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Koh HG, Cho JM, Jeon S, Chang YK, Lee B, Kang NK. Transcriptional insights into Chlorella sp. ABC-001: a comparative study of carbon fixation and lipid synthesis under different CO 2 conditions. BIOTECHNOLOGY FOR BIOFUELS AND BIOPRODUCTS 2023; 16:113. [PMID: 37454088 PMCID: PMC10350272 DOI: 10.1186/s13068-023-02358-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Accepted: 06/11/2023] [Indexed: 07/18/2023]
Abstract
BACKGROUND Microalgae's low tolerance to high CO2 concentrations presents a significant challenge for its industrial application, especially when considering the utilization of industrial exhaust gas streams with high CO2 content-an economically and environmentally attractive option. Therefore, the objectives of this study were to investigate the metabolic changes in carbon fixation and lipid accumulation of microalgae under ambient air and high CO2 conditions, deepen our understanding of the molecular mechanisms driving these processes, and identify potential target genes for metabolic engineering in microalgae. To accomplish these goals, we conducted a transcriptomic analysis of the high CO2-tolerant strain, Chlorella sp. ABC-001, under two different carbon dioxide levels (ambient air and 10% CO2) and at various growth phases. RESULTS Cells cultivated with 10% CO2 exhibited significantly better growth and lipid accumulation rates, achieving up to 2.5-fold higher cell density and twice the lipid content by day 7. To understand the relationship between CO2 concentrations and phenotypes, transcriptomic analysis was conducted across different CO2 conditions and growth phases. According to the analysis of differentially expressed genes and gene ontology, Chlorella sp. ABC-001 exhibited the development of chloroplast organelles during the early exponential phase under high CO2 conditions, resulting in improved CO2 fixation and enhanced photosynthesis. Cobalamin-independent methionine synthase expression was also significantly elevated during the early growth stage, likely contributing to the methionine supply required for various metabolic activities and active proliferation. Conversely, the cells showed sustained repression of carbonic anhydrase and ferredoxin hydrogenase, involved in the carbon concentrating mechanism, throughout the cultivation period under high CO2 conditions. This study also delved into the transcriptomic profiles in the Calvin cycle, nitrogen reductase, and lipid synthesis. Particularly, Chlorella sp. ABC-001 showed high expression levels of genes involved in lipid synthesis, such as glycerol-3-phosphate dehydrogenase and phospholipid-diacylglycerol acyltransferase. These findings suggest potential targets for metabolic engineering aimed at enhancing lipid production in microalgae. CONCLUSIONS We expect that our findings will help understand the carbon concentrating mechanism, photosynthesis, nitrogen assimilation, and lipid accumulation metabolisms of green algae according to CO2 concentrations. This study also provides insights into systems metabolic engineering of microalgae for improved performance in the future.
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Affiliation(s)
- Hyun Gi Koh
- Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL, USA
| | - Jun Muk Cho
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Seungjib Jeon
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141, Republic of Korea
| | - Bongsoo Lee
- Department of Microbial Biotechnology, College of Science and Technology, Mokwon University, 88 Doanbuk-ro, Seo-gu, Daejeon, 35349, Republic of Korea.
| | - Nam Kyu Kang
- Department of Chemical Engineering, College of Engineering, Kyung Hee University, Yongin, 17104, Republic of Korea.
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Glyceroglycolipid Metabolism Regulations under Phosphate Starvation Revealed by Transcriptome Analysis in Synechococcus elongatus PCC 7942. Mar Drugs 2020; 18:md18070360. [PMID: 32668657 PMCID: PMC7401256 DOI: 10.3390/md18070360] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Revised: 07/04/2020] [Accepted: 07/10/2020] [Indexed: 12/12/2022] Open
Abstract
Glyceroglycolipids, abundant in cyanobacteria's photosynthetic membranes, present bioactivities and pharmacological activities, and can be widely used in the pharmaceutical industry. Environmental factors could alter the contents and compositions of cyanobacteria glyceroglycolipids, but the regulation mechanism remains unclear. Therefore, the glyceroglycolipids contents and the transcriptome in Synechococcus elongatus PCC 7942 were analyzed under phosphate starvation. Under phosphate starvation, the decrease of monogalactosyl diacylglycerol (MGDG) and increases of digalactosyl diacylglycerol (DGDG) and sulfoquinovosyl diacylglycerol (SQDG) led to a decrease in the MGDG/DGDG ratio, from 4:1 to 5:3, after 12 days of cultivation. However, UDP-sulfoquinovose synthase gene sqdB, and the SQDG synthase gene sqdX, were down-regulated, and the decreased MGDG/DGDG ratio was later increased back to 2:1 after 15 days of cultivation, suggesting the regulation of glyceroglycolipids on day 12 was based on the MGDG/DGDG ratio maintaining glyceroglycolipid homeostasis. There are 12 differentially expressed transcriptional regulators that could be potential candidates related to glyceroglycolipid regulation, according to the transcriptome analysis. The transcriptome analysis also suggested post-transcriptional or post-translational regulations in glyceroglycolipid synthesis. This study provides further insights into glyceroglycolipid metabolism, as well as the scientific basis for glyceroglycolipid synthesis optimization and cyanobacteria glyceroglycolipids utilization via metabolic engineering.
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Zhao Y, Hou Y, Chai W, Liu Z, Wang X, He C, Hu Z, Chen S, Wang W, chen F. Transcriptome analysis of Haematococcus pluvialis of multiple defensive systems against nitrogen starvation. Enzyme Microb Technol 2020; 134:109487. [DOI: 10.1016/j.enzmictec.2019.109487] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2019] [Revised: 11/05/2019] [Accepted: 12/05/2019] [Indexed: 10/25/2022]
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Qian H, Xu J, Lu T, Zhang Q, Qu Q, Yang Z, Pan X. Responses of unicellular alga Chlorella pyrenoidosa to allelochemical linoleic acid. THE SCIENCE OF THE TOTAL ENVIRONMENT 2018; 625:1415-1422. [PMID: 29996438 DOI: 10.1016/j.scitotenv.2018.01.053] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2017] [Revised: 01/02/2018] [Accepted: 01/07/2018] [Indexed: 06/08/2023]
Abstract
Linoleic acid (LA), is the product of secondary metabolism secreted from Microcystis aeruginosa, and it exhibits allelopathic activity against eukaryotic algae. However, information about on the mechanisms associated with the inhibition of algal activity by LA is limited. In this study, Chlorella pyrenoidosa was treated with LA (20-120 μg L-1) for 4 days, and its growth inhibition and physiological responses were examined for potential toxic mechanisms. The photosynthetic efficiency of C. pyrenoidosa was inhibited by LA treatments, and the Fv/Fm parameter decreased significantly compared to that of controls; however, the photosynthetic pigment content did not change significantly. Peroxidase activity was enhanced, relieving oxidative damage in algae after LA treatments. However, superoxide dismutase and catalase were suppressed, ultimately leading to the aggravation of lipid peroxidation. Transcriptome-based gene expression analysis revealed that the 120 μg L-1 LA treatment significantly inhibited the transcription of genes related to photosynthesis, carbon metabolism, and amino acid metabolism in C. pyrenoidosa, suggesting that these genes might be key LA targets in C. pyrenoidosa. Moreover, the expression of genes involved in vitamin, lipid, nitrogen cycling, terpenoid, and ascorbate metabolism was also affected, suggesting that LA inhibits algal cell growth through multiple pathways. The identification of LA-responsive genes in C. pyrenoidosa provides new insight into LA stress responses in eukaryotic algae.
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Affiliation(s)
- Haifeng Qian
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China; College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China.
| | - Jiahui Xu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Qi Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Qian Qu
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
| | - Zhaopeng Yang
- Xinjiang Key Laboratory of Environmental Pollution and Bioremediation, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences, Urumqi 830011, PR China
| | - Xiangliang Pan
- College of Environment, Zhejiang University of Technology, Hangzhou 310032, PR China
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Arora N, Pienkos PT, Pruthi V, Poluri KM, Guarnieri MT. Leveraging algal omics to reveal potential targets for augmenting TAG accumulation. Biotechnol Adv 2018; 36:1274-1292. [PMID: 29678388 DOI: 10.1016/j.biotechadv.2018.04.005] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2017] [Revised: 04/11/2018] [Accepted: 04/15/2018] [Indexed: 02/08/2023]
Abstract
Ongoing global efforts to commercialize microalgal biofuels have expedited the use of multi-omics techniques to gain insights into lipid biosynthetic pathways. Functional genomics analyses have recently been employed to complement existing sequence-level omics studies, shedding light on the dynamics of lipid synthesis and its interplay with other cellular metabolic pathways, thus revealing possible targets for metabolic engineering. Here, we review the current status of algal omics studies to reveal potential targets to augment TAG accumulation in various microalgae. This review specifically aims to examine and catalog systems level data related to stress-induced TAG accumulation in oleaginous microalgae and inform future metabolic engineering strategies to develop strains with enhanced bioproductivity, which could pave a path for sustainable green energy.
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Affiliation(s)
- Neha Arora
- Department of Biotechnology, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Philip T Pienkos
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA
| | - Vikas Pruthi
- Department of Biotechnology, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Krishna Mohan Poluri
- Department of Biotechnology, Indian Institute of Technology Roorkee, Uttarakhand 247667, India
| | - Michael T Guarnieri
- National Bioenergy Center, National Renewable Energy Laboratory, Golden, CO 80401, USA.
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Lu T, Zhu Y, Xu J, Ke M, Zhang M, Tan C, Fu Z, Qian H. Evaluation of the toxic response induced by azoxystrobin in the non-target green alga Chlorella pyrenoidosa. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2018; 234:379-388. [PMID: 29202416 DOI: 10.1016/j.envpol.2017.11.081] [Citation(s) in RCA: 74] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/13/2017] [Revised: 11/20/2017] [Accepted: 11/25/2017] [Indexed: 06/07/2023]
Abstract
The top-selling strobilurin, azoxystrobin (AZ), is a broad-spectrum fungicide that protects against many kinds of pathogenic fungi by preventing their ATP production. The extensive use of AZ can have negative consequences on non-target species and its effects and toxic mechanisms on algae are still poorly understood. In this work, Chlorella pyrenoidosa that had been grown in BG-11 medium was exposed to AZ (0.5-10 mg L-1) for 10 d. The physiological and molecular responses of the algae to AZ treatment, including photosynthetic efficiency, lipid peroxidation level, antioxidant enzyme activities, as well as transcriptome-based analysis of gene expression, were examined to investigate the potential toxic mechanism. Results shows that the photosynthetic pigment (per cell) increased slightly after AZ treatments, indicating that the photosystem of C. pyrenoidosa may have been strengthened. Glutathione and ascorbate contents were increased, and antioxidant enzyme activities were induced to relieve oxidative damage (e.g., from lipid peroxidation) in algae after AZ treatment. Transcriptome-based analysis of gene expression combined with physiological verification suggested that the 5 mg L-1 AZ treatment did not inhibit ATP generation in C. pyrenoidosa, but did significantly alter amino acid metabolism, especially in aspartate- and glutamine-related reactions. Moreover, perturbation of ascorbate synthesis, fat acid metabolism, and RNA translation was also observed, suggesting that AZ inhibits algal cell growth through multiple pathways. The identification of AZ-responsive genes in the eukaryotic alga C. pyrenoidosa provides new insight into AZ stress responses in a non-target organism.
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Affiliation(s)
- Tao Lu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Youchao Zhu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Jiahui Xu
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Mingjing Ke
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Meng Zhang
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Chengxia Tan
- College of Chemical Engineering, Zhejiang University of Technology, Hangzhou 310014, Zhejiang, PR China
| | - Zhengwei Fu
- College of Biotechnology and Bioengineering, Zhejiang University of Technology, Hangzhou 310014, PR China
| | - Haifeng Qian
- College of Environment, Zhejiang University of Technology, Hangzhou 310014, PR China.
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Ren L, Hu X, Zhao X, Chen S, Wu Y, Li D, Yu Y, Geng L, Ji X, Huang H. Transcriptomic Analysis of the Regulation of Lipid Fraction Migration and Fatty Acid Biosynthesis in Schizochytrium sp. Sci Rep 2017; 7:3562. [PMID: 28620184 PMCID: PMC5472558 DOI: 10.1038/s41598-017-03382-9] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Accepted: 04/27/2017] [Indexed: 11/26/2022] Open
Abstract
Schizochytrium sp. is the main source of docosahexaenoic acid-rich oil, which is widely used in food additive and pharmaceutical industry. In this study, using RNA-seq, comparative transcriptomic analyses were performed at four stages of DHA fermentation by Schizochytrium sp to get potential genes related to cell transition from cell growth to lipid accumulation and then to lipid turnover. 1406, 385, 1384 differently expressed genes were identified by comparisons in pairs of S2 vs S1, S3 vs S2 and S4 vs S3. Functional analysis revealed that binding and single-organism process might be involve in the cell transition from cell growth to lipid accumulation while oxidation-reduction process played an important role in the transition from lipid accumulation to lipid turnover. pfaC in the PKS pathway showed higher sensitivity to the environmental change, which might be the key regulator for enhancing PUFA biosynthesis in the future. Some other genes in signal transduction and cell transport were revealed to be related to lipid turnover, which would enrich the current knowledge regarding lipid metabolism and help to enhance the DHA production and enrich different lipid fractions by Schizochytrium in the future.
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Affiliation(s)
- Lujing Ren
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xuechao Hu
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xiaoyan Zhao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Shenglan Chen
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Yi Wu
- Xiamen Kingdomway Group company, No. 299 West Yangguang Road, Haicang, Xiamen, 361022, China
| | - Dan Li
- Xiamen Kingdomway Group company, No. 299 West Yangguang Road, Haicang, Xiamen, 361022, China
| | - Yadong Yu
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Lingjun Geng
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xiaojun Ji
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - He Huang
- Jiangsu National Synergetic Innovation Center for Advanced Materials, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China.
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China.
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