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Vijayan J, Wase N, Liu K, Morse W, Zhang C, Riekhof WR. ROS-mediated thylakoid membrane remodeling and triacylglycerol biosynthesis under nitrogen starvation in the alga Chlorella sorokiniana. FRONTIERS IN PLANT SCIENCE 2024; 15:1418049. [PMID: 39040507 PMCID: PMC11261311 DOI: 10.3389/fpls.2024.1418049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/15/2024] [Accepted: 06/11/2024] [Indexed: 07/24/2024]
Abstract
Many microbes accumulate energy storage molecules such as triglycerides (TAG) and starch during nutrient limitation. In eukaryotic green algae grown under nitrogen-limiting conditions, triglyceride accumulation is coupled with chlorosis and growth arrest. In this study, we show that reactive oxygen species (ROS) actively accumulate during nitrogen limitation in the microalga Chlorella sorokiniana. Accumulation of ROS is mediated by the downregulation of genes encoding ROS-quenching enzymes, such as superoxide dismutases, catalase, peroxiredoxin, and glutathione peroxidase-like, and by the upregulation of enzymes involved in generating ROS, such as NADPH oxidase, xanthine oxidase, and amine oxidases. The expression of genes involved in ascorbate and glutathione metabolism is also affected under this condition. ROS accumulation contributes to the degradation of monogalactosyl diacylglycerol (MGDG) and thylakoid membrane remodeling, leading to chlorosis. Quenching ROS under nitrogen limitation reduces the degradation of MGDG and the accumulation of TAG. This work shows that ROS accumulation, membrane remodeling, and TAG accumulation under nitrogen limitation are intricately linked in the microalga C. sorokiniana.
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Affiliation(s)
- Jithesh Vijayan
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
- Department of Biochemistry, University of Nebraska-Lincoln, Lincoln, NE, United States
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Nishikant Wase
- PPD, part of ThermoFisher Scientific, Henrico, VA, United States
| | - Kan Liu
- Mayo Clinic, Rochester, MN, United States
| | - Wyatt Morse
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Chi Zhang
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
- Center for Plant Science Innovation, University of Nebraska-Lincoln, Lincoln, NE, United States
| | - Wayne R. Riekhof
- School of Biological Sciences, University of Nebraska-Lincoln, Lincoln, NE, United States
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Devadasu E, Subramanyam R. Enhanced Lipid Production in Chlamydomonas reinhardtii Caused by Severe Iron Deficiency. FRONTIERS IN PLANT SCIENCE 2021; 12:615577. [PMID: 33927732 PMCID: PMC8076870 DOI: 10.3389/fpls.2021.615577] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2020] [Accepted: 03/23/2021] [Indexed: 05/19/2023]
Abstract
Microalgae are used as a source of lipids for the production of biofuels. Most algae produce neutral lipids under stress conditions. Here, lipid accumulation by the unicellular alga Chlamydomonas reinhardtii was examined during cultivation under iron-limiting conditions. Severe iron stress caused the cells to accumulate a significant amount of lipid, specifically triacylglycerols (TAGs), by compromising the growth. Semi-quantitative measurements by Fourier transform infrared (FTIR) spectroscopy showed an increase in both carbohydrate and lipid content in iron-stressed C. reinhardtii cells compared to control. Analysis by flow cytometry and thin layer chromatography confirmed that severe iron deficiency-induced TAG accumulation to fourfold higher than in iron-replete control cells. This accumulation of TAGs was mostly degraded from chloroplast lipids accompanied by overexpression of diacylglycerol acyltransferase (DGAT2A) protein. Furthermore, liquid chromatography-mass spectrometry (LC-MS) analysis demonstrated significantly enhanced levels of C16:0, C18:2, and C18:3 fatty acids (FAs). These results indicate that iron stress triggers the rapid accumulation of TAGs in C. reinhardtii cells. The enhanced production of these lipids caused by the iron deficiency may contribute to the efficient production of algal biofuels if we escalate to the photobioreactor's growth conditions.
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Sun XM, Ren LJ, Zhao QY, Zhang LH, Huang H. Application of chemicals for enhancing lipid production in microalgae-a short review. BIORESOURCE TECHNOLOGY 2019; 293:122135. [PMID: 31540787 DOI: 10.1016/j.biortech.2019.122135] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 05/05/2023]
Abstract
Microalgae have attracted great attention as a promising sustainable resource for biofuel production. In studies aiming to improve lipid accumulation, many key enzymes involved in lipid biosynthesis were identified and confirmed, but genetic engineering remains a challenge in most species of microalgae. In an alternative approach, various chemical modulators can be used to directly regulate the lipid biosynthesis pathway, with similar effects to gene overexpression and interference approaches, including improving the precursor supply and blocking competing pathways. The produced lipid can be protected from being converted into other metabolites by the chemicals such as lipase inhibitors. In addition, a few chemicals were also demonstrated to greatly influence cell growth and lipid accumulation by indirect regulation of the lipid biosynthesis pathway, such as increasing cell permeability or regulating oxidative stress. Thus, adding chemical modulators can be a useful alternative strategy for improving lipid accumulation in large-scale cultivation of microalgae.
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Affiliation(s)
- Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, Jiangsu Province, China
| | - Lu-Jing Ren
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
| | - Quan-Yu Zhao
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
| | - Li-Hui Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, Jiangsu Province, China.
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, Jiangsu Province, China; Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
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Chai S, Shi J, Huang T, Guo Y, Wei J, Guo M, Li L, Dou S, Liu L, Liu G. Characterization of Chlorella sorokiniana growth properties in monosaccharide-supplemented batch culture. PLoS One 2018; 13:e0199873. [PMID: 29969497 PMCID: PMC6029798 DOI: 10.1371/journal.pone.0199873] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 06/15/2018] [Indexed: 11/18/2022] Open
Abstract
To reveal growth properties of Chlorella sorokiniana UTEX 1230, four monosaccharides (glucose, fructose, galactose and xylose) were individually supplemented into medium as carbon sources for the cultivation of C. sorokiniana UTEX 1230. Supplementation with glucose increased OD750, biomass and lipid yield but decreased protein abundance per unit dry weight of biomass under all concentrations examined, the maximum OD750, biomass and lipid yield increased 2.04, 6.78 and 12.43 times, respectively, compared with autotrophic controls. A low concentration of glucose (<4 g/L) simultaneously promoted the biosynthesis of chlorophylls and protein abundance per unit culture volume, but decreased the lipid content per unit dry weight of biomass and all supplemented glucose can be exhausted within 7 days. Higher glucose concentrations (≥4 g/L) decreased the biosynthesis of chlorophylls and protein abundance per unit culture volume, but increased the lipid content per unit dry weight of biomass. In glucose supplemented scenario, C. sorokiniana UTEX 1230 growth was light-independent. Supplementation with fructose promoted C. sorokiniana UTEX 1230 growth to a much lesser extent compared with glucose, whereas supplementation with galactose had no effect and supplementation with xylose even inhibited growth. Our findings represent basic experimental data on the effect of monosaccharides and can serve as the basis for a robust cultivation system to increase biomass and lipid yield.
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Affiliation(s)
- Shuaijie Chai
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Jianan Shi
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Teng Huang
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Yalu Guo
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Jian Wei
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Meicen Guo
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Liyun Li
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Shijuan Dou
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Lijuan Liu
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
| | - Guozhen Liu
- Institute of Bioenergy, Hebei Agricultural University, Baoding, Hebei Province, China
- * E-mail:
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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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Current advances in molecular, biochemical, and computational modeling analysis of microalgal triacylglycerol biosynthesis. Biotechnol Adv 2016; 34:1046-1063. [DOI: 10.1016/j.biotechadv.2016.06.004] [Citation(s) in RCA: 64] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Revised: 06/08/2016] [Accepted: 06/12/2016] [Indexed: 12/12/2022]
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