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Klińska-Bąchor S, Demski K, Gong Y, Banaś A. Biochemical characterization of acyl-CoA:diacylglycerol acyltransferase2 from the diatom Phaeodactylum tricornutum and its potential effect on LC-PUFAs biosynthesis in planta. BMC PLANT BIOLOGY 2024; 24:309. [PMID: 38649801 PMCID: PMC11036593 DOI: 10.1186/s12870-024-05014-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/08/2024] [Accepted: 04/12/2024] [Indexed: 04/25/2024]
Abstract
BACKGROUND Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), belonging to ω-3 long-chain polyunsaturated fatty acids (ω3-LC-PUFAs), are essential components of human diet. They are mainly supplemented by marine fish consumption, although their native producers are oleaginous microalgae. Currently, increasing demand for fish oils is insufficient to meet the entire global needs, which puts pressure on searching for the alternative solutions. One possibility may be metabolic engineering of plants with an introduced enzymatic pathway producing ω3-LC-PUFAs. RESULT In this study we focused on the acyl-CoA:diacylglycerol acyltransferase2b (PtDGAT2b) from the diatom Phaeodactylum tricornutum, an enzyme responsible for triacylglycerol (TAG) biosynthesis via acyl-CoA-dependent pathway. Gene encoding PtDGAT2b, incorporated into TAG-deficient yeast strain H1246, was used to confirm its activity and conduct biochemical characterization. PtDGAT2b exhibited a broad acyl-CoA preference with both di-16:0-DAG and di-18:1-DAG, whereas di-18:1-DAG was favored. The highest preference for acyl donors was observed for 16:1-, 10:0- and 12:0-CoA. PtDGAT2b also very efficiently utilized CoA-conjugated ω-3 LC-PUFAs (stearidonic acid, eicosatetraenoic acid and EPA). Additionally, verification of the potential role of PtDGAT2b in planta, through its transient expression in tobacco leaves, indicated increased TAG production with its relative amount increasing to 8%. Its co-expression with the gene combinations aimed at EPA biosynthesis led to, beside elevated TAG accumulation, efficient accumulation of EPA which constituted even 25.1% of synthesized non-native fatty acids (9.2% of all fatty acids in TAG pool). CONCLUSIONS This set of experiments provides a comprehensive biochemical characterization of DGAT enzyme from marine microalgae. Additionally, this study elucidates that PtDGAT2b can be used successfully in metabolic engineering of plants designed to obtain a boosted TAG level, enriched not only in ω-3 LC-PUFAs but also in medium-chain and ω-7 fatty acids.
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Affiliation(s)
- Sylwia Klińska-Bąchor
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland.
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden.
| | - Kamil Demski
- Department of Plant Breeding, Swedish University of Agricultural Sciences, Alnarp, Sweden
| | - Yangmin Gong
- Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan, China
| | - Antoni Banaś
- Intercollegiate Faculty of Biotechnology, University of Gdańsk and Medical University of Gdańsk, Gdańsk, Poland
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2
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Pan Y, Zhang W, Wang X, Jouhet J, Maréchal E, Liu J, Xia XQ, Hu H. Allele-dependent expression and functionality of lipid enzyme phospholipid:diacylglycerol acyltransferase affect diatom carbon storage and growth. PLANT PHYSIOLOGY 2024; 194:1024-1040. [PMID: 37930282 DOI: 10.1093/plphys/kiad581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2023] [Revised: 09/06/2023] [Accepted: 10/11/2023] [Indexed: 11/07/2023]
Abstract
In the acyl-CoA-independent pathway of triacylglycerol (TAG) synthesis unique to plants, fungi, and algae, TAG formation is catalyzed by the enzyme phospholipid:diacylglycerol acyltransferase (PDAT). The unique PDAT gene of the model diatom Phaeodactylum tricornutum strain CCMP2561 boasts 47 single nucleotide variants within protein coding regions of the alleles. To deepen our understanding of TAG synthesis, we observed the allele-specific expression of PDAT by the analysis of 87 published RNA-sequencing (RNA-seq) data and experimental validation. The transcription of one of the two PDAT alleles, Allele 2, could be specifically induced by decreasing nitrogen concentrations. Overexpression of Allele 2 in P. tricornutum substantially enhanced the accumulation of TAG by 44% to 74% under nutrient stress; however, overexpression of Allele 1 resulted in little increase of TAG accumulation. Interestingly, a more serious growth inhibition was observed in the PDAT Allele 1 overexpression strains compared with Allele 2 counterparts. Heterologous expression in yeast (Saccharomyces cerevisiae) showed that enzymes encoded by PDAT Allele 2 but not Allele 1 had TAG biosynthetic activity, and 7 N-terminal and 3 C-terminal amino acid variants between the 2 allele-encoded proteins substantially affected enzymatic activity. P. tricornutum PDAT, localized in the innermost chloroplast membrane, used monogalactosyldiacylglycerol and phosphatidylcholine as acyl donors as demonstrated by the increase of the 2 lipids in PDAT knockout lines, which indicated a common origin in evolution with green algal PDATs. Our study reveals unequal roles among allele-encoded PDATs in mediating carbon storage and growth in response to nitrogen stress and suggests an unsuspected strategy toward lipid and biomass improvement for biotechnological purposes.
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Affiliation(s)
- Yufang Pan
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Wanting Zhang
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG-LPCV, Grenoble Cedex 9 38054, France
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG-LPCV, Grenoble Cedex 9 38054, France
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xiao-Qin Xia
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanhua Hu
- Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Murison V, Hérault J, Schoefs B, Marchand J, Ulmann L. Bioinformatics-Based Screening Approach for the Identification and Characterization of Lipolytic Enzymes from the Marine Diatom Phaeodactylum tricornutum. Mar Drugs 2023; 21:md21020125. [PMID: 36827166 PMCID: PMC9964374 DOI: 10.3390/md21020125] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/13/2023] [Accepted: 02/14/2023] [Indexed: 02/17/2023] Open
Abstract
Oleaginous diatoms accumulate lipids of biotechnological interest when exposed to nutrient stress conditions such as nitrogen starvation. While accumulation mechanisms are well-known and have been engineered to improve lipid production, degradation mechanisms remain poorly investigated in diatoms. Identifying lipid-degrading enzymes is the initial step to understanding the catabolic processes. In this study, an in silico screening of the genome of Phaeodactylum tricornutum led to the identification of 57 putative triacylglycerol lipases (EC 3.1.1.3) grouped in 4 families. Further analysis revealed the presence of conserved domains and catalytic residues of lipases. Physico-chemical characteristics and subcellular localization predictions highlighted that a majority of these putative proteins are hydrophilic and cytosolic, suggesting they could be recruited to lipid droplets directly from the cytosol. Among the 57 identified putative proteins, three lipases were identified as possibly involved in lipophagy due to a potential vacuolar localization. The expression of the mRNA corresponding to the 57 proteins was then searched in 3 transcriptomic datasets obtained under nitrogen starvation. Nine genes were highly regulated and were considered as encoding enzymes with a probable important function in lipid catabolism. A tertiary structure prediction of these nine candidates yielded eight functional 3D models. Among those, two downregulated enzymes, Phatr3_J54974 and Phatr3_EG00720, were highlighted as good targets for future functional genomics and purification studies to investigate their role in lipid degradation.
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Affiliation(s)
- Victor Murison
- BiOSSE, Biology of Organisms: Stress, Health, Environment, Département Génie Biologique, Institut Universitaire de Technologie, Le Mans Université, F-53020 Laval, France
| | - Josiane Hérault
- BiOSSE, Biology of Organisms: Stress, Health, Environment, Département Génie Biologique, Institut Universitaire de Technologie, Le Mans Université, F-53020 Laval, France
| | - Benoît Schoefs
- BiOSSE, Biology of Organisms: Stress, Health, Environment, UFR Sciences et Techniques, Le Mans Université, F-72085 Le Mans, France
| | - Justine Marchand
- BiOSSE, Biology of Organisms: Stress, Health, Environment, UFR Sciences et Techniques, Le Mans Université, F-72085 Le Mans, France
| | - Lionel Ulmann
- BiOSSE, Biology of Organisms: Stress, Health, Environment, Département Génie Biologique, Institut Universitaire de Technologie, Le Mans Université, F-53020 Laval, France
- Correspondence:
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4
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Agarwal A, Di R, Falkowski PG. Light-harvesting complex gene regulation by a MYB-family transcription factor in the marine diatom, Phaeodactylum tricornutum. PHOTOSYNTHESIS RESEARCH 2022; 153:59-70. [PMID: 35391595 DOI: 10.1007/s11120-022-00915-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 03/16/2022] [Indexed: 06/14/2023]
Abstract
Unicellular photoautotrophs adapt to variations in light intensity by changing the abundance of light harvest pigment-protein complexes (LHCs) on time scales of hours to days. This process requires a feedback signal between the plastid (where light intensity is sensed) to the nucleus (where the genes for LHCs are encoded). The signals must include heretofore unidentified transcription factors that modify the expression level of the LHCs. Analysis of the nuclear genome of the model diatom Phaeodactylum tricornutum revealed that all the lhc genes have potential binding sites for transcription factors belonging to the MYB-family proteins. Functional studies involving antisense RNA interference of a hypothetical protein with a MYB DNA-binding domain were performed. The resultant strains with altered photosynthetic and physiological characteristics lost their ability to acclimate to changes in irradiance; i.e., cellular chlorophyll content became independent of growth irradiance. Our results strongly suggest that the inter-organellar signaling cascade was disrupted, and the cell could no longer communicate the environmental signal from the plastid to the nucleus. Here, we identify, for the first time, an LHC Regulating Myb (LRM) transcription factor, which we propose is involved in lhc gene regulation and photoacclimation mechanisms in response to changes in light intensity.
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Affiliation(s)
- Ananya Agarwal
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA
- Department of Biochemistry and Microbiology, Rutgers University, New Brunswick, NJ, USA
| | - Rong Di
- Department of Plant Biology, Rutgers University, New Brunswick, NJ, USA
| | - Paul G Falkowski
- Environmental Biophysics and Molecular Ecology Program, Department of Marine and Coastal Sciences, Rutgers University, New Brunswick, NJ, USA.
- Department of Earth and Planetary Sciences, Rutgers University, Piscataway, NJ, USA.
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5
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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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Karpagam R, Jawaharraj K, Ashokkumar B, Pugalendhi A, Varalakshmi P. A cheap two-step cultivation of Phaeodactylum tricornutum for increased TAG production and differential expression of TAG biosynthesis associated genes. J Biotechnol 2022; 354:53-62. [PMID: 35709890 DOI: 10.1016/j.jbiotec.2022.06.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Revised: 05/06/2022] [Accepted: 06/06/2022] [Indexed: 12/28/2022]
Abstract
A cheap cultivation of microalgae greatly reduces the biodiesel production cost. Subsequently in this study, citric acid and effluents from sugar and tannery industries were used as the nutritional supplements for the improvement of biomass and TAG production in Phaeodactylum tricornutum using two-step cultivation. When compared to control (media without supplementation), a considerable increase in biomass and chlorophyll a was obtained with citric acid (CA) and sugar industry effluent (SIE) supplemented media. In the two-step cultivation method, biomass raised from CA (100mg·L-1) and SIE (1.5mL·L-1) supplementations in the first step, viz. biomass production (BP) step was allowed for lipid accumulation in the second step, viz. lipid production (LP) step, and thus yielded enhanced lipids of 11.5 ± 0.7mg·L-1·day-1 and 13.5 ± 1.9mg·L-1·day-1 respectively, with improved TAG synthesis. Further, differential expression analysis of TAG biosynthetic genes of P. tricornutum under single-step and two-step cultivation modes were performed, and the gene expression patterns were studied.
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Affiliation(s)
- Rathinasamy Karpagam
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India
| | - Kalimuthu Jawaharraj
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India
| | - Balasubramaniem Ashokkumar
- Department of Genetic Engineering, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India
| | - Arivazhagan Pugalendhi
- Innovative Green Product Syntheis and Renewable Environment Development Research Group, Faculty of Environment and Labour Safety, TonDuc Thang University, Ho Chi Minh City, Vietnam
| | - Perumal Varalakshmi
- Department of Molecular Microbiology, School of Biotechnology, Madurai Kamaraj University, Madurai 625021, Tamil Nadu, India.
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7
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Li X, Gu D, You J, Qiao T, Yu X. Gamma-aminobutyric acid coupled with copper ion stress stimulates lipid production of green microalga Monoraphidium sp. QLY-1 through multiple mechanisms. BIORESOURCE TECHNOLOGY 2022; 352:127091. [PMID: 35364236 DOI: 10.1016/j.biortech.2022.127091] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2022] [Revised: 03/27/2022] [Accepted: 03/28/2022] [Indexed: 06/14/2023]
Abstract
Induction of copper ion (Cu2+) stress is a method used to increase lipid accumulation in microalgae, but it decreases cell growth. In this work, the impacts of gamma-aminobutyric acid (GABA) coupled with Cu2+ stress on the biomass and oil yield in Monoraphidium sp. QLY-1 were investigated. Results suggested that the combined treatment of GABA and Cu2+ resulted in a higher lipid content (55.13%) than Cu2+ treatment (48.43%). Furthermore, GABA addition upregulated the levels of lipid-relevant genes, cellular GABA, ethylene (ETH), and antioxidant enzyme activities and alleviated oxidative damage caused by Cu2+ stress. The autophagy-relevant gene atg8 was also upregulated by GABA treatment. Further exploration indicated that cell autophagy induced the lipid content up to 58.09% with GABA and Cu2+ stress treatment. This investigation demonstrates that the coupling strategy can stimulate lipid production and shed light on the underlying mechanisms in lipid biosynthesis, cell autophagy, and stress response of microalgae.
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Affiliation(s)
- Ximing Li
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China; School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Dan Gu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China
| | - Jinkun You
- Kunming Edible Fungi Institute of All China Federation of Supply and Marketing Cooperatives, Kunming 650032, China
| | - Tengsheng Qiao
- Key Laboratory of Mariculture, Ocean University of China, Ministry of Education, Qingdao 266003, China
| | - Xuya Yu
- Faculty of Life Science and Technology, Kunming University of Science and Technology, Kunming 650500, China.
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Santin A, Russo MT, Ferrante MI, Balzano S, Orefice I, Sardo A. Highly Valuable Polyunsaturated Fatty Acids from Microalgae: Strategies to Improve Their Yields and Their Potential Exploitation in Aquaculture. Molecules 2021; 26:7697. [PMID: 34946780 PMCID: PMC8707597 DOI: 10.3390/molecules26247697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Microalgae have a great potential for the production of healthy food and feed supplements. Their ability to convert carbon into high-value compounds and to be cultured in large scale without interfering with crop cultivation makes these photosynthetic microorganisms promising for the sustainable production of lipids. In particular, microalgae represent an alternative source of polyunsaturated fatty acids (PUFAs), whose consumption is related to various health benefits for humans and animals. In recent years, several strategies to improve PUFAs' production in microalgae have been investigated. Such strategies include selecting the best performing species and strains and the optimization of culturing conditions, with special emphasis on the different cultivation systems and the effect of different abiotic factors on PUFAs' accumulation in microalgae. Moreover, developments and results obtained through the most modern genetic and metabolic engineering techniques are described, focusing on the strategies that lead to an increased lipid production or an altered PUFAs' profile. Additionally, we provide an overview of biotechnological applications of PUFAs derived from microalgae as safe and sustainable organisms, such as aquafeed and food ingredients, and of the main techniques (and their related issues) for PUFAs' extraction and purification from microalgal biomass.
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Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Monia Teresa Russo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Sergio Balzano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Department of Marine Microbiology and Biogeochemistry, Netherland Institute for Sea Research, Landsdiep 4, 1793 AB Texel, The Netherlands
| | - Ida Orefice
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Angela Sardo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello”, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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9
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Metabolic engineering of the oleaginous alga Nannochloropsis for enriching eicosapentaenoic acid in triacylglycerol by combined pulling and pushing strategies. Metab Eng 2021; 69:163-174. [PMID: 34864212 DOI: 10.1016/j.ymben.2021.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/20/2021] [Accepted: 11/30/2021] [Indexed: 11/23/2022]
Abstract
The marine alga Nannochloropsis oceanica has been considered as a promising photosynthetic cell factory for synthesizing eicosapentaenoic acid (EPA), yet the accumulation of EPA in triacylglycerol (TAG) is restricted to an extreme low level. Poor channeling of EPA to TAG was observed in N. oceanica under TAG induction conditions, likely due to the weak activity of endogenous diacylglycerol acyltransferases (DGATs) on EPA-CoA. Screening over thirty algal DGATs revealed potent enzymes acting on EPA-CoA. Whilst overexpressing endogenous DGATs had no or slight effect on EPA abundance in TAG, introducing selected DGATs with strong activity on EPA-CoA, particularly the Chlamydomonas-derived CrDGTT1, which resided at the outermost membrane of the chloroplast and provided a strong pulling power to divert EPA to TAG for storage and protection, led to drastic increases in EPA abundance in TAG and TAG-derived EPA level in N. oceanica. They were further promoted by additional overexpression of an elongase gene involved in EPA biosynthesis, reaching 5.9- and 12.3-fold greater than the control strain, respectively. Our results together demonstrate the concept of applying combined pulling and pushing strategies to enrich EPA in algal TAG and provide clues for the enrichment of other desired fatty acids in TAG as well.
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Genetic engineering of microalgae for enhanced lipid production. Biotechnol Adv 2021; 52:107836. [PMID: 34534633 DOI: 10.1016/j.biotechadv.2021.107836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 12/24/2022]
Abstract
Microalgae have the potential to become microbial cell factories for lipid production. Their ability to convert sunlight and CO2 into valuable lipid compounds has attracted interest from cosmetic, biofuel, food and feed industries. In order to make microalgae-derived products cost-effective and commercially competitive, enhanced growth rates and lipid productivities are needed, which require optimization of cultivation systems and strain improvement. Advances in genetic tool development and omics technologies have increased our understanding of lipid metabolism, which has opened up possibilities for targeted metabolic engineering. In this review we provide a comprehensive overview on the developments made to genetically engineer microalgal strains over the last 30 years. We focus on the strategies that lead to an increased lipid content and altered fatty acid profile. These include the genetic engineering of the fatty acid synthesis pathway, Kennedy pathway, polyunsaturated fatty acid and triacylglycerol metabolisms and fatty acid catabolism. Moreover, genetic engineering of specific transcription factors, NADPH generation and central carbon metabolism, which lead to increase of lipid accumulation are also reviewed.
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Zhang Y, Ye Y, Bai F, Liu J. The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:119. [PMID: 33992124 PMCID: PMC8126118 DOI: 10.1186/s13068-021-01969-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/07/2021] [Indexed: 05/05/2023]
Abstract
The algal lipids-based biodiesel, albeit having advantages over plant oils, still remains high in the production cost. Co-production of value-added products with lipids has the potential to add benefits and is thus believed to be a promising strategy to improve the production economics of algal biodiesel. Chromochloris zofingiensis, a unicellular green alga, has been considered as a promising feedstock for biodiesel production because of its robust growth and ability of accumulating high levels of triacylglycerol under multiple trophic conditions. This alga is also able to synthesize high-value keto-carotenoids and has been cited as a candidate producer of astaxanthin, the strongest antioxidant found in nature. The concurrent accumulation of triacylglycerol and astaxanthin enables C. zofingiensis an ideal cell factory for integrated production of the two compounds and has potential to improve algae-based production economics. Furthermore, with the advent of chromosome-level whole genome sequence and genetic tools, C. zofingiensis becomes an emerging model for studying lipid metabolism and carotenogenesis. In this review, we summarize recent progress on the production of triacylglycerol and astaxanthin by C. zofingiensis. We also update our understanding in the distinctive molecular mechanisms underlying lipid metabolism and carotenogenesis, with an emphasis on triacylglycerol and astaxanthin biosynthesis and crosstalk between the two pathways. Furthermore, strategies for trait improvements are discussed regarding triacylglycerol and astaxanthin synthesis in C. zofingiensis.
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Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China.
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12
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Overexpression of Type 1 and 2 Diacylglycerol Acyltransferase Genes ( JcDGAT1 and JcDGAT2) Enhances Oil Production in the Woody Perennial Biofuel Plant Jatropha curcas. PLANTS 2021; 10:plants10040699. [PMID: 33916393 PMCID: PMC8066779 DOI: 10.3390/plants10040699] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 03/29/2021] [Accepted: 04/02/2021] [Indexed: 12/19/2022]
Abstract
Diacylglycerol acyltransferase (DGAT) is the only enzyme that catalyzes the acyl-CoA-dependent acylation of sn-1, 2-diacylglycerol (DAG) to form triacylglycerol (TAG). The two main types of DGAT enzymes in the woody perennial biofuel plant Jatropha curcas, JcDGAT1 and JcDGAT2, were previously characterized only in heterologous systems. In this study, we investigated the functions of JcDGAT1 and JcDGAT2 in J. curcas.JcDGAT1 and JcDGAT2 were found to be predominantly expressed during the late stages of J. curcas seed development, in which large amounts of oil accumulated. As expected, overexpression of JcDGAT1 or JcDGAT2 under the control of the CaMV35S promoter gave rise to an increase in seed kernel oil production, reaching a content of 53.7% and 55.7% of the seed kernel dry weight, respectively, which were respectively 25% and 29.6% higher than that of control plants. The increase in seed oil content was accompanied by decreases in the contents of protein and soluble sugars in the seeds. Simultaneously, there was a two- to four-fold higher leaf TAG content in transgenic plants than in control plants. Moreover, by analysis of the fatty acid (FA) profiles, we found that JcDGAT1 and JcDGAT2 had the same substrate specificity with preferences for C18:2 in seed TAGs, and C16:0, C18:0, and C18:1 in leaf TAGs. Therefore, our study confirms the important role of JcDGAT1 and JcDGAT2 in regulating oil production in J. curcas.
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Leyland B, Zarka A, Didi-Cohen S, Boussiba S, Khozin-Goldberg I. High Resolution Proteome of Lipid Droplets Isolated from the Pennate Diatom Phaeodactylum tricornutum (Bacillariophyceae) Strain pt4 provides mechanistic insights into complex intracellular coordination during nitrogen deprivation. JOURNAL OF PHYCOLOGY 2020; 56:1642-1663. [PMID: 32779202 DOI: 10.1111/jpy.13063] [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: 03/30/2020] [Revised: 05/14/2020] [Accepted: 07/12/2020] [Indexed: 05/08/2023]
Abstract
Lipid droplets (LDs) are an organelle conserved amongst all eukaryotes, consisting of a neutral lipid core surrounded by a polar lipid monolayer. Many species of microalgae accumulate LDs in response to stress conditions, such as nitrogen starvation. Here, we report the isolation and proteomic profiling of LD proteins from the model oleaginous pennate diatom Phaeodactylum tricornutum, strain Pt4 (UTEX 646). We also provide a quantitative description of LD morphological ontogeny, and fatty acid content. Novel cell disruption and LD isolation methods, combined with suspension-trapping and nanoflow liquid chromatography coupled to high resolution mass spectrometry, yielded an unprecedented number of LD proteins. Predictive annotation of the LD proteome suggests a broad assemblage of proteins with diverse functions, including lipid metabolism and vesicle trafficking, as well as ribosomal and proteasomal machinery. These proteins provide mechanistic insights into LD processes, and evidence for interactions between LDs and other organelles. We identify for the first time several key steps in diatom LD-associated triacylglycerol biosynthesis. Bioinformatic analyses of the LD proteome suggests multiple protein targeting mechanisms, including amphipathic helices, post-translational modifications, and translocation machinery. This work corroborates recent findings from other strains of P. tricornutum, other diatoms, and other eukaryotic organisms, suggesting that the fundamental proteins orchestrating LDs are conserved, and represent an ancient component of the eukaryotic endomembrane system. We postulate a comprehensive model of nitrogen starvation-induced diatom LDs on a molecular scale, and provide a wealth of candidates for metabolic engineering, with the potential to eventually customize LD contents.
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Affiliation(s)
- Ben Leyland
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Aliza Zarka
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Shoshana Didi-Cohen
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Sammy Boussiba
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
| | - Inna Khozin-Goldberg
- The Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede Boker Campus, Be'er Sheva, 84990, Israel
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Seo S, Kim J, Lee JW, Nam O, Chang KS, Jin E. Enhanced pyruvate metabolism in plastids by overexpression of putative plastidial pyruvate transporter in Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:120. [PMID: 32670407 PMCID: PMC7350735 DOI: 10.1186/s13068-020-01760-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/26/2020] [Accepted: 07/02/2020] [Indexed: 05/10/2023]
Abstract
BACKGROUND The development of microalgal strains for enhanced biomass and biofuel production has received increased attention. Moreover, strain development via metabolic engineering for commercial production is being considered as the most efficient strategy. Pyruvate is an essential metabolite in the cells and plays an essential role in amino acid biosynthesis and de novo fatty acid biosynthesis in plastids. Although pyruvate can be a valuable target for metabolic engineering, its transporters have rarely been studied in microalgae. In this study, we aimed to identify the plastidial pyruvate transporter of Phaeodactylum tricornutum and utilize it for strain development. RESULTS We identified putative pyruvate transporter localized in the plastid membrane of Phaeodactylum tricornutum. Transformants overexpressing the pyruvate transporter were generated to increase the influx of pyruvate into plastids. Overexpression of a plastidial pyruvate transporter in P. tricornutum resulted in enhanced biomass (13.6% to 21.9%), lipid contents (11% to 30%), and growth (3.3% to 8.0%) compared to those of wild type during one-stage cultivation. CONCLUSION To regulate the pyruvate influx and its metabolism in plastids, we generated transformants overexpressing the putative plastidial pyruvate transporter in P. tricornutum. They showed that its overexpression for compartmentalizing pyruvate in plastids could be an attractive strategy for the effective production of biomass and lipids with better growth, via enhanced pyruvate metabolism in plastids.
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Affiliation(s)
- Seungbeom Seo
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763 Republic of Korea
| | - Joon Kim
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763 Republic of Korea
| | - Jun-Woo Lee
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763 Republic of Korea
| | - Onyou Nam
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763 Republic of Korea
| | - Kwang Suk Chang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763 Republic of Korea
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, 04763 Republic of Korea
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Khan S, Fu P. Biotechnological perspectives on algae: a viable option for next generation biofuels. Curr Opin Biotechnol 2020; 62:146-152. [DOI: 10.1016/j.copbio.2019.09.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 10/25/2022]
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Leyland B, Boussiba S, Khozin-Goldberg I. A Review of Diatom Lipid Droplets. BIOLOGY 2020; 9:biology9020038. [PMID: 32098118 PMCID: PMC7168155 DOI: 10.3390/biology9020038] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Revised: 02/12/2020] [Accepted: 02/14/2020] [Indexed: 12/20/2022]
Abstract
The dynamic nutrient availability and photon flux density of diatom habitats necessitate buffering capabilities in order to maintain metabolic homeostasis. This is accomplished by the biosynthesis and turnover of storage lipids, which are sequestered in lipid droplets (LDs). LDs are an organelle conserved among eukaryotes, composed of a neutral lipid core surrounded by a polar lipid monolayer. LDs shield the intracellular environment from the accumulation of hydrophobic compounds and function as a carbon and electron sink. These functions are implemented by interconnections with other intracellular systems, including photosynthesis and autophagy. Since diatom lipid production may be a promising objective for biotechnological exploitation, a deeper understanding of LDs may offer targets for metabolic engineering. In this review, we provide an overview of diatom LD biology and biotechnological potential.
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Butler T, Kapoore RV, Vaidyanathan S. Phaeodactylum tricornutum: A Diatom Cell Factory. Trends Biotechnol 2020; 38:606-622. [PMID: 31980300 DOI: 10.1016/j.tibtech.2019.12.023] [Citation(s) in RCA: 88] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2019] [Revised: 12/17/2019] [Accepted: 12/18/2019] [Indexed: 01/12/2023]
Abstract
A switch from a petroleum-based to a biobased economy requires the capacity to produce both high-value low-volume and low-value high-volume products. Recent evidence supports the development of microalgae-based microbial cell factories with the objective of establishing environmentally sustainable manufacturing solutions. Diatoms display rich diversity and potential in this regard. We focus on Phaeodactylum tricornutum, a pennate diatom that is commonly found in marine ecosystems, and discuss recent trends in developing the diatom chassis for the production of a suite of natural and genetically engineered products. Both upstream and downstream developments are reviewed for the commercial development of P. tricornutum as a cell factory for a spectrum of marketable products.
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Affiliation(s)
- Thomas Butler
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, S1 3JD, UK
| | - Rahul Vijay Kapoore
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, S1 3JD, UK; Present address: Department of Biosciences, College of Science, Swansea University, Swansea, SA2 8PP, UK
| | - Seetharaman Vaidyanathan
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield, S1 3JD, UK.
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Haslam RP, Hamilton ML, Economou CK, Smith R, Hassall KL, Napier JA, Sayanova O. Overexpression of an endogenous type 2 diacylglycerol acyltransferase in the marine diatom Phaeodactylum tricornutum enhances lipid production and omega-3 long-chain polyunsaturated fatty acid content. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:87. [PMID: 32467729 PMCID: PMC7227059 DOI: 10.1186/s13068-020-01726-8] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 05/08/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Oleaginous microalgae represent a valuable resource for the production of high-value molecules. Considering the importance of omega-3 long-chain polyunsaturated fatty acids (LC-PUFAs) for human health and nutrition the yields of high-value eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) require significant improvement to meet demand; however, the current cost of production remains high. A promising approach is to metabolically engineer strains with enhanced levels of triacylglycerols (TAGs) enriched in EPA and DHA. RESULTS Recently, we have engineered the marine diatom Phaeodactylum tricornutum to accumulate enhanced levels of DHA in TAG. To further improve the incorporation of omega-3 LC-PUFAs in TAG, we focused our effort on the identification of a type 2 acyl-CoA:diacylglycerol acyltransferase (DGAT) capable of improving lipid production and the incorporation of DHA in TAG. DGAT is a key enzyme in lipid synthesis. Following a diatom based in vivo screen of candidate DGATs, a native P. tricornutum DGAT2B was taken forward for detailed characterisation. Overexpression of the endogenous P. tricornutum DGAT2B was confirmed by qRT-PCR and the transgenic strain grew successfully in comparison to wildtype. PtDGAT2B has broad substrate specificity with preferences for C16 and LC-PUFAs acyl groups. Moreover, the overexpression of an endogenous DGAT2B resulted in higher lipid yields and enhanced levels of DHA in TAG. Furthermore, a combined overexpression of the endogenous DGAT2B and ectopic expression of a Δ5-elongase showed how iterative metabolic engineering can be used to increase DHA and TAG content, irrespective of nitrogen treatment. CONCLUSION This study provides further insight into lipid metabolism in P. tricornutum and suggests a metabolic engineering approach for the efficient production of EPA and DHA in microalgae.
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Affiliation(s)
- Richard P. Haslam
- Department of Plant Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Mary L. Hamilton
- Department of Plant Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
- St Albans Girls School, St Albans, Hertfordshire, AL3 6DB UK
| | - Chloe K. Economou
- Department of Plant Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
- School of Biological and Chemical Sciences, Queen Mary University of London, Mile End Road, London, E1 4NS UK
| | - Richard Smith
- Department of Plant Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
- Algenuity, Eden Laboratory, Broadmead Road, Stewartby, BEDS, Bedford, MK43 9ND UK
| | - Kirsty L. Hassall
- Department of Computational and Analytical Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Johnathan A. Napier
- Department of Plant Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
| | - Olga Sayanova
- Department of Plant Sciences, Rothamsted Research, Harpenden, Herts AL5 2JQ UK
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Maréchal E, Lupette J. Relationship between acyl-lipid and sterol metabolisms in diatoms. Biochimie 2019; 169:3-11. [PMID: 31291593 DOI: 10.1016/j.biochi.2019.07.005] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2019] [Accepted: 07/05/2019] [Indexed: 12/22/2022]
Abstract
Diatoms are a phylum of unicellular photosynthetic eukaryotes living in oceans and fresh waters, characterized by the complexity of their plastid, resulting from a secondary endosymbiosis event. In the model diatom Phaeodactylum tricornutum, fatty acids (FAs) are synthesized from acetyl-CoA in the stroma of the plastid, producing palmitic acid. FAs are elongated and desaturated to form very-long chain polyunsaturated fatty acids (VLC-PUFAs) in domains of the endomembrane system that need to be identified. Synthesis of VLC-PUFAs is coupled with their import to the core of the plastid via the so-called "omega" pathway. The biosynthesis of sterols in diatoms is likely to be localized in the endoplasmic reticulum as well as using precursors deriving from the mevalonate pathway, using acetyl-CoA as initial substrate. These metabolic modules can be characterized functionally by genetic analyzes or chemical treatments with appropriate inhibitors. Some 'metabolic modules' are characterized by a very low level of metabolic intermediates. Since some chemical treatments or genetic perturbation of lipid metabolism induce the accumulation of these intermediates, channeling processes are possibly involved, suggesting that protein-protein interactions might occur between enzymes within large size complexes or metabolons. At the junction of these modules, metabolic intermediates might therefore play dramatic roles in directing carbon fluxes from one direction to another. Here, acetyl-CoA seems determinant in the balance between TAGs and sterols. Future lines of research and potential utilization for biotechnological applications are discussed.
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Affiliation(s)
- Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale, CNRS, CEA, INRA, Université Grenoble Alpes, Institut de Recherche Interdisciplinaire de Grenoble, CEA Grenoble, 17 avenue des Martyrs, 38000, Grenoble, France
| | - Josselin Lupette
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, 48824, USA.
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20
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Liu J, Sun Z, Mao X, Gerken H, Wang X, Yang W. Multiomics analysis reveals a distinct mechanism of oleaginousness in the emerging model alga Chromochloris zofingiensis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1060-1077. [PMID: 30828893 DOI: 10.1111/tpj.14302] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Chromochloris zofingiensis, featured due to its capability to simultaneously synthesize triacylglycerol (TAG) and astaxanthin, is emerging as a leading candidate alga for production uses. To better understand the oleaginous mechanism of this alga, we conducted a multiomics analysis by systematically integrating time-resolved transcriptomes, lipidomes and metabolomes in response to nitrogen deprivation. The data analysis unraveled the distinct mechanism of TAG accumulation, which involved coordinated stimulation of multiple biological processes including supply of energy and reductants, carbon reallocation from protein and starch, and 'pushing' and 'pulling' carbon to TAG synthesis. Unlike the model alga Chlamydomonas, de novo fatty acid synthesis in C. zofingiensis was promoted, together with enhanced turnover of both glycolipids and phospholipids, supporting the drastic need of acyls for TAG assembly. Moreover, genomewide analysis identified many key functional enzymes and transcription factors that had engineering potential for TAG modulation. Two genes encoding glycerol-3-phosphate acyltransferase (GPAT), the first committed enzyme for TAG assembly, were found in the C. zofingiensis genome; in vivo functional characterization revealed that extrachloroplastic GPAT instead of chloroplastic GPAT played a central role in TAG synthesis. These findings illuminate distinct oleaginousness mechanisms in C. zofingiensis and pave the way towards rational manipulation of this alga to becone an emerging model for trait improvements.
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Affiliation(s)
- Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Zheng Sun
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Henri Gerken
- School of Sustainable Engineering and the Built Environment, Arizona State University Polytechnic campus, Mesa, AZ, 85212, USA
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Wenqiang Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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21
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Bt Md Nasir NAN, Islam AKMA, Anuar N, Yaakob Z. Genetic Improvement and Challenges for Cultivation of Microalgae for Biodiesel: A Review. MINI-REV ORG CHEM 2019. [DOI: 10.2174/1570193x15666180627115502] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Microalgae are a viable alternative for biofuel production to replace the world dependency on
fossil fuel. It has a wide range of application for the sustainable production of biomaterials. Microalgae
can convert solar energy into important natural components by utilizing marginal nutrients, wastewater
and exhaust CO2 without sharing expensive crop field. Microalgae also have the potentiality to generate
several promising components such as Polyunsaturated Fatty Acids (PUFAs), organic pigments and
pharmaceutically important hydrocarbons. Cultivation and production of microalgae biomass have multifaceted
challenges due to the requirement of large volume of water for the algae growth, high processing
cost and contamination by pathogens. Genetic improvement and modifications are essential to
construct superior microalgae for manufacturing industries using various methods such as selection of
novel strain, stress tolerance, resistance to pathogens, product development and metabolic pathways and
cellular contents. In addition, technologies related to cultivation, harvesting, extraction and processing
are essential to develop for the growth of novel microalgae strains.
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Affiliation(s)
- Nor-Anis N. Bt Md Nasir
- Department of Plant Science, Kulliyyah of Science, International Islamic University Malaysia, Kuantan Kampus, 25710, Kuantan, Pahang Darul Makmur, Malaysia
| | - A. K. M. Aminul Islam
- Department of Genetics and Plant Breeding, Faculty of Agriculture, Bangabandhu Sheikh Mujibur Rahman Agricultural University, Gazipur 1706, Bangladesh
| | - Nurina Anuar
- Department of Chemical and Process Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, 43600, Malaysia
| | - Zahira Yaakob
- Department of Chemical and Process Engineering, Faculty of Engineering & Built Environment, Universiti Kebangsaan Malaysia (UKM), Bangi, Selangor, 43600, Malaysia
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22
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Muñoz CF, Weusthuis RA, D’Adamo S, Wijffels RH. Effect of Single and Combined Expression of Lysophosphatidic Acid Acyltransferase, Glycerol-3-Phosphate Acyltransferase, and Diacylglycerol Acyltransferase on Lipid Accumulation and Composition in Neochloris oleoabundans. FRONTIERS IN PLANT SCIENCE 2019; 10:1573. [PMID: 31850043 PMCID: PMC6895027 DOI: 10.3389/fpls.2019.01573] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2019] [Accepted: 11/11/2019] [Indexed: 05/03/2023]
Abstract
Microalgal lipids are promising feedstocks for food and biofuels. Since lipid production by microalgae is not yet economically feasible, genetic engineering is becoming a promising strategy to achieve higher lipid accumulation and productivities. Enzymes involved in the Kennedy pathway such as glycerol-3-phosphate acyltransferase (GPAT), lysophosphatidic acid acyltransferase (LPAT), and diacylglycerol acyltransferase (DGAT) catalyze key steps in the formation of triacylglycerol, which is the main constituent of lipids in N. oleoabundans. The overexpression of these enzymes in the targeted strain has a great potential to further increase their triacylglycerol content. We overexpressed single and multiple encoding genes for LPAT, GPAT, and DGAT from Acutodesmus obliquus in N. oleoabundans. Strains overexpressing single genes produced up to 52% and 45% g · gDW-1, which corresponds to 1.3- and 1.4-fold increase in total fatty acids and triacylglycerols, respectively. The orchestrated expression of the three genes resulted in 49% and 39% g · gDW-1, which is 1.2-folds increase in total fatty acids and triacylglycerols. Single expression of LPAT, GPAT, and DGAT genes resulted in higher lipid productivities during starvation without a significant effect on growth and photosynthetic activity during replete conditions. On the other hand, the simultaneous expression of LPAT, GPAT, and DGAT genes resulted in 52% lower growth rate, 14% lower photosynthetic activity and 4-folds increase in cell diameter. Moreover, the multigene expressing line showed a decrease in carbohydrates and protein content and an increase in pigments during nitrogen starved condition. The single and multiple expression of heterologous genes LPAT, GPAT, and DGAT showed to significantly enhanced the lipid accumulation in N. oleoabundans. Single gene expression resulted in higher lipid production and productivities without having a significant impact in the physiological status of the strains. This approach shows the potential for the generation of microalgal strains with higher economical potential for the production of lipids.
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Affiliation(s)
- Camilo F. Muñoz
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
- *Correspondence: Camilo F. Muñoz,
| | - Ruud A. Weusthuis
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
| | - Sarah D’Adamo
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
| | - René H. Wijffels
- Bioprocess Engineering, Wageningen University and Research, Wageningen, Netherlands
- Biosciences and Aquaculture, Nord University, Bodø, Norway
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Remmers IM, D'Adamo S, Martens DE, de Vos RC, Mumm R, America AH, Cordewener JH, Bakker LV, Peters SA, Wijffels RH, Lamers PP. Orchestration of transcriptome, proteome and metabolome in the diatom Phaeodactylum tricornutum during nitrogen limitation. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.08.012] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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24
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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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Wang X, Wei W, Li NJ, Yuan W, Ding Y, Yang WD, Liu JS, Balamurugan S, Li HY. Heterogeneous expression of human PNPLA3 triggers algal lipid accumulation and lipid droplet enlargement. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
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26
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Zulu NN, Zienkiewicz K, Vollheyde K, Feussner I. Current trends to comprehend lipid metabolism in diatoms. Prog Lipid Res 2018. [DOI: 10.1016/j.plipres.2018.03.001] [Citation(s) in RCA: 104] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
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27
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Rengel R, Smith RT, Haslam RP, Sayanova O, Vila M, León R. Overexpression of acetyl-CoA synthetase (ACS) enhances the biosynthesis of neutral lipids and starch in the green microalga Chlamydomonas reinhardtii. ALGAL RES 2018. [DOI: 10.1016/j.algal.2018.02.009] [Citation(s) in RCA: 67] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Huete-Ortega M, Okurowska K, Kapoore RV, Johnson MP, Gilmour DJ, Vaidyanathan S. Effect of ammonium and high light intensity on the accumulation of lipids in Nannochloropsis oceanica (CCAP 849/10) and Phaeodactylum tricornutum (CCAP 1055/1). BIOTECHNOLOGY FOR BIOFUELS 2018; 11:60. [PMID: 29541157 PMCID: PMC5844138 DOI: 10.1186/s13068-018-1061-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 02/23/2018] [Indexed: 06/09/2023]
Abstract
BACKGROUND Microalgae accumulate lipids when exposed to stressful conditions such as nutrient limitation that can be used to generate biofuels. Nitrogen limitation or deprivation is a strategy widely employed to elicit this response. However, this strategy is associated with a reduction in the microalgal growth, leading to overall poor lipid productivities. Here, we investigated the combined effect of a reduced source of nitrogen (ammonium) and super-saturating light intensities on the growth and induction of lipid accumulation in two model but diverse microalgal species, Phaeodactylum tricornutum and Nannochloropsis oceanica. We hypothesized that the lower energy cost of assimilating ammonium would allow the organisms to use more reductant power for lipid biosynthesis without compromising growth and that this would be further stimulated by the effect of high light (1000 µmol m-2 s-1) stress. We studied the changes in growth and physiology of both species when grown in culture media that either contained nitrate or ammonium as the nitrogen source, and an additional medium that contained ammonium with tungsten in place of molybdenum and compared this with growth in media without nitrogen. We focused our investigation on the early stages of exposure to the treatments to correspond to events relevant to induction of lipid accumulation in these two species. RESULTS At super-saturating light intensities, lipid productivity in P. tricornutum increased twofold when grown in ammonium compared to nitrogen free medium that increased further when tungsten was present in the medium in place of molybdenum. Conversely, N. oceanica growth and physiology was not compromised by the high light intensities used, and the use of ammonium had a negative effect on the lipid productivity, which was even more marked when tungsten was present. CONCLUSIONS Whilst the use of ammonium and super-saturating light intensities in P. tricornutum was revealed to be a good strategy for increasing lipid biosynthesis, no changes in the lipid productivity of N. oceanica were observed, under these conditions. Both results provide relevant direction for the better design of processes to produce biofuels in microalgae by manipulating growth conditions without the need to subject them to genetic engineering manipulation.
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Affiliation(s)
- María Huete-Ortega
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, UK
| | - Katarzyna Okurowska
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
| | - Rahul Vijay Kapoore
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
| | - Matthew P. Johnson
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - D. James Gilmour
- Department of Molecular Biology and Biotechnology, The University of Sheffield, Firth Court, Western Bank, Sheffield, UK
| | - Seetharaman Vaidyanathan
- Department of Chemical and Biological Engineering, Advanced Biomanufacturing Centre, The University of Sheffield, Sir Robert Hadfield Building, Mappin Street, Sheffield, UK
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Cheah YE, Young JD. Isotopically nonstationary metabolic flux analysis (INST-MFA): putting theory into practice. Curr Opin Biotechnol 2018. [PMID: 29522915 DOI: 10.1016/j.copbio.2018.02.013] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Typically, 13C flux analysis relies on assumptions of both metabolic and isotopic steady state. If metabolism is steady but isotope labeling is not allowed to fully equilibrate, isotopically nonstationary metabolic flux analysis (INST-MFA) can be used to estimate fluxes. This requires solution of differential equations that describe the time-dependent labeling of network metabolites, while iteratively adjusting the flux and pool size parameters to match the transient labeling measurements. INST-MFA holds a number of unique advantages over approaches that rely solely upon steady-state isotope enrichments. First, INST-MFA can be applied to estimate fluxes in autotrophic systems, which consume only single-carbon substrates. Second, INST-MFA is ideally suited to systems that label slowly due to the presence of large intermediate pools or pathway bottlenecks. Finally, INST-MFA provides increased measurement sensitivity to estimate reversible exchange fluxes and metabolite pool sizes, which represents a potential framework for integrating metabolomic analysis with 13C flux analysis. This review highlights the unique capabilities of INST-MFA, describes newly available software tools that automate INST-MFA calculations, presents several practical examples of recent INST-MFA applications, and discusses the technical challenges that lie ahead.
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Affiliation(s)
- Yi Ern Cheah
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, PMB 351604, Nashville, TN 37235-1604, USA
| | - Jamey D Young
- Department of Chemical and Biomolecular Engineering, Vanderbilt University, PMB 351604, Nashville, TN 37235-1604, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University, PMB 351604, Nashville, TN 37235-1604, USA.
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Vuppaladadiyam AK, Yao JG, Florin N, George A, Wang X, Labeeuw L, Jiang Y, Davis RW, Abbas A, Ralph P, Fennell PS, Zhao M. Impact of Flue Gas Compounds on Microalgae and Mechanisms for Carbon Assimilation and Utilization. CHEMSUSCHEM 2018; 11:334-355. [PMID: 29165921 DOI: 10.1002/cssc.201701611] [Citation(s) in RCA: 45] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/23/2017] [Indexed: 06/07/2023]
Abstract
To shift the world to a more sustainable future, it is necessary to phase out the use of fossil fuels and focus on the development of low-carbon alternatives. However, this transition has been slow, so there is still a large dependence on fossil-derived power, and therefore, carbon dioxide is released continuously. Owing to the potential for assimilating and utilizing carbon dioxide to generate carbon-neutral products, such as biodiesel, the application of microalgae technology to capture CO2 from flue gases has gained significant attention over the past decade. Microalgae offer a more sustainable source of biomass, which can be converted into energy, over conventional fuel crops because they grow more quickly and do not adversely affect the food supply. This review focuses on the technical feasibility of combined carbon fixation and microalgae cultivation for carbon reuse. A range of different carbon metabolisms and the impact of flue gas compounds on microalgae are appraised. Fixation of flue gas carbon dioxide is dependent on the selected microalgae strain and on flue gas compounds/concentrations. Additionally, current pilot-scale demonstrations of microalgae technology for carbon dioxide capture are assessed and its future prospects are discussed. Practical implementation of this technology at an industrial scale still requires significant research, which necessitates multidisciplinary research and development to demonstrate its viability for carbon dioxide capture from flue gases at the commercial level.
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Affiliation(s)
| | - Joseph G Yao
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
| | - Nicholas Florin
- Institute for Sustainable Futures, University of Technology Sydney, Sydney, 2007, NSW, Australia
| | - Anthe George
- Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Xiaoxiong Wang
- School of Environment, Tsinghua University, Beijing, 100084, PR China
| | - Leen Labeeuw
- Climate Change Cluster, University of Technology Sydney, Sydney, 2007, NSW, Australia
| | - Yuelu Jiang
- Institute of Ocean Science and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, PR China
| | - Ryan W Davis
- Sandia National Laboratories, Livermore, CA, 94551, USA
| | - Ali Abbas
- School of Chemical & Biomolecular Engineering, The University of Sydney, Sydney, NSW, 2006, Australia
| | - Peter Ralph
- Climate Change Cluster, University of Technology Sydney, Sydney, 2007, NSW, Australia
| | - Paul S Fennell
- Department of Chemical Engineering, Imperial College London, London, SW7 2AZ, UK
- Current address: Joint Bioenergy Institute, 5885 Hollis St, Emeryville, CA, 94608, USA
| | - Ming Zhao
- School of Environment, Tsinghua University, Beijing, 100084, PR China
- Key Laboratory for Solid Waste Management and Environmental Safety, Ministry of Education, Beijing, 100084, PR China
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Lim DKY, Schuhmann H, Thomas-Hall SR, Chan KCK, Wass TJ, Aguilera F, Adarme-Vega TC, Dal'Molin CGO, Thorpe GJ, Batley J, Edwards D, Schenk PM. RNA-Seq and metabolic flux analysis of Tetraselmis sp. M8 during nitrogen starvation reveals a two-stage lipid accumulation mechanism. BIORESOURCE TECHNOLOGY 2017; 244:1281-1293. [PMID: 28625352 DOI: 10.1016/j.biortech.2017.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Revised: 05/31/2017] [Accepted: 06/01/2017] [Indexed: 05/18/2023]
Abstract
To map out key lipid-related pathways that lead to rapid triacylglyceride accumulation in oleaginous microalgae, RNA-Seq was performed with Tetraselmis sp. M8 at 24h after exhaustion of exogenous nitrogen to reveal molecular changes during early stationary phase. Further gene expression profiling by quantitative real-time PCR at 16-72h revealed a distinct shift in expression of the fatty acid/triacylglyceride biosynthesis and β-oxidation pathways, when cells transitioned from log-phase into early-stationary and stationary phase. Metabolic reconstruction modeling combined with real-time PCR and RNA-Seq gene expression data indicates that the increased lipid accumulation is a result of a decrease in lipid catabolism during the early-stationary phase combined with increased metabolic fluxes in lipid biosynthesis during the stationary phase. During these two stages, Tetraselmis shifts from reduced lipid consumption to active lipid production. This process appears to be independent from DGAT expression, a key gene for lipid accumulation in microalgae.
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Affiliation(s)
- David K Y Lim
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Holger Schuhmann
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Skye R Thomas-Hall
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Kenneth C K Chan
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia; School of Plant Biology, The University of Western Australia, Perth 6009, Australia
| | - Taylor J Wass
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Felipe Aguilera
- School of Biological Sciences, The University of Queensland, Brisbane 4072, Australia
| | - T Catalina Adarme-Vega
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia
| | - Cristiana G O Dal'Molin
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane 4072, Australia
| | - Glen J Thorpe
- Australian Institute for Bioengineering and Nanotechnology, The University of Queensland, Brisbane 4072, Australia
| | - Jacqueline Batley
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia; School of Plant Biology, The University of Western Australia, Perth 6009, Australia
| | - David Edwards
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia; School of Plant Biology, The University of Western Australia, Perth 6009, Australia
| | - Peer M Schenk
- School of Agriculture and Food Sciences, The University of Queensland, Brisbane 4072, Australia.
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Gruber A, Kroth PG. Intracellular metabolic pathway distribution in diatoms and tools for genome-enabled experimental diatom research. Philos Trans R Soc Lond B Biol Sci 2017; 372:20160402. [PMID: 28717012 PMCID: PMC5516111 DOI: 10.1098/rstb.2016.0402] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/21/2017] [Indexed: 11/12/2022] Open
Abstract
Diatoms are important primary producers in the oceans and can also dominate other aquatic habitats. One reason for the success of this phylogenetically relatively young group of unicellular organisms could be the impressive redundancy and diversity of metabolic isoenzymes in diatoms. This redundancy is a result of the evolutionary origin of diatom plastids by a eukaryote-eukaryote endosymbiosis, a process that implies temporary redundancy of functionally complete eukaryotic genomes. During the establishment of the plastids, this redundancy was partially reduced via gene losses, and was partially retained via gene transfer to the nucleus of the respective host cell. These gene transfers required re-assignment of intracellular targeting signals, a process that simultaneously altered the intracellular distribution of metabolic enzymes compared with the ancestral cells. Genome annotation, the correct assignment of the gene products and the prediction of putative function, strongly depends on the correct prediction of the intracellular targeting of a gene product. Here again diatoms are very peculiar, because the targeting systems for organelle import are partially different to those in land plants. In this review, we describe methods of predicting intracellular enzyme locations, highlight findings of metabolic peculiarities in diatoms and present genome-enabled approaches to study their metabolism.This article is part of the themed issue 'The peculiar carbon metabolism in diatoms'.
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Affiliation(s)
- Ansgar Gruber
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
| | - Peter G Kroth
- Fachbereich Biologie, Universität Konstanz, 78457 Konstanz, Germany
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33
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A chemical approach to manipulate the algal growth, lipid content and high-value alpha-linolenic acid for biodiesel production. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.08.016] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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Zulu NN, Popko J, Zienkiewicz K, Tarazona P, Herrfurth C, Feussner I. Heterologous co-expression of a yeast diacylglycerol acyltransferase ( ScDGA1) and a plant oleosin ( AtOLEO3) as an efficient tool for enhancing triacylglycerol accumulation in the marine diatom Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2017; 10:187. [PMID: 28725267 PMCID: PMC5514505 DOI: 10.1186/s13068-017-0874-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/11/2017] [Indexed: 05/03/2023]
Abstract
BACKGROUND Microalgae are promising alternate and renewable sources for producing valuable products such as biofuel and essential fatty acids. Although this is the case, there are still challenges impeding on the effective commercial production of microalgal products. For instance, their product yield is still too low. Therefore, this study was oriented towards enhancing triacylglycerol (TAG) accumulation in the diatom Phaeodactylum tricornutum (strain Pt4). To achieve this, a type 2 acyl-CoA:diacylglycerol acyltransferase from yeast (ScDGA1) and the lipid droplet (LD) stabilizing oleosin protein 3 from Arabidopsis thaliana (AtOLEO3) were expressed in Pt4. RESULTS The individual expression of ScDGA1 and AtOLEO3 in Pt4 resulted in a 2.3- and 1.4-fold increase in TAG levels, respectively, in comparison to the wild type. The co-expression of both, ScDGA1 and AtOLEO3, was accompanied by a 3.6-fold increase in TAG content. On the cellular level, the lines co-expressing ScDGA1 and AtOLEO3 showed the presence of the larger and increased numbers of lipid droplets when compared to transformants expressing single genes and an empty vector. Under nitrogen stress, TAG productivity was further increased twofold in comparison to nitrogen-replete conditions. While TAG accumulation was enhanced in the analyzed transformants, the fatty acid composition remained unchanged neither in the total lipid nor in the TAG profile. CONCLUSIONS The co-expression of two genes was shown to be a more effective strategy for enhancing TAG accumulation in P. tricornutum strain Pt4 than a single gene strategy. For the first time in a diatom, a LD protein from a vascular plant, oleosin, was shown to have an impact on TAG accumulation and on LD organization.
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Affiliation(s)
- Nodumo Nokulunga Zulu
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
- Novagreen Projektmanagement GmbH, 49377 Vechta, Germany
| | - Jennifer Popko
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Krzysztof Zienkiewicz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Pablo Tarazona
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Cornelia Herrfurth
- 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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35
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Zulu NN, Popko J, Zienkiewicz K, Tarazona P, Herrfurth C, Feussner I. Heterologous co-expression of a yeast diacylglycerol acyltransferase ( ScDGA1) and a plant oleosin ( AtOLEO3) as an efficient tool for enhancing triacylglycerol accumulation in the marine diatom Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2017. [PMID: 28725267 DOI: 10.1186/s13068-017-0874] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
BACKGROUND Microalgae are promising alternate and renewable sources for producing valuable products such as biofuel and essential fatty acids. Although this is the case, there are still challenges impeding on the effective commercial production of microalgal products. For instance, their product yield is still too low. Therefore, this study was oriented towards enhancing triacylglycerol (TAG) accumulation in the diatom Phaeodactylum tricornutum (strain Pt4). To achieve this, a type 2 acyl-CoA:diacylglycerol acyltransferase from yeast (ScDGA1) and the lipid droplet (LD) stabilizing oleosin protein 3 from Arabidopsis thaliana (AtOLEO3) were expressed in Pt4. RESULTS The individual expression of ScDGA1 and AtOLEO3 in Pt4 resulted in a 2.3- and 1.4-fold increase in TAG levels, respectively, in comparison to the wild type. The co-expression of both, ScDGA1 and AtOLEO3, was accompanied by a 3.6-fold increase in TAG content. On the cellular level, the lines co-expressing ScDGA1 and AtOLEO3 showed the presence of the larger and increased numbers of lipid droplets when compared to transformants expressing single genes and an empty vector. Under nitrogen stress, TAG productivity was further increased twofold in comparison to nitrogen-replete conditions. While TAG accumulation was enhanced in the analyzed transformants, the fatty acid composition remained unchanged neither in the total lipid nor in the TAG profile. CONCLUSIONS The co-expression of two genes was shown to be a more effective strategy for enhancing TAG accumulation in P. tricornutum strain Pt4 than a single gene strategy. For the first time in a diatom, a LD protein from a vascular plant, oleosin, was shown to have an impact on TAG accumulation and on LD organization.
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Affiliation(s)
- Nodumo Nokulunga Zulu
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
- Novagreen Projektmanagement GmbH, 49377 Vechta, Germany
| | - Jennifer Popko
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Krzysztof Zienkiewicz
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Pablo Tarazona
- Department of Plant Biochemistry, Albrecht-von-Haller-Institute for Plant Sciences, University of Goettingen, 37077 Goettingen, Germany
| | - Cornelia Herrfurth
- 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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