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Mao BD, Vadiveloo A, Qiu J, Gao F. Artificial photosynthesis: Promising approach for the efficient production of high-value bioproducts by microalgae. BIORESOURCE TECHNOLOGY 2024; 401:130718. [PMID: 38641303 DOI: 10.1016/j.biortech.2024.130718] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2024] [Revised: 04/11/2024] [Accepted: 04/17/2024] [Indexed: 04/21/2024]
Abstract
Recently, microalgae had received extensive attention for carbon capture and utilization. But its overall efficiency still could not reach a satisfactory degree. Artificial photosynthesis showed better efficiency in the conversion of carbon dioxide. However, artificial photosynthesis could generally only produce C1-C3 organic matters at present. Some studies showed that heterotrophic microalgae can efficiently synthesize high value organic matters by using simple organic matter such as acetate. Therefore, the combination of artificial photosynthesis with heterotrophic microalgae culture showed great potential for efficient carbon capture and high-value organic matter production. This article systematically analyzed the characteristics and challenges of carbon dioxide conversion by microalgae and artificial photosynthesis. On this basis, the coupling mode and development trend of artificial photosynthesis combined with microalgae culture were discussed. In summary, the combination of artificial photosynthesis and microalgae culture has great potential in the field of carbon capture and utilization, and deserves further study.
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Affiliation(s)
- Bin-Di Mao
- School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan 316000, China
| | - Ashiwin Vadiveloo
- Centre for Water, Energy and Waste, Harry Butler Institute, Murdoch University, Perth 6150, Australia
| | - Jian Qiu
- School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan 316000, China
| | - Feng Gao
- School of Petrochemical Engineering & Environment, Zhejiang Ocean University, Zhoushan 316000, China.
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2
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Canini D, Ceschi E, Perozeni F. Toward the Exploitation of Sustainable Green Factory: Biotechnology Use of Nannochloropsis spp. BIOLOGY 2024; 13:292. [PMID: 38785776 PMCID: PMC11117969 DOI: 10.3390/biology13050292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/19/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Securing food, energy, and raw materials for a growing population is one of the most significant challenges of our century. Algae play a central role as an alternative to plants. Wastewater and flue gas can secure nutrients and CO2 for carbon fixation. Unfortunately, algae domestication is necessary to enhance biomass production and reduce cultivation costs. Nannochloropsis spp. have increased in popularity among microalgae due to their ability to accumulate high amounts of lipids, including PUFAs. Recently, the interest in the use of Nannochloropsis spp. as a green bio-factory for producing high-value products increased proportionally to the advances of synthetic biology and genetic tools in these species. In this review, we summarized the state of the art of current nuclear genetic manipulation techniques and a few examples of their application. The industrial use of Nannochloropsis spp. has not been feasible yet, but genetic tools can finally lead to exploiting this full-of-potential microalga.
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Affiliation(s)
| | | | - Federico Perozeni
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (D.C.); (E.C.)
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3
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Ye Y, Liu M, Yu L, Sun H, Liu J. Nannochloropsis as an Emerging Algal Chassis for Light-Driven Synthesis of Lipids and High-Value Products. Mar Drugs 2024; 22:54. [PMID: 38393025 PMCID: PMC10890015 DOI: 10.3390/md22020054] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2023] [Revised: 01/14/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
In light of the escalating global energy crisis, microalgae have emerged as highly promising producers of biofuel and high-value products. Among these microalgae, Nannochloropsis has received significant attention due to its capacity to generate not only triacylglycerol (TAG) but also eicosapentaenoic acid (EPA) and valuable carotenoids. Recent advancements in genetic tools and the field of synthetic biology have revolutionized Nannochloropsis into a powerful biofactory. This comprehensive review provides an initial overview of the current state of cultivation and utilization of the Nannochloropsis genus. Subsequently, our review examines the metabolic pathways governing lipids and carotenoids, emphasizing strategies to enhance oil production and optimize carbon flux redirection toward target products. Additionally, we summarize the utilization of advanced genetic manipulation techniques in Nannochloropsis. Together, the insights presented in this review highlight the immense potential of Nannochloropsis as a valuable model for biofuels and synthetic biology. By effectively integrating genetic tools and metabolic engineering, the realization of this potential becomes increasingly feasible.
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Affiliation(s)
- Ying Ye
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
| | - Meijing Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Center for Algae Innovation & Engineering Research, School of Resources and Environment, Nanchang University, Nanchang 330031, China
| | - Lihua Yu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
| | - Han Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Center for Algae Innovation & Engineering Research, School of Resources and Environment, Nanchang University, Nanchang 330031, China
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Wang M, Ye X, Bi H, Shen Z. Microalgae biofuels: illuminating the path to a sustainable future amidst challenges and opportunities. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2024; 17:10. [PMID: 38254224 PMCID: PMC10804497 DOI: 10.1186/s13068-024-02461-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Accepted: 01/11/2024] [Indexed: 01/24/2024]
Abstract
The development of microalgal biofuels is of significant importance in advancing the energy transition, alleviating food pressure, preserving the natural environment, and addressing climate change. Numerous countries and regions across the globe have conducted extensive research and strategic planning on microalgal bioenergy, investing significant funds and manpower into this field. However, the microalgae biofuel industry has faced a downturn due to the constraints of high costs. In the past decade, with the development of new strains, technologies, and equipment, the feasibility of large-scale production of microalgae biofuel should be re-evaluated. Here, we have gathered research results from the past decade regarding microalgae biofuel production, providing insights into the opportunities and challenges faced by this industry from the perspectives of microalgae selection, modification, and cultivation. In this review, we suggest that highly adaptable microalgae are the preferred choice for large-scale biofuel production, especially strains that can utilize high concentrations of inorganic carbon sources and possess stress resistance. The use of omics technologies and genetic editing has greatly enhanced lipid accumulation in microalgae. However, the associated risks have constrained the feasibility of large-scale outdoor cultivation. Therefore, the relatively controllable cultivation method of photobioreactors (PBRs) has made it the mainstream approach for microalgae biofuel production. Moreover, adjusting the performance and parameters of PBRs can also enhance lipid accumulation in microalgae. In the future, given the relentless escalation in demand for sustainable energy sources, microalgae biofuels should be deemed a pivotal constituent of national energy planning, particularly in the case of China. The advancement of synthetic biology helps reduce the risks associated with genetically modified (GM) microalgae and enhances the economic viability of their biofuel production.
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Affiliation(s)
- Min Wang
- Institute of Agricultural Remote Sensing and Information, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China.
| | - Xiaoxue Ye
- Sanya Research Institute of Chinese Academy of Tropical Agricultural Sciences, Sanya, 572025, China
| | - Hongwen Bi
- Institute of Agricultural Remote Sensing and Information, Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China
| | - Zhongbao Shen
- Grass and Science Institute of Heilongjiang Academy of Agricultural Sciences, Harbin, 150086, China.
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5
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Sun H, Gao Z, Zhang L, Wang X, Gao M, Wang Q. A comprehensive review on microbial lipid production from wastes: research updates and tendencies. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:79654-79675. [PMID: 37328718 DOI: 10.1007/s11356-023-28123-6] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 06/01/2023] [Indexed: 06/18/2023]
Abstract
Microbial lipids have recently attracted attention as an intriguing alternative for the biodiesel and oleochemical industries to achieve sustainable energy generation. However, large-scale lipid production remains limited due to the high processing costs. As multiple variables affect lipid synthesis, an up-to-date overview that will benefit researchers studying microbial lipids is necessary. In this review, the most studied keywords from bibliometric studies are first reviewed. Based on the results, the hot topics in the field were identified to be associated with microbiology studies that aim to enhance lipid synthesis and reduce production costs, focusing on the biological and metabolic engineering involved. The research updates and tendencies of microbial lipids were then analyzed in depth. In particular, feedstock and associated microbes, as well as feedstock and corresponding products, were analyzed in detail. Strategies for lipid biomass enhancement were also discussed, including feedstock adoption, value-added product synthesis, selection of oleaginous microbes, cultivation mode optimization, and metabolic engineering strategies. Finally, the environmental implications of microbial lipid production and possible research directions were presented.
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Affiliation(s)
- Haishu Sun
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Shunde Innovation School, University of Science and Technology Beijing, Foshan, 528399, China
| | - Zhen Gao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Lirong Zhang
- Tianjin College, University of Science and Technology, Beijing, Tianjin, 301811, China
| | - Xiaona Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
- Shunde Innovation School, University of Science and Technology Beijing, Foshan, 528399, China.
| | - Ming Gao
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
| | - Qunhui Wang
- School of Energy and Environmental Engineering, University of Science and Technology Beijing, Beijing, 100083, China
- Tianjin College, University of Science and Technology, Beijing, Tianjin, 301811, China
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Liu M, Ding W, Pan Y, Hu H, Liu J. Zeaxanthin epoxidase is involved in the carotenoid biosynthesis and light-dependent growth of the marine alga Nannochloropsis oceanica. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:74. [PMID: 37138328 PMCID: PMC10157934 DOI: 10.1186/s13068-023-02326-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 04/24/2023] [Indexed: 05/05/2023]
Abstract
BACKGROUND The marine alga Nannochloropsis oceanica, an emerging model belonging to Heterokont, is considered as a promising light-driven eukaryotic chassis for transforming carbon dioxide to various compounds including carotenoids. Nevertheless, the carotenogenic genes and their roles in the alga remain less understood and to be further explored. RESULTS Here, two phylogenetically distant zeaxanthin epoxidase (ZEP) genes from N. oceanica (NoZEP1 and NoZEP2) were functionally characterized. Subcellular localization experiment demonstrated that both NoZEP1 and NoZEP2 reside in the chloroplast yet with differential distribution patterns. Overexpression of NoZEP1 or NoZEP2 led to increases of violaxanthin and its downstream carotenoids at the expense of zeaxanthin in N. oceanica, with the extent of changes mediated by NoZEP1 overexpression being greater as compared to NoZEP2 overexpression. Suppression of NoZEP1 or NoZEP2, on the other hand, caused decreases of violaxanthin and its downstream carotenoids as well as increases of zeaxanthin; similarly, the extent of changes mediated by NoZEP1 suppression was larger than that by NoZEP2 suppression. Interestingly, chlorophyll a dropped following violaxanthin decrease in a well-correlated manner in response to NoZEP suppression. The thylakoid membrane lipids including monogalactosyldiacylglycerol also correlated with the violaxanthin decreases. Accordingly, NoZEP1 suppression resulted in more attenuated algal growth than NoZEP2 suppression did under either normal light or high light stage. CONCLUSIONS The results together support that both NoZEP1 and NoZEP2, localized in the chloroplast, have overlapping roles in epoxidating zeaxanthin to violaxanthin for the light-dependent growth, yet with NoZEP1 being more functional than NoZEP2 in N. oceanica. Our study provides implications into the understanding of carotenoid biosynthesis and future manipulation of N. oceanica for carotenoid production.
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Affiliation(s)
- Meijing Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Wei Ding
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Hanhua Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, 430072 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
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7
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Li X, Yang M, Sun D, Shi J, Yang M, Feng Y, Xue S. Unique recognition of the microalgal plastidial glycerol-3-phosphate acyltransferase for acyl-ACP. PLANT SCIENCE : AN INTERNATIONAL JOURNAL OF EXPERIMENTAL PLANT BIOLOGY 2023; 332:111725. [PMID: 37142097 DOI: 10.1016/j.plantsci.2023.111725] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 04/29/2023] [Accepted: 05/02/2023] [Indexed: 05/06/2023]
Abstract
Plastidial glycerol-3-phosphate acyltransferases (GPATs) catalyze acyl-ACP and glycerol-3-phosphate to synthesize lysophosphatidic acid in vivo, which initiates the formation of various glycerolipids. Although the physiological substrates of plastidial GPATs are acyl-ACPs, acyl-CoAs have been commonly studied on the GPATs in vitro. However, little is known whether there are any distinct features of GPATs towards acyl-ACP and acyl-CoA. In this study, the results showed that the microalgal plastidial GPATs preferred acyl-ACP to acyl-CoA, while surprisingly, the plant-derived plastidial GPATs showed no obvious preferences towards these two acyl carriers. The key residues responsible for the distinct feature of microalgal plastidial GPATs were compared with plant-derived plastidial GPATs in their efficiency to catalyze acyl-ACP and acyl-CoA. Microalgal plastidial GPATs uniquely recognized acyl-ACP as compared to with other acyltransferases. The structure of the acyltransferases-ACP complex highlights only the involvement of the large structural domain in ACP in microalgal plastidial GPAT while in the other acyltransferases, both large and small structural domains were involved in the recognition process. The interaction sites on the plastidial GPAT from the green alga Myrmecia incisa (MiGPAT1) with ACP turned out to be K204, R212 and R266. A unique recognition between the microalgal plastidial GPAT and ACP was elucidated.
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Affiliation(s)
- Xianglong Li
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Miao Yang
- Key Laboratory of Plant Biotechnology of Liaoning Province, School of Life Sciences, Liaoning Normal University, Dalian, 116081, China
| | - Dongru Sun
- Institute of Drug Discovery Technology, Ningbo University, Ningbo 315211, Zhejiang, China
| | - Jianping Shi
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Ming Yang
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China
| | - Yanbin Feng
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China.
| | - Song Xue
- School of Bioengineering, Dalian University of Technology, Dalian 116024, China.
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Liu K, Li J, Xing C, Yuan H, Yang J. Characterization of Auxenochlorella protothecoides acyltransferases and potential of their protein interactions to promote the enrichment of oleic acid. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:69. [PMID: 37085915 PMCID: PMC10120206 DOI: 10.1186/s13068-023-02318-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/14/2022] [Accepted: 04/10/2023] [Indexed: 04/23/2023]
Abstract
BACKGROUND After centuries of heavy reliance on fossil fuel energy, the world suffers from an energy crisis and global warming, calling for carbon emission reduction and a transition to clean energy. Microalgae have attracted much attention as a potential feedstock for biofuel production due to their high triacylglycerol content and CO2 sequestration ability. Many diacylglycerol acyltransferases (DGAT) species have been characterized, which catalyze the final committed step in triacylglycerol biosynthesis. However, the detailed structure-function features of DGATs and the role of the interactions among DGAT proteins in lipid metabolism remained largely unknown. RESULTS In this study, the three characterized DGATs of Auxenochlorella protothecoides 2341 showed distinct structural and functional conservation. Functional complementation analyses showed that ApDGAT1 had higher activity than ApDGAT2b in yeast and model microalgae, and ApDGAT2a had no activity in yeast. The N-terminus was not essential to the catalysis function of ApDGAT1 but was crucial to ApDGAT2b as its enzyme activity was sensitive to any N-terminus modifications. Similarly, when acyl-CoA binding proteins (ACBPs) were fused to the N-terminus of ApDGAT1 and ApDGAT2b, zero and significant activity changes were observed, respectively. Interestingly, the ApACBP3 + ApDGAT1 variant contributed to higher oil accumulation than the original DGAT1, and ApACBP1 + ApDGAT1 fusion boosted oleic acid content in yeast. Overexpression of the three DGATs and the variation of ApACBP3 + ApDGAT1 increased the content of C18:1 of Chlamydomonas reinhardtii CC-5235. Significantly, ApDGAT1 interacted with itself, ApDGAT2b, and ApACBP1, which indicated that these three lipid metabolic proteins might have been a part of a dynamic protein interactome that facilitated the enrichment of oleic acid. CONCLUSIONS This study provided new insights into the functional and structural characteristics of DGATs and elucidated the importance of these physical interactions in potential lipid channeling.
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Affiliation(s)
- Kui Liu
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinyu Li
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Chao Xing
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Hongli Yuan
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China
| | - Jinshui Yang
- State Key Laboratory of Animal Biotech Breeding, College of Biological Sciences, China Agricultural University, Beijing, 100193, China.
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Yu R, Chang L, Cao J, Yang B, Chen H, Chen W. Applications of Diacylglycerol Acyltransferase for Triacylglycerol Production in Mortierella alpina. J Fungi (Basel) 2023; 9:jof9020219. [PMID: 36836332 PMCID: PMC9965251 DOI: 10.3390/jof9020219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2022] [Revised: 02/01/2023] [Accepted: 02/02/2023] [Indexed: 02/10/2023] Open
Abstract
Triacylglycerol (TG) with high-value long-chain polyunsaturated fatty acids is beneficial to human health; consequently, there is an urgent need to broaden its sources due to the current growing demand. Mortierella alpina, one of the most representative oleaginous fungi, is the only certificated source of dietary arachidonic acid-rich oil supplied in infant formula. This study was conducted to improve TG production in M. alpina by homologous overexpression of diacylglycerol acyltransferase (DGAT) and linseed oil (LSO) supplementation. Our results showed that the homologous overexpression of MaDGAT1B and MaDGAT2A strengthened TG biosynthesis and significantly increased the TG content compared to the wild-type by 12.24% and 14.63%, respectively. The supplementation with an LSO concentration of 0.5 g/L elevated the TG content to 83.74% and total lipid yield to 4.26 ± 0.38 g/L in the M. alpina-MaDGAT2A overexpression strain. Our findings provide an effective strategy for enhancing TG production and highlight the role of DGAT in TG biosynthesis in M. alpina.
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Affiliation(s)
- Ruilin Yu
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Lulu Chang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Jun Cao
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Bo Yang
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
| | - Haiqin Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- Correspondence:
| | - Wei Chen
- State Key Laboratory of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- School of Food Science and Technology, Jiangnan University, Wuxi 214122, China
- National Engineering Research Center for Functional Food, Jiangnan University, Wuxi 214122, China
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10
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Südfeld C, Kiyani A, Wefelmeier K, Wijffels RH, Barbosa MJ, D’Adamo S. Expression of glycerol-3-phosphate acyltransferase increases non-polar lipid accumulation in Nannochloropsis oceanica. Microb Cell Fact 2023; 22:12. [PMID: 36647076 PMCID: PMC9844033 DOI: 10.1186/s12934-022-01987-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2022] [Accepted: 12/09/2022] [Indexed: 01/18/2023] Open
Abstract
Microalgae are considered a suitable production platform for high-value lipids and oleochemicals. Several species including Nannochloropsis oceanica produce large amounts of essential [Formula: see text]-3 polyunsaturated fatty acids (PUFAs) which are integral components of food and feed and have been associated with health-promoting effects. N. oceanica can further accumulate high contents of non-polar lipids with chemical properties that render them a potential replacement for plant oils such as palm oil. However, biomass and lipid productivities obtained with microalgae need to be improved to reach commercial feasibility. Genetic engineering can improve biomass and lipid productivities, for instance by increasing carbon flux to lipids. Here, we report the overexpression of glycerol-3-phosphate acyltransferase (GPAT) in N. oceanica during favorable growth conditions as a strategy to increase non-polar lipid content. Transformants overproducing either an endogenous (NoGPAT) or a heterologous (Acutodesmus obliquus GPAT) GPAT enzyme targeted to the endoplasmic reticulum had up to 42% and 51% increased non-polar lipid contents, respectively, compared to the wild type. Biomass productivities of transformant strains were not substantially impaired, resulting in lipid productivities that were increased by up to 37% and 42% for NoGPAT and AoGPAT transformants, respectively. When exposed to nutrient stress, transformants and wild type had similar lipid contents, suggesting that GPAT enzyme exerts strong flux control on lipid synthesis in N. oceanica under favorable growth conditions. NoGPAT transformants further accumulated PUFAs in non-polar lipids, reaching a total of 6.8% PUFAs per biomass, an increase of 24% relative to the wild type. Overall, our results indicate that GPAT is an interesting target for engineering of lipid metabolism in microalgae, in order to improve non-polar lipid and PUFAs accumulation in microalgae.
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Affiliation(s)
- Christian Südfeld
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
| | - Aamna Kiyani
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands ,grid.412621.20000 0001 2215 1297Department of Microbiology, Quaid-I-Azam University, Islamabad, 45320 Pakistan
| | - Katrin Wefelmeier
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
| | - René H. Wijffels
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands ,grid.465487.cFaculty of Biosciences and Aquaculture, Nord University, N-8049 Bodø, Norway
| | - Maria J. Barbosa
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
| | - Sarah D’Adamo
- grid.4818.50000 0001 0791 5666Wageningen University, Bioprocess Engineering, PO Box 16, 6700 AA Wageningen, Netherlands
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11
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Xu Y. Biochemistry and Biotechnology of Lipid Accumulation in the Microalga Nannochloropsis oceanica. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2022; 70:11500-11509. [PMID: 36083864 DOI: 10.1021/acs.jafc.2c05309] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/15/2023]
Abstract
Oils are among the most important agricultural commodities and have wide applications in food/nutrition, biofuels, and oleochemicals. The oleaginous microalga Nannochloropsis oceanica can produce large amounts of oils and the high-value ω-3 eicosapentaenoic acid, which represents a promising resource for oil production targeting biodiesel, nutraceutical, and aquaculture industries. In recent years, with the availability of omics databases and the development of genetic tools, N. oceanica has been extensively investigated as a model photosynthetic organism for studying lipid metabolism and as a green cellular factory to produce lipids for industrial applications. This review summarizes the current knowledge on the lipid composition and biosynthetic pathways of N. oceanica and reviews the recent advances in metabolic engineering of lipid production in this microalga.
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Affiliation(s)
- Yang Xu
- Department of Molecular and Cellular Biology, University of Guelph, Guelph, Ontario N1G 2W1, Canada
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12
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Liu M, Ding W, Yu L, Shi Y, Liu J. Functional characterization of carotenogenic genes provides implications into carotenoid biosynthesis and engineering in the marine alga Nannochloropsis oceanica. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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13
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Chen G, Harwood JL, Lemieux MJ, Stone SJ, Weselake RJ. Acyl-CoA:diacylglycerol acyltransferase: Properties, physiological roles, metabolic engineering and intentional control. Prog Lipid Res 2022; 88:101181. [PMID: 35820474 DOI: 10.1016/j.plipres.2022.101181] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 05/31/2022] [Accepted: 07/04/2022] [Indexed: 12/15/2022]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT, EC 2.3.1.20) catalyzes the last reaction in the acyl-CoA-dependent biosynthesis of triacylglycerol (TAG). DGAT activity resides mainly in membrane-bound DGAT1 and DGAT2 in eukaryotes and bifunctional wax ester synthase-diacylglycerol acyltransferase (WSD) in bacteria, which are all membrane-bound proteins but exhibit no sequence homology to each other. Recent studies also identified other DGAT enzymes such as the soluble DGAT3 and diacylglycerol acetyltransferase (EaDAcT), as well as enzymes with DGAT activities including defective in cuticular ridges (DCR) and steryl and phytyl ester synthases (PESs). This review comprehensively discusses research advances on DGATs in prokaryotes and eukaryotes with a focus on their biochemical properties, physiological roles, and biotechnological and therapeutic applications. The review begins with a discussion of DGAT assay methods, followed by a systematic discussion of TAG biosynthesis and the properties and physiological role of DGATs. Thereafter, the review discusses the three-dimensional structure and insights into mechanism of action of human DGAT1, and the modeled DGAT1 from Brassica napus. The review then examines metabolic engineering strategies involving manipulation of DGAT, followed by a discussion of its therapeutic applications. DGAT in relation to improvement of livestock traits is also discussed along with DGATs in various other eukaryotic organisms.
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Affiliation(s)
- Guanqun Chen
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada.
| | - John L Harwood
- School of Biosciences, Cardiff University, Cardiff CF10 3AX, UK
| | - M Joanne Lemieux
- Department of Biochemistry, University of Alberta, Membrane Protein Disease Research Group, Edmonton T6G 2H7, Canada
| | - Scot J Stone
- Department of Biochemistry, Microbiology and Immunology, University of Saskatchewan, Saskatoon, Saskatchewan S7N 5E5, Canada.
| | - Randall J Weselake
- Department of Agricultural, Food, and Nutritional Science, University of Alberta, Edmonton, Alberta T6H 2P5, Canada
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14
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Yang J, Liu J, Pan Y, Maréchal E, Amato A, Liu M, Gong Y, Li Y, Hu H. PDAT regulates PE as transient carbon sink alternative to triacylglycerol in Nannochloropsis. PLANT PHYSIOLOGY 2022; 189:1345-1362. [PMID: 35385114 PMCID: PMC9237688 DOI: 10.1093/plphys/kiac160] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 03/14/2022] [Indexed: 05/21/2023]
Abstract
Triacylglycerols (TAGs) are the main storage lipids in photosynthetic organisms under stress. In the oleaginous alga Nannochloropsis oceanica, while multiple acyl CoA:diacylglycerol (DAG) acyltransferases (NoDGATs) are involved in TAG production, the role of the unique phospholipid:DAG acyltransferase (NoPDAT) remains unknown. Here, we performed a functional complementation assay in TAG-deficient yeast (Saccharomyces cerevisiae) and an in vitro assay to probe the acyltransferase activity of NoPDAT. Subcellular localization, overexpression, and knockdown (KD) experiments were also conducted to elucidate the role of NoPDAT in N. oceanica. NoPDAT, residing at the outermost plastid membrane, does not phylogenetically fall into the clades of algae or plants and uses phosphatidylethanolamine (PE) and phosphatidylglycerol with 16:0, 16:1, and 18:1 at position sn-2 as acyl-donors in vivo. NoPDAT KD, not triggering any compensatory mechanism via DGATs, led to an ∼30% decrease of TAG content, accompanied by a vast accumulation of PEs rich in 16:0, 16:1, and 18:1 fatty acids (referred to as "LU-PE") that was positively associated with CO2 availability. We conclude that the NoPDAT pathway is parallel to and independent of the NoDGAT pathway for oil production. LU-PE can serve as an alternative carbon sink for photosynthetically assimilated carbon in N. oceanica when PDAT-mediated TAG biosynthesis is compromised or under stress in the presence of high CO2 levels.
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Affiliation(s)
| | | | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG‐LPCV, 38054 Grenoble Cedex 9, France
| | - Alberto Amato
- Laboratoire de Physiologie Cellulaire Végétale, Université Grenoble Alpes, CEA, CNRS, INRA, IRIG‐LPCV, 38054 Grenoble Cedex 9, France
| | - Meijing Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yangmin Gong
- Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Oil Crops Research Institute of Chinese Academy of Agricultural Sciences, Wuhan 430062, China
| | - Yantao Li
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Science and University of Maryland Baltimore County, Baltimore, Maryland 21202, USA
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15
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Zhang P, Xin Y, He Y, Tang X, Shen C, Wang Q, Lv N, Li Y, Hu Q, Xu J. Exploring a blue-light-sensing transcription factor to double the peak productivity of oil in Nannochloropsis oceanica. Nat Commun 2022; 13:1664. [PMID: 35351909 PMCID: PMC8964759 DOI: 10.1038/s41467-022-29337-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Accepted: 03/08/2022] [Indexed: 12/19/2022] Open
Abstract
Oleaginous microalgae can produce triacylglycerol (TAG) under stress, yet the underlying mechanism remains largely unknown. Here, we show that, in Nannochloropsis oceanica, a bZIP-family regulator NobZIP77 represses the transcription of a type-2 diacylgycerol acyltransferase encoding gene NoDGAT2B under nitrogen-repletion (N+), while nitrogen-depletion (N−) relieves such inhibition and activates NoDGAT2B expression and synthesis of TAG preferably from C16:1. Intriguingly, NobZIP77 is a sensor of blue light (BL), which reduces binding of NobZIP77 to the NoDGAT2B-promoter, unleashes NoDGAT2B and elevates TAG under N−. Under N+ and white light, NobZIP77 knockout fully preserves cell growth rate and nearly triples TAG productivity. Moreover, exposing the NobZIP77-knockout line to BL under N− can double the peak productivity of TAG. These results underscore the potential of coupling light quality to oil synthesis in feedstock or bioprocess development. Microalgae are promising feedstock for oil production. The authors report that a transcription factor NobZIP77 can regulate oil synthesis by sensing the blue light, and explore these findings to greatly enhance oil productivity via genetic and process engineering in Nannochloropsis oceanica.
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16
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Latest Expansions in Lipid Enhancement of Microalgae for Biodiesel Production: An Update. ENERGIES 2022. [DOI: 10.3390/en15041550] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Research progress on sustainable and renewable biofuel has gained motion over the years, not just due to the rapid reduction of dwindling fossil fuel supplies but also due to environmental and potential energy security issues as well. Intense interest in microalgae (photosynthetic microbes) as a promising feedstock for third-generation biofuels has grown over recent years. Fuels derived from algae are now considered sustainable biofuels that are promising, renewable, and clean. Therefore, selecting the robust species of microalgae with substantial features for quality biodiesel production is the first step in the way of biofuel production. A contemporary investigation is more focused on several strategies and techniques to achieve higher biomass and triglycerides in microalgae. The improvement in lipid enhancement in microalgae species by genetic manipulation approaches, such as metabolic or genetic alteration, and the use of nanotechnology are the most recent ways of improving the production of biomass and lipids. Hence, the current review collects up-to-date approaches for microalgae lipid increase and biodiesel generation. The strategies for high biomass and high lipid yield are discussed. Additionally, various pretreatment procedures that may aid in lipid harvesting efficiency and improve lipid recovery rate are described.
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17
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Kang NK, Baek K, Koh HG, Atkinson CA, Ort DR, Jin YS. Microalgal metabolic engineering strategies for the production of fuels and chemicals. BIORESOURCE TECHNOLOGY 2022; 345:126529. [PMID: 34896527 DOI: 10.1016/j.biortech.2021.126529] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/02/2021] [Accepted: 12/03/2021] [Indexed: 06/14/2023]
Abstract
Microalgae are promising sustainable resources because of their ability to convert CO2 into biofuels and chemicals directly. However, the industrial production and economic feasibility of microalgal bioproducts are still limited. As such, metabolic engineering approaches have been undertaken to enhance the productivities of microalgal bioproducts. In the last decade, impressive advances in microalgae metabolic engineering have been made by developing genetic engineering tools and multi-omics analysis. This review presents comprehensive microalgal metabolic pathways and metabolic engineering strategies for producing lipids, long chain-polyunsaturated fatty acids, terpenoids, and carotenoids. Additionally, promising metabolic engineering approaches specific to target products are summarized. Finally, this review discusses current challenges and provides future perspectives for the effective production of chemicals and fuels via microalgal metabolic engineering.
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Affiliation(s)
- Nam Kyu Kang
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Kwangryul Baek
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Hyun Gi Koh
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Christine Anne Atkinson
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Donald R Ort
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Global Change and Photosynthesis Research Unit, Agricultural Research Service, United States Department of Agriculture, Urbana, IL, USA; Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Plant Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Yong-Su Jin
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA; DOE Center for Advanced Bioenergy and Bioproducts Innovation, University of Illinois at Urbana-Champaign, Urbana, IL, USA; Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign, Urbana, IL, USA.
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18
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Ma H, Zheng J, Li Y, Zhao L, Zou S, Hu Q, Han D. A Novel Bifunctional Wax Ester Synthase Involved in Early Triacylglycerol Accumulation in Unicellular Green Microalga Haematococcus pluvialis Under High Light Stress. Front Bioeng Biotechnol 2022; 9:794714. [PMID: 35111735 PMCID: PMC8802113 DOI: 10.3389/fbioe.2021.794714] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2021] [Accepted: 11/30/2021] [Indexed: 11/20/2022] Open
Abstract
The bulk of neutral lipids, including astaxanthin esters and triacylglycerols (TAGs), are accumulated in the green microalga Haematococcus pluvialis under high light (HL) stress. In this study, a novel bifunctional wax ester synthase (WS) gene was cloned from H. pluvialis upon HL stress. The overexpression of HpWS restored the biosynthesis of wax esters and TAGs in neutral lipid-deficient yeast mutant Saccharomyces cerevisiae H1246 fed with C18 alcohol and C18:1/C18:3 fatty acids, respectively. Under HL stress, HpWS was substantially upregulated at the transcript level, prior to that of the type I diacylglycerol:acyl-CoA acyltransferase encoding gene (HpDGAT1). HpDGAT1 is the major TAG synthase in H. pluvialis. In addition, the application of xanthohumol (a DGAT1/2 inhibitor) in the H. pluvialis cells did not completely eliminate the TAG biosynthesis under HL stress at 24 h. These results indicated that HpWS may contribute to the accumulation of TAGs in H. pluvialis at the early stage under HL stress. In addition, the overexpression of HpWS in Chlamydomonas reinhardtii bkt5, which is engineered to produce free astaxanthin, enhanced the production of TAGs and astaxanthin. Our findings broaden the understanding of TAG biosynthesis in microalgae and provide a new molecular target for genetic manipulation in biotechnological applications.
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Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- *Correspondence: Haiyan Ma,
| | - Jie Zheng
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Song Zou
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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19
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Manipulation of triacylglycerol biosynthesis in Nannochloropsis oceanica by overexpressing an Arabidopsis thaliana diacylglycerol acyltransferase gene. ALGAL RES 2022. [DOI: 10.1016/j.algal.2021.102590] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
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20
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Santin A, Russo MT, Ferrante MI, Balzano S, Orefice I, Sardo A. Highly Valuable Polyunsaturated Fatty Acids from Microalgae: Strategies to Improve Their Yields and Their Potential Exploitation in Aquaculture. Molecules 2021; 26:7697. [PMID: 34946780 PMCID: PMC8707597 DOI: 10.3390/molecules26247697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Microalgae have a great potential for the production of healthy food and feed supplements. Their ability to convert carbon into high-value compounds and to be cultured in large scale without interfering with crop cultivation makes these photosynthetic microorganisms promising for the sustainable production of lipids. In particular, microalgae represent an alternative source of polyunsaturated fatty acids (PUFAs), whose consumption is related to various health benefits for humans and animals. In recent years, several strategies to improve PUFAs' production in microalgae have been investigated. Such strategies include selecting the best performing species and strains and the optimization of culturing conditions, with special emphasis on the different cultivation systems and the effect of different abiotic factors on PUFAs' accumulation in microalgae. Moreover, developments and results obtained through the most modern genetic and metabolic engineering techniques are described, focusing on the strategies that lead to an increased lipid production or an altered PUFAs' profile. Additionally, we provide an overview of biotechnological applications of PUFAs derived from microalgae as safe and sustainable organisms, such as aquafeed and food ingredients, and of the main techniques (and their related issues) for PUFAs' extraction and purification from microalgal biomass.
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Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Monia Teresa Russo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Sergio Balzano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Department of Marine Microbiology and Biogeochemistry, Netherland Institute for Sea Research, Landsdiep 4, 1793 AB Texel, The Netherlands
| | - Ida Orefice
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Angela Sardo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello”, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
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21
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Metabolic engineering of the oleaginous alga Nannochloropsis for enriching eicosapentaenoic acid in triacylglycerol by combined pulling and pushing strategies. Metab Eng 2021; 69:163-174. [PMID: 34864212 DOI: 10.1016/j.ymben.2021.11.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2021] [Revised: 11/20/2021] [Accepted: 11/30/2021] [Indexed: 11/23/2022]
Abstract
The marine alga Nannochloropsis oceanica has been considered as a promising photosynthetic cell factory for synthesizing eicosapentaenoic acid (EPA), yet the accumulation of EPA in triacylglycerol (TAG) is restricted to an extreme low level. Poor channeling of EPA to TAG was observed in N. oceanica under TAG induction conditions, likely due to the weak activity of endogenous diacylglycerol acyltransferases (DGATs) on EPA-CoA. Screening over thirty algal DGATs revealed potent enzymes acting on EPA-CoA. Whilst overexpressing endogenous DGATs had no or slight effect on EPA abundance in TAG, introducing selected DGATs with strong activity on EPA-CoA, particularly the Chlamydomonas-derived CrDGTT1, which resided at the outermost membrane of the chloroplast and provided a strong pulling power to divert EPA to TAG for storage and protection, led to drastic increases in EPA abundance in TAG and TAG-derived EPA level in N. oceanica. They were further promoted by additional overexpression of an elongase gene involved in EPA biosynthesis, reaching 5.9- and 12.3-fold greater than the control strain, respectively. Our results together demonstrate the concept of applying combined pulling and pushing strategies to enrich EPA in algal TAG and provide clues for the enrichment of other desired fatty acids in TAG as well.
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22
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Genetic engineering of microalgae for enhanced lipid production. Biotechnol Adv 2021; 52:107836. [PMID: 34534633 DOI: 10.1016/j.biotechadv.2021.107836] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 09/09/2021] [Accepted: 09/09/2021] [Indexed: 12/24/2022]
Abstract
Microalgae have the potential to become microbial cell factories for lipid production. Their ability to convert sunlight and CO2 into valuable lipid compounds has attracted interest from cosmetic, biofuel, food and feed industries. In order to make microalgae-derived products cost-effective and commercially competitive, enhanced growth rates and lipid productivities are needed, which require optimization of cultivation systems and strain improvement. Advances in genetic tool development and omics technologies have increased our understanding of lipid metabolism, which has opened up possibilities for targeted metabolic engineering. In this review we provide a comprehensive overview on the developments made to genetically engineer microalgal strains over the last 30 years. We focus on the strategies that lead to an increased lipid content and altered fatty acid profile. These include the genetic engineering of the fatty acid synthesis pathway, Kennedy pathway, polyunsaturated fatty acid and triacylglycerol metabolisms and fatty acid catabolism. Moreover, genetic engineering of specific transcription factors, NADPH generation and central carbon metabolism, which lead to increase of lipid accumulation are also reviewed.
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23
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Wu T, Yu L, Zhang Y, Liu J. Characterization of fatty acid desaturases reveals stress-induced synthesis of C18 unsaturated fatty acids enriched in triacylglycerol in the oleaginous alga Chromochloris zofingiensis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:184. [PMID: 34535156 PMCID: PMC8447527 DOI: 10.1186/s13068-021-02037-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/07/2021] [Indexed: 05/16/2023]
Abstract
BACKGROUND The green microalga Chromochloris zofingiensis is capable of producing high levels of triacylglycerol rich in C18 unsaturated fatty acids (UFAs). FA desaturation degree is regulated by FA desaturases (FADs). Nevertheless, it remains largely unknown regarding what FADs are involved in FA desaturations and how these FADs collaborate to contribute to the high abundance of C18 UFAs in triacylglycerol in C. zofingiensis. RESULTS To address these issues, we firstly determined the transcription start sites of 11 putative membrane-bound FAD-coding genes (CzFADs) and updated their gene models. Functional validation of these CzFADs in yeast and cyanobacterial cells revealed that seven are bona fide FAD enzymes with distinct substrates. Combining the validated functions and predicted subcellular compartments of CzFADs and the FA profiles of C. zofingiensis, the FA desaturation pathways in this alga were reconstructed. Furthermore, a multifaceted lipidomic analysis by systematically integrating thin-layer chromatography, gas chromatography-mass spectrometry and liquid chromatography-mass spectrometry techniques was conducted, unraveling profiles of polar membrane lipids in C. zofingiensis and major desaturation steps occurring in these lipids. By correlating transcriptional patterns of CzFAD genes and changes of lipids upon abiotic stress conditions, our results highlighted collaboration of CzFADs for C18 UFA synthesis and supported that both de novo FA synthesis and membrane lipid remodeling contributed C18 UFAs to triacylglycerol for storage. CONCLUSIONS Taken together, our study for the first time elucidated the pathways of C18 FA desaturations and comprehensive profiles of polar membrane lipids in C. zofingiensis and shed light on collaboration of CzFADs for the synthesis and enrichment of C18 UFAs in triacylglycerol.
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Affiliation(s)
- Tao Wu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Lihua Yu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
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24
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Shi Y, Liu M, Pan Y, Hu H, Liu J. Δ6 Fatty Acid Elongase is Involved in Eicosapentaenoic Acid Biosynthesis Via the ω6 Pathway in the Marine Alga Nannochloropsis oceanica. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:9837-9848. [PMID: 34414763 DOI: 10.1021/acs.jafc.1c04192] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Nannochloropsis oceanica represents a promising sunlight-driven alga for producing eicosapentaenoic acid (EPA, 20:5Δ5,8,11,14,17), a value-added very long-chain polyunsaturated fatty acid (VLC-PUFA). Here, we unraveled the function and roles of a Δ6 fatty acid elongase (NoΔ6-FAE) in N. oceanica. Heterologous expression of NoΔ6-FAE in yeast confirmed its function in elongating C18 Δ6-PUFAs rather than others. Subcellular localization experiments suggested that NoΔ6-FAE resides in the chloroplast endoplasmic reticulum. NoΔ6-FAE knockdown attenuated C20:3Δ8,11,14, C20:4Δ5,8,11,14, and EPA yet enhanced C18:3Δ6,9,12, leading to overall decreases in total fatty acids, triacylglycerol, diacylglycerol, free fatty acids, and polar membrane lipids. In contrast, NoΔ6-FAE overexpression in N. oceanica caused nearly opposite phenotypes. Moreover, N. oceanica lacked detectable C18:3Δ9,12,15, C18:4Δ6,9,12,15, and C20:4Δ8,11,14,17 even under NoΔ6-FAE knockdown or overexpression. Our results reveal the involvement of NoΔ6-FAE in EPA biosynthesis via the ω6 pathway in N. oceanica and highlight the potential of manipulating NoΔ6-FAE for improved lipid production.
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Affiliation(s)
- Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Meijing Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yufang Pan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Hanhua Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
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25
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Hulatt CJ, Wijffels RH, Posewitz MC. The Genome of the Haptophyte Diacronema lutheri (Pavlova lutheri, Pavlovales): A Model for Lipid Biosynthesis in Eukaryotic Algae. Genome Biol Evol 2021; 13:6337978. [PMID: 34343248 PMCID: PMC8379373 DOI: 10.1093/gbe/evab178] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/27/2021] [Indexed: 12/28/2022] Open
Abstract
Haptophytes are biogeochemically and industrially important protists with underexplored genomic diversity. We present a nuclear genome assembly for the class Pavlovales, which was assembled with PacBio long-read data into highly contiguous sequences. We sequenced strain Diacronema lutheri NIVA-4/92, formerly known as Pavlova lutheri, because it has established roles in aquaculture and has been a key organism for studying microalgal lipid biosynthesis. Our data show that D. lutheri has the smallest and most streamlined haptophycean genome assembled to date, with an assembly size of 43.503 Mb and 14,446 protein-coding genes. Together with its high nuclear GC content, Diacronema is an important genus for investigating selective pressures on haptophyte genome evolution, contrasting with the much larger and more repetitive genome of the coccolithophore Emiliania huxleyi. The D. lutheri genome will be a valuable resource for resolving the genetic basis of algal lipid biosynthesis and metabolic remodeling that takes place during adaptation and stress response in natural and engineered environments.
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Affiliation(s)
- Chris J Hulatt
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway.,Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
| | - René H Wijffels
- Faculty of Biosciences and Aquaculture, Nord University, Mørkvedbukta Research Station, Bodø, Norway.,Bioprocess Engineering, AlgaePARC, Wageningen University and Research, The Netherlands
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, Colorado, USA
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Zhang L, Ye SC, Chen WB, Han JC, Tian JJ, Zhang YB, Xu JL, Cao JY, Qin C. Screening the rate-limiting genes in the ω6 polyunsaturated fatty acid biosynthesis pathway in Nannochloropsis oceanica. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102342] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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27
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Bo DD, Magneschi L, Bedhomme M, Billey E, Deragon E, Storti M, Menneteau M, Richard C, Rak C, Lapeyre M, Lembrouk M, Conte M, Gros V, Tourcier G, Giustini C, Falconet D, Curien G, Allorent G, Petroutsos D, Laeuffer F, Fourage L, Jouhet J, Maréchal E, Finazzi G, Collin S. Consequences of Mixotrophy on Cell Energetic Metabolism in Microchloropsis gaditana Revealed by Genetic Engineering and Metabolic Approaches. FRONTIERS IN PLANT SCIENCE 2021; 12:628684. [PMID: 34113360 PMCID: PMC8185151 DOI: 10.3389/fpls.2021.628684] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Accepted: 03/31/2021] [Indexed: 06/12/2023]
Abstract
Algae belonging to the Microchloropsis genus are promising organisms for biotech purposes, being able to accumulate large amounts of lipid reserves. These organisms adapt to different trophic conditions, thriving in strict photoautotrophic conditions, as well as in the concomitant presence of light plus reduced external carbon as energy sources (mixotrophy). In this work, we investigated the mixotrophic responses of Microchloropsis gaditana (formerly Nannochloropsis gaditana). Using the Biolog growth test, in which cells are loaded into multiwell plates coated with different organic compounds, we could not find a suitable substrate for Microchloropsis mixotrophy. By contrast, addition of the Lysogeny broth (LB) to the inorganic growth medium had a benefit on growth, enhancing respiratory activity at the expense of photosynthetic performances. To further dissect the role of respiration in Microchloropsis mixotrophy, we focused on the mitochondrial alternative oxidase (AOX), a protein involved in energy management in other algae prospering in mixotrophy. Knocking-out the AOX1 gene by transcription activator-like effector nuclease (TALE-N) led to the loss of capacity to implement growth upon addition of LB supporting the hypothesis that the effect of this medium was related to a provision of reduced carbon. We conclude that mixotrophic growth in Microchloropsis is dominated by respiratory rather than by photosynthetic energetic metabolism and discuss the possible reasons for this behavior in relationship with fatty acid breakdown via β-oxidation in this oleaginous alga.
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Affiliation(s)
- Davide Dal Bo
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Leonardo Magneschi
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Mariette Bedhomme
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Elodie Billey
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
- Total Refining Chemicals, Tour Coupole, Paris La Défense, France
| | - Etienne Deragon
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Mattia Storti
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Mathilde Menneteau
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Christelle Richard
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Camille Rak
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Morgane Lapeyre
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Mehdi Lembrouk
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Melissa Conte
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Valérie Gros
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Guillaume Tourcier
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Cécile Giustini
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Denis Falconet
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Gilles Curien
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Guillaume Allorent
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Dimitris Petroutsos
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | | | - Laurent Fourage
- Total Refining Chemicals, Tour Coupole, Paris La Défense, France
| | - Juliette Jouhet
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Eric Maréchal
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Giovanni Finazzi
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
| | - Séverine Collin
- Université Grenoble Alpes (UGA), Centre National Recherche Scientifique (CNRS), Commissariat Energie Atomique, Energies Alternatives (CEA), Institut National Recherche Agriculture, Alimentation, Environnement (INRAE), Interdisciplinary Research Institute of Grenoble, IRIG-Laboratoire de Physiologie Cellulaire et Végétale, Grenoble, France
- Total Refining Chemicals, Tour Coupole, Paris La Défense, France
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Zhang Y, Ye Y, Bai F, Liu J. The oleaginous astaxanthin-producing alga Chromochloris zofingiensis: potential from production to an emerging model for studying lipid metabolism and carotenogenesis. BIOTECHNOLOGY FOR BIOFUELS 2021; 14:119. [PMID: 33992124 PMCID: PMC8126118 DOI: 10.1186/s13068-021-01969-z] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/12/2021] [Accepted: 05/07/2021] [Indexed: 05/05/2023]
Abstract
The algal lipids-based biodiesel, albeit having advantages over plant oils, still remains high in the production cost. Co-production of value-added products with lipids has the potential to add benefits and is thus believed to be a promising strategy to improve the production economics of algal biodiesel. Chromochloris zofingiensis, a unicellular green alga, has been considered as a promising feedstock for biodiesel production because of its robust growth and ability of accumulating high levels of triacylglycerol under multiple trophic conditions. This alga is also able to synthesize high-value keto-carotenoids and has been cited as a candidate producer of astaxanthin, the strongest antioxidant found in nature. The concurrent accumulation of triacylglycerol and astaxanthin enables C. zofingiensis an ideal cell factory for integrated production of the two compounds and has potential to improve algae-based production economics. Furthermore, with the advent of chromosome-level whole genome sequence and genetic tools, C. zofingiensis becomes an emerging model for studying lipid metabolism and carotenogenesis. In this review, we summarize recent progress on the production of triacylglycerol and astaxanthin by C. zofingiensis. We also update our understanding in the distinctive molecular mechanisms underlying lipid metabolism and carotenogenesis, with an emphasis on triacylglycerol and astaxanthin biosynthesis and crosstalk between the two pathways. Furthermore, strategies for trait improvements are discussed regarding triacylglycerol and astaxanthin synthesis in C. zofingiensis.
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Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Ying Ye
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Fan Bai
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology and Innovation, College of Engineering, Peking University, Beijing, 100871, China.
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Ma H, Wu X, Wei Z, Zhao L, Li Z, Liang Q, Zheng J, Wang Y, Li Y, Huang L, Hu Q, Han D. Functional divergence of diacylglycerol acyltransferases in the unicellular green alga Haematococcus pluvialis. JOURNAL OF EXPERIMENTAL BOTANY 2021; 72:510-524. [PMID: 33005924 PMCID: PMC7853605 DOI: 10.1093/jxb/eraa451] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 10/05/2020] [Indexed: 05/03/2023]
Abstract
Acyl-CoA:diacylglycerol acyltransferase (DGAT) catalyzes the final committed step in triacylglycerol biosynthesis in eukaryotes. In microalgae, the copy number of DGAT genes is extraordinarily expanded, yet the functions of many DGATs remain largely unknown. This study revealed that microalgal DGAT can function as a lysophosphatidic acyltransferase (LPAAT) both in vitro and in vivo while losing its original function as DGAT. Among the five DGAT-encoding genes identified and cloned from the green microalga Haematococcus pluvialis, four encoded HpDGATs that showed triacylglycerol synthase activities in yeast functional complementation analyses; the exception was one of the type II DGAT encoding genes, HpDGTT2. The hydrophobic recombinant HpDGTT2 protein was purified in soluble form and was found to function as a LPAAT via enzymatic assay. Introducing this gene into the green microalga Chlamydomonas reinhardtii led to retarded cellular growth, enlarged cell size, and enhanced triacylglycerol accumulation, identical to the phenotypes of transgenic strains overexpressing CrLPAAT. This study provides a framework for dissecting uncharacterized DGATs, and could pave the way to decrypting the structure-function relationship of this large group of enzymes that are critical to lipid biosynthesis.
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Affiliation(s)
- Haiyan Ma
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Xiaoying Wu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Ziwang Wei
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Department of Chemistry, The University of British Columbia, Vancouver, BC, Canada
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Zhongze Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qing Liang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Jie Zheng
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yu Wang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yanhua Li
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Linfei Huang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, China
- Institute for Advanced Study, Shenzhen University, Shenzhen, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Beijing Key Laboratory of Algae Biomass, SDIC Biotech Investment Corporation, Beijing, China
- Correspondence: or
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- Key Laboratory for Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
- The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
- Correspondence: or
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Cui H, Zhao C, Xu W, Zhang H, Hang W, Zhu X, Ji C, Xue J, Zhang C, Li R. Characterization of type-2 diacylglycerol acyltransferases in Haematococcus lacustris reveals their functions and engineering potential in triacylglycerol biosynthesis. BMC PLANT BIOLOGY 2021; 21:20. [PMID: 33407140 PMCID: PMC7788937 DOI: 10.1186/s12870-020-02794-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2020] [Accepted: 12/09/2020] [Indexed: 05/05/2023]
Abstract
BACKGROUND Haematococcus lacustris is an ideal source of astaxanthin (AST), which is stored in oil bodies containing esterified AST (EAST) and triacylglycerol (TAG). Diacylglycerol acyltransferases (DGATs) catalyze the last step of acyl-CoA-dependent TAG biosynthesis and are also considered as crucial enzymes involved in EAST biosynthesis in H. lacustris. Previous studies have identified four putative DGAT2-encoding genes in H. lacustris, and only HpDGAT2D allowed the recovery of TAG biosynthesis, but the engineering potential of HpDGAT2s in TAG biosynthesis remains ambiguous. RESULTS Five putative DGAT2 genes (HpDGAT2A, HpDGAT2B, HpDGAT2C, HpDGAT2D, and HpDGAT2E) were identified in H. lacustris. Transcription analysis showed that the expression levels of the HpDGAT2A, HpDGAT2D, and HpDGAT2E genes markedly increased under high light and nitrogen deficient conditions with distinct patterns, which led to significant TAG and EAST accumulation. Functional complementation demonstrated that HpDGAT2A, HpDGAT2B, HpDGAT2D, and HpDGAT2E had the capacity to restore TAG synthesis in a TAG-deficient yeast strain (H1246) showing a large difference in enzymatic activity. Fatty acid (FA) profile assays revealed that HpDGAT2A, HpDGAT2D, and HpDGAT2E, but not HpDGAT2B, preferred monounsaturated fatty acyl-CoAs (MUFAs) for TAG synthesis in yeast cells, and showed a preference for polyunsaturated fatty acyl-CoAs (PUFAs) based on their feeding strategy. The heterologous expression of HpDGAT2D in Arabidopsis thaliana and Chlamydomonas reinhardtii significantly increased the TAG content and obviously promoted the MUFAs and PUFAs contents. CONCLUSIONS Our study represents systematic work on the characterization of HpDGAT2s by integrating expression patterns, AST/TAG accumulation, functional complementation, and heterologous expression in yeast, plants, and algae. These results (1) update the gene models of HpDGAT2s, (2) prove the TAG biosynthesis capacity of HpDGAT2s, (3) show the strong preference for MUFAs and PUFAs, and (4) offer target genes to modulate TAG biosynthesis by using genetic engineering methods.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Hongjiang Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Wei Hang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Xiaoli Zhu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, 030801 Shanxi China
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Cui H, Xu W, Zhu X, Zhao C, Cui Y, Ji C, Zhang C, Xue J, Qin S, Jia X, Li R. Characterization of a Haematococcus pluvialis Diacylglycerol Acyltransferase 1 and Its Potential in Unsaturated Fatty Acid-Rich Triacylglycerol Production. FRONTIERS IN PLANT SCIENCE 2021; 12:771300. [PMID: 34950166 PMCID: PMC8688921 DOI: 10.3389/fpls.2021.771300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/08/2021] [Indexed: 05/17/2023]
Abstract
The unicellular green alga Haematococcus pluvialis has been recognized as an industry strain to produce simultaneously esterified astaxanthin (EAST) and triacylglycerol (TAG) under stress induction. It is necessary to identify the key enzymes involving in synergistic accumulation of EAST and TAG in H. pluvialis. In this study, a novel diacylglycerol acyltransferase 1 was systematically characterized by in vivo and in silico assays. The upregulated expression of HpDGAT1 gene was positively associated with the significant increase of TAG and EAST contents under stress conditions. Functional complementation by overexpressing HpDGAT1 in a TAG-deficient yeast strain H1246 revealed that HpDGAT1 could restore TAG biosynthesis and exhibited a high substrate preference for monounsaturated fatty acyl-CoAs (MUFAs) and polyunsaturated fatty acyl-CoAs (PUFAs). Notably, heterogeneous expression of HpDGAT1 in Chlamydomonas reinhardtii and Arabidopsis thaliana resulted in a significant enhancement of total oils and concurrently a high accumulation of MUFAs- and PUFAs-rich TAGs. Furthermore, molecular docking analysis indicated that HpDGAT1 contained AST-binding sites. These findings evidence a possible dual-function role for HpDGAT1 involving in TAG and EAST synthesis, demonstrating that it is a potential target gene to enrich AST accumulation in this alga and to design oil production in both commercial algae and oil crops.
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Affiliation(s)
- Hongli Cui
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Wenxin Xu
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Xiaoli Zhu
- College of Plant Protection, Shanxi Agricultural University, Taigu, China
| | - Chunchao Zhao
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Yulin Cui
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Chunli Ji
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Chunhui Zhang
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Jinai Xue
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
| | - Song Qin
- Key Laboratory of Coastal Biology and Biological Resource Utilization, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai, China
| | - Xiaoyun Jia
- College of Life Sciences, Shanxi Agricultural University, Taigu, China
| | - Runzhi Li
- College of Agriculture, Institute of Molecular Agriculture and Bioenergy, Shanxi Agricultural University, Taigu, China
- *Correspondence: Runzhi Li,
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Fatty acid composition and distribution in triacylglycerols of cultured fishes in Japan. BIOCATALYSIS AND AGRICULTURAL BIOTECHNOLOGY 2021. [DOI: 10.1016/j.bcab.2020.101687] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
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Sanya DRA, Onesime D, Kunze G, Neuveglise C, Crutz-Le Coq AM. The native acyltransferase-coding genes DGA1 and DGA2 affect lipid accumulation in Blastobotrys raffinosifermentans differently when overexpressed. FEMS Yeast Res 2020; 20:5989697. [PMID: 33206977 DOI: 10.1093/femsyr/foaa060] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 11/16/2020] [Indexed: 12/19/2022] Open
Abstract
Blastobotrys raffinosifermentans is an ascomycetous yeast with biotechnological applications, recently shown to be an oleaginous yeast accumulating lipids under nitrogen limitation. Diacylglycerol acyltransferases (DGATs) act in the lipid storage pathway, in the last step of triacylglycerol biosynthesis. Two DGAT families are widespread in eukaryotes. We first checked that B. raffinosifermentans strain LS3 possessed both types of DGAT, and we then overexpressed the native DGAT-encoding genes, DGA1 and DGA2, separately or together. DGA2 (from the DGAT1 family) overexpression was sufficient to increase lipid content significantly in LS3, to up to 26.5% of dry cell weight (DCW), 1.6 times the lipid content of the parental strain (16.90% of DCW) in glucose medium under nitrogen limitation. By contrast, DGA1 (of the DGAT2 type) overexpression led to a large increase (up to 140-fold) in the amount of the corresponding transcript, but had no effect on overall lipid content relative to the parental strain. Analysis of the expression of the native genes over time in the parental strain revealed that DGA2 transcript levels quadrupled between 8 and 24 h in the N-limited lipogenic medium, whereas DGA1 transcript levels remained stable. This survey highlights the predominant role of the DGAT1 family in lipid accumulation and demonstrates the suitability of B. raffinosifermentans for engineering for lipid production.
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Affiliation(s)
- Daniel Ruben Akiola Sanya
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| | - Djamila Onesime
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| | - Gotthard Kunze
- Leibniz Institute of Plant Genetics and Crop Plant Research (IPK), Department of Physiology and Cell Biology, Correnstr. 3, Gatersleben 06466, Germany
| | - Cécile Neuveglise
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
| | - Anne-Marie Crutz-Le Coq
- Université Paris-Saclay, INRAE, AgroParisTech, Micalis Institute,Domaine de Vilvert, Jouy-en-Josas 78350, France
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Steadman CR, Banerjee S, Kunde YA, Sanders CK, Marrone BL, Twary SN. Inhibition of DNA Methylation in Picochlorum soloecismus Alters Algae Productivity. Front Genet 2020; 11:560444. [PMID: 33193644 PMCID: PMC7593850 DOI: 10.3389/fgene.2020.560444] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 09/03/2020] [Indexed: 12/28/2022] Open
Abstract
Eukaryotic organisms regulate the organization, structure, and accessibility of their genomes through chromatin remodeling that can be inherited as epigenetic modifications. These DNA and histone protein modifications are ultimately responsible for an organism's molecular adaptation to the environment, resulting in distinctive phenotypes. Epigenetic manipulation of algae holds yet untapped potential for the optimization of biofuel production and bioproduct formation; however, epigenetic machinery and modes-of-action have not been well characterized in algae. We sought to determine the extent to which the biofuel platform species Picochlorum soloecismus utilizes DNA methylation to regulate its genome. We found candidate genes with domains for DNA methylation in the P. soloecismus genome. Whole-genome bisulfite sequencing revealed DNA methylation in all three cytosine contexts (CpG, CHH, and CHG). While global DNA methylation is low overall (∼1.15%), it occurs in appreciable quantities (12.1%) in CpG dinucleotides in a bimodal distribution in all genomic contexts, though terminators contain the greatest number of CpG sites per kilobase. The P. soloecismus genome becomes hypomethylated during the growth cycle in response to nitrogen starvation. Algae cultures were treated daily across the growth cycle with 20 μM 5-aza-2'-deoxycytidine (5AZA) to inhibit propagation of DNA methylation in daughter cells. 5AZA treatment significantly increased optical density and forward and side scatter of cells across the growth cycle (16 days). This increase in cell size and complexity correlated with a significant increase (∼66%) in lipid accumulation. Site specific CpG DNA methylation was significantly altered with 5AZA treatment over the time course, though nitrogen starvation itself induced significant hypomethylation in CpG contexts. Genes involved in several biological processes, including fatty acid synthesis, had altered methylation ratios in response to 5AZA; we hypothesize that these changes are potentially responsible for the phenotype of early induction of carbon storage as lipids. This is the first report to utilize epigenetic manipulation strategies to alter algal physiology and phenotype. Collectively, these data suggest these strategies can be utilized to fine-tune metabolic responses, alter growth, and enhance environmental adaption of microalgae for desired outcomes.
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Affiliation(s)
- Christina R Steadman
- Los Alamos National Laboratory, Bioenergy and Biome Sciences, Los Alamos, NM, United States
| | - Shounak Banerjee
- Los Alamos National Laboratory, Bioenergy and Biome Sciences, Los Alamos, NM, United States
| | - Yuliya A Kunde
- Los Alamos National Laboratory, Bioenergy and Biome Sciences, Los Alamos, NM, United States
| | - Claire K Sanders
- Los Alamos National Laboratory, Bioenergy and Biome Sciences, Los Alamos, NM, United States
| | - Babetta L Marrone
- Los Alamos National Laboratory, Bioenergy and Biome Sciences, Los Alamos, NM, United States
| | - Scott N Twary
- Los Alamos National Laboratory, Bioenergy and Biome Sciences, Los Alamos, NM, United States
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Shi Y, Liu M, Ding W, Liu J. Novel Insights into Phosphorus Deprivation Boosted Lipid Synthesis in the Marine Alga Nannochloropsis oceanica without Compromising Biomass Production. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:11488-11502. [PMID: 32955875 DOI: 10.1021/acs.jafc.0c04899] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Nannochloropsis oceanica represents a preferred oleaginous alga for producing lipids. Here we found that phosphorus deprivation (PD) caused a severe decrease in protein and a considerable increase in lipids including triacylglycerol (TAG), yet it had little effect on the carbohydrate level and biomass production of N. oceanica. The combinatorial analysis by integrating physiological, biochemical, and transcriptomic data unraveled the molecular mechanisms underlying PD-induced lipid accumulation. Albeit attenuating the Calvin-Benson cycle, PD stimulated the C4-like pathway to maintain CO2 fixation for biomass production. PD attenuated nitrogen utilization and enhanced protein catabolism thus leading to protein decrease, from which the carbon was likely salvaged into the stimulated tricarboxylic acid cycle for supplying lipid synthesis with carbon precursors. The impairment of TAG catabolism by downregulating certain lipases rather than the stimulation of TAG assembly pathways contributed to PD-boosted TAG increase. These findings provide novel insights into PD-induced lipogenesis without compromising biomass production by N. oceanica.
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Affiliation(s)
- Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Meijing Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Wei Ding
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
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Shi TQ, Wang LR, Zhang ZX, Sun XM, Huang H. Stresses as First-Line Tools for Enhancing Lipid and Carotenoid Production in Microalgae. Front Bioeng Biotechnol 2020; 8:610. [PMID: 32850686 PMCID: PMC7396513 DOI: 10.3389/fbioe.2020.00610] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 05/18/2020] [Indexed: 12/30/2022] Open
Abstract
Microalgae can produce high-value-added products such as lipids and carotenoids using light or sugars, and their biosynthesis mechanism can be triggered by various stress conditions. Under nutrient deprivation or environmental stresses, microalgal cells accumulate lipids as an energy-rich carbon storage battery and generate additional amounts of carotenoids to alleviate the oxidative damage induced by stress conditions. Though stressful conditions are unfavorable for biomass accumulation and can induce oxidative damage, stress-based strategies are widely used in this field due to their effectiveness and economy. For the overproduction of different target products, it is required and meaningful to deeply understand the effects and mechanisms of various stress conditions so as to provide guidance on choosing the appropriate stress conditions. Moreover, the underlying molecular mechanisms under stress conditions can be clarified by omics technologies, which exhibit enormous potential in guiding rational genetic engineering for improving lipid and carotenoid biosynthesis.
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Affiliation(s)
- Tian-Qiong Shi
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Ling-Ru Wang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Zi-Xu Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Nanjing, China
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Fayyaz M, Chew KW, Show PL, Ling TC, Ng IS, Chang JS. Genetic engineering of microalgae for enhanced biorefinery capabilities. Biotechnol Adv 2020; 43:107554. [PMID: 32437732 DOI: 10.1016/j.biotechadv.2020.107554] [Citation(s) in RCA: 57] [Impact Index Per Article: 14.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Revised: 05/06/2020] [Accepted: 05/06/2020] [Indexed: 02/06/2023]
Abstract
Microalgae-based bioproducts are in limelight because of their promising future, novel characteristics, the current situation of population needs, and rising prices of rapidly depleting energy resources. Algae-based products are considered as clean sustainable energy and food resources. At present, they are not commercialized due to their high production cost and low yield. In recent years, novel genome editing tools like RNAi, ZNFs, TALENs, and CRISPR/Cas9 are used to enhance the quality and quantity of the desired products. Genetic and metabolic engineering are frequently applied because of their rapid and precise results than random mutagenesis. Omic approaches help enhance biorefinery capabilities and are now in the developing stage for algae. The future is very bright for transgenic algae with increased biomass yield, carbon dioxide uptake rate, accumulating high-value compounds, reduction in cultivation, and production costs, thus reaching the goal in the global algal market and capital flow. However, microalgae are primary producers and any harmful exposure to the wild strains can affect the entire ecosystem. Therefore, strict regulation and monitoring are required to assess the potential risks before introducing genetically modified microalgae into the natural ecosystem.
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Affiliation(s)
- Mehmooda Fayyaz
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia
| | - Kit Wayne Chew
- School of Energy and Chemical Engineering, Xiamen University Malaysia, Jalan Sunsuria, Bandar Sunsuria, 43900 Sepang, Selangor, Malaysia
| | - Pau Loke Show
- Department of Chemical and Environmental Engineering, Faculty of Science and Engineering, University of Nottingham Malaysia, Jalan Broga, 43500 Semenyih, Selangor, Malaysia.
| | - Tau Chuan Ling
- Institute of Biological Sciences, Faculty of Science, University of Malaya, 50603 Kuala Lumpur, Malaysia
| | - I-Son Ng
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Tainan 701, Taiwan; Department of Chemical and Materials Engineering, College of Engineering, Tunghai University, Taichung 407, Taiwan; Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung 407, Taiwan.
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Xu Y, Caldo KMP, Falarz L, Jayawardhane K, Chen G. Kinetic improvement of an algal diacylglycerol acyltransferase 1 via fusion with an acyl-CoA binding protein. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2020; 102:856-871. [PMID: 31991039 DOI: 10.1111/tpj.14708] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 11/26/2019] [Accepted: 01/21/2020] [Indexed: 05/03/2023]
Abstract
Microalgal oils in the form of triacylglycerols (TAGs) are broadly used as nutritional supplements and biofuels. Diacylglycerol acyltransferase (DGAT) catalyzes the final step of acyl-CoA-dependent biosynthesis of TAG, and is considered a key target for manipulating oil production. Although a growing number of DGAT1s have been identified and over-expressed in some algal species, the detailed structure-function relationship, as well as the improvement of DGAT1 performance via protein engineering, remain largely untapped. Here, we explored the structure-function features of the hydrophilic N-terminal domain of DGAT1 from the green microalga Chromochloris zofingiensis (CzDGAT1). The results indicated that the N-terminal domain of CzDGAT1 was less disordered than those of the higher eukaryotic enzymes and its partial truncation or complete removal could substantially decrease enzyme activity, suggesting its possible role in maintaining enzyme performance. Although the N-terminal domains of animal and plant DGAT1s were previously found to bind acyl-CoAs, replacement of CzDGAT1 N-terminus by an acyl-CoA binding protein (ACBP) could not restore enzyme activity. Interestingly, the fusion of ACBP to the N-terminus of the full-length CzDGAT1 could enhance the enzyme affinity for acyl-CoAs and augment protein accumulation levels, which ultimately drove oil accumulation in yeast cells and tobacco leaves to higher levels than the full-length CzDGAT1. Overall, our findings unravel the distinct features of the N-terminus of algal DGAT1 and provide a strategy to engineer enhanced performance in DGAT1 via protein fusion, which may open a vista in generating improved membrane-bound acyl-CoA-dependent enzymes and boosting oil biosynthesis in plants and oleaginous microorganisms.
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Affiliation(s)
- Yang Xu
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Kristian Mark P Caldo
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Lucas Falarz
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
- Department of Biological Sciences, University of Manitoba, Winnipeg, Manitoba, R3T 2N2, Canada
| | - Kethmi Jayawardhane
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
| | - Guanqun Chen
- Department of Agricultural, Food and Nutritional Science, University of Alberta, Edmonton, Alberta, T6G 2P5, Canada
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Wu T, Fu Y, Shi Y, Li Y, Kou Y, Mao X, Liu J. Functional Characterization of Long-Chain Acyl-CoA Synthetase Gene Family from the Oleaginous Alga Chromochloris zofingiensis. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:4473-4484. [PMID: 32208653 DOI: 10.1021/acs.jafc.0c01284] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Long-chain acyl-coenzyme A (CoA) synthetase (LACS) catalyzes the formation of acyl-CoAs from free fatty acids, which is pivotal for lipid metabolism. Here, we confirmed the presence of six CzLACS genes in Chromochloris zofingiensis. Functional complementation and in vitro enzymatic assay indicated that CzLACS2 through CzLACS5 rather than CzLACS1 or CzLACS6 are bona fide LACS enzymes and they have overlapping yet distinct substrate preference. The results of the subcellular colocalization experiment and different expression patterns under three triacylglycerol (TAG)-inducing conditions showed that CzLACS2 through CzLACS4 reside at endoplasmic reticulum (ER) and are involved in TAG biosynthesis, while CzLACS5 resides in peroxisome and participates in fatty acid β-oxidation. The yeast one-hybrid assay using a library of 50 transcription factors (TFs) constructed in our study identified 12 TFs potentially involved in regulating the expression of CzLACSs. Moreover, heterologous expression of CzLACSs demonstrated their engineering potential for modulating TAG synthesis in yeast and algal cells.
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Affiliation(s)
- Tao Wu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Yunlei Fu
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Ying Shi
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Yuelian Li
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Yaping Kou
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
- BIC-ESAT, College of Engineering, Peking University, Beijing 100871, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
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Khan S, Fu P. Biotechnological perspectives on algae: a viable option for next generation biofuels. Curr Opin Biotechnol 2020; 62:146-152. [DOI: 10.1016/j.copbio.2019.09.020] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2019] [Revised: 09/23/2019] [Accepted: 09/25/2019] [Indexed: 10/25/2022]
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Vecchi V, Barera S, Bassi R, Dall’Osto L. Potential and Challenges of Improving Photosynthesis in Algae. PLANTS 2020; 9:plants9010067. [PMID: 31947868 PMCID: PMC7020468 DOI: 10.3390/plants9010067] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 11/16/2022]
Abstract
Sunlight energy largely exceeds the energy required by anthropic activities, and therefore its exploitation represents a major target in the field of renewable energies. The interest in the mass cultivation of green microalgae has grown in the last decades, as algal biomass could be employed to cover a significant portion of global energy demand. Advantages of microalgal vs. plant biomass production include higher light-use efficiency, efficient carbon capture and the valorization of marginal lands and wastewaters. Realization of this potential requires a decrease of the current production costs, which can be obtained by increasing the productivity of the most common industrial strains, by the identification of factors limiting biomass yield, and by removing bottlenecks, namely through domestication strategies aimed to fill the gap between the theoretical and real productivity of algal cultures. In particular, the light-to-biomass conversion efficiency represents one of the major constraints for achieving a significant improvement of algal cell lines. This review outlines the molecular events of photosynthesis, which regulate the conversion of light into biomass, and discusses how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. This review highlights the most recent results in the manipulation of the fundamental mechanisms of algal photosynthesis, which revealed that a significant yield enhancement is feasible. Moreover, metabolic engineering of microalgae, focused upon the development of renewable fuel biorefineries, has also drawn attention and resulted in efforts for enhancing productivity of oil or isoprenoids.
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Affiliation(s)
| | | | | | - Luca Dall’Osto
- Correspondence: ; Tel.: +39-045-8027806; Fax: +39-045-8027929
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Genetic Engineering for Enhancement of Biofuel Production in Microalgae. CLEAN ENERGY PRODUCTION TECHNOLOGIES 2020. [DOI: 10.1007/978-981-15-9593-6_21] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Mao X, Zhang Y, Wang X, Liu J. Novel insights into salinity-induced lipogenesis and carotenogenesis in the oleaginous astaxanthin-producing alga Chromochloris zofingiensis: a multi-omics study. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:73. [PMID: 32322303 PMCID: PMC7161124 DOI: 10.1186/s13068-020-01714-y] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 04/09/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Chromochloris zofingiensis, a freshwater alga capable of synthesizing both triacylglycerol (TAG) and astaxanthin, has been receiving increasing attention as a leading candidate producer. While the mechanism of oleaginousness and/or carotenogenesis has been studied under such induction conditions as nitrogen deprivation, high light and glucose feeding, it remains to be elucidated in response to salt stress, a condition critical for reducing freshwater footprint during algal production processes. RESULTS Firstly, the effect of salt concentrations on growth, lipids and carotenoids was examined for C. zofingiensis, and 0.2 M NaCl demonstrated to be the optimal salt concentration for maximizing both TAG and astaxanthin production. Then, the time-resolved lipid and carotenoid profiles and comparative transcriptomes and metabolomes were generated in response to the optimized salt concentration for congruent analysis. A global response was triggered in C. zofingiensis allowing acclimation to salt stress, including photosynthesis impairment, ROS build-up, protein turnover, starch degradation, and TAG and astaxanthin accumulation. The lipid metabolism involved a set of stimulated biological pathways that contributed to carbon precursors, energy and reductant molecules, pushing and pulling power, and storage sink for TAG accumulation. On the other hand, salt stress suppressed lutein biosynthesis, stimulated astaxanthin biosynthesis (mainly via ketolation), yet had little effect on total carotenoid flux, leading to astaxanthin accumulation at the expense of lutein. Astaxanthin was predominantly esterified and accumulated in a well-coordinated manner with TAG, pointing to the presence of common regulators and potential communication for the two compounds. Furthermore, the comparison between salt stress and nitrogen deprivation conditions revealed distinctions in TAG and astaxanthin biosynthesis as well as critical genes with engineering potential. CONCLUSIONS Our multi-omics data and integrated analysis shed light on the salt acclimation of C. zofingiensis and underlying mechanisms of TAG and astaxanthin biosynthesis, provide engineering implications into future trait improvements, and will benefit the development of this alga for production uses under saline environment, thus reducing the footprint of freshwater.
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Affiliation(s)
- Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
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Wang X, Liu SF, Li RY, Yang WD, Liu JS, Lin CSK, Balamurugan S, Li HY. TAG pathway engineering via GPAT2 concurrently potentiates abiotic stress tolerance and oleaginicity in Phaeodactylum tricornutum. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:160. [PMID: 32944076 PMCID: PMC7491103 DOI: 10.1186/s13068-020-01799-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/20/2020] [Accepted: 09/04/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Despite the great potential of marine diatoms in biofuel sector, commercially viable biofuel production from native diatom strain is impractical. Targeted engineering of TAG pathway represents a promising approach; however, recruitment of potential candidate has been regarded as critical. Here, we identified a glycerol-3-phosphate acyltransferase 2 (GPAT2) isoform and overexpressed in Phaeodactylum tricornutum. RESULTS GPAT2 overexpression did not impair growth and photosynthesis. GPAT2 overexpression reduced carbohydrates and protein content, however, lipid content were significantly increased. Specifically, TAG content was notably increased by 2.9-fold than phospho- and glyco-lipids. GPAT2 overexpression elicited the push-and-pull strategy by increasing the abundance of substrates for the subsequent metabolic enzymes, thereby increased the expression of LPAAT and DGAT. Besides, GPAT2-mediated lipid overproduction coordinated the expression of NADPH biosynthetic genes. GPAT2 altered the fatty acid profile in TAGs with C16:0 as the predominant fatty acid moieties. We further investigated the impact of GPAT2 on conferring abiotic stress, which exhibited enhanced tolerance to hyposaline (70%) and chilling (10 ºC) conditions via altered fatty acid saturation level. CONCLUSIONS Collectively, our results exemplified the critical role of GPAT2 in hyperaccumulating TAGs with altered fatty acid profile, which in turn uphold resistance to abiotic stress conditions.
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Affiliation(s)
- Xiang Wang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Si-Fen Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Ruo-Yu Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Wei-Dong Yang
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Jie-Sheng Liu
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
| | - Carol Sze Ki Lin
- School of Energy and Environment, City University of Hong Kong, Tat Chee Avenue, Kowloon, Hong Kong, China
| | - Srinivasan Balamurugan
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
- Department of Biotechnology, Bharathidasan University, Tiruchirappalli, 620024 India
| | - Hong-Ye Li
- Key Laboratory of Eutrophication and Red Tide Prevention of Guangdong Higher Education Institutes, College of Life Science, Jinan University, Guangzhou, 510632 China
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Ran W, Wang H, Liu Y, Qi M, Xiang Q, Yao C, Zhang Y, Lan X. Storage of starch and lipids in microalgae: Biosynthesis and manipulation by nutrients. BIORESOURCE TECHNOLOGY 2019; 291:121894. [PMID: 31387839 DOI: 10.1016/j.biortech.2019.121894] [Citation(s) in RCA: 66] [Impact Index Per Article: 13.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2019] [Revised: 07/22/2019] [Accepted: 07/23/2019] [Indexed: 05/28/2023]
Abstract
Microalgae accumulate starch and lipid as storage metabolites under nutrient depletion, which can be used as sustainable feedstock for biorefinery. Omics analysis coupled with enzymatic and genetic verifications uncovered a partial picture of pathways and important enzymes or regulators related to starch and lipid biosynthesis as well as the carbon partitioning between them under nutrient depletion conditions. Depletion of macronutrients (N, P, and S) resulted in considerable enhancement of starch and/or lipid content in microalgae, but the accompanying declined photosynthesis hampered the achievements of high concentrations. This review summarized the current knowledge on the pathways and the committed steps as well as their carbon allocation involved in starch and lipid biosynthesis, and focused on the manipulation of different nutrients and the alleviation of oxidative stress for enhanced storage metabolites production. The biological and engineering approaches to cope with the conflict between biomass production and storage metabolites accumulation are proposed.
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Affiliation(s)
- Wenyi Ran
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Haitao Wang
- National Engineering Research Center of Seafood, School of Food Science and Technology, Dalian Polytechnic University, Dalian, Liaoning 116034, China
| | - Yinghui Liu
- Information Management Center of Sichuan University, Chengdu, Sichuan 610065, China
| | - Man Qi
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Qi Xiang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Changhong Yao
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
| | - Yongkui Zhang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xianqiu Lan
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
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Vingiani GM, De Luca P, Ianora A, Dobson ADW, Lauritano C. Microalgal Enzymes with Biotechnological Applications. Mar Drugs 2019; 17:md17080459. [PMID: 31387272 PMCID: PMC6723882 DOI: 10.3390/md17080459] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 12/26/2022] Open
Abstract
Enzymes are essential components of biological reactions and play important roles in the scaling and optimization of many industrial processes. Due to the growing commercial demand for new and more efficient enzymes to help further optimize these processes, many studies are now focusing their attention on more renewable and environmentally sustainable sources for the production of these enzymes. Microalgae are very promising from this perspective since they can be cultivated in photobioreactors, allowing the production of high biomass levels in a cost-efficient manner. This is reflected in the increased number of publications in this area, especially in the use of microalgae as a source of novel enzymes. In particular, various microalgal enzymes with different industrial applications (e.g., lipids and biofuel production, healthcare, and bioremediation) have been studied to date, and the modification of enzymatic sequences involved in lipid and carotenoid production has resulted in promising results. However, the entire biosynthetic pathways/systems leading to synthesis of potentially important bioactive compounds have in many cases yet to be fully characterized (e.g., for the synthesis of polyketides). Nonetheless, with recent advances in microalgal genomics and transcriptomic approaches, it is becoming easier to identify sequences encoding targeted enzymes, increasing the likelihood of the identification, heterologous expression, and characterization of these enzymes of interest. This review provides an overview of the state of the art in marine and freshwater microalgal enzymes with potential biotechnological applications and provides future perspectives for this field.
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Affiliation(s)
- Giorgio Maria Vingiani
- Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, CAP80121 (NA) Villa Comunale, Italy
| | - Pasquale De Luca
- Research Infrastructure for Marine Biological Resources Department, Stazione Zoologica Anton Dohrn, CAP80121 (NA) Villa Comunale, Italy
| | - Adrianna Ianora
- Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, CAP80121 (NA) Villa Comunale, Italy
| | - Alan D W Dobson
- School of Microbiology, University College Cork, College Road, T12 YN60 Cork, Ireland
- Environmental Research Institute, University College Cork, Lee Road, T23XE10 Cork, Ireland
| | - Chiara Lauritano
- Marine Biotechnology Department, Stazione Zoologica Anton Dohrn, CAP80121 (NA) Villa Comunale, Italy.
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Liu J, Sun Z, Mao X, Gerken H, Wang X, Yang W. Multiomics analysis reveals a distinct mechanism of oleaginousness in the emerging model alga Chromochloris zofingiensis. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2019; 98:1060-1077. [PMID: 30828893 DOI: 10.1111/tpj.14302] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Revised: 02/15/2019] [Accepted: 02/19/2019] [Indexed: 06/09/2023]
Abstract
Chromochloris zofingiensis, featured due to its capability to simultaneously synthesize triacylglycerol (TAG) and astaxanthin, is emerging as a leading candidate alga for production uses. To better understand the oleaginous mechanism of this alga, we conducted a multiomics analysis by systematically integrating time-resolved transcriptomes, lipidomes and metabolomes in response to nitrogen deprivation. The data analysis unraveled the distinct mechanism of TAG accumulation, which involved coordinated stimulation of multiple biological processes including supply of energy and reductants, carbon reallocation from protein and starch, and 'pushing' and 'pulling' carbon to TAG synthesis. Unlike the model alga Chlamydomonas, de novo fatty acid synthesis in C. zofingiensis was promoted, together with enhanced turnover of both glycolipids and phospholipids, supporting the drastic need of acyls for TAG assembly. Moreover, genomewide analysis identified many key functional enzymes and transcription factors that had engineering potential for TAG modulation. Two genes encoding glycerol-3-phosphate acyltransferase (GPAT), the first committed enzyme for TAG assembly, were found in the C. zofingiensis genome; in vivo functional characterization revealed that extrachloroplastic GPAT instead of chloroplastic GPAT played a central role in TAG synthesis. These findings illuminate distinct oleaginousness mechanisms in C. zofingiensis and pave the way towards rational manipulation of this alga to becone an emerging model for trait improvements.
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Affiliation(s)
- Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Zheng Sun
- International Research Center for Marine Biosciences, Ministry of Science and Technology, Shanghai Ocean University, Shanghai, 201306, China
| | - Xuemei Mao
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Henri Gerken
- School of Sustainable Engineering and the Built Environment, Arizona State University Polytechnic campus, Mesa, AZ, 85212, USA
| | - Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871, China
| | - Wenqiang Yang
- Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China
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Nobusawa T, Yamakawa-Ayukawa K, Saito F, Nomura S, Takami A, Ohta H. A homolog of Arabidopsis SDP1 lipase in Nannochloropsis is involved in degradation of de novo-synthesized triacylglycerols in the endoplasmic reticulum. Biochim Biophys Acta Mol Cell Biol Lipids 2019; 1864:1185-1193. [PMID: 31152796 DOI: 10.1016/j.bbalip.2019.05.013] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2019] [Revised: 04/26/2019] [Accepted: 05/25/2019] [Indexed: 01/22/2023]
Abstract
Organisms of the microalgal genus Nannochloropsis produce high levels of triacylglycerols (TAGs), an efficient raw material for biofuels. A complete understanding of the TAG-breakdown pathway is critical for improving the productivity of TAGs to meet future needs. Among a number of lipases annotated as TAG lipase in the genomes of every organism, Arabidopsis SUGAR-DEPENDENT 1 (AtSDP1) lipases are characterized as a type of crucial TAG lipase in plants, similar to ScTgl3-5 in Saccharomyces cerevisiae. Homologs of the AtSDP1 TAG lipases are universally found in the genomes of plants, fungi, and algae. Here we identified two homologs of AtSDP1 TAG lipases in the oleaginous microalga species Nannochloropsis oceanica, NoTGL1 and NoTGL2. We generated single- and double-knockout strains for these lipases by homologous recombination. Whereas overall TAG content in the NoTGL2 single-knockout mutant was identical to that of wild type, the NoTGL1 knockout showed a two-fold increase in TAG content per cell in early log phase under nutrient-sufficient conditions without affecting growth. Homologs of AtSDP1 in S. cerevisiae are localized to the surface of lipid droplets, and AtSDP1 is transported from peroxisomes to the surface of lipid droplets. In contrast, NoTGL1 localized to the endoplasmic reticulum in both Nannochloropsis and yeast. We suggest that homologs of AtSDP1 lipases in Nannochloropsis modulate de novo TAG biosynthesis in the endoplasmic reticulum, unlike the roles of these lipases in other organisms. These results provide important insights into the mechanisms of TAG metabolism catalyzed by homologs of AtSDP1 lipase, which are highly conserved across species.
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Affiliation(s)
- Takashi Nobusawa
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan; Graduate School of Integrated Sciences for Life, Hiroshima University, 1-4-3, Kagamiyama, Higashi-Hiroshima 739-8526, Japan
| | - Kaoru Yamakawa-Ayukawa
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan
| | - Fumihiko Saito
- Technical Research Center, Mazda Motor Corporation, 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima, 730-8670, Japan
| | - Seiji Nomura
- Technical Research Center, Mazda Motor Corporation, 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima, 730-8670, Japan
| | - Akihide Takami
- Technical Research Center, Mazda Motor Corporation, 3-1, Shinchi, Fuchu-cho, Aki-gun, Hiroshima, 730-8670, Japan
| | - Hiroyuki Ohta
- School of Life Science and Technology, Tokyo Institute of Technology, 4259-B-65 Nagatsuta-cho, Midori-ku, Yokohama 226-8501, Japan.
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He Y, Wang X, Wei H, Zhang J, Chen B, Chen F. Direct enzymatic ethanolysis of potential Nannochloropsis biomass for co-production of sustainable biodiesel and nutraceutical eicosapentaenoic acid. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:78. [PMID: 30992715 PMCID: PMC6449970 DOI: 10.1186/s13068-019-1418-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/27/2019] [Indexed: 05/24/2023]
Abstract
BACKGROUND Marine microalga Nannochloropsis is a promising source for the production of renewable and sustainable biodiesel in replacement of depleting petroleum. Other than biodiesel, Nannochloropsis is a green and potential resource for the commercial production of nutraceutical eicosapentaenoic acid (EPA, C20:5). In recent studies, low-value biodiesel can be achieved by transesterification of Nannochloropsis biomass. However, it is undoubtedly wasteful to produce microalgal biodiesel containing EPA from nutritional and economical aspects. A new strategy was addressed and exploited to produce low-value bulky biodiesel along with EPA enrichment via enzymatic ethanolysis of Nannochloropsis biomass with a specific lipase. RESULTS Cellulase pretreatment on Nannochloropsis sp. biomass significantly improved the biodiesel conversion by direct ethanolysis with five enzymes from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TL), Rhizomucor miehei (RM), and Aspergillus oryzae (PLA). Among these five biocatalysts, CALA was the best suitable enzyme to yield high biodiesel conversion and effectively enrich EPA. After optimization, the maximum biodiesel conversion (46.53-48.57%) was attained by CALA at 8:1 ethanol/biomass ratio (v/w) in 10-15% water content with 10% lipase weight at 35 °C for 72 h. Meanwhile, EPA (60.81%) was highly enriched in microalgae NPLs (neutral lipids and polar lipids), increasing original EPA levels by 1.51-fold. Moreover, this process was re-evaluated with two Nannochloropsis species (IMET1 and Salina 537). Under the optimized conditions, the biodiesel conversions of IMET1 and Salina 537 by CALA were 63.41% and 54.33%, respectively. EPA contents of microalgal NPLs were 50.06% for IMET1 and 53.73% for Salina 537. CONCLUSION CALA was the potential biocatalyst to discriminate against EPA in the ethanolysis of Nannochloropsis biomass. The biodiesel conversion and EPA enrich efficiency of CALA were greatly dependent on lipidic class and fatty acid compositions of Nannochloropsis biomass. CALA-catalyzed ethanolysis with Nannochloropsis biomass was a promising approach for co-production of low-value biodiesel and high-value microalgae products rich in EPA.
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Affiliation(s)
- Yongjin He
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
- Key Laboratory of Feed Biotechnology, The Ministry of Agriculture of the People’s Republic of China, Beijing, 100081 China
- College of Life Science, Fujian Normal University, Fuzhou, 350117 China
| | - Xiaofei Wang
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
| | - Hehong Wei
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
| | - Jianzhi Zhang
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
| | - Bilian Chen
- College of Life Science, Fujian Normal University, Fuzhou, 350117 China
| | - Feng Chen
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518000 China
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50
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Xin Y, Shen C, She Y, Chen H, Wang C, Wei L, Yoon K, Han D, Hu Q, Xu J. Biosynthesis of Triacylglycerol Molecules with a Tailored PUFA Profile in Industrial Microalgae. MOLECULAR PLANT 2019; 12:474-488. [PMID: 30580039 DOI: 10.1016/j.molp.2018.12.007] [Citation(s) in RCA: 51] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/10/2018] [Revised: 11/29/2018] [Accepted: 12/13/2018] [Indexed: 05/06/2023]
Abstract
The composition of polyunsaturated fatty acids (PUFAs) in triacylglycerols (TAGs) is key to health benefits and for oil applications, yet the underlying genetic mechanism remains poorly understood. In this study, by in silico, ex vivo, and in vivo profiling of type-2 diacylglycerol acyltransferases (DGAT2s) in Nannochloropsis oceanica we revealed two novel PUFA-preferring enzymes that discriminate individual PUFA species in TAG assembly, with NoDGAT2J for linoleic acid (LA) and NoDGAT2K for eicosapentaenoic acid (EPA). The LA and EPA composition of TAG molecules is mediated in vivo via the functional partitioning between NoDGAT2J and 2K, both of which are localized in the chloroplast envelope. By modulating transcript abundance of the DGAT2s, an N. oceanica strain bank was created, where proportions of LA and EPA in TAG vary by 18.7-fold (between 0.21% and 3.92% dry weight) and 34.7-fold (between 0.09% and 3.12% dry weight), respectively. These findings lay the foundation for producing designer TAG molecules with tailored health benefits or for biofuel applications in industrial microalgae and higher-plant crops.
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Affiliation(s)
- Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Chen Shen
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Yiting She
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hong Chen
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Cong Wang
- Core Laboratory, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kangsup Yoon
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Danxiang Han
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China
| | - Qiang Hu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei 430072, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong 266101, China; Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong 266237, China; University of Chinese Academy of Sciences, Beijing 100049, China.
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