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Jung M, Kim YE, Lee N, Yu H, Lee J, Lee SY, Lee YC, Oh YK. Simultaneous enhancement of lipid biosynthesis and solvent extraction of Chlorella using aminoclay nanoparticles. BIORESOURCE TECHNOLOGY 2023; 384:129314. [PMID: 37311525 DOI: 10.1016/j.biortech.2023.129314] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 06/07/2023] [Accepted: 06/08/2023] [Indexed: 06/15/2023]
Abstract
Magnesium aminoclay nanoparticles (MgANs) exert opposing effects on photosynthetic microalgae by promoting carbon dioxide (CO2) uptake and inducing oxidative stress. This study explored the potential application of MgAN in the production of algal lipids under high CO2 concentrations. The impact of MgAN (0.05-1.0 g/L) on cell growth, lipid accumulation, and solvent extractability varied among three tested oleaginous Chlorella strains (N113, KR-1, and M082). Among them, only KR-1 exhibited significant improvement in both total lipid content (379.4 mg/g cell) and hexane lipid extraction efficiency (54.5%) in the presence of MgAN compared to those of controls (320.3 mg/g cell and 46.1%, respectively). This improvement was attributed to the increased biosynthesis of triacylglycerols and a thinner cell wall based on thin-layer chromatography and electronic microscopy, respectively. These findings suggest that using MgAN with robust algal strains can enhance the efficiency of cost-intensive extraction processes while simultaneously increasing the algal lipid content.
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Affiliation(s)
- Mikyoung Jung
- School of Chemical Engineering, Pusan National University, Busan 46241, South Korea
| | - Young-Eun Kim
- School of Chemical Engineering, Pusan National University, Busan 46241, South Korea; Environmental Measurement and Analysis Center, National Institute of Environmental Research, Incheon 22689, South Korea
| | - Nakyeong Lee
- Institute for Environment & Energy, Pusan National University, Busan 46241, South Korea; Division of Environmental Materials, Honam National Institute of Biological Resources, Mokpo 58762, South Korea
| | - Hyoji Yu
- School of Chemical Engineering, Pusan National University, Busan 46241, South Korea
| | - Jiye Lee
- Gwangju Clean Energy Research Center, Korea Institute of Energy Research, Daejeon 34129, South Korea
| | - Soo Youn Lee
- Gwangju Clean Energy Research Center, Korea Institute of Energy Research, Daejeon 34129, South Korea
| | - Young-Chul Lee
- Department of BioNano Technology, Gachon University, Seongnam-si 13120, South Korea
| | - You-Kwan Oh
- School of Chemical Engineering, Pusan National University, Busan 46241, South Korea; Institute for Environment & Energy, Pusan National University, Busan 46241, South Korea.
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2
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Choi BY, Shim D, Kong F, Auroy P, Lee Y, Li-Beisson Y, Lee Y, Yamaoka Y. The Chlamydomonas transcription factor MYB1 mediates lipid accumulation under nitrogen depletion. THE NEW PHYTOLOGIST 2022; 235:595-610. [PMID: 35383411 DOI: 10.1111/nph.18141] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/29/2022] [Indexed: 06/14/2023]
Abstract
Microalgae accumulate high levels of oil under stress, but the underlying biosynthetic pathways are not fully understood. We sought to identify key regulators of lipid metabolism under stress conditions. We found that the Chlamydomonas reinhardtii gene encoding the MYB-type transcription factor MYB1 is highly induced under stress conditions. Two myb1 mutants accumulated less total fatty acids and storage lipids than their parental strain upon nitrogen (N) depletion. Transcriptome analysis revealed that genes involved in lipid metabolism are highly enriched in the wild-type but not in the myb1-1 mutant after 4 h of N depletion. Among these genes were several involved in the transport of fatty acids from the chloroplast to the endoplasmic reticulum (ER): acyl-ACP thioesterase (FAT1), Fatty Acid EXporters (FAX1, FAX2), and long-chain acyl-CoA synthetase1 (LACS1). Furthermore, overexpression of FAT1 in the chloroplast increased lipid production. These results suggest that, upon N depletion, MYB1 promotes lipid accumulation by facilitating fatty acid transport from the chloroplast to the ER. This study identifies MYB1 as an important positive regulator of lipid accumulation in C. reinhardtii upon N depletion, adding another player to the established regulators of this process, including NITROGEN RESPONSE REGULATOR 1 (NRR1) and TRIACYLGLYCEROL ACCUMULATION REGULATOR 1 (TAR1).
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Affiliation(s)
- Bae Young Choi
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Donghwan Shim
- Department of Biological Sciences, Chungnam National University, Daejeon, 34134, Korea
| | - Fantao Kong
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
- School of Bioengineering, Dalian University of Technology, Dalian, 116024, China
| | - Pascaline Auroy
- CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, Aix Marseille Université, CEA Cadarache, Saint Paul-Lez-Durance, 13108, France
| | - Yuree Lee
- School of Biological Sciences, Seoul National University, Seoul, 08826, Korea
- Research Center for Plant Plasticity, Seoul National University, Seoul, 08826, Korea
- Plant Genomics and Breeding Institute, Seoul National University, Seoul, 08826, Korea
| | - Yonghua Li-Beisson
- CEA, CNRS, BIAM, Institut de Biosciences et Biotechnologies Aix-Marseille, Aix Marseille Université, CEA Cadarache, Saint Paul-Lez-Durance, 13108, France
| | - Youngsook Lee
- Department of Life Science, Pohang University of Science and Technology (POSTECH), Pohang, 37673, Korea
| | - Yasuyo Yamaoka
- Division of Biotechnology, The Catholic University of Korea, Bucheon, 420-743, Korea
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3
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Choi SA, Lee SY, Lee J, Cho JM, Lee JS, Kim SW, Kim DY, Park SK, Jin CS, Oh YK. Rapid induction of edible lipids in Chlorella by mild electric stimulation. BIORESOURCE TECHNOLOGY 2019; 292:121950. [PMID: 31398549 DOI: 10.1016/j.biortech.2019.121950] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 06/10/2023]
Abstract
In this work, a new stress-based method for rapid induction of triacylglycerol (TAG) and total and polyunsaturated fatty acid accumulations in Chlorella sp. by mild electric stimulation is presented. When a cathodic current of 31 mA (voltage: 4 V) was applied to the algal cells for 4 h, the TAG content of the electro-treated cells was sharply increased to a level 2.1 times that of the untreated control. The contents of the polyunsaturated linoleic (C18:2n6) and linolenic (C18:3n3) acids in the electro-treated cells were also 36 and 57% higher than those in the untreated cells, respectively. Cyclic voltammetry and various biochemical analyses indicate that TAG and fatty acid formations are electro-stimulated via de novo fatty acid biosynthesis and metabolic transformation in the Chlorella cells.
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Affiliation(s)
- Sun-A Choi
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Republic of Korea; Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Republic of Korea
| | - Soo Youn Lee
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Republic of Korea
| | - Jiye Lee
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Republic of Korea
| | - Jun Muk Cho
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea
| | - Jin-Suk Lee
- Gwangju Bio/Energy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Republic of Korea
| | - Seung Wook Kim
- Department of Chemical and Biological Engineering, Korea University, Seoul 02841, Republic of Korea; Department of Chemistry, Faculty of Science and Technology, Universitas Airlangga, 60115, Indonesia
| | - Dong-Yeon Kim
- CO(2) Energy Vector Research Group, Korea Research Institute of Chemical Technology, Daejeon 34114, Republic of Korea
| | - Se-Kook Park
- Energy ICT-ESS Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Chang-Soo Jin
- Energy ICT-ESS Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - You-Kwan Oh
- School of Chemical & Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea.
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4
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Wase N, Tu B, Rasineni GK, Cerny R, Grove R, Adamec J, Black PN, DiRusso CC. Remodeling of Chlamydomonas Metabolism Using Synthetic Inducers Results in Lipid Storage during Growth. PLANT PHYSIOLOGY 2019; 181:1029-1049. [PMID: 31501300 PMCID: PMC6836844 DOI: 10.1104/pp.19.00758] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 08/23/2019] [Indexed: 05/19/2023]
Abstract
Microalgae accumulate lipids during stress such as that of nutrient deprivation, concomitant with cessation of growth and depletion of chloroplasts. By contrast, certain small chemical compounds selected by high-throughput screening in Chlamydomonas reinhardtii can induce lipid accumulation during growth, maintaining biomass. Comprehensive pathway analyses using proteomics, transcriptomics, and metabolomics data were acquired from Chlamydomonas cells grown in the presence of one of two structurally distinct lipid activators. WD10784 stimulates both starch and lipid accumulation, whereas WD30030-treated cells accumulate only lipids. The differences in starch accumulation are largely due to differential effects of the two compounds on substrate levels that feed into starch synthesis and on genes encoding starch metabolic enzymes. The compounds had differential effects on photosynthesis, respiration, and oxidative stress pathways. Cells treated with WD10784 showed slowed growth over time and reduced abundance of photosynthetic proteins, decreased respiration, and increased oxidative stress proteins, glutathione, and reactive oxygen species specific to this compound. Both compounds maintained central carbon and nitrogen metabolism, including the tricarboxylic acid cycle, glycolysis, respiration, and the Calvin-Benson-Bassham cycle. There were few changes in proteins and transcripts related to fatty acid biosynthesis, whereas proteins and transcripts for triglyceride production were elevated, suggesting that lipid synthesis is largely driven by substrate availability. This study reports that the compound WD30030 and, to a lesser extent WD10784, increases lipid and lipid droplet synthesis and storage without restricting growth or biomass accumulation by mechanisms that are substantially different from nutrient deprivation.
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Affiliation(s)
- Nishikant Wase
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Boqiang Tu
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | | | - Ronald Cerny
- Department of Chemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Ryan Grove
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Jiri Adamec
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Paul N Black
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
| | - Concetta C DiRusso
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, Nebraska 68588
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5
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Yamaoka Y, Shin S, Choi BY, Kim H, Jang S, Kajikawa M, Yamano T, Kong F, Légeret B, Fukuzawa H, Li-Beisson Y, Lee Y. The bZIP1 Transcription Factor Regulates Lipid Remodeling and Contributes to ER Stress Management in Chlamydomonas reinhardtii. THE PLANT CELL 2019; 31:1127-1140. [PMID: 30894460 PMCID: PMC6533020 DOI: 10.1105/tpc.18.00723] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 01/29/2019] [Accepted: 03/18/2019] [Indexed: 05/24/2023]
Abstract
Endoplasmic reticulum (ER) stress is caused by the stress-induced accumulation of unfolded proteins in the ER. Here, we identified proteins and lipids that function downstream of the ER stress sensor INOSITOL-REQUIRING ENZYME1 (CrIRE1) that contributes to ER stress tolerance in Chlamydomonas (Chlamydomonas reinhardtii). Treatment with the ER stress inducer tunicamycin resulted in the splicing of a 32-nucleotide fragment of a basic leucine zipper 1 (bZIP1) transcription factor (CrbZIP1) mRNA by CrIRE1 that, in turn, resulted in the loss of the transmembrane domain in CrbZIP1, and the translocation of CrbZIP1 from the ER to the nucleus. Mutants deficient in CrbZIP1 failed to induce the expression of the unfolded protein response genes and grew poorly under ER stress. Levels of diacylglyceryltrimethylhomoserine (DGTS) and pinolenic acid (18:3Δ5,9,12) increased in the parental strains but decreased in the crbzip1 mutants under ER stress. A yeast one-hybrid assay revealed that CrbZIP1 activated the expression of enzymes catalyzing the biosynthesis of DGTS and pinolenic acid. Moreover, two lines harboring independent mutant alleles of Chlamydomonas desaturase (CrDES) failed to synthesize pinolenic acid and were more sensitive to ER stress than were their parental lines. Together, these results indicate that CrbZIP1 is a critical component of the ER stress response mediated by CrIRE1 in Chlamydomonas that acts via lipid remodeling.
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Affiliation(s)
- Yasuyo Yamaoka
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Seungjun Shin
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Bae Young Choi
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
| | - Hanul Kim
- Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Sunghoon Jang
- Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Korea
| | - Masataka Kajikawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Takashi Yamano
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Fantao Kong
- Aix Marseille Université, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Biosciences and Biotechnologies Institute of Aix-Marseille, 13108 Saint Paul-Lez-Durance, France
| | - Bertrand Légeret
- Aix Marseille Université, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Biosciences and Biotechnologies Institute of Aix-Marseille, 13108 Saint Paul-Lez-Durance, France
| | - Hideya Fukuzawa
- Graduate School of Biostudies, Kyoto University, Kyoto 606-8501, Japan
| | - Yonghua Li-Beisson
- Aix Marseille Université, Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique, Biosciences and Biotechnologies Institute of Aix-Marseille, 13108 Saint Paul-Lez-Durance, France
| | - Youngsook Lee
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang 790-784, Korea
- Department of Life Science, Pohang University of Science and Technology, Pohang 37673, Korea
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6
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7
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Wase N, Black P, DiRusso C. Innovations in improving lipid production: Algal chemical genetics. Prog Lipid Res 2018; 71:101-123. [DOI: 10.1016/j.plipres.2018.07.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 06/25/2018] [Accepted: 07/06/2018] [Indexed: 01/01/2023]
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8
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Oh YK, Hwang KR, Kim C, Kim JR, Lee JS. Recent developments and key barriers to advanced biofuels: A short review. BIORESOURCE TECHNOLOGY 2018. [PMID: 29523378 DOI: 10.1016/j.biortech.2018.02.089] [Citation(s) in RCA: 58] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Biofuels are regarded as one of the most viable options for reduction of CO2 emissions in the transport sector. However, conventional plant-based biofuels (e.g., biodiesel, bioethanol)'s share of total transportation-fuel consumption in 2016 was very low, about 4%, due to several major limitations including shortage of raw materials, low CO2 mitigation effect, blending wall, and poor cost competitiveness. Advanced biofuels such as drop-in, microalgal, and electro biofuels, especially from inedible biomass, are considered to be a promising solution to the problem of how to cope with the growing biofuel demand. In this paper, recent developments in oxy-free hydrocarbon conversion via catalytic deoxygenation reactions, the selection of and lipid-content enhancement of oleaginous microalgae, electrochemical biofuel conversion, and the diversification of valuable products from biomass and intermediates are reviewed. The challenges and prospects for future development of eco-friendly and economically advanced biofuel production processes also are outlined herein.
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Affiliation(s)
- You-Kwan Oh
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Kyung-Ran Hwang
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Changman Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jung Rae Kim
- School of Chemical and Biomolecular Engineering, Pusan National University, Busan 46241, Republic of Korea
| | - Jin-Suk Lee
- Gwangju Bioenergy R&D Center, Korea Institute of Energy Research, Gwangju 61003, Republic of Korea.
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9
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Yamaoka Y, Choi BY, Kim H, Shin S, Kim Y, Jang S, Song WY, Cho CH, Yoon HS, Kohno K, Lee Y. Identification and functional study of the endoplasmic reticulum stress sensor IRE1 in Chlamydomonas reinhardtii. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2018; 94:91-104. [PMID: 29385296 DOI: 10.1111/tpj.13844] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 01/07/2018] [Accepted: 01/15/2018] [Indexed: 06/07/2023]
Abstract
In many eukaryotes, endoplasmic reticulum (ER) stress activates the unfolded protein response (UPR) via the transmembrane endoribonuclease IRE1 to maintain ER homeostasis. The ER stress response in microalgae has not been studied in detail. Here, we identified Chlamydomonas reinhardtii IRE1 (CrIRE1) and characterized two independent knock-down alleles of this gene. CrIRE1 is similar to IRE1s identified in budding yeast, plants, and humans, in terms of conserved domains, but differs in having the tandem zinc-finger domain at the C terminus. CrIRE1 was highly induced under ER stress conditions, and the expression of a chimeric protein consisting of the luminal N-terminal region of CrIRE1 fused to the cytosolic C-terminal region of yeast Ire1p rescued the yeast ∆ire1 mutant. Both allelic ire1 knock-down mutants ire1-1 and ire1-2 were much more sensitive than their parental strain CC-4533 to the ER stress inducers tunicamycin, dithiothreitol and brefeldin A. Treatment with a low concentration of tunicamycin resulted in growth arrest and cytolysis in ire1 mutants, but not in CC-4533 cells. Furthermore, in the mutants, ER stress marker gene expression was reduced, and reactive oxygen species (ROS) marker gene expression was increased. The survival of ire1 mutants treated with tunicamycin improved in the presence of the ROS scavenger glutathione, suggesting that ire1 mutants failed to maintain ROS levels under ER stress. Together, these results indicate that CrIRE1 functions as an important component of the ER stress response in Chlamydomonas, and suggest that the ER stress sensor IRE1 is highly conserved during the evolutionary history.
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Affiliation(s)
- Yasuyo Yamaoka
- Department of Life Science, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Bae Young Choi
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Hanul Kim
- Department of Life Science, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Seungjun Shin
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Yeongho Kim
- Department of Life Science, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Sunghoon Jang
- Department of Life Science, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Won-Yong Song
- Department of Life Science, Pohang University of Science and Technology, Pohang, 37673, Korea
| | - Chung H Cho
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Hwan Su Yoon
- Department of Biological Sciences, Sungkyunkwan University, Suwon, 16419, Korea
| | - Kenji Kohno
- Graduate School of Biological Sciences and Institute for Research Initiatives, Nara Institute of Science and Technology, Ikoma, Nara, 630-0192, Japan
| | - Youngsook Lee
- Department of Life Science, Pohang University of Science and Technology, Pohang, 37673, Korea
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, 37673, Korea
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10
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Lipid turnover between membrane lipids and neutral lipids via inhibition of diacylglyceryl N,N,N-trimethylhomoserine synthesis in Chlamydomonas reinhardtii. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.09.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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11
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Wase N, Tu B, Allen JW, Black PN, DiRusso CC. Identification and Metabolite Profiling of Chemical Activators of Lipid Accumulation in Green Algae. PLANT PHYSIOLOGY 2017; 174:2146-2165. [PMID: 28652262 PMCID: PMC5543952 DOI: 10.1104/pp.17.00433] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2017] [Accepted: 06/21/2017] [Indexed: 05/02/2023]
Abstract
Microalgae are proposed as feedstock organisms useful for producing biofuels and coproducts. However, several limitations must be overcome before algae-based production is economically feasible. Among these is the ability to induce lipid accumulation and storage without affecting biomass yield. To overcome this barrier, a chemical genetics approach was employed in which 43,783 compounds were screened against Chlamydomonas reinhardtii, and 243 compounds were identified that increase triacylglyceride (TAG) accumulation without terminating growth. Identified compounds were classified by structural similarity, and 15 were selected for secondary analyses addressing impacts on growth fitness, photosynthetic pigments, and total cellular protein and starch concentrations. TAG accumulation was verified using gas chromatography-mass spectrometry quantification of total fatty acids, and targeted TAG and galactolipid measurements were performed using liquid chromatography-multiple reaction monitoring/mass spectrometry. These results demonstrated that TAG accumulation does not necessarily proceed at the expense of galactolipid. Untargeted metabolite profiling provided important insights into pathway shifts due to five different compound treatments and verified the anabolic state of the cells with regard to the oxidative pentose phosphate pathway, Calvin cycle, tricarboxylic acid cycle, and amino acid biosynthetic pathways. Metabolite patterns were distinct from nitrogen starvation and other abiotic stresses commonly used to induce oil accumulation in algae. The efficacy of these compounds also was demonstrated in three other algal species. These lipid-inducing compounds offer a valuable set of tools for delving into the biochemical mechanisms of lipid accumulation in algae and a direct means to improve algal oil content independent of the severe growth limitations associated with nutrient deprivation.
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Affiliation(s)
- Nishikant Wase
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Boqiang Tu
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - James W Allen
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Paul N Black
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
| | - Concetta C DiRusso
- Department of Biochemistry, University of Nebraska, Lincoln, Nebraska 68588
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12
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Moutel B, Gonçalves O, Le Grand F, Long M, Soudant P, Legrand J, Grizeau D, Pruvost J. Development of a screening procedure for the characterization of Botryococcus braunii strains for biofuel application. Process Biochem 2016. [DOI: 10.1016/j.procbio.2016.05.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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13
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Praveenkumar R, Kim B, Lee J, Vijayan D, Lee K, Nam B, Jeon SG, Kim DM, Oh YK. Mild pressure induces rapid accumulation of neutral lipid (triacylglycerol) in Chlorella spp. BIORESOURCE TECHNOLOGY 2016; 220:661-665. [PMID: 27634024 DOI: 10.1016/j.biortech.2016.09.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/17/2016] [Revised: 09/04/2016] [Accepted: 09/06/2016] [Indexed: 06/06/2023]
Abstract
Effective enhancement of neutral lipid (especially triacylglycerol, TAG) content in microalgae is an important issue for commercialization of microalgal biorefineries. Pressure is a key physical factor affecting the morphological, physiological, and biochemical behaviors of organisms. In this paper, we report a new stress-based method for induction of TAG accumulation in microalgae (specifically, Chlorella sp. KR-1 and Ch. sp. AG20150) by very-short-duration application of mild pressure. Pressure treatments of 10-15bar for 2h resulted in a considerable, ∼55% improvement of the 10-100g/Lcells' TAG contents compared with the untreated control. The post-pressure-treatment increase of cytoplasmic TAG granules was further confirmed by transmission electron microscopy (TEM). Notwithstanding the increased TAG content, the total lipid content was not changed by pressurization, implying that pressure stress possibly induces rapid remodeling/transformation of algal lipids rather than de novo biosynthesis of TAG.
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Affiliation(s)
- Ramasamy Praveenkumar
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea; Department of Chemistry and Bioengineering, Tampere University of Technology, Tampere 33720, Finland
| | - Bohwa Kim
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea; Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Jiye Lee
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Durairaj Vijayan
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Kyubock Lee
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea; Graduate School of Energy Science and Technology, Chungnam National University, Daejeon 34134, Republic of Korea
| | - Bora Nam
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Sang Goo Jeon
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea
| | - Dong-Myung Kim
- Department of Fine Chemical Engineering and Applied Chemistry, Chungnam National University, Daejeon 34134, Republic of Korea
| | - You-Kwan Oh
- Biomass and Waste Energy Laboratory, Korea Institute of Energy Research, Daejeon 34129, Republic of Korea.
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Goold HD, Cuiné S, Légeret B, Liang Y, Brugière S, Auroy P, Javot H, Tardif M, Jones B, Beisson F, Peltier G, Li-Beisson Y. Saturating Light Induces Sustained Accumulation of Oil in Plastidal Lipid Droplets in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2016; 171:2406-17. [PMID: 27297678 PMCID: PMC4972293 DOI: 10.1104/pp.16.00718] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2016] [Accepted: 06/10/2016] [Indexed: 05/02/2023]
Abstract
Enriching algal biomass in energy density is an important goal in algal biotechnology. Nitrogen (N) starvation is considered the most potent trigger of oil accumulation in microalgae and has been thoroughly investigated. However, N starvation causes the slow down and eventually the arrest of biomass growth. In this study, we show that exposing a Chlamydomonas reinhardtii culture to saturating light (SL) under a nonlimiting CO2 concentration in turbidostatic photobioreactors induces a sustained accumulation of lipid droplets (LDs) without compromising growth, which results in much higher oil productivity than N starvation. We also show that the polar membrane lipid fraction of SL-induced LDs is rich in plastidial lipids (approximately 70%), in contrast to N starvation-induced LDs, which contain approximately 60% lipids of endoplasmic reticulum origin. Proteomic analysis of LDs isolated from SL-exposed cells identified more than 200 proteins, including known proteins of lipid metabolism, as well as 74 proteins uniquely present in SL-induced LDs. LDs induced by SL and N depletion thus differ in protein and lipid contents. Taken together, lipidomic and proteomic data thus show that a large part of the sustained oil accumulation occurring under SL is likely due to the formation of plastidial LDs. We discuss our data in relation to the different metabolic routes used by microalgae to accumulate oil reserves depending on cultivation conditions. Finally, we propose a model in which oil accumulation is governed by an imbalance between photosynthesis and growth, which can be achieved by impairing growth or by boosting photosynthetic carbon fixation, with the latter resulting in higher oil productivity.
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Affiliation(s)
- Hugh Douglas Goold
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Stéphan Cuiné
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Bertrand Légeret
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Yuanxue Liang
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Sabine Brugière
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Pascaline Auroy
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Hélène Javot
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Marianne Tardif
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Brian Jones
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Fred Beisson
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Gilles Peltier
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
| | - Yonghua Li-Beisson
- Commissariat à l'Energie Atomique, Centre National de la Recherche Scientifique Aix Marseille Université, Unité Mixte de Recherche 7265, Institut de Biosciences et Biotechnologies, Cadarache 13108, France (H.D.G., S.C., B.L., Y.L., P.A., H.J., F.B., G.P., Y.L.-B.);Faculty of Agriculture and the Environment, University of Sydney, Sydney, New South Wales 2006, Australia (H.D.G., B.J.); andCommissariat à l'Energie Atomique, INSERM, Université Grenoble Alpes, Institut de Biosciences et Biotechnologies de Grenoble, Grenoble 38000, France (S.B., M.T.)
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Légeret B, Schulz-Raffelt M, Nguyen HM, Auroy P, Beisson F, Peltier G, Blanc G, Li-Beisson Y. Lipidomic and transcriptomic analyses of Chlamydomonas reinhardtii under heat stress unveil a direct route for the conversion of membrane lipids into storage lipids. PLANT, CELL & ENVIRONMENT 2016; 39:834-47. [PMID: 26477535 DOI: 10.1111/pce.12656] [Citation(s) in RCA: 92] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 10/01/2015] [Accepted: 10/06/2015] [Indexed: 05/18/2023]
Abstract
Studying how photosynthetic cells modify membrane lipids in response to heat stress is important to understand how plants and microalgae adapt to daily fluctuations in temperature and to investigate new lipid pathways. Here, we investigate changes occurring in lipid molecular species and lipid metabolism genes during early response to heat stress in the model photosynthetic microorganism Chlamydomonas reinhardtii. Lipid molecular species analyses revealed that, after 60 min at 42 °C, a strong decrease in specific polyunsaturated membrane lipids was observed together with an increase in polyunsaturated triacylglycerols (TAGs) and diacylglycerols (DAGs). The fact that decrease in the major chloroplastic monogalactosyldiacylglycerol sn1-18:3/sn2-16:4 was mirrored by an accumulation of DAG sn1-18:3/sn2-16:4 and TAG sn1-18:3/sn2-16:4/sn3-18:3 indicated that newly accumulated TAGs were formed via direct conversion of monogalactosyldiacylglycerols to DAGs then TAGs. Lipidomic analyses showed that the third fatty acid of a TAG likely originated from a phosphatidylethanolamine or a diacylglyceryl-O-4'-(N,N,N,-trimethyl)-homoserine betaine lipid species. Candidate genes for this TAG synthesis pathway were provided through comparative transcriptomic analysis and included a phospholipase A2 homolog and the DAG acyltransferase DGTT1. This study gives insights into the molecular events underlying changes in membrane lipids during heat stress and reveals an alternative route for TAG synthesis.
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Affiliation(s)
- B Légeret
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
| | - M Schulz-Raffelt
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
| | - H M Nguyen
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
| | - P Auroy
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
| | - F Beisson
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
| | - G Peltier
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
| | - G Blanc
- Laboratoire Information Génomique & Structurale, UMR7256 (IMM FR3479) CNRS Aix-Marseille Université, Marseille, France
| | - Y Li-Beisson
- Commissariat à l'Energie Atomique et aux Energies Alternatives, Institut de Biologie Environnementale et Biotechnologie, CEA Cadarache, Saint-Paul-lez-Durance, France
- Centre National de la Recherche Scientifique, UMR7265, Saint-Paul-lez-Durance, France
- Aix-Marseille Université, UMR7265, Marseille, France
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Abedini Najafabadi H, Vossoughi M, Pazuki G. The role of co-solvents in improving the direct transesterification of wet microalgal biomass under supercritical condition. BIORESOURCE TECHNOLOGY 2015; 193:90-96. [PMID: 26117240 DOI: 10.1016/j.biortech.2015.06.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/10/2015] [Revised: 06/09/2015] [Accepted: 06/10/2015] [Indexed: 06/04/2023]
Abstract
In this research, direct conversion of wet algal biomass into biodiesel using supercritical methanol was studied. In this process, microalgal lipids simultaneously was extracted and converted to biodiesel under high pressure and temperature conditions without using any catalyst. Several experiments have been performed to optimize the methanol amount and it has been revealed that the best performance was achieved by using methanol/wet biomass ratio of 8:1. The effect of using various co-solvents in increasing the efficiency of the supercritical process was investigated. It has been shown that hexane was the most effective co-solvent and its optimal ratio respect to wet biomass was 6:1. The results indicated that compare to conventional extraction plus transesterification reaction, fatty acid methyl esters (FAMEs) yield was slightly higher in the direct conversion process. Moreover, increasing the moisture content up to 80% has no significant effect on reducing the performance of this process.
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Affiliation(s)
| | - Manouchehr Vossoughi
- Department of Chemical and Petroleum Engineering, Sharif University of Technology, Tehran, Iran; Institute for Biotechnology and Environment (IBE), Sharif University of Technology, Tehran, Iran.
| | - Gholamreza Pazuki
- Department of Chemical Engineering, Amirkabir University of Technology (Tehran Polytechnic), Tehran, Iran
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Engineering of oleaginous organisms for lipid production. Curr Opin Biotechnol 2015; 36:32-9. [PMID: 26319892 DOI: 10.1016/j.copbio.2015.08.001] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 07/29/2015] [Accepted: 08/06/2015] [Indexed: 12/18/2022]
Abstract
Phototrophs are attractive candidates for commercial lipid production. Lipid biosynthetic pathways in these organisms have been largely characterized but the mechanisms partitioning resources toward storage lipids are poorly understood. One promising strategy to study and enhance biomass lipid bioproduction in oleaginous microorganisms is to combine genome-scale metabolic modeling and genetic and metabolic engineering. Here we describe recent advances in in vitro, in vivo, and in silico manipulations of phototrophic metabolism that increase total lipid content or redirect lipid production toward more favorable products such as polyunsaturated fatty acids used as nutritional supplements or in biofuel production.
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