1
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Sun K, Meesapyodsuk D, Qiu X. Biosynthetic mechanisms of omega-3 polyunsaturated fatty acids in microalgae. J Biol Chem 2024:107699. [PMID: 39173949 DOI: 10.1016/j.jbc.2024.107699] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2024] [Revised: 08/08/2024] [Accepted: 08/12/2024] [Indexed: 08/24/2024] Open
Abstract
Marine microalgae are the primary producers of ω3 polyunsaturated fatty acids (PUFAs), such as octadecapentaenoic acid (OPA, 18:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) for food chains. However, the biosynthetic mechanisms of these PUFAs in the algae remain elusive. To study how these fatty acids are synthesized in microalgae, a series of radiolabeled precursors were used to trace the biosynthetic process of PUFAs in Emiliania huxleyi. Feeding the alga with 14C-labeled acetic acid in a time course showed that OPA was solely found in glycoglycerolipids such as monogalactosyldiacylglycerol (MGDG) and digalactosyldiacylglycerol (DGDG) synthesized plastidically by sequential desaturations while DHA was exclusively found in phospholipids synthesized extraplastidically. Feeding the alga with 14C-labeled α-linolenic acid (ALA), linoleic acid (LA) and oleic acid (OA) showed that DHA was synthesized extraplastidically from fed ALA and LA, but not from OA, implying that the aerobic pathway of DHA biosynthesis is incomplete with missing a Δ12 desaturation step. The in vitro enzymatic assays with 14C-labeled malonyl-CoA showed that DHA was synthesized from acetic acid by a PUFA synthase. These results provide the first and conclusive biochemistry evidence that OPA is synthesized by a plastidic aerobic pathway through sequential desaturations with the last step of Δ3 desaturation, while DHA is synthesized by an extraplastidic anaerobic pathway catalyzed by a PUFA synthase in the microalga.
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Affiliation(s)
- Kaiwen Sun
- Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada
| | | | - Xiao Qiu
- Department of Food & Bioproduct Sciences, University of Saskatchewan, Saskatoon, Saskatchewan, S7N 5A8, Canada.
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2
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Ishikawa T, Domergue F, Amato A, Corellou F. Characterization of Unique Eukaryotic Sphingolipids with Temperature-Dependent Δ8-Unsaturation from the Picoalga Ostreococcus tauri. PLANT & CELL PHYSIOLOGY 2024; 65:1029-1046. [PMID: 38252418 DOI: 10.1093/pcp/pcae007] [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: 09/20/2023] [Revised: 11/28/2023] [Accepted: 01/18/2024] [Indexed: 01/23/2024]
Abstract
Sphingolipids (SLs) are ubiquitous components of eukaryotic cell membranes and are found in some prokaryotic organisms and viruses. They are composed of a sphingoid backbone that may be acylated and glycosylated. Assembly of various sphingoid base, fatty acyl and glycosyl moieties results in highly diverse structures. The functional significance of variations in SL chemical diversity and abundance is still in the early stages of investigation. Among SL modifications, Δ8-desaturation of the sphingoid base occurs only in plants and fungi. In plants, SL Δ8-unsaturation is involved in cold hardiness. Our knowledge of the structure and functions of SLs in microalgae lags far behind that of animals, plants and fungi. Original SL structures have been reported from microalgae. However, functional studies are still missing. Ostreococcus tauri is a minimal microalga at the base of the green lineage and is therefore a key organism for understanding lipid evolution. In the present work, we achieved the detailed characterization of O. tauri SLs and unveiled unique glycosylceramides as sole complex SLs. The head groups are reminiscent of bacterial SLs, as they contain hexuronic acid residues and can be polyglycosylated. Ceramide backbones show a limited variety, and SL modification is restricted to Δ8-unsaturation. The Δ8-SL desaturase from O. tauri only produced E isomers. Expression of both Δ8-SL desaturase and Δ8-unsaturation of sphingolipids varied with temperature, with lower levels at 24°C than at 14°C. Overexpression of the Δ8-SL desaturase dramatically increases the level of Δ8 unsaturation at 24°C and is paralleled by a failure to increase cell size. Our work provides the first characterization of O. tauri SLs and functional evidence for the involvement of SL Δ8-unsaturation for temperature acclimation in microalgae, suggesting that this function is an ancestral feature in the green lineage.
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Affiliation(s)
- Toshiki Ishikawa
- Graduate School of Science and Engineering, Saitama University, 225 Shimo-Okubo, Sakura-ku, Saitama-city, Saitama, 338-8570 Japan
| | - Frédéric Domergue
- Laboratoire de Biogenèse Membranaire, University of Bordeaux, CNRSUMR 5200, Av. Edouard Bourlaux, Villenave d'Ornon 33140, France
| | - Alberto Amato
- Laboratoire de Physiologie Végétale et Cellulaire, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Centre National de la Recherche Scientifique UMR 5168, Université Grenoble Alpes, CEA, IRIG, 17 Av. Des Martyrs, Grenoble 38000, France
| | - Florence Corellou
- Laboratoire de Physiologie Végétale et Cellulaire, Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Centre National de la Recherche Scientifique UMR 5168, Université Grenoble Alpes, CEA, IRIG, 17 Av. Des Martyrs, Grenoble 38000, France
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3
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Dalmia A, Daga P, Datey A, Chakravortty D, Tumaney AW. Biochemical characterization of lipid metabolic genes of Aurantiochytrium limacinum. Int J Biol Macromol 2024; 259:129078. [PMID: 38176490 DOI: 10.1016/j.ijbiomac.2023.129078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2023] [Revised: 11/23/2023] [Accepted: 12/18/2023] [Indexed: 01/06/2024]
Abstract
Docosahexaenoic acid (DHA) is known to have numerous health benefits and immense dietary value. There is a pressing need to have a deeper understanding of DHA metabolism. Acyl CoA: Diacylglycerol Acyltransferase (DGAT) is an important enzyme of lipid anabolism and an essential piece of the puzzle. Aurantiochytrium limacinum, a primary producer of DHA, is a good model for studying DHA metabolism. Thus, we aimed to investigate important lipid metabolic genes from A. limacinum. We cloned four putative DGATs (DGAT2a, DGAT2b, DGAT2c, and DGAT2d) from A. limacinum and performed detailed in vivo and in vitro characterization. Functional characterization showed that not all the studied genes exhibited DGAT activity. DGAT2a and DGAT2d conferred DGAT activity whereas DGAT2b showed wax synthase (WS) activity and DGAT2c showed dual function of both WS and DGAT. Based on their identified function, DGAT2b and DGAT2c were renamed as AlWS and AlWS/DGAT respectively. DGAT2a was found to exhibit a preference for DHA as a substrate. DGAT2d was found to have robust activity and emerged as a promising candidate for genetic engineering aimed at increasing oil yield. The study enriches our knowledge of lipid biosynthetic enzymes in A. limacinum, which can be utilized to design suitable application strategies.
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Affiliation(s)
- Ayushi Dalmia
- Department of Lipid Science, Council of Scientific and Industrial Research - Central Food Technological Research Institute, Mysore 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Palak Daga
- Department of Lipid Science, Council of Scientific and Industrial Research - Central Food Technological Research Institute, Mysore 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India
| | - Akshay Datey
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Dipshikha Chakravortty
- Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore 560012, India
| | - Ajay W Tumaney
- Department of Lipid Science, Council of Scientific and Industrial Research - Central Food Technological Research Institute, Mysore 570020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201002, India; Department of Biochemistry, School of Life Sciences, University of Hyderabad, Hyderabad 500046, India.
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4
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Han L, Silvestre S, Sayanova O, Haslam RP, Napier JA. Using field evaluation and systematic iteration to rationalize the accumulation of omega-3 long-chain polyunsaturated fatty acids in transgenic Camelina sativa. PLANT BIOTECHNOLOGY JOURNAL 2022; 20:1833-1852. [PMID: 35656640 PMCID: PMC9398312 DOI: 10.1111/pbi.13867] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 05/26/2022] [Accepted: 05/27/2022] [Indexed: 06/15/2023]
Abstract
The Brassicaceae Camelina sativa (gold of pleasure) is now an established niche crop and being used as a transgenic host for a range of novel seed traits. Most notable of these is the accumulation of omega-3 long-chain polyunsaturates such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), fatty acids normally only found in marine organisms. As part of continued efforts to optimize the accumulation of these non-native fatty acids via seed-specific expression of algal genes, a new series of iterative constructs was built and introduced into Camelina. Seed fatty acid composition was determined, and the presence of EPA and DHA was confirmed. To provide an additional level of evaluation, full environmental release was carried out on selected events, providing a real-world gauntlet against which to assess the performance of these novel lines. Composition of the seed oil triacylglycerol was determined by mass spectrometry, allowing for conclusions as to the contribution of different activities to the final accumulation of EPA and DHA. Since these data were derived from field-grown material, they also represent a robust demonstration of the stability of the omega-3 LC-PUFA trait in Camelina. We propose that field trialling should be routinely incorporated in the plant synthetic biology 'design-build-test-learn' cycle.
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Affiliation(s)
- Lihua Han
- Plant SciencesRothamsted ResearchHarpenden, HertsUK
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5
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Zhuang XY, Zhang YH, Xiao AF, Zhang AH, Fang BS. Key Enzymes in Fatty Acid Synthesis Pathway for Bioactive Lipids Biosynthesis. Front Nutr 2022; 9:851402. [PMID: 35284441 PMCID: PMC8905437 DOI: 10.3389/fnut.2022.851402] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Accepted: 01/25/2022] [Indexed: 11/13/2022] Open
Abstract
Dietary bioactive lipids, one of the three primary nutrients, is not only essential for growth and provides nutrients and energy for life's activities but can also help to guard against disease, such as Alzheimer's and cardiovascular diseases, which further strengthen the immune system and maintain many body functions. Many microorganisms, such as yeast, algae, and marine fungi, have been widely developed for dietary bioactive lipids production. These biosynthetic processes were not limited by the climate and ground, which are also responsible for superiority of shorter periods and high conversion rate. However, the production process was also exposed to the challenges of low stability, concentration, and productivity, which was derived from the limited knowledge about the critical enzyme in the metabolic pathway. Fortunately, the development of enzymatic research methods provides powerful tools to understand the catalytic process, including site-specific mutagenesis, protein dynamic simulation, and metabolic engineering technology. Thus, we review the characteristics of critical desaturase and elongase involved in the fatty acids' synthesis metabolic pathway, which aims to not only provide extensive data for enzyme rational design and modification but also provides a more profound and comprehensive understanding of the dietary bioactive lipids' synthetic process.
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Affiliation(s)
- Xiao-Yan Zhuang
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Yong-Hui Zhang
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - An-Feng Xiao
- College of Food and Biological Engineering, Jimei University, Xiamen, China
| | - Ai-Hui Zhang
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
- *Correspondence: Ai-Hui Zhang
| | - Bai-Shan Fang
- College of Food and Biological Engineering, Jimei University, Xiamen, China
- Department of Chemical and Biochemical Engineering, College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, China
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6
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Han L, Usher S, Sandgrind S, Hassall K, Sayanova O, Michaelson LV, Haslam RP, Napier JA. High level accumulation of EPA and DHA in field-grown transgenic Camelina - a multi-territory evaluation of TAG accumulation and heterogeneity. PLANT BIOTECHNOLOGY JOURNAL 2020; 18:2280-2291. [PMID: 32304615 PMCID: PMC7589388 DOI: 10.1111/pbi.13385] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2019] [Revised: 03/17/2020] [Accepted: 04/07/2020] [Indexed: 05/06/2023]
Abstract
The transgene-directed accumulation of non-native omega-3 long chain polyunsaturated fatty acids in the seed oil of Camelina sativa (Camelina) was evaluated in the field, in distinct geographical and regulatory locations. A construct, DHA2015.1, containing an optimal combination of biosynthetic genes, was selected for experimental field release in the UK, USA and Canada, and the accumulation of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) determined. The occurrence of these fatty acids in different triacylglycerol species was monitored and found to follow a broad trend irrespective of the agricultural environment. This is a clear demonstration of the stability and robust nature of the transgenic trait for omega-3 long chain polyunsaturated fatty acids in Camelina. Examination of non-seed tissues for the unintended accumulation of EPA and DHA failed to identify their presence in leaf, stem, flower, anther or capsule shell material, confirming the seed-specific accumulation of these novel fatty acids. Collectively, these data confirm the promise of GM plant-based sources of so-called omega-3 fish oils as a sustainable replacement for oceanically derived oils.
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Affiliation(s)
- Lihua Han
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
| | - Sarah Usher
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
| | - Sjur Sandgrind
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
- Present address:
Department of Plant BreedingSwedish University of Agricultural SciencesAlnarpSweden
| | - Kirsty Hassall
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
| | - Olga Sayanova
- Department of Plant SciencesRothamsted ResearchHarpendenHertsUK
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7
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Cui J, Chen H, Tang X, Zhao J, Zhang H, Chen YQ, Chen W. Δ6 fatty acid desaturases in polyunsaturated fatty acid biosynthesis: insights into the evolution, function with substrate specificities and biotechnological use. Appl Microbiol Biotechnol 2020; 104:9947-9963. [PMID: 33094384 DOI: 10.1007/s00253-020-10958-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2020] [Revised: 10/05/2020] [Accepted: 10/12/2020] [Indexed: 12/23/2022]
Abstract
Δ6 fatty acid desaturases (FADS6) have different substrate specificities that impact the ratio of omega-6/omega-3 polyunsaturated fatty acids, which are involved in regulating multiple signalling pathways associated with various diseases. For decades, FADS6 with different substrate specificities have been characterized and the functions of these crucial enzymes have been investigated, while it remains enigmatic that the substrate specificities of FADS6 from various species have a huge difference. This review summarizes the substrate specificities of FADS6 in different species and reveals the underlying relationship. Further evaluation of biochemical properties has revealed that the FADS6 prefer linoleic acid that is more hydrophilic and stable. Domain-swapping and site-directed mutagenesis have been employed to delineate the regions and sites that affect the substrate specificities of FADS6. These analyses improve our understanding of the functions of FADS6 and offer information for the discovery of novel biological resources. KEY POINTS: • Outline of the excavation and identification of Δ6 fatty acid desaturases. • Overview of methods used to determine the pivotal resides of desaturases. • Application of substrate properties to generate specific fatty acids.
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Affiliation(s)
- Jie Cui
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China. .,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.
| | - Xin Tang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Jianxin Zhao
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China
| | - Hao Zhang
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, People's Republic of China.,Wuxi Translational Medicine Research Center and Jiangsu Translational Medicine Research Institute Wuxi Branch, Wuxi, 214122, People's Republic of China
| | - Yong Q Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,Department of Cancer Biology, Wake Forest School of Medicine, 5, Winston-Salem, NC, 27127, USA
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,School of Food Science and Technology, Jiangnan University, Wuxi, 214122, People's Republic of China.,National Engineering Research Center for Functional Food, Jiangnan University, Wuxi, 214122, People's Republic of China.,Beijing Innovation Center of Food Nutrition and Human Health, Beijing Technology and Business University (BTBU), Beijing, 100048, People's Republic of China
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8
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Plant-Unique cis/ trans Isomerism of Long-Chain Base Unsaturation is Selectively Required for Aluminum Tolerance Resulting from Glucosylceramide-Dependent Plasma Membrane Fluidity. PLANTS 2019; 9:plants9010019. [PMID: 31877922 PMCID: PMC7020186 DOI: 10.3390/plants9010019] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 12/13/2019] [Accepted: 12/20/2019] [Indexed: 12/11/2022]
Abstract
Cis/trans isomerism of the Δ8 unsaturation of long-chain base (LCB) is found only in plant sphingolipids. This unique geometry is generated by sphingolipid LCB Δ8 desaturase SLD which produces both isomers at various ratios, resulting in diverse cis/trans ratios in plants. However, the biological significance of this isomeric diversity remains controversial. Here, we show that the plant-specific cis unsaturation of LCB selectively contributes to glucosylceramide (GlcCer)-dependent tolerance to aluminum toxicity. We established three transgenic rice lines with altered LCB unsaturation profiles. Overexpression of SLD from rice (OsSLD-OX), which preferentially exhibits cis-activity, or Arabidopsis (AtSLD-OX), showing preference for trans-activity, facilitated Δ8 unsaturation in different manners: a slight increase of cis-unsaturated glycosylinositolphosphoceramide (GIPC) in OsSLD-OX, and a drastic increase of trans-unsaturated GlcCer and GIPC in AtSLD-OX. Disruption of LCB Δ4 desaturase (des) significantly decreased the content of GlcCer. Fluorescence imaging analysis revealed that OsSLD-OX and AtSLD-OX showed increased plasma membrane fluidity, whereas des had less fluidity, demonstrating that the isomers universally contributed to increasing membrane fluidity. However, the results of a hydroponic assay showed decreased aluminum tolerance in AtSLD-OX and des compared to OsSLD-OX and the control plants, which did not correlate with membrane fluidity. These results suggest that cis-unsaturated GlcCer, not GIPC, selectively serves to maintain the membrane fluidity specifically associated with aluminum tolerance.
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9
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O'Donnell DR, Du Z, Litchman E. Experimental evolution of phytoplankton fatty acid thermal reaction norms. Evol Appl 2019; 12:1201-1211. [PMID: 31768190 PMCID: PMC6866708 DOI: 10.1111/eva.12798] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Revised: 03/13/2019] [Accepted: 04/02/2019] [Indexed: 01/12/2023] Open
Abstract
Temperature effects on the fatty acid (FA) profiles of phytoplankton, major primary producers in the ocean, have been widely studied due to their importance as industrial feedstocks and to their indispensable role as global producers of long-chain, polyunsaturated FA (PUFA), including omega-3 (ω3) FA required by organisms at higher trophic levels. The latter is of global ecological concern for marine food webs, as some evidence suggests an ongoing decline in global marine-derived ω3 FA due to both a global decline in phytoplankton abundance and to a physiological reduction in ω3 production by phytoplankton as temperatures rise. Here, we examined both short-term (physiological) and long-term (evolutionary) responses of FA profiles to temperature by comparing FA thermal reaction norms of the marine diatom Thalassiosira pseudonana after ~500 generations (ca. 2.5 years) of experimental evolution at low (16°C) and high (31°C) temperatures. We showed that thermal reaction norms for some key FA classes evolved rapidly in response to temperature selection, often in ways contrary to our predictions based on prior research. Notably, 31°C-selected populations showed higher PUFA percentages (including ω3 FA) than 16°C-selected populations at the highest assay temperature (31°C, above T. pseudonana's optimum temperature for population growth), suggesting that high-temperature selection led to an evolved ability to sustain high PUFA production at high temperatures. Rapid evolution may therefore mitigate some of the decline in global phytoplankton-derived ω3 FA production predicted by recent studies. Beyond its implications for marine food webs, knowledge of the effects of temperature on fatty acid profiles is of fundamental importance to our understanding of the mechanistic causes and consequences of thermal adaptation.
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Affiliation(s)
- Daniel R. O'Donnell
- W. K. Kellogg Biological StationMichigan State UniversityHickory CornersMichigan
- Department of Integrative BiologyMichigan State UniversityEast LansingMichigan
- Program in Ecology, Evolutionary Biology and BehaviorMichigan State UniversityEast LansingMichigan
| | - Zhi‐yan Du
- Department of Biochemistry and Molecular BiologyMichigan State UniversityEast LansingMichigan
- MSU‐DOE Plant Research LaboratoryMichigan State UniversityEast LansingMichigan
| | - Elena Litchman
- W. K. Kellogg Biological StationMichigan State UniversityHickory CornersMichigan
- Department of Integrative BiologyMichigan State UniversityEast LansingMichigan
- Program in Ecology, Evolutionary Biology and BehaviorMichigan State UniversityEast LansingMichigan
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10
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Sun XM, Ren LJ, Zhao QY, Ji XJ, Huang H. Enhancement of lipid accumulation in microalgae by metabolic engineering. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:552-566. [DOI: 10.1016/j.bbalip.2018.10.004] [Citation(s) in RCA: 63] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2018] [Revised: 07/30/2018] [Accepted: 10/05/2018] [Indexed: 01/08/2023]
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11
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Shi H, Luo X, Wu R, Yue X. Production of eicosapentaenoic acid by application of a delta-6 desaturase with the highest ALA catalytic activity in algae. Microb Cell Fact 2018; 17:7. [PMID: 29331150 PMCID: PMC5766975 DOI: 10.1186/s12934-018-0857-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2017] [Accepted: 01/02/2018] [Indexed: 01/03/2023] Open
Abstract
Dunaliella salina is a unicellular green alga with a high α-linolenic acid (ALA) level, but a low eicosapentaenoic acid (EPA) level. In a previous analysis of the catalytic activity of delta 6 fatty acid desaturase (FADS6) from various species, FADS6 from Thalassiosira pseudonana (TpFADS6), a marine diatom, showed the highest catalytic activity for ALA. In this study, to enhance EPA production in D. salina, FADS6 from D. salina (DsFADS6) was identified, and substrate specificities for DsFADS6 and TpFADS6 were characterized. Furthermore, a plasmid harboring the TpFADS6 gene was constructed and overexpressed in D. salina. Our results revealed that EPA production reached 21.3 ± 1.5 mg/L in D. salina transformants. To further increase EPA production, myoinositol (MI) was used as a growth-promoting agent; it increased the dry cell weight of D. salina transformants, and EPA production reached 91.3 ± 11.6 mg/L. The combination of 12% CO2 aeration with glucose/KNO3 in the medium improved EPA production to 192.9 ± 25.7 mg/L in the Ds-TpFADS6 transformant. We confirmed that the increase in ALA was optimal at 8 °C; the EPA percentage reached 41.12 ± 4.78%. The EPA yield was further increased to 554.3 ± 95.6 mg/L by supplementation with 4 g/L perilla seed meal (PeSM), 500 mg/L MI, and 12% CO2 aeration with glucose/KNO3 at varying temperatures. EPA production and the percentage of EPA in D. salina were 343.8-fold and 25-fold higher than those in wild-type D. salina, respectively. IMPORTANCE FADS6 from Thalassiosira pseudonana, which demonstrates high catalytic activity toward α-linolenic acid, was used to enhance EPA production by Dunaliella salina. Transformation of FADS6 from Thalassiosira pseudonana into Dunaliella salina with myoinositol, CO2, low temperatures, and perilla seed meal supplementation substantially increased EPA production in Dunaliella salina to 554.3 ± 95.6 mg/L. Accordingly, D. salina could be a potential alternative source of EPA and is suitable for its large-scale production.
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Affiliation(s)
- Haisu Shi
- College of Food Science, Shenyang Agricultural University, Shenyang, 110866, People's Republic of China
| | - Xue Luo
- College of Food Science, Shenyang Agricultural University, Shenyang, 110866, People's Republic of China
| | - Rina Wu
- College of Food Science, Shenyang Agricultural University, Shenyang, 110866, People's Republic of China.
| | - Xiqing Yue
- College of Food Science, Shenyang Agricultural University, Shenyang, 110866, People's Republic of China.
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12
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Xin Y, Lu Y, Lee YY, Wei L, Jia J, Wang Q, Wang D, Bai F, Hu H, Hu Q, Liu J, Li Y, Xu J. Producing Designer Oils in Industrial Microalgae by Rational Modulation of Co-evolving Type-2 Diacylglycerol Acyltransferases. MOLECULAR PLANT 2017; 10:1523-1539. [PMID: 29107033 DOI: 10.1016/j.molp.2017.10.011] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2017] [Revised: 10/17/2017] [Accepted: 10/21/2017] [Indexed: 05/03/2023]
Abstract
Microalgal oils, depending on their degree of unsaturation, can be utilized as either nutritional supplements or fuels; thus, a feedstock with genetically designed and tunable degree of unsaturation is desirable to maximize process efficiency and product versatility. Systematic profiling of ex vivo (in yeast), in vitro, and in vivo activities of type-2 diacylglycerol acyltransferases in Nannochloropsis oceanica (NoDGAT2s or NoDGTTs), via reverse genetics, revealed that NoDGAT2A prefers saturated fatty acids (SFAs), NoDGAT2D prefers monounsaturated fatty acids (MUFAs), and NoDGAT2C exhibits the strongest activity toward polyunsaturated fatty acids (PUFAs). As NoDGAT2A, 2C, and 2D originated from the green alga, red alga, and eukaryotic host ancestral participants of secondary endosymbiosis, respectively, a mechanistic model of oleaginousness was unveiled, in which the indigenous and adopted NoDGAT2s formulated functional complementarity and specific transcript abundance ratio that underlie a rigid SFA:MUFA:PUFA hierarchy in triacylglycerol (TAG). By rationally modulating the ratio of NoDGAT2A:2C:2D transcripts, a bank of N. oceanica strains optimized for nutritional supplement or fuel production with a wide range of degree of unsaturation were created, in which proportion of SFAs, MUFAs, and PUFAs in TAG varied by 1.3-, 3.7-, and 11.2-fold, respectively. This established a novel strategy to simultaneously improve productivity and quality of oils from industrial microalgae.
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Affiliation(s)
- Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yandu Lu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yi-Ying Lee
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland, Baltimore County, Baltimore, MD 21202, USA
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jing Jia
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Dongmei Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fali Bai
- Core Laboratory, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hanhua Hu
- Diatom Biology Group, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jin Liu
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland, Baltimore County, Baltimore, MD 21202, USA; Institute for Food and Bioresource Engineering and Department of Energy and Resource Engineering, College of Engineering, Peking University, Beijing 100871, China.
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland, Baltimore County, Baltimore, MD 21202, USA.
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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13
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Shi 史海粟 H, Wu 乌日娜 R, Zheng 郑艳 Y, Yue 岳喜庆 X. Molecular mechanisms underlying catalytic activity of delta 6 desaturase from Glossomastix chrysoplasta and Thalassiosira pseudonana. J Lipid Res 2017; 59:79-88. [PMID: 29167410 DOI: 10.1194/jlr.m079806] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2017] [Revised: 11/15/2017] [Indexed: 12/19/2022] Open
Abstract
Delta 6 desaturase (FADS2) is a critical bifunctional enzyme required for PUFA biosynthesis. In some organisms, FADS2s have high substrate specificity, whereas in others, they have high catalytic activity. Previously, we analyzed the molecular mechanisms underlying high FADS2 substrate specificity; in this study, we assessed those underlying the high catalytic activity of FADS2s from Glossomastix chrysoplasta and Thalassiosira pseudonana To understand the structural basis of this catalytic activity, GcFADS2 and TpFADS2 sequences were divided into nine sections, and a domain-swapping approach was applied to examine the role of each section in facilitating the catalytic activity of the overall protein. The results revealed two regions essential to this process: one that extends from the end of the fourth to the beginning of the fifth cytoplasmic transmembrane domain, and another that includes the C-terminal region that occurs after the sixth cytoplasmic transmembrane domain. Based on the domain-swapping analyses, the amino acid residues at ten sites were identified to differ between the GcFADS2 and TpFADS2 sequences, and therefore further analyzed by site-directed mutagenesis. T302V, S322A, Y375F, and M384S/M385 substitutions in TpFADS2 significantly affected FADS2 catalytic efficiency. This study offers a solid basis for in-depth understanding of catalytic efficiency of FADS2.
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Affiliation(s)
- Haisu Shi 史海粟
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, P.R. China
| | - Rina Wu 乌日娜
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, P.R. China
| | - Yan Zheng 郑艳
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, P.R. China
| | - Xiqing Yue 岳喜庆
- College of Food Science, Shenyang Agricultural University, Shenyang 110866, P.R. China
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14
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Paliwal C, Mitra M, Bhayani K, Bharadwaj SVV, Ghosh T, Dubey S, Mishra S. Abiotic stresses as tools for metabolites in microalgae. BIORESOURCE TECHNOLOGY 2017; 244:1216-1226. [PMID: 28552566 DOI: 10.1016/j.biortech.2017.05.058] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/08/2017] [Accepted: 05/10/2017] [Indexed: 05/28/2023]
Abstract
Microalgae, due to various environmental stresses, constantly tune their cellular mechanisms to cope with them. The accumulation of the stress metabolites is closely related to the changes occurring in their metabolic pathways. The biosynthesis of metabolites can be triggered by a number of abiotic stresses like temperature, salinity, UV- radiation and nutrient deprivation. Although, microalgae have been considered as an alternative sustainable source for nutraceutical products like pigments and omega-3 polyunsaturated fatty acids (PUFAs) to cater the requirement of emerging human population but inadequate biomass generation makes the process economically impractical. The stress metabolism for carotenoid regulation in green algae is a 2-step metabolism. There are a few major stresses which can influence the formation of phycobiliprotein in cyanobacteria. This review would primarily focus on the cellular level changes under stress conditions and their corresponding effects on lipids (including omega-3 PUFAs), pigments and polymers.
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Affiliation(s)
- Chetan Paliwal
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research, AcSIR-CSMCRI, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
| | - Madhusree Mitra
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research, AcSIR-CSMCRI, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
| | - Khushbu Bhayani
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
| | - S V Vamsi Bharadwaj
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research, AcSIR-CSMCRI, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
| | - Tonmoy Ghosh
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research, AcSIR-CSMCRI, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
| | - Sonam Dubey
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India
| | - Sandhya Mishra
- Salt and Marine Chemicals Division, CSIR-Central Salt & Marine Chemicals Research Institute, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India; Academy of Scientific and Innovative Research, AcSIR-CSMCRI, Gijubhai Badheka Marg, Bhavnagar 364002, Gujarat, India.
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15
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Jang SH, Jeong HJ, Kwon JE. High contents of eicosapentaenoic acid and docosahexaenoic acid in the mixotrophic dinoflagellate Paragymnodinium shiwhaense and identification of putative omega-3 biosynthetic genes. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.06.020] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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16
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Cisgenesis and intragenesis in microalgae: promising advancements towards sustainable metabolites production. Appl Microbiol Biotechnol 2016; 100:10225-10235. [DOI: 10.1007/s00253-016-7948-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2016] [Revised: 10/12/2016] [Accepted: 10/18/2016] [Indexed: 11/26/2022]
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17
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Dong Y, Wang S, Chen J, Zhang Q, Liu Y, You C, Monroig Ó, Tocher DR, Li Y. Hepatocyte Nuclear Factor 4α (HNF4α) Is a Transcription Factor of Vertebrate Fatty Acyl Desaturase Gene as Identified in Marine Teleost Siganus canaliculatus. PLoS One 2016; 11:e0160361. [PMID: 27472219 PMCID: PMC4966944 DOI: 10.1371/journal.pone.0160361] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2016] [Accepted: 07/18/2016] [Indexed: 11/18/2022] Open
Abstract
Rabbitfish Siganus canaliculatus was the first marine teleost demonstrated to have the capability of biosynthesizing long-chain polyunsaturated fatty acids (LC-PUFA) from C18 precursors, and to possess a Δ4 fatty acyl desaturase (Δ4 Fad) which was the first report in vertebrates, and is a good model for studying the regulatory mechanisms of LC-PUFA biosynthesis in teleosts. In order to understand regulatory mechanisms of transcription of Δ4 Fad, the gene promoter was cloned and characterized in the present study. An upstream sequence of 1859 bp from the initiation codon ATG was cloned as the promoter candidate. On the basis of bioinformatic analysis, several binding sites of transcription factors (TF) including GATA binding protein 2 (GATA-2), CCAAT enhancer binding protein (C/EBP), nuclear factor 1 (NF-1), nuclear factor Y (NF-Y), hepatocyte nuclear factor 4α (HNF4α) and sterol regulatory element (SRE), were identified in the promoter by site-directed mutation and functional assays. HNF4α and NF-1 were confirmed to interact with the core promoter of Δ4 Fad by gel shift assay and mass spectrometry. Moreover, over-expression of HNF4α increased promoter activity in HEK 293T cells and mRNA level of Δ4 Fad in rabbitfish primary hepatocytes, respectively. The results indicated that HNF4α is a TF of rabbitfish Δ4 Fad. To our knowledge, this is the first report on promoter structure of a Δ4 Fad, and also the first demonstration of HNF4α as a TF of vertebrate Fad gene involved in transcription regulation of LC-PUFA biosynthesis.
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Affiliation(s)
- Yewei Dong
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
| | - Shuqi Wang
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
| | - Junliang Chen
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
| | - Qinghao Zhang
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
| | - Yang Liu
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
| | - Cuihong You
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
| | - Óscar Monroig
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK94LA, Scotland, United Kingdom
| | - Douglas R. Tocher
- Institute of Aquaculture, School of Natural Sciences, University of Stirling, Stirling, FK94LA, Scotland, United Kingdom
| | - Yuanyou Li
- Marine Biology Institute & Guangdong Provincial Key Laboratory of Marine Biotechnology, Shantou University, Shantou, 515063, Guangdong, China
- * E-mail:
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Beld J, Abbriano R, Finzel K, Hildebrand M, Burkart MD. Probing fatty acid metabolism in bacteria, cyanobacteria, green microalgae and diatoms with natural and unnatural fatty acids. MOLECULAR BIOSYSTEMS 2016; 12:1299-312. [PMID: 26886879 DOI: 10.1039/c5mb00804b] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
In both eukaryotes and prokaryotes, fatty acid synthases are responsible for the biosynthesis of fatty acids in an iterative process, extending the fatty acid by two carbon units every cycle. Thus, odd numbered fatty acids are rarely found in nature. We tested whether representatives of diverse microbial phyla have the ability to incorporate odd-chain fatty acids as substrates for their fatty acid synthases and their downstream enzymes. We fed various odd and short chain fatty acids to the bacterium Escherichia coli, cyanobacterium Synechocystis sp. PCC 6803, green microalga Chlamydomonas reinhardtii and diatom Thalassiosira pseudonana. Major differences were observed, specifically in the ability among species to incorporate and elongate short chain fatty acids. We demonstrate that E. coli, C. reinhardtii, and T. pseudonana can produce longer fatty acid products from short chain precursors (C3 and C5), while Synechocystis sp. PCC 6803 lacks this ability. However, Synechocystis can incorporate and elongate longer chain fatty acids due to acyl-acyl carrier protein synthetase (AasS) activity, and knockout of this protein eliminates the ability to incorporate these fatty acids. In addition, expression of a characterized AasS from Vibrio harveyii confers a similar capability to E. coli. The ability to desaturate exogenously added fatty acids was only observed in Synechocystis and C. reinhardtii. We further probed fatty acid metabolism of these organisms by feeding desaturase inhibitors to test the specificity of long-chain fatty acid desaturases. In particular, supplementation with thia fatty acids can alter fatty acid profiles based on the location of the sulfur in the chain. We show that coupling sensitive gas chromatography mass spectrometry to supplementation of unnatural fatty acids can reveal major differences between fatty acid metabolism in various organisms. Often unnatural fatty acids have antibacterial or even therapeutic properties. Feeding of short precursors now gives us easy access to these extended molecules.
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Affiliation(s)
- Joris Beld
- Department of Chemistry and Biochemistry, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0358, USA.
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Abstract
Microalgae present a huge and still insufficiently tapped resource of very long-chain omega-3 and omega-6 polyunsaturated fatty acids (VLC-PUFA) for human nutrition and medicinal applications. This chapter describes the diversity of unicellular eukaryotic microalgae in respect to VLC-PUFA biosynthesis. Then, we outline the major biosynthetic pathways mediating the formation of VLC-PUFA by sequential desaturation and elongation of C18-PUFA acyl groups. We address the aspects of spatial localization of those pathways and elaborate on the role for VLC-PUFA in microalgal cells. Recent progress in microalgal genetic transformation and molecular engineering has opened the way to increased production efficiencies for VLC-PUFA. The perspectives of photobiotechnology and metabolic engineering of microalgae for altered or enhanced VLC-PUFA production are also discussed.
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Affiliation(s)
- Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel.
| | - Stefan Leu
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel
| | - Sammy Boussiba
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, J. Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Sede Boqer Campus, 84990, Israel
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Bellou S, Baeshen MN, Elazzazy AM, Aggeli D, Sayegh F, Aggelis G. Microalgal lipids biochemistry and biotechnological perspectives. Biotechnol Adv 2014; 32:1476-93. [PMID: 25449285 DOI: 10.1016/j.biotechadv.2014.10.003] [Citation(s) in RCA: 177] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2014] [Revised: 10/02/2014] [Accepted: 10/06/2014] [Indexed: 01/05/2023]
Abstract
In the last few years, there has been an intense interest in using microalgal lipids in food, chemical and pharmaceutical industries and cosmetology, while a noteworthy research has been performed focusing on all aspects of microalgal lipid production. This includes basic research on the pathways of solar energy conversion and on lipid biosynthesis and catabolism, and applied research dealing with the various biological and technical bottlenecks of the lipid production process. In here, we review the current knowledge in microalgal lipids with respect to their metabolism and various biotechnological applications, and we discuss potential future perspectives. The committing step in fatty acid biosynthesis is the carboxylation of acetyl-CoA to form malonyl-CoA that is then introduced in the fatty acid synthesis cycle leading to the formation of palmitic and stearic acids. Oleic acid may also be synthesized after stearic acid desaturation while further conversions of the fatty acids (i.e. desaturations, elongations) occur after their esterification with structural lipids of both plastids and the endoplasmic reticulum. The aliphatic chains are also used as building blocks for structuring storage acylglycerols via the Kennedy pathway. Current research, aiming to enhance lipogenesis in the microalgal cell, is focusing on over-expressing key-enzymes involved in the earlier steps of the pathway of fatty acid synthesis. A complementary plan would be the repression of lipid catabolism by down-regulating acylglycerol hydrolysis and/or β-oxidation. The tendency of oleaginous microalgae to synthesize, apart from lipids, significant amounts of other energy-rich compounds such as sugars, in processes competitive to lipogenesis, deserves attention since the lipid yield may be considerably increased by blocking competitive metabolic pathways. The majority of microalgal production occurs in outdoor cultivation and for this reason biotechnological applications face some difficulties. Therefore, algal production systems need to be improved and harvesting systems need to be more effective in order for their industrial applications to become more competitive and economically viable. Besides, a reduction of the production cost of microalgal lipids can be achieved by combining lipid production with other commercial applications. The combined production of bioactive products and lipids, when possible, can support the commercial viability of both processes. Hydrophobic compounds can be extracted simultaneously with lipids and then purified, while hydrophilic compounds such as proteins and sugars may be extracted from the defatted biomass. The microalgae also have applications in environmental biotechnology since they can be used for bioremediation of wastewater and to monitor environmental toxicants. Algal biomass produced during wastewater treatment may be further valorized in the biofuel manufacture. It is anticipated that the high microalgal lipid potential will force research towards finding effective ways to manipulate biochemical pathways involved in lipid biosynthesis and towards cost effective algal cultivation and harvesting systems, as well.
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Affiliation(s)
- Stamatia Bellou
- Division of Genetics, Cell & Development Biology, Department of Biology, University of Patras, Patras 26504, Greece
| | - Mohammed N Baeshen
- Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - Ahmed M Elazzazy
- Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia; Department of Chemistry of Natural and Microbial Products, National Research Centre, Dokki 12622, Giza, Egypt
| | - Dimitra Aggeli
- Department of Genetics, Stanford University, Stanford, CA 94305, USA
| | - Fotoon Sayegh
- Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia
| | - George Aggelis
- Division of Genetics, Cell & Development Biology, Department of Biology, University of Patras, Patras 26504, Greece; Department of Biological Sciences, King Abdulaziz University, Jeddah 21589, Saudi Arabia.
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22
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Advances in the Production of High-Value Products by Microalgae. Ind Biotechnol (New Rochelle N Y) 2014. [DOI: 10.1089/ind.2013.0039] [Citation(s) in RCA: 168] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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23
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Lim ZL, Senger T, Vrinten P. Four amino acid residues influence the substrate chain-length and regioselectivity of Siganus canaliculatus Δ4 and Δ5/6 desaturases. Lipids 2014; 49:357-67. [PMID: 24477708 DOI: 10.1007/s11745-014-3880-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Accepted: 01/06/2014] [Indexed: 11/26/2022]
Abstract
Although ω3- and ω6- desaturases have been well studied in terms of substrate preference and regiospecificity, relatively little is known about the membrane-bound, "front-end" long chain fatty acid desaturases, such as ∆4, Δ5 or Δ6 desaturases. The first vertebrate ∆4 desaturase was recently identified in the marine teleost fish Siganus canaliculatus (S. canaliculatus), which also possesses a bifunctional Δ5/6 desaturase. These two long chain polyunsaturated fatty acid desaturases are very different in terms of regiospecificity and substrate chain-length, but share an unusually high degree of amino acid identity (83 %). We took advantage of this similarity by constructing a series of chimeric enzymes, replacing regions of one enzyme with the corresponding sequence of the other. Heterologous expression of the chimeric series of enzymes in yeast indicated that the substitution of a four amino acid region was sufficient to convert a ∆4 desaturase to an enzyme with ∆6 desaturase activity, and convert a ∆5/6 desaturase to an enzyme with a low level of ∆4 desaturase activity. In addition, enzymes having both ∆4 and ∆6 desaturase activities were produced by single or double amino acid substitutions within this four-amino acid region.
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Affiliation(s)
- Ze Long Lim
- Bioriginal Food and Science Corporation, Saskatoon, SK, S7N 0W9, Canada
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Li HY, Lu Y, Zheng JW, Yang WD, Liu JS. Biochemical and genetic engineering of diatoms for polyunsaturated fatty acid biosynthesis. Mar Drugs 2014; 12:153-66. [PMID: 24402175 PMCID: PMC3917266 DOI: 10.3390/md12010153] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 12/10/2013] [Accepted: 12/12/2013] [Indexed: 11/16/2022] Open
Abstract
The role of diatoms as a source of bioactive compounds has been recently explored. Diatom cells store a high amount of fatty acids, especially certain polyunsaturated fatty acids (PUFAs). However, many aspects of diatom metabolism and the production of PUFAs remain unclear. This review describes a number of technical strategies, such as modulation of environmental factors (temperature, light, chemical composition of culture medium) and culture methods, to influence the content of PUFAs in diatoms. Genetic engineering, a newly emerging field, also plays an important role in controlling the synthesis of fatty acids in marine microalgae. Several key points in the biosynthetic pathway of PUFAs in diatoms as well as recent progresses are also a critical part and are summarized here.
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Affiliation(s)
- Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
| | - Yang Lu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
| | - Jian-Wei Zheng
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, Jinan University, Guangzhou 510632, China.
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Vaezi R, Napier JA, Sayanova O. Identification and functional characterization of genes encoding omega-3 polyunsaturated fatty acid biosynthetic activities from unicellular microalgae. Mar Drugs 2013; 11:5116-29. [PMID: 24351909 PMCID: PMC3877907 DOI: 10.3390/md11125116] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2013] [Revised: 11/20/2013] [Accepted: 11/26/2013] [Indexed: 12/27/2022] Open
Abstract
In order to identify novel genes encoding enzymes involved in the biosynthesis of nutritionally important omega-3 long chain polyunsaturated fatty acids, a database search was carried out in the genomes of the unicellular photoautotrophic green alga Ostreococcus RCC809 and cold-water diatom Fragilariopsis cylindrus. The search led to the identification of two putative “front-end” desaturases (Δ6 and Δ4) from Ostreococcus RCC809 and one Δ6-elongase from F. cylindrus. Heterologous expression of putative open reading frames (ORFs) in yeast revealed that the encoded enzyme activities efficiently convert their respective substrates: 54.1% conversion of α-linolenic acid for Δ6-desaturase, 15.1% conversion of 22:5n-3 for Δ4-desaturase and 38.1% conversion of γ-linolenic acid for Δ6-elongase. The Δ6-desaturase from Ostreococcus RCC809 displays a very strong substrate preference resulting in the predominant synthesis of stearidonic acid (C18:4Δ6,9,12,15). These data confirm the functional characterization of omega-3 long chain polyunsaturated fatty acid biosynthetic genes from these two species which have until now not been investigated for such activities. The identification of these new genes will also serve to expand the repertoire of activities available for metabolically engineering the omega-3 trait in heterologous hosts as well as providing better insights into the synthesis of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in marine microalgae.
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Affiliation(s)
| | | | - Olga Sayanova
- Department of Biological Chemistry and Crop Protection, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK.
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Ishikawa T, Imai H, Maki KY. Development of an LC-MS/MS method for the analysis of free sphingoid bases using 4-fluoro-7-nitrobenzofurazan (NBD-F). Lipids 2013; 49:295-304. [PMID: 24310230 DOI: 10.1007/s11745-013-3871-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2013] [Accepted: 11/19/2013] [Indexed: 02/01/2023]
Abstract
The molecular species of sphingoid bases were tagged with the fluorescent amino group reagent, 4-fluoro-7-nitrobenzofurazan (NBD-F). The NBD-sphingoid bases were analyzed by a highly selective and sensitive liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) technique capable of reliable detection of several fmol of the derivatives. Lipid extracts from plant samples were derivatized with NBD-F, and all nine species of free sphingoid bases present in plant sphingolipids were separated and quantified for the first time; a complete baseline resolution was achieved for cis-8 and trans-8 isomers of sphingoid bases by reversed phase HPLC on a C18 column. The extraction and derivatization procedures and LC-MS/MS method can facilitate the progress of the studies for seeking the active components of sphingoid bases species in response to biological challenges.
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Affiliation(s)
- Toshiki Ishikawa
- Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama, 338-8570, Japan
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Muto M, Kubota C, Tanaka M, Satoh A, Matsumoto M, Yoshino T, Tanaka T. Identification and functional analysis of delta-9 desaturase, a key enzyme in PUFA Synthesis, isolated from the oleaginous diatom Fistulifera. PLoS One 2013; 8:e73507. [PMID: 24039966 PMCID: PMC3764056 DOI: 10.1371/journal.pone.0073507] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Accepted: 07/22/2013] [Indexed: 12/29/2022] Open
Abstract
Oleaginous microalgae are one of the promising resource of nonedible biodiesel fuel (BDF) feed stock alternatives. Now a challenge task is the decrease of the long-chain polyunsaturated fatty acids (PUFAs) content affecting on the BDF oxidative stability by using gene manipulation techniques. However, only the limited knowledge has been available concerning the fatty acid and PUFA synthesis pathways in microalgae. Especially, the function of Δ9 desaturase, which is a key enzyme in PUFA synthesis pathway, has not been determined in diatom. In this study, 4 Δ(9) desaturase genes (fD9desA, fD9desB, fD9desC and fD9desD) from the oleaginous diatom Fistulifera were newly isolated and functionally characterized. The putative Δ(9) acyl-CoA desaturases in the endoplasmic reticulum (ER) showed 3 histidine clusters that are well-conserved motifs in the typical Δ(9) desaturase. Furthermore, the function of these Δ(9) desaturases was confirmed in the Saccharomyces cerevisiae ole1 gene deletion mutant (Δole1). All the putative Δ(9) acyl-CoA desaturases showed Δ(9) desaturation activity for C16∶0 fatty acids; fD9desA and fD9desB also showed desaturation activity for C18∶0 fatty acids. This study represents the first functional analysis of Δ(9) desaturases from oleaginous microalgae and from diatoms as the first enzyme to introduce a double bond in saturated fatty acids during PUFA synthesis. The findings will provide beneficial insights into applying metabolic engineering processes to suppressing PUFA synthesis in this oleaginous microalgal strain.
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Affiliation(s)
- Masaki Muto
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
| | - Chihiro Kubota
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Masayoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
| | - Akira Satoh
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
- BT Development Group, Research and Development Section, Technology Center, Yamaha Motor Co. Ltd., Fukuroi, Shizuoka, Japan
| | - Mitsufumi Matsumoto
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
- Biotechnology Laboratory, Electric Power Development Co. Ltd., Yanagisaki-machi, Wakamatsu-ku, Kitakyusyu, Japan
| | - Tomoko Yoshino
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
| | - Tsuyoshi Tanaka
- Division of Biotechnology and Life Science, Institute of Engineering, Tokyo University of Agriculture and Technology, Koganei, Tokyo, Japan
- JST, CREST, Sanbancho 5, Chiyoda-ku, Tokyo, Japan
- * E-mail:
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Michaelson LV, Markham JE, Zäeuner S, Matsumoto M, Chen M, Cahoon EB, Napier JA. Identification of a cytochrome b5-fusion desaturase responsible for the synthesis of triunsaturated sphingolipid long chain bases in the marine diatom Thalassiosira pseudonana. PHYTOCHEMISTRY 2013; 90:50-5. [PMID: 23510654 DOI: 10.1016/j.phytochem.2013.02.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2012] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 05/10/2023]
Abstract
Triunsaturated sphingolipid long chain bases (LCBs) have previously been reported in some specialised tissues of marine invertebrates. We report the presence of similar LCBs in the marine diatom Thalassiosira pseudonana and identify the cytochrome b5-fusion desaturase responsible for the introduction of the third double bond at the Δ10 position in d18:3Δ4,8,10. This study extends the catalytic repertoire of the cytochrome b5 fusion desaturase family, also indicating the presence of orthologues in other marine invertebrates. The function of these polyunsaturated sphingolipid LCBs is currently unknown but it was previously suggested that they play an essential role in primitive animals. The identification of the desaturase responsible for their synthesis paves the way for further studies.
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Affiliation(s)
- Louise V Michaelson
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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Two novel Physcomitrella patens fatty acid elongases (ELOs): identification and functional characterization. Appl Microbiol Biotechnol 2012; 97:3485-97. [DOI: 10.1007/s00253-012-4556-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2012] [Revised: 10/25/2012] [Accepted: 10/25/2012] [Indexed: 12/15/2022]
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Adarme-Vega TC, Lim DKY, Timmins M, Vernen F, Li Y, Schenk PM. Microalgal biofactories: a promising approach towards sustainable omega-3 fatty acid production. Microb Cell Fact 2012; 11:96. [PMID: 22830315 PMCID: PMC3465194 DOI: 10.1186/1475-2859-11-96] [Citation(s) in RCA: 256] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2012] [Accepted: 07/06/2012] [Indexed: 01/18/2023] Open
Abstract
Omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) provide significant health benefits and this has led to an increased consumption as dietary supplements. Omega-3 fatty acids EPA and DHA are found in animals, transgenic plants, fungi and many microorganisms but are typically extracted from fatty fish, putting additional pressures on global fish stocks. As primary producers, many marine microalgae are rich in EPA (C20:5) and DHA (C22:6) and present a promising source of omega-3 fatty acids. Several heterotrophic microalgae have been used as biofactories for omega-3 fatty acids commercially, but a strong interest in autotrophic microalgae has emerged in recent years as microalgae are being developed as biofuel crops. This paper provides an overview of microalgal biotechnology and production platforms for the development of omega-3 fatty acids EPA and DHA. It refers to implications in current biotechnological uses of microalgae as aquaculture feed and future biofuel crops and explores potential applications of metabolic engineering and selective breeding to accumulate large amounts of omega-3 fatty acids in autotrophic microalgae.
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Affiliation(s)
- T Catalina Adarme-Vega
- Algae Biotechnology Laboratory, School of Agriculture and Food Sciences, The University of Queensland, Brisbane, QLD 4072, Australia
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A cytochrome b5-containing plastid-located fatty acid desaturase from Chlamydomonas reinhardtii. EUKARYOTIC CELL 2012; 11:856-63. [PMID: 22562471 DOI: 10.1128/ec.00079-12] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Monogalactosyldiacylglycerol (MGDG) in Chlamydomonas reinhardtii and other green algae contains hexadeca-4,7,10,13-tetraenoic acid (16:4) in the glycerol sn-2 position. While many genes necessary for the introduction of acyl chain double bonds have been functionally characterized, the Δ4-desaturase remained unknown. Using a phylogenetic comparison, a candidate gene encoding the MGDG-specific Δ4-desaturase from Chlamydomonas (CrΔ4FAD) was identified. CrΔ4FAD shows all characteristic features of a membrane-bound desaturase, including three histidine boxes and a transit peptide for chloroplast targeting. But it also has an N-terminal cytochrome b(5) domain, distinguishing it from other known plastid desaturases. Cytochrome b(5) is the primary electron donor for endoplasmic reticulum (ER) desaturases and is often fused to the desaturase domain in desaturases modifying the carboxyl end of the acyl group. Difference absorbance spectra of the recombinant cytochrome b(5) domain of CrΔ4FAD showed that it is functional in vitro. Green fluorescent protein fusions of CrΔ4FAD localized to the plastid envelope in Chlamydomonas. Interestingly, overproduction of CrΔ4FAD in Chlamydomonas not only increased levels of 16:4 acyl groups in cell extracts but specifically increased the total amount of MGDG. Vice versa, the amount of MGDG was lowered in lines with reduced levels of CrΔ4FAD. These data suggest a link between MGDG molecular species composition and galactolipid abundance in the alga, as well as a specific function for this fatty acid in MGDG.
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Morais S, Castanheira F, Martinez-Rubio L, Conceição LE, Tocher DR. Long chain polyunsaturated fatty acid synthesis in a marine vertebrate: Ontogenetic and nutritional regulation of a fatty acyl desaturase with Δ4 activity. Biochim Biophys Acta Mol Cell Biol Lipids 2012; 1821:660-71. [DOI: 10.1016/j.bbalip.2011.12.011] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2011] [Revised: 12/13/2011] [Accepted: 12/16/2011] [Indexed: 12/21/2022]
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Sayanova O, Ruiz-Lopez N, Haslam RP, Napier JA. The role of Δ6-desaturase acyl-carrier specificity in the efficient synthesis of long-chain polyunsaturated fatty acids in transgenic plants. PLANT BIOTECHNOLOGY JOURNAL 2012; 10:195-206. [PMID: 21902798 DOI: 10.1111/j.1467-7652.2011.00653.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The role of acyl-CoA-dependent Δ6-desaturation in the heterologous synthesis of omega-3 long-chain polyunsaturated fatty acids was systematically evaluated in transgenic yeast and Arabidopsis thaliana. The acyl-CoA Δ6-desaturase from the picoalga Ostreococcus tauri and orthologous activities from mouse (Mus musculus) and salmon (Salmo salar) were shown to generate substantial levels of Δ6-desaturated acyl-CoAs, in contrast to the phospholipid-dependent Δ6-desaturases from higher plants that failed to modify this metabolic pool. Transgenic plants expressing the acyl-CoA Δ6-desaturases from either O. tauri or salmon, in conjunction with the two additional activities required for the synthesis of C20 polyunsaturated fatty acids, contained higher levels of eicosapentaenoic acid compared with plants expressing the borage phospholipid-dependent Δ6-desaturase. The use of acyl-CoA-dependent Δ6-desaturases almost completely abolished the accumulation of unwanted biosynthetic intermediates such as γ-linolenic acid in total seed lipids. Expression of acyl-CoA Δ6-desaturases resulted in increased distribution of long-chain polyunsaturated fatty acids in the polar lipids of transgenic plants, reflecting the larger substrate pool available for acylation by enzymes of the Kennedy pathway. Expression of the O. tauriΔ6-desaturase in transgenic Camelina sativa plants also resulted in the accumulation of high levels of Δ6-desaturated fatty acids. This study provides evidence for the efficacy of using acyl-CoA-dependent Δ6-desaturases in the efficient metabolic engineering of transgenic plants with high value traits such as the synthesis of omega-3 LC-PUFAs.
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Affiliation(s)
- Olga Sayanova
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts, UK
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The front-end desaturase: structure, function, evolution and biotechnological use. Lipids 2011; 47:227-37. [PMID: 22009657 DOI: 10.1007/s11745-011-3617-2] [Citation(s) in RCA: 88] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2011] [Accepted: 08/26/2011] [Indexed: 10/16/2022]
Abstract
Very long chain polyunsaturated fatty acids such as arachidonic acid (ARA, 20:4n-6), eicosapentaenoic acid (EPA, 20:5n-3), docosapentaenoic acid (DPA, 22:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) are essential components of cell membranes, and are precursors for a group of hormone-like bioactive compounds (eicosanoids and docosanoids) involved in regulation of various physiological activities in animals and humans. The biosynthesis of these fatty acids involves an alternating process of fatty acid desaturation and elongation. The desaturation is catalyzed by a unique class of oxygenases called front-end desaturases that introduce double bonds between the pre-existing double bond and the carboxyl end of polyunsaturated fatty acids. The first gene encoding a front-end desaturase was cloned in 1993 from cyanobacteria. Since then, front-end desaturases have been identified and characterized from a wide range of eukaryotic species including algae, protozoa, fungi, plants and animals including humans. Unlike front-end desaturases from bacteria, those from eukaryotes are structurally characterized by the presence of an N-terminal cytochrome b₅-like domain fused to the main desaturation domain. Understanding the structure, function and evolution of front-end desaturases, as well as their roles in the biosynthesis of very long chain polyunsaturated fatty acids offers the opportunity to engineer production of these fatty acids in transgenic oilseed plants for nutraceutical markets.
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LC-PUFA from photosynthetic microalgae: occurrence, biosynthesis, and prospects in biotechnology. Appl Microbiol Biotechnol 2011; 91:905-15. [PMID: 21720821 DOI: 10.1007/s00253-011-3441-x] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2011] [Revised: 06/10/2011] [Accepted: 06/11/2011] [Indexed: 01/31/2023]
Abstract
Microalgae offer potential for numerous commercial applications, among them the production of long-chain polyunsaturated fatty acids (LC-PUFAs). These valuable fatty acids are important for a variety of nutraceutical and pharmaceutical purposes, and the market for these products is continually growing. An appropriate ratio of LC-PUFA of the ω-3 and ω-6 groups is vital for "healthy" nutrition, and adequate dietary intake has strong health benefits in humans. Microalgae of diverse classes are primary natural producers of LC-PUFA. This mini-review presents an introductory overview of LC-PUFA-related health benefits in humans, describes LC-PUFA occurrence in diverse microalgal classes, depicts the major pathways of their biosynthesis in microalgae, and discusses the prospects for microalgal LC-PUFA production.
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Sayanova O, Haslam RP, Calerón MV, López NR, Worthy C, Rooks P, Allen MJ, Napier JA. Identification and functional characterisation of genes encoding the omega-3 polyunsaturated fatty acid biosynthetic pathway from the coccolithophore Emiliania huxleyi. PHYTOCHEMISTRY 2011; 72:594-600. [PMID: 21316718 DOI: 10.1016/j.phytochem.2011.01.022] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/01/2010] [Revised: 01/11/2011] [Accepted: 01/12/2011] [Indexed: 05/30/2023]
Abstract
The Prymnesiophyceae coccolithophore Emiliania huxleyi is one of the most abundant alga in our oceans and therefore plays a central role in marine foodwebs. E. huxleyi is notable for the synthesis and accumulation of the omega-3 long chain polyunsaturated fatty acid docosahexaenoic acid (DHA; 22:6Δ(4,7,10,13,16,19), n-3) which is accumulated in fish oils and known to have health-beneficial properties to humans, preventing cardiovascular disease and related pathologies. Here we describe the identification and functional characterisation of the five E. huxleyi genes which direct the synthesis of docosahexaenoic acid in this alga. Surprisingly, E. huxleyi does not use the conventional Δ6-pathway, instead using the alternative Δ8-desaturation route which has previously only been observed in a few unrelated microorganisms. Given that E. huxleyi accumulates significant levels of the Δ6-desaturated fatty acid stearidonic acid (18:4Δ(6,9,12,15), n-3), we infer that the biosynthesis of DHA is likely to be metabolically compartmentalised from the synthesis of stearidonic acid.
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Affiliation(s)
- Olga Sayanova
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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37
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Nagano N, Sakaguchi K, Taoka Y, Okita Y, Honda D, Ito M, Hayashi M. Detection of Genes Involved in Fatty Acid Elongation and Desaturation in Thraustochytrid Marine Eukaryotes. J Oleo Sci 2011; 60:475-81. [DOI: 10.5650/jos.60.475] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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38
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Michaelson LV, Dunn TM, Napier JA. Viral trans-dominant manipulation of algal sphingolipids. TRENDS IN PLANT SCIENCE 2010; 15:651-655. [PMID: 20934366 DOI: 10.1016/j.tplants.2010.09.004] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2010] [Revised: 09/08/2010] [Accepted: 09/09/2010] [Indexed: 05/30/2023]
Abstract
Emiliania huxleyi is the host for the coccolithovirus (EhV), which is responsible for the demise of large oceanic blooms formed by this alga. The EhV-86 virus genome sequence has identified several genes apparently involved in sphingolipid metabolism. Recently, an unusual glucosylceramide from E. huxleyi infected with EhV-86 was isolated, implicating sphingolipids in the lysis of this alga. However, the EhV-86-encoded genes contain only a subset of the activities required to generate the novel sphingolipid, implying that its synthesis is the result of coordinated interactions between algal- and viral-encoded biosynthetic enzymes. Here, we discuss the likely role for EhV-86 open reading frames (ORFs) in the synthesis of novel sphingolipids and also consider the concept of the trans-dominant manipulation of lipid metabolism.
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Affiliation(s)
- Louise V Michaelson
- Department of Biological Chemistry, Rothamsted Research, Harpenden, Herts AL5 2JQ, UK
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Khozin-Goldberg I, Cohen Z. Unraveling algal lipid metabolism: Recent advances in gene identification. Biochimie 2010; 93:91-100. [PMID: 20709142 DOI: 10.1016/j.biochi.2010.07.020] [Citation(s) in RCA: 123] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2010] [Revised: 07/12/2010] [Accepted: 07/30/2010] [Indexed: 01/08/2023]
Abstract
Microalgae are now the focus of intensive research due to their potential as a renewable feedstock for biodiesel. This research requires a thorough understanding of the biochemistry and genetics of these organisms' lipid-biosynthesis pathways. Genes encoding lipid-biosynthesis enzymes can now be identified in the genomes of various eukaryotic microalgae. However, an examination of the predicted proteins at the biochemical and molecular levels is mandatory to verify their function. The essential molecular and genetic tools are now available for a comprehensive characterization of genes coding for enzymes of the lipid-biosynthesis pathways in some algal species. This review mainly summarizes the novel information emerging from recently obtained algal gene identification.
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Affiliation(s)
- Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institutes for Desert Research, Ben-Gurion University of the Negev, Midreshet Ben-Gurion 84990, Israel.
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40
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Identification and Characterization of Δ12, Δ6, and Δ5 Desaturases from the Green Microalga Parietochloris incisa. Lipids 2010; 45:519-30. [DOI: 10.1007/s11745-010-3421-4] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2010] [Accepted: 04/15/2010] [Indexed: 10/19/2022]
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42
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Grossman AR. In the Grip of Algal Genomics. TRANSGENIC MICROALGAE AS GREEN CELL FACTORIES 2008; 616:54-76. [DOI: 10.1007/978-0-387-75532-8_6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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43
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Isolation and characterization of a Delta5-desaturase from Oblongichytrium sp. Biosci Biotechnol Biochem 2008; 72:2224-7. [PMID: 18685196 DOI: 10.1271/bbb.80235] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We isolated a cDNA clone with homology to known desaturase genes from Oblongichytrium sp., recently classified as a new genus of thraustochytrids (Labyrinthulomycetes), and found that it encoded Delta5-desaturase by its heterologous expression in yeast. The enzyme had higher activity toward 20:4n-3 than 20:3n-6, indicating that this Delta5-desaturase can be used in the production of n-3 polyunsaturated fatty acids in transgenic organisms.
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44
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Chi X, Zhang X, Guan X, Ding L, Li Y, Wang M, Lin H, Qin S. Fatty acid biosynthesis in eukaryotic photosynthetic microalgae: Identification of a microsomal delta 12 desaturase in Chlamydomonas reinhardtii. J Microbiol 2008; 46:189-201. [DOI: 10.1007/s12275-007-0223-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2007] [Accepted: 01/08/2008] [Indexed: 12/14/2022]
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45
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Faramarzi MA, Adrangi S, Yazdi MT. MICROALGAL BIOTRANSFORMATION OF STEROIDS(1). JOURNAL OF PHYCOLOGY 2008; 44:27-37. [PMID: 27041037 DOI: 10.1111/j.1529-8817.2007.00446.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Microbial biotransformation of steroids is not a new concept, but most studies in this field have focused on fungal and bacterial systems. Microalgae, despite their photosynthetic ability and immense biodiversity, have not received much attention in this aspect until recently. Since the publication of the first article on microalgal biotransformation of steroids about 20 years ago, there have been many reports describing different modifications, including hydroxylation, reduction, side-chain degradation, and isomerization introduced by these microorganisms on estrane, androstane, and pregnane derivatives. On the other hand, the development of new large-scale cultivation systems, the adaptation of existing fermentation techniques to microalgae, and the introduction of microalgal genetic manipulation methods have made these organisms promising candidates for a wide range of biotechnological processes, including biotransformations. In this review, we have summarized the steroid transformation patterns of several microalgal strains and present a perspective of the future trends in microalgal biotechnology, including the possibility of adapting relatively new techniques, such as organic media catalysis and cell immobilization, to this specific field.
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Affiliation(s)
- Mohammad Ali Faramarzi
- Department of Pharmaceutical Biotechnology, Biotechnology Research Centre, Faculty of Pharmacy, Medical Sciences University of Tehran, PO Box 14155-6451, Tehran 14174, Iran
| | - Sina Adrangi
- Department of Pharmaceutical Biotechnology, Biotechnology Research Centre, Faculty of Pharmacy, Medical Sciences University of Tehran, PO Box 14155-6451, Tehran 14174, Iran
| | - Mojtaba Tabatabaei Yazdi
- Department of Pharmaceutical Biotechnology, Biotechnology Research Centre, Faculty of Pharmacy, Medical Sciences University of Tehran, PO Box 14155-6451, Tehran 14174, Iran
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García-Maroto F, Garrido-Cárdenas JA, Michaelson LV, Napier JA, Alonso DL. Cloning and molecular characterisation of a Delta8-sphingolipid-desaturase from Nicotiana tabacum closely related to Delta6-acyl-desaturases. PLANT MOLECULAR BIOLOGY 2007; 64:241-50. [PMID: 17325828 DOI: 10.1007/s11103-007-9148-9] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/23/2006] [Accepted: 02/08/2007] [Indexed: 05/14/2023]
Abstract
Investigation on the absence of Delta(6)-desaturase activity in Nicotiana tabacum has led to the cloning of a new desaturase gene from this organism (NTDXDES) that exhibited unexpected biochemical activity. Cladistic analysis shows clustering of NTDXDES together with functional Delta(6)-acyl-desaturases of near Solanales plants, such as Borago and Echium. This group lies apart from that of previously characterised Delta(8)-sphingolipid-desaturases, which also includes two putative tobacco members identified in this study. Moreover, strong expression of NTDXDES is found in leaves, flowers, fruits and developing seeds of tobacco plants that is highly dependent on the development phase, with transcriptional activity being higher at stages of active tissue growth. This pattern is similar to that showed by Delta(6)-acyl-desaturases characterised in Boraginaceae species. However, functional assays using a yeast expression system revealed that the protein encoded by NTDXDES lacks Delta(6)-desaturase activity, but instead it is able to desaturate sphingolipid substrates by introducing a double bond on the Delta(8)-position. These data indicate that NTDXDES represent a novel desaturase gene placed in a different evolutionary lineage to that of previously characterised Delta(8)-desaturases.
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Affiliation(s)
- Federico García-Maroto
- Area de Bioquímica, Facultad de Ciencias Experimentales, Universidad de Almería, 04120, Almeria, Spain.
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Bopp SK, Lettieri T. Gene regulation in the marine diatom Thalassiosira pseudonana upon exposure to polycyclic aromatic hydrocarbons (PAHs). Gene 2007; 396:293-302. [PMID: 17540515 DOI: 10.1016/j.gene.2007.03.013] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2006] [Revised: 03/23/2007] [Accepted: 03/23/2007] [Indexed: 11/20/2022]
Abstract
Diatoms are eukaryotic algae, which can be found worldwide in oceans and freshwaters. These organisms are ecologically relevant due to their key role in the global carbon cycle, contributing to about 25% to the global primary production [Falciatore, A., Bowler, C., 2002. Revealing the molecular secrets of marine diatoms. Annu. Rev. Plant Biol. 53, 109-130]. We investigated the effects of three polycyclic aromatic hydrocarbons (PAHs, pyrene, fluoranthene, and benzo[a]pyrene), either as single compound or as mixture, at molecular level. Dose-response curves for growth inhibition were determined and four concentrations eliciting from "no effect" up to a severe growth inhibition were chosen for further investigation to detect alterations at gene expression level by Real-Time PCR. Among the eight selected genes, two were strongly influenced by the PAH treatment. lacsA, which is involved in the fatty acid metabolism, was found to be strongly up-regulated by all single PAHs, as well as by the mixture. sil3, involved in the formation of the silica shell, was repressed by a factor up to three even at low PAH concentrations not eliciting any growth inhibition. For other genes, involved e.g. in photosynthesis, a slight down-regulation was detected. Based on the effects at gene expression level it can be assumed that PAHs impair the fatty acid metabolism and silica shell formation.
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Affiliation(s)
- Stephanie K Bopp
- European Commission -- DG Joint Research Centre, Institute for Environment and Sustainability, Rural, Water, and Ecosystem Resources Unit, T.P. 300, Via E. Fermi 1, 21020 Ispra (VA), Italy
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Graham IA, Larson T, Napier JA. Rational metabolic engineering of transgenic plants for biosynthesis of omega-3 polyunsaturates. Curr Opin Biotechnol 2007; 18:142-7. [PMID: 17292601 DOI: 10.1016/j.copbio.2007.01.014] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2006] [Revised: 01/05/2007] [Accepted: 01/31/2007] [Indexed: 12/29/2022]
Abstract
The health-beneficial effects of long-chain polyunsaturated fatty acids (LC-PUFAs), derived mainly from fish oil, coupled with the growing requirement for an alternative and sustainable source of these compounds, has led to efforts to engineer oilseed crops for their production. LC-PUFA synthesis has been achieved using combinations of heterologous endomembrane desaturases and elongases expressed in model oilseed plants. Two general approaches have been employed that both use endogenous 18 carbon fatty acids as the starting substrates: the Delta6- and Delta8-pathways, which perform desaturation followed by elongation or elongation followed by desaturation, respectively. However, yields above 20% have not yet been realized owing to bottlenecks that become apparent in the endogenous biosynthetic pathways when heterologous genes are expressed. These bottlenecks might be caused partly by inefficient non-native enzymes in the host system or also by suboptimal acyl-exchange mechanisms between the acyl-CoA and lipid class pools. The fine-tuning of the fatty acid flux between the acyl-CoA, phospholipid, and triacylglycerol pools will be essential to maximise polyunsaturated fatty acid yields in seed oils. In addition, efficient substrate channelling and lipid synthesis could depend on specific endoplasmic reticulum subdomain localisation for key endogenous enzymes, and this organization could be compromised in heterologous systems.
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Affiliation(s)
- Ian A Graham
- CNAP, Department of Biology (Area 7), University of York, PO Box 373, York YO10 5YW, UK.
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Abstract
The ability to genetically engineer plants has facilitated the generation of oilseeds synthesizing non-native fatty acids. Two particular classes of fatty acids are considered in this review. First, so-called industrial fatty acids, which usually contain functional groups such as hydroxyl, epoxy, or acetylenic bonds, and second, very long chain polyunsaturated fatty acids normally found in fish oils and marine microorganisms. For industrial fatty acids, there has been limited progress toward obtaining high-level accumulation of these products in transgenic plants. For very long chain polyunsaturated fatty acids, although they have a much more complex biosynthesis, accumulation of some target fatty acids has been remarkably successful. In this review, we consider the probable factors responsible for these different outcomes, as well as the potential for further optimization of the transgenic production of unusual fatty acids in transgenic plants.
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