiu
- Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, Canada
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15
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A Possible Trifunctional β-Carotene Synthase Gene Identified in the Draft Genome of Aurantiochytrium sp. Strain KH105. Genes (Basel) 2018; 9:genes9040200. [PMID: 29642531 PMCID: PMC5924542 DOI: 10.3390/genes9040200] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2018] [Revised: 03/27/2018] [Accepted: 03/27/2018] [Indexed: 01/19/2023] Open
Abstract
Labyrinthulomycetes have been regarded as a promising industrial source of xanthophylls, including astaxanthin and canthaxanthin, polyunsaturated fatty acids such as docosahexaenoic acid and docosapentaenoic acid, ω-3 oils, and terpenic hydrocarbons, such as sterols and squalene. A Thraustochytrid, Aurantiochytrium sp. KH105 produces carotenoids, including astaxanthin, with strong antioxidant activity. To gain genomic insights into this capacity, we decoded its 97-Mbp genome and characterized genes for enzymes involved in carotenoid biosynthesis. Interestingly, all carotenogenic genes, as well as other eukaryotic genes, appeared duplicated, suggesting that this strain is diploid. In addition, among the five genes involved in the pathway from geranylgeranyl pyrophosphate to astaxanthin, geranylgeranyl phytoene synthase (crtB), phytoene desaturase (crtI) and lycopene cyclase (crtY) were fused into single gene (crtIBY) with no internal stop codons. Functionality of the trifunctional enzyme, CrtIBY, to catalyze the reaction from geranylgeranyl diphosphate to β-carotene was confirmed using a yeast assay system and mass spectrometry. Furthermore, analyses of differential gene expression showed characteristic up-regulation of carotenoid biosynthetic genes during stationary and starvation phases under these culture conditions. This suggests genetic engineering events to promote more efficient production of carotenoids. We also showed an occurrence of crtIBY in other Thraustochytrid species.
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16
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Xie X, Meesapyodsuk D, Qiu X. Functional analysis of the dehydratase domains of a PUFA synthase from Thraustochytrium in Escherichia coli. Appl Microbiol Biotechnol 2017; 102:847-856. [PMID: 29177940 DOI: 10.1007/s00253-017-8635-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Revised: 10/23/2017] [Accepted: 11/07/2017] [Indexed: 01/03/2023]
Abstract
Thraustochytrium sp. 26185, a unicellular marine protist, synthesizes docosahexaenoic acid, an omega-3 very long chain polyunsaturated fatty acid (VLC-PUFAs), by a polyunsaturated fatty acid (PUFA) synthase comprising three large subunits with multiple catalytic dehydratase (DH) domains critical for introducing double bonds at the specific position of fatty acids. To investigate functions of these DH domains, one DH domain from subunit-A and two DH domains from subunit-C of the PUFA synthase were dissected and expressed as stand-alone enzymes in Escherichia coli. The results showed that all these DH domains could complement the defective phenotype of a E. coli FabA temperature sensitive mutant, despite they have only modest sequence similarity with FabA, indicating they can function as 3-hydroxyacyl-ACP dehydratase for the biosynthesis of unsaturated fatty acids in E. coli. Site-directed mutagenesis analysis confirmed the authenticity of active site residues in these domains. In addition, overexpression of the three domains in a wild type E. coli strain resulted in the substantial alteration of fatty acid profiles including productions and ratio of unsaturated to saturated fatty acids. A combination of evidences from sequence comparison, functional expression, and mutagenesis analysis suggest that the DH domain from subunit-A is similar to DH domains from polyketide synthases, while the DH domains from subunit-C are more comparable to E. coli FabA in catalytic functions. Successful complementation and functional expression of the embedded DH domains from the PUFA synthase in E. coli is an important step towards for elucidating the molecular mechanism in the biosynthesis of VLC-PUFAs in Thraustochytrium.
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Affiliation(s)
- Xi Xie
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| | - Dauenpen Meesapyodsuk
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada
| | - Xiao Qiu
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, SK, S7N 5A8, Canada.
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Zhao X, Qiu X. Analysis of the biosynthetic process of fatty acids in Thraustochytrium. Biochimie 2017; 144:108-114. [PMID: 29097280 DOI: 10.1016/j.biochi.2017.10.024] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/25/2017] [Indexed: 10/18/2022]
Abstract
Thraustochytrium is a marine protist producing a specific profile of nutritionally important fatty acids, including very long chain polyunsaturated fatty acids (VLCPUFAs) docosahexaenoic acid (DHA, 22:6n-3), even chain saturated fatty acids (SFAs) palmitic acid (16:0), and odd chain SFAs pentadecanoic acid (15:0). To study how these fatty acids are synthesized, a series of radiolabeled precursors were used to trace the biosynthetic process in vivo and in vitro. When Thraustochytrium was fed with long chain fatty acid intermediates such as [1-14C]-oleic acid, [1-14C]-linoleic acid and [1-14C]-α-linolenic acid, no VLCPUFAs were produced, indicating that the aerobic pathway for the biosynthesis of VLCPUFAs was not functional in Thraustochytrium. When fed with [1-14C]-acetic acid, both SFAs and VLCPUFAs were labeled, and when fed with [1-14C]-propionic acid, mainly SFAs were labeled. However, when fed with [1-14C]-acetic acid in the presence of cerulenin, a type I FAS inhibitor, only VLCPUFAs were labeled, and when fed with [1-14C]-propionic acid in the presence of cerulenin, neither SFAs nor VLCPUFAs were labeled. This result clearly indicates that the type I fatty acid synthase (FAS) in Thraustochytrium could use acetic acid and propionic acid as the primers to synthesize even chain and odd chain SFAs, respectively, and VLCPUFAs were synthesized by the PUFA synthase using acetic acid as the primer. In addition, radioactive acetic acid could label both phospholipids (PL) and triacylglycerols (TAG), and VLCPUFAs appeared first and were largely accumulated in PL, whereas TAG accumulated much more SFAs than VLCPUFAs. The in vitro assay with [1-14C]-malonyl-CoA in presence of cerulenin showed that the crude protein of Thraustochytrium produced only VLCPUFAs, not SFAs, further confirming the role of the PUFA synthase in the biosynthesis of VLCPUFAs. Collectively, these results have elucidated the biochemical mechanisms for the biosynthesis of all fatty acids in Thraustochytrium.
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Affiliation(s)
- Xianming Zhao
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada
| | - Xiao Qiu
- Department of Food and Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada.
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18
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Ren L, Hu X, Zhao X, Chen S, Wu Y, Li D, Yu Y, Geng L, Ji X, Huang H. Transcriptomic Analysis of the Regulation of Lipid Fraction Migration and Fatty Acid Biosynthesis in Schizochytrium sp. Sci Rep 2017; 7:3562. [PMID: 28620184 PMCID: PMC5472558 DOI: 10.1038/s41598-017-03382-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/27/2017] [Indexed: 11/26/2022] Open
Abstract
Schizochytrium sp. is the main source of docosahexaenoic acid-rich oil, which is widely used in food additive and pharmaceutical industry. In this study, using RNA-seq, comparative transcriptomic analyses were performed at four stages of DHA fermentation by Schizochytrium sp to get potential genes related to cell transition from cell growth to lipid accumulation and then to lipid turnover. 1406, 385, 1384 differently expressed genes were identified by comparisons in pairs of S2 vs S1, S3 vs S2 and S4 vs S3. Functional analysis revealed that binding and single-organism process might be involve in the cell transition from cell growth to lipid accumulation while oxidation-reduction process played an important role in the transition from lipid accumulation to lipid turnover. pfaC in the PKS pathway showed higher sensitivity to the environmental change, which might be the key regulator for enhancing PUFA biosynthesis in the future. Some other genes in signal transduction and cell transport were revealed to be related to lipid turnover, which would enrich the current knowledge regarding lipid metabolism and help to enhance the DHA production and enrich different lipid fractions by Schizochytrium in the future.
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Affiliation(s)
- Lujing Ren
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xuechao Hu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xiaoyan Zhao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Shenglan Chen
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Yi Wu
- Xiamen Kingdomway Group company, No. 299 West Yangguang Road, Haicang, Xiamen, 361022, China
| | - Dan Li
- Xiamen Kingdomway Group company, No. 299 West Yangguang Road, Haicang, Xiamen, 361022, China
| | - Yadong Yu
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Lingjun Geng
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xiaojun Ji
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - He Huang
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China.
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China.
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Ketoacylsynthase Domains of a Polyunsaturated Fatty Acid Synthase in Thraustochytrium sp. Strain ATCC 26185 Can Effectively Function as Stand-Alone Enzymes in Escherichia coli. Appl Environ Microbiol 2017; 83:AEM.03133-16. [PMID: 28213537 DOI: 10.1128/aem.03133-16] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Accepted: 02/03/2017] [Indexed: 11/20/2022] Open
Abstract
Thraustochytrium sp. strain ATCC 26185 accumulates a high level of docosahexaenoic acid (DHA), a nutritionally important ω-3 very-long-chain polyunsaturated fatty acid (VLCPUFA) synthesized primarily by polyunsaturated fatty acid (PUFA) synthase, a type I polyketide synthase-like megaenzyme. The PUFA synthase in this species comprises three large subunits, each with multiple catalytic domains. It was hypothesized that among these domains, ketoacylsynthase (KS) domains might be critical for catalyzing the condensation of specific unsaturated acyl-acyl carrier proteins (ACPs) with malonyl-ACP, thereby retaining double bonds in an extended acyl chain. To investigate the functions of these putative KS domains, two segment sequences from subunit A (KS-A) and subunit B (KS-B) of the PUFA synthase were dissected and then expressed as stand-alone enzymes in Escherichia coli The results showed that both KS-A and KS-B domains could complement the defective phenotypes of both E. colifabB and fabF mutants. Overexpression of these domains in wild-type E. coli led to increases in total fatty acid production. KS-B produced a higher ratio of unsaturated fatty acids (UFAs) to saturated fatty acids (SFAs), while KS-A could improve the overall production of fatty acids more effectively, particularly for the production of SFAs, implying that KS-A is more comparable to FabF, while KS-B is more similar to FabB in catalytic functions. Successful complementation and functional expression of the embedded KS domains in E. coli are the first step forward in studying the molecular mechanism of the PUFA synthase for the biosynthesis of VLCPUFAs in ThraustochytriumIMPORTANCE Very-long-chain polyunsaturated fatty acids (VLCPUFAs) are important for human health. They can be biosynthesized in either an aerobic pathway or an anaerobic pathway in nature. However, abundant VLCPUFAs in marine microorganisms are primarily synthesized by polyunsaturated fatty acid (PUFA) synthase, a megaenzyme with multiple subunits, each with multiple catalytic domains. Furthermore, the fundamental mechanism for this enzyme to synthesize these fatty acids still remains unknown. This report started with dissecting the embedded KS domains of the PUFA synthase from marine protist Thraustochytrium sp. strain ATCC 26185 and then expressing them in wild-type E. coli and mutants defective in condensation of acyl-ACP with malonyl-ACP. Successful complementation of the mutants and improved fatty acid production in the overexpression experiments indicate that these KS domains can effectively function as stand-alone enzymes in E. coli This result has paved the way for further studying of molecular mechanisms of the PUFA synthase for the biosynthesis of VLCPUFAs.
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