1
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Chowdhary AK, Kishi M, Toda T. A novel process for the production of Chromochloris zofingiensis through dark-induced multi-nuclei formation. ALGAL RES 2023. [DOI: 10.1016/j.algal.2023.103053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/18/2023]
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2
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Je S, Yamaoka Y. Biotechnological Approaches for Biomass and Lipid Production Using Microalgae Chlorella and Its Future Perspectives. J Microbiol Biotechnol 2022; 32:1357-1372. [PMID: 36310359 PMCID: PMC9720082 DOI: 10.4014/jmb.2209.09012] [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: 09/07/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 11/05/2022]
Abstract
Heavy reliance on fossil fuels has been associated with increased climate disasters. As an alternative, microalgae have been proposed as an effective agent for biomass production. Several advantages of microalgae include faster growth, usage of non-arable land, recovery of nutrients from wastewater, efficient CO2 capture, and high amount of biomolecules that are valuable for humans. Microalgae Chlorella spp. are a large group of eukaryotic, photosynthetic, unicellular microorganisms with high adaptability to environmental variations. Over the past decades, Chlorella has been used for the large-scale production of biomass. In addition, Chlorella has been actively used in various food industries for improving human health because of its antioxidant, antidiabetic, and immunomodulatory functions. However, the major restrictions in microalgal biofuel technology are the cost-consuming cultivation, processing, and lipid extraction processes. Therefore, various trials have been performed to enhance the biomass productivity and the lipid contents of Chlorella cells. This study provides a comprehensive review of lipid enhancement strategies mainly published in the last five years and aimed at regulating carbon sources, nutrients, stresses, and expression of exogenous genes to improve biomass production and lipid synthesis.
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Affiliation(s)
- Sujeong Je
- Division of Biotechnology, The Catholic University of Korea, Bucheon 14662, Republic of Korea
| | - Yasuyo Yamaoka
- Division of Biotechnology, The Catholic University of Korea, Bucheon 14662, Republic of Korea,Corresponding author Phone: +82-2-2164-4034 Fax: +82-2-2164-4778 E-mail:
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3
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Malik S, Ashraf MUF, Shahid A, Javed MR, Khan AZ, Usman M, Manivannan A, Mehmood MA, Ashraf GA. Characterization of a newly isolated self-flocculating microalga Bracteacoccus pseudominor BERC09 and its evaluation as a candidate for a multiproduct algal biorefinery. CHEMOSPHERE 2022; 304:135346. [PMID: 35714954 DOI: 10.1016/j.chemosphere.2022.135346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/29/2022] [Accepted: 06/12/2022] [Indexed: 06/15/2023]
Abstract
Microalgae have the highest capability to fix the atmospheric carbon and wastewater-derived nutrients to produce high-value bioproducts including lipids and carotenoids. However, their lower titers and single-product-oriented biomass processing have made the overall process expensive. Hence, increased metabolite titer and processing of the biomass for more than one product are required to ensure the commercial robustness of the algal biorefinery. In this study, a newly isolated algal strain was identified as Bracteacoccus pseudominor BERC09 through phylogenetic analysis based on the 18S rRNA gene sequence. Basic characterization of the strain revealed its promising potential to produce carotenoids and lipids. The lipids and carotenoid biosynthesis pathways of BERC09 were further triggered by manipulating the abiotic factors including nitrogen sources (NaNO3, KNO3, NH4Cl, Urea), nitrogen concentrations (0.06-0.36 gL-1), light intensity (150 μmolm-2s-1 to 300 μmolm-2s-1), and light quality (white and blue). Resultantly, 300 μmolm-2s-1 of blue light yielded 0.768 gL-1 of biomass, 8.4 mgg-1 of carotenoids, and 390 mgg-1 of lipids, and supplementation of 0.36 gL-1 of KNO3 further improved metabolism and yielded 0.814 gL-1 of biomass, 11.86 mgg-1 of carotenoids, and 424 mgg-1 of lipids. Overall, the optimal combination of light and nitrogen concurrently improved biomass, carotenoids, and lipids by 3.5-fold, 6-fold, and 4-fold than control, respectively. Besides, the excellent glycoproteins-based self-flocculation ability of the strain rendered an easier harvesting via gravity sedimentation. Hence, this biomass can be processed in a cascading fashion to use this strain as a candidate for a multiproduct biorefinery to achieve commercial robustness and environmental sustainability.
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Affiliation(s)
- Sana Malik
- Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Muhammad Umer Farooq Ashraf
- Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Ayesha Shahid
- Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Muhammad Rizwan Javed
- Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan
| | - Aqib Zafar Khan
- State Key Laboratory of Microbial Metabolism, Joint International Research Laboratory of Metabolic & Developmental Sciences, School of Life Sciences and Biotechnology, Shanghai Jiao Tong University, Shanghai, China
| | - Muhammad Usman
- School of Chemical Engineering, Zhengzhou University, Zhengzhou, 450001, China
| | - Arthi Manivannan
- Saveetha School of Engineering, Saveetha Institute of Medical and Technical Sciences, Chennai, India
| | - Muhammad Aamer Mehmood
- Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad, Pakistan.
| | - Ghulam Abbas Ashraf
- Department of Physics, Zhejiang Normal University, Zhejiang, 321004, Jinhua, China.
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4
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Corrêa PS, de M. Júnior WG, Caetano NS. Antioxidant potential of extracts of Chromochloris zofingiensis cultivated in pilot-scale outdoor tubular photobioreactors under nitrogen limitation. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102859] [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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5
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Shi M, Yu L, Shi J, Liu J. A conserved MYB transcription factor is involved in regulating lipid metabolic pathways for oil biosynthesis in green algae. THE NEW PHYTOLOGIST 2022; 235:576-594. [PMID: 35342951 DOI: 10.1111/nph.18119] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 03/21/2022] [Indexed: 06/14/2023]
Abstract
Green algae can accumulate high levels of triacylglycerol (TAG), yet knowledge remains fragmented on the regulation of lipid metabolic pathways by transcription factors (TFs). Here, via bioinformatics and in vitro and in vivo analyses, we revealed the roles of a myeloblastosis (MYB) TF in regulating TAG accumulation in green algae. CzMYB1, an R2R3-MYB from Chromochloris zofingiensis, was transcriptionally upregulated upon TAG-inducing conditions and correlated well with many genes involved in the de novo fatty acid synthesis, fatty acid activation and desaturation, membrane lipid turnover, and TAG assembly. Most promoters of these genes were transactivated by CzMYB1 in the yeast one-hybrid assay and contained the binding elements CNGTTA that were recognized by CzMYB1 through the electrophoretic mobility shift assay. CrMYB1, a close homologue of CzMYB1 from Chlamydomonas reinhardtii that recognized similar elements for binding, also transcriptionally correlated with many lipid metabolic genes. Insertional disruption of CrMYB1 severely suppressed the transcriptional expression of CrMYB1, as well as of key lipogenic genes, and impaired TAG level considerably under stress conditions. Our results reveal that this MYB, conserved in green algae, is involved in regulating global lipid metabolic pathways for TAG biosynthesis and accumulation.
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Affiliation(s)
- Meicheng Shi
- 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
| | - Jianan Shi
- 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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6
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Microalgal carotenoids: A promising alternative to synthetic dyes. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102823] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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7
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Wood EE, Ross ME, Jubeau S, Montalescot V, Stanley MS. Progress towards a targeted biorefinery of Chromochloris zofingiensis: a review. BIOMASS CONVERSION AND BIOREFINERY 2022; 14:8127-8152. [PMID: 38510795 PMCID: PMC10948469 DOI: 10.1007/s13399-022-02955-7] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 06/09/2022] [Accepted: 06/13/2022] [Indexed: 03/22/2024]
Abstract
Biorefinery approaches offer the potential to improve the economics of the microalgae industry by producing multiple products from a single source of biomass. Chromochloris zofingiensis shows great promise for biorefinery due to high biomass productivity and a diverse range of products including secondary carotenoids, predominantly astaxanthin; lipids such as TAGs; carbohydrates including starch; and proteins and essential amino acids. Whilst this species has been demonstrated to accumulate multiple products, the development of an integrated downstream process to obtain these is lacking. The objective of this review paper is to assess the research that has taken place and to identify the steps that must be taken to establish a biorefinery approach for C. zofingiensis. In particular, the reasons why C. zofingiensis is a promising species to target for biorefinery are discussed in terms of cellular structure, potential products, and means to accumulate desirable components via the alteration of culture conditions. Future advances and the challenges that lie ahead for successful biorefinery of this species are also reviewed along with potential solutions to address them. Supplementary Information The online version contains supplementary material available at 10.1007/s13399-022-02955-7.
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Affiliation(s)
- Eleanor E. Wood
- University of the Highlands and Islands (UHI); Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, PA37 1QA UK
- Xanthella Ltd, Malin House, European Marine Science Park, Dunstaffnage, Argyll, Oban PA37 1SZ Scotland, UK
| | - Michael E. Ross
- University of the Highlands and Islands (UHI); Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, PA37 1QA UK
| | - Sébastien Jubeau
- Xanthella Ltd, Malin House, European Marine Science Park, Dunstaffnage, Argyll, Oban PA37 1SZ Scotland, UK
| | | | - Michele S. Stanley
- University of the Highlands and Islands (UHI); Scottish Association for Marine Science (SAMS), Scottish Marine Institute, Oban, PA37 1QA UK
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8
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Enhanced growth of Chromochloris zofingiensis through the transition of nutritional modes. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102723] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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9
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Basiony M, Ouyang L, Wang D, Yu J, Zhou L, Zhu M, Wang X, Feng J, Dai J, Shen Y, Zhang C, Hua Q, Yang X, Zhang L. Optimization of microbial cell factories for astaxanthin production: Biosynthesis and regulations, engineering strategies and fermentation optimization strategies. Synth Syst Biotechnol 2022; 7:689-704. [PMID: 35261927 PMCID: PMC8866108 DOI: 10.1016/j.synbio.2022.01.002] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 12/08/2021] [Accepted: 01/03/2022] [Indexed: 12/29/2022] Open
Abstract
The global market demand for natural astaxanthin is rapidly increasing owing to its safety, the potential health benefits, and the diverse applications in food and pharmaceutical industries. The major native producers of natural astaxanthin on industrial scale are the alga Haematococcus pluvialis and the yeast Xanthopyllomyces dendrorhous. However, the natural production via these native producers is facing challenges of limited yield and high cost of cultivation and extraction. Alternatively, astaxanthin production via metabolically engineered non-native microbial cell factories such as Escherichia coli, Saccharomyces cerevisiae and Yarrowia lipolytica is another promising strategy to overcome these limitations. In this review we summarize the recent scientific and biotechnological progresses on astaxanthin biosynthetic pathways, transcriptional regulations, the interrelation with lipid metabolism, engineering strategies as well as fermentation process control in major native and non-native astaxanthin producers. These progresses illuminate the prospects of producing astaxanthin by microbial cell factories on industrial scale.
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Huy M, Kristin Vatland A, Kumar G. Nutraceutical productions from microalgal derived compounds via circular bioeconomy perspective. BIORESOURCE TECHNOLOGY 2022; 347:126575. [PMID: 34923082 DOI: 10.1016/j.biortech.2021.126575] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 12/10/2021] [Accepted: 12/11/2021] [Indexed: 06/14/2023]
Abstract
Circular bioeconomy has become a sustainable business model for commercial production that promises to reuse, recycle & recover while considering less environmental footprints in nutraceutical industries. Microalgae biotechnology has the synergy to bioremediate waste stream while generating high-value-added compounds such as astaxanthin, protein and polyunsaturated fatty acids that are potential compounds used in various industries, thus, the integration of this approach provides economic advantages. However, since the industrial production of these compounds is costly and affected byunstable climate in the Nordic regions such as low temperature, light intensity, and polar circle, the focus of biosynthesis has shifted from less tolerant commercial strains towards indigenous strains. Nutraceutical productions such as polyunsaturated fatty acids and protein can now be synthesized at low temperatures which significantly improve the industry's economy. In this review, the above-mentioned compounds with potential strains were discussed based on a Nordic region's perspective.
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Affiliation(s)
- Menghour Huy
- Department of Chemistry, Bioscience, and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Box 8600 Forus, 4036 Stavanger, Norway
| | - Ann Kristin Vatland
- Department of Chemistry, Bioscience, and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Box 8600 Forus, 4036 Stavanger, Norway
| | - Gopalakrishnan Kumar
- Department of Chemistry, Bioscience, and Environmental Engineering, Faculty of Science and Technology, University of Stavanger, Box 8600 Forus, 4036 Stavanger, Norway.
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11
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Suarez-Montes D, Borrell YJ, Gonzalez JM, Rico JM. Isolation and identification of microalgal strains with potential as carotenoids producers from a municipal solid waste landfill. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 802:149755. [PMID: 34525767 DOI: 10.1016/j.scitotenv.2021.149755] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Revised: 08/12/2021] [Accepted: 08/15/2021] [Indexed: 06/13/2023]
Abstract
Derived from their great capacity of adaptation, microalgae have several industrial applications, including pigment production for nutraceutical sector. However, the scarcity of studies on the diversity and life histories from several environments, highlight the need for more research on new species and habitats. Based on this, the present study assessed the microalgal diversity in water bodies of a municipal solid waste (MSW) landfill in Asturias (Spain). A total of 14 strains were successfully isolated and scaled up in liquid monocultures. They were identified through a combination of morphologic features with molecular assignation by DNA barcoding via the 18S and ITS1-5.8S-ITS2 genes. The results of the genetic procedures (BLAST assignments and the 18S and ITS1-5.8S-ITS2 genealogies) showed that 10 of the 14 assayed isolates were identified at the species level. The available genetic data were not sufficient for species classifications of the remaining isolates. It is possible that some might be new species not previously studied or described. Indeed, a new species, Coelastrella cogersae, was proposed in this study. Moreover, 3 of the 14 isolates (including the newly proposed species) exhibited caretogenic activity under specific conditions during the culture. These results are a great step forward in both the screening of lesser-known environments and the discovery of new sources of bioactive compounds. The study could be of great value to the nutraceutical industries and markets.
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Affiliation(s)
- David Suarez-Montes
- Neoalgae Micro Seaweed Products, C/ Carmen Leal Mata 191, 33211 Gijón, Spain; Department of Organisms and Systems Biology, University of Oviedo, C/ Catedrático Valentín Andrés Álvarez s/n, 33006 Oviedo, Spain.
| | - Yaisel Juan Borrell
- Department of Functional Biology, University of Oviedo, C/ Catedrático Valentín Andrés Álvarez s/n, 33006 Oviedo, Spain
| | | | - Jose Manuel Rico
- Department of Organisms and Systems Biology, University of Oviedo, C/ Catedrático Valentín Andrés Álvarez s/n, 33006 Oviedo, Spain
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12
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Bai F, Zhang Y, Liu J. A bZIP transcription factor is involved in regulating lipid and pigment metabolisms in the green alga Chlamydomonas reinhardtii. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102450] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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13
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Maltsev Y, Maltseva K, Kulikovskiy M, Maltseva S. Influence of Light Conditions on Microalgae Growth and Content of Lipids, Carotenoids, and Fatty Acid Composition. BIOLOGY 2021; 10:1060. [PMID: 34681157 PMCID: PMC8533579 DOI: 10.3390/biology10101060] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Revised: 10/13/2021] [Accepted: 10/14/2021] [Indexed: 02/06/2023]
Abstract
Microalgae are a valuable natural resource for a variety of value-added products. The growth of microalgae is determined by the impact of many factors, but, from the point of view of the implementation of autotrophic growth, light is of primary importance. This work presents an overview of the influence of light conditions on the growth of microalgae, the content of lipids, carotenoids, and the composition of fatty acids in their biomass, taking into account parameters such as the intensity, duration of lighting, and use of rays of different spectral composition. The optimal light intensity for the growth of microalgae lies in the following range: 26-400 µmol photons m-2 s-1. An increase in light intensity leads to an activation of lipid synthesis. For maximum lipid productivity, various microalgae species and strains need lighting of different intensities: from 60 to 700 µmol photons m-2 s-1. Strong light preferentially increases the triacylglyceride content. The intensity of lighting has a regulating effect on the synthesis of fatty acids, carotenoids, including β-carotene, lutein and astaxanthin. In intense lighting conditions, saturated fatty acids usually accumulate, as well as monounsaturated ones, and the number of polyunsaturated fatty acids decreases. Red as well as blue LED lighting improves the biomass productivity of microalgae of various taxonomic groups. Changing the duration of the photoperiod, the use of pulsed light can stimulate microalgae growth, the production of lipids, and carotenoids. The simultaneous use of light and other stresses contributes to a stronger effect on the productivity of algae.
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Affiliation(s)
- Yevhen Maltsev
- Laboratory of Molecular Systematics of Aquatic Plants, K.A. Timiryazev Institute of Plant Physiology RAS, IPP RAS, 127276 Moscow, Russia; (M.K.); (S.M.)
| | - Kateryna Maltseva
- Faculty of Chemistry and Biology, Bogdan Khmelnitsky Melitopol State Pedagogical University, 72312 Melitopol, Ukraine;
| | - Maxim Kulikovskiy
- Laboratory of Molecular Systematics of Aquatic Plants, K.A. Timiryazev Institute of Plant Physiology RAS, IPP RAS, 127276 Moscow, Russia; (M.K.); (S.M.)
| | - Svetlana Maltseva
- Laboratory of Molecular Systematics of Aquatic Plants, K.A. Timiryazev Institute of Plant Physiology RAS, IPP RAS, 127276 Moscow, Russia; (M.K.); (S.M.)
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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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15
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Zhang H, Zhao L, Chen Y, Zhu M, Xu Q, Wu M, Han D, Hu Q. Trophic Transition Enhanced Biomass and Lipid Production of the Unicellular Green Alga Scenedesmus acuminatus. Front Bioeng Biotechnol 2021; 9:638726. [PMID: 34095093 PMCID: PMC8176925 DOI: 10.3389/fbioe.2021.638726] [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: 12/07/2020] [Accepted: 04/08/2021] [Indexed: 11/18/2022] Open
Abstract
Microalgal heterotrophic cultivation is an emerging technology that can enable producing high cell-density algal cell cultures, which can be coupled with photoautotrophic cultivation for valuable chemicals such as lipids manufacturing. However, how the heterotrophically grown algal cells respond to the lipid-inducing conditions has not been fully elucidated so far. In this study, when the heterotrophically grown Scenedesmus acuminatus cells were subjected to the high light (HL) and nitrogen-limited (NL) conditions, both the biomass and lipid productivity were enhanced as compared to that of the photoautotrophically grown counterparts. The chlorophyll a fluorometry analysis showed that the Fv/Fm and Y(II) of the heterotrophically grown cells subjected to the HL and NL conditions was recovered to the maximum value of 0.75 and 0.43, respectively, much higher than those of the photoautotrophically grown cells under the same stress conditions. Transcriptomic analysis revealed that heterotrophically grown cells fully expressed the genes coding for the photosystems proteins, including the key photoprotective proteins D1, PsbS, light-harvesting-complex (LHC) I and LHC II. Meanwhile, downregulation of the carotenoid biosynthesis and upregulation of the glycolysis/gluconeogenesis, tricarboxylic acid (TCA) cycle and oxidative phosphorylation pathways were observed when the heterotrophically grown cells were subjected to the HL and N-limited conditions for lipid production. It was deduced that regulation of these pathways not only enhanced the light utilization but also provided the reducing power and ATP by which the biomass accumulation was significantly elevated. Besides, upregulation of the acetyl-CoA carboxylase/biotin carboxylase, digalactosyl diacylglycerol synthase and diacylglycerol acyltransferase 2 encoding genes may be attributable to the enhanced lipid production. Understanding the cellular responses during the trophic transition process could guide improvement of the strength of trophic transition enhancing microalgal biomass and lipid production.
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Affiliation(s)
- Hu Zhang
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Liang Zhao
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
| | - Yi Chen
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Mianmian Zhu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Quan Xu
- Center for Microalgal Biotechnology and Biofuels, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China.,College of Life Sciences, University of Chinese Academy of Sciences, Beijing, China
| | - Mingcan Wu
- Center for Microalgal Biotechnology and Biofuels, 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.,The Innovative Academy of Seed Design, Chinese Academy of Sciences, Beijing, China
| | - Qiang Hu
- 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.,Institute for Advanced Study, Shenzhen University, Shenzhen, China.,State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, China
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16
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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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Mócsai R, Kaehlig H, Blaukopf M, Stadlmann J, Kosma P, Altmann F. The Structural Difference of Isobaric N-Glycans of Two Microalgae Samples Reveals Taxonomic Distance. FRONTIERS IN PLANT SCIENCE 2021; 12:643249. [PMID: 33981323 PMCID: PMC8107433 DOI: 10.3389/fpls.2021.643249] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/27/2021] [Accepted: 03/18/2021] [Indexed: 06/12/2023]
Abstract
Microalgae of the Chlorella clade are extensively investigated as an environmentally friendly source of renewable biofuels and high-value nutrients. In addition, essentially unprocessed Chlorella serves as wholesome food additive. A recent study on 80 commercial Chlorella preparations revealed an unexpected variety of protein-linked N-glycan patterns with unprecedented structural features, such as the occurrence of arabinose. Two groups of products exhibited a characteristic major N-glycan isobaric to the Man2GlcNAc2XylFuc N-glycan known from pineapple stem bromelain, but tandem mass spectrometry (MS/MS) analysis pointed at two types of N-glycan different from the bromelain structure, as well as from each other. Here we report the exact structures of these two novel N-glycan structures, elucidated by nuclear magnetic resonance spectroscopy and MS/MS, as well as on their phylogenetic context. Despite their humble size, these two N-glycans exhibited a very different design with structural features unrelated to those recently described for other Chlorella-clade strains. The major glycans of this study presented several novel structural features such as substitution by arabinose or xylose of the internal N-acetylglucosamine, as well as methylated sugars. ITS1-5.8S-ITS2 rDNA barcode analyses revealed that the xylose-containing structure derived from a product primarily comprising Scenedesmus species, and the arabinose-containing glycan type related to Chlorella species (SAG211-34 and FACHB-31) and to Auxenochlorella. This is another example where characteristic N-glycan structures distinguish phylogenetically different groups of microalgae.
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Affiliation(s)
- Réka Mócsai
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Hanspeter Kaehlig
- Department of Organic Chemistry, Faculty of Chemistry, University of Vienna, Vienna, Austria
| | - Markus Blaukopf
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Johannes Stadlmann
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Paul Kosma
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
| | - Friedrich Altmann
- Department of Chemistry, University of Natural Resources and Life Sciences, Vienna, Austria
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Rodríguez-Sifuentes L, Marszalek JE, Hernández-Carbajal G, Chuck-Hernández C. Importance of Downstream Processing of Natural Astaxanthin for Pharmaceutical Application. FRONTIERS IN CHEMICAL ENGINEERING 2021. [DOI: 10.3389/fceng.2020.601483] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Astaxanthin (ASX) is a xanthophyll pigment considered as a nutraceutical with high antioxidant activity. Several clinical trials have shown the multiple health benefits of this molecule; therefore, it has various pharmaceutical industry applications. Commercial astaxanthin can be produced by chemical synthesis or through biosynthesis within different microorganisms. The molecule produced by the microorganisms is highly preferred due to its zero toxicity and superior therapeutic properties. However, the biotechnological production of the xanthophyll is not competitive against the chemical synthesis, since the downstream process may represent 70–80% of the process production cost. These operations denote then an opportunity to optimize the process and make this alternative more competitive. Since ASX is produced intracellularly by the microorganisms, high investment and high operational costs, like centrifugation and bead milling or high-pressure homogenization, are mainly used. In cell recovery, flocculation and flotation may represent low energy demanding techniques, whereas, after cell disruption, an efficient extraction technique is necessary to extract the highest percentage of ASX produced by the cell. Solvent extraction is the traditional method, but large-scale ASX production has adopted supercritical CO2 (SC-CO2), an efficient and environmentally friendly technology. On the other hand, assisted technologies are extensively reported since the cell disruption, and ASX extraction can be carried out in a single step. Because a high-purity product is required in pharmaceuticals and nutraceutical applications, the use of chromatography is necessary for the downstream process. Traditionally liquid-solid chromatography techniques are applied; however, the recent emergence of liquid-liquid chromatography like high-speed countercurrent chromatography (HSCCC) coupled with liquid-solid chromatography allows high productivity and purity up to 99% of ASX. Additionally, the use of SC-CO2, coupled with two-dimensional chromatography, is very promising. Finally, the purified ASX needs to be formulated to ensure its stability and bioavailability; thus, encapsulation is widely employed. In this review, we focus on the processes of cell recovery, cell disruption, drying, extraction, purification, and formulation of ASX mainly produced in Haematococcus pluvialis, Phaffia rhodozyma, and Paracoccus carotinifaciens. We discuss the current technologies that are being developed to make downstream operations more efficient and competitive in the biotechnological production process of this carotenoid.
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Wan X, Zhou XR, Moncalian G, Su L, Chen WC, Zhu HZ, Chen D, Gong YM, Huang FH, Deng QC. Reprogramming microorganisms for the biosynthesis of astaxanthin via metabolic engineering. Prog Lipid Res 2020; 81:101083. [PMID: 33373616 DOI: 10.1016/j.plipres.2020.101083] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2020] [Revised: 12/21/2020] [Accepted: 12/21/2020] [Indexed: 12/21/2022]
Abstract
There is an increasing demand for astaxanthin in food, feed, cosmetics and pharmaceutical applications because of its superior anti-oxidative and coloring properties. However, naturally produced astaxanthin is expensive, mainly due to low productivity and limited sources. Reprogramming of microorganisms for astaxanthin production via metabolic engineering is a promising strategy. We primarily focus on the application of synthetic biology, enzyme engineering and metabolic engineering in enhancing the synthesis and accumulation of astaxanthin in microorganisms in this review. We also discuss the biosynthetic pathways of astaxanthin within natural producers, and summarize the achievements and challenges in reprogramming microorganisms for enhancing astaxanthin production. This review illuminates recent biotechnological advances in microbial production of astaxanthin. Future perspectives on utilization of new technologies for boosting microbial astaxanthin production are also discussed.
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Affiliation(s)
- Xia Wan
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, PR China; Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, PR China.
| | | | - Gabriel Moncalian
- Departamento de Biología Molecular, Universidad de Cantabria and Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC), CSIC-Universidad de Cantabria, Santander, Spain
| | - Lin Su
- College of Food Science and Engineering, Inner Mongolia Agricultural University, Hohhot 010018, PR China
| | - Wen-Chao Chen
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, PR China; Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, PR China
| | - Hang-Zhi Zhu
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Dan Chen
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China
| | - Yang-Min Gong
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, PR China; Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, PR China
| | - Feng-Hong Huang
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, PR China; Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, PR China.
| | - Qian-Chun Deng
- Oil Crops Research Institute of the Chinese Academy of Agricultural Sciences, Wuhan 430062, PR China; Key Laboratory of Biology and Genetic Improvement of Oil Crops, Ministry of Agriculture, Wuhan 430062, PR China; Oil Crops and Lipids Process Technology National & Local Joint Engineering Laboratory, Wuhan 430062, PR China.
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Kou Y, Liu M, Sun P, Dong Z, Liu J. High light boosts salinity stress-induced biosynthesis of astaxanthin and lipids in the green alga Chromochloris zofingiensis. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101976] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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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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Cheng P, Cheng JJ, Cobb K, Zhou C, Zhou N, Addy M, Chen P, Yan X, Ruan R. Tribonema sp. and Chlorella zofingiensis co-culture to treat swine wastewater diluted with fishery wastewater to facilitate harvest. BIORESOURCE TECHNOLOGY 2020; 297:122516. [PMID: 31830716 DOI: 10.1016/j.biortech.2019.122516] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/26/2019] [Accepted: 11/28/2019] [Indexed: 06/10/2023]
Abstract
Cultivating microalgae on wastewaters is an effective way to produce algal biomass whereas harvesting microalgae is a costly operation. This study we examined the feasibility of co-culturing a high-value microalga with an auto-flocculating strain to enable efficient recovery of biomass. Experiments were conducted to co-cultivate Chlorella zofingiensis with Tribonema sp. on swine wastewater diluted by fishery wastewater under different conditions. The result showed the optimal inoculum ratio of Tribonema sp. to Chlorella zofingiensis was 1:1. The removal efficiencies of pollutants (NH4+-N, TN, TP, and COD) and lipid content were high when the co-culture ratios of Tribonema sp. were high. Also, some larger chain fatty acids, specifically C20:5 and C22:6 were present when the two strains co-culture. The recovery efficiency increased with the increasing proportion of auto-flocculating Tribonema sp.. Algae co-culture has the potential to address limitations in substrate utilization by individual strains, also improve the recovery of biomass.
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Affiliation(s)
- Pengfei Cheng
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315211, China; Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA
| | - Jay J Cheng
- Department of Biological and Agricultural Engineering, North Carolina State University, Box 7625, Raleigh, NC 27695, USA
| | - Kirk Cobb
- Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA
| | - Chengxu Zhou
- College of Food and Pharmaceutical Sciences, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Nan Zhou
- Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA
| | - Min Addy
- Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA
| | - Paul Chen
- Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA
| | - Xiaojun Yan
- Key Laboratory of Marine Biotechnology of Zhejiang Province, Ningbo University, Ningbo, Zhejiang 315211, China
| | - Roger Ruan
- Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota-Twin Cities, Saint Paul, MN 55108, USA.
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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, Wei H, Mao X, Liu J. Proteomics Analysis of Lipid Droplets from the Oleaginous Alga Chromochloris zofingiensis Reveals Novel Proteins for Lipid Metabolism. GENOMICS PROTEOMICS & BIOINFORMATICS 2019; 17:260-272. [PMID: 31494267 PMCID: PMC6818385 DOI: 10.1016/j.gpb.2019.01.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 11/13/2018] [Accepted: 01/04/2019] [Indexed: 11/30/2022]
Abstract
Chromochloris zofingiensis represents an industrially relevant and unique green alga, given its capability of synthesizing triacylglycerol (TAG) and astaxanthin simultaneously for storage in lipid droplets (LDs). To further decipher lipid metabolism, the nitrogen deprivation (ND)-induced LDs from C. zofingiensis were isolated, purified, and subjected to proteomic analysis. Intriguingly, many C. zofingiensis LD proteins had no orthologs present in LD proteome of the model alga Chlamydomonas reinhardtii. Seven novel LD proteins (i.e., two functionally unknown proteins, two caleosins, two lipases, and one l-gulonolactone oxidase) and the major LD protein (MLDP), which were all transcriptionally up-regulated by ND, were selected for further investigation. Heterologous expression in yeast demonstrated that all tested LD proteins were localized to LDs and all except the two functionally unknown proteins enabled yeast to produce more TAG. MLDP could restore the phenotype of mldp mutant strain and enhance TAG synthesis in wild-type strain of C. reinhardtii. Although MLDP and caleosins had a comparable abundance in LDs, they responded distinctly to ND at the transcriptional level. The two lipases, instead of functioning as TAG lipases, likely recycled polar lipids to support TAG synthesis. For the first time, we reported that l-gulonolactone oxidase was abundant in LDs and facilitated TAG accumulation. Moreover, we also proposed a novel working model for C. zofingiensis LDs. Taken together, our work unravels the unique characteristics of C. zofingiensis LDs and provides insights into algal LD biogenesis and TAG synthesis, which would facilitate genetic engineering of this alga for TAG improvement.
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Affiliation(s)
- Xiaofei Wang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China
| | - Hehong Wei
- 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
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China.
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Wu T, Mao X, Kou Y, Li Y, Sun H, He Y, Chen F. Characterization of Microalgal Acetyl-CoA Synthetases with High Catalytic Efficiency Reveals Their Regulatory Mechanism and Lipid Engineering Potential. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:9569-9578. [PMID: 31385495 DOI: 10.1021/acs.jafc.9b03370] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
Acetyl-CoA synthetase (ACS) plays a key role in microalgal lipid biosynthesis and acetyl-CoA industrial production. In the present study, two ACSs were cloned and characterized from the oleaginous microalga Chromochloris zofingiensis. In vitro kinetic analysis showed that the Km values of CzACS1 and CzACS2 for potassium acetate were 0.99 and 0.81 mM, respectively. Moreover, CzACS1 and CzACS2 had outstanding catalytic efficiencies (kcat/Km), which were 70.67 and 79.98 s-1 mM-1, respectively, and these values were higher than that of other reported ACSs. CzACS1 and CzACS2 exhibited differential expression patterns at the transcriptional level under various conditions. Screening a recombinant library of 52 transcription factors (TFs) constructed in the present study via yeast one-hybrid assay pointed to seven TFs with potential involvement in the regulation of the two ACS genes. Expression correlation analysis implied that GATA20 was likely an important regulator of CzACS2 and that ERF9 could regulate two CzACSs simultaneously.
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Affiliation(s)
| | | | | | | | - Han Sun
- Institute for Advanced Study , Shenzhen University , Shenzhen 518060 , China
| | | | - Feng Chen
- Institute for Advanced Study , Shenzhen University , Shenzhen 518060 , China
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Zhang Y, Shi M, Mao X, Kou Y, Liu J. Time-resolved carotenoid profiling and transcriptomic analysis reveal mechanism of carotenogenesis for astaxanthin synthesis in the oleaginous green alga Chromochloris zofingiensis. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:287. [PMID: 31890015 PMCID: PMC6913025 DOI: 10.1186/s13068-019-1626-1] [Citation(s) in RCA: 36] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/21/2019] [Accepted: 12/04/2019] [Indexed: 05/03/2023]
Abstract
BACKGROUND Chromochloris zofingiensis is emerging as an industrially relevant alga given its robust growth for the production of lipids and astaxanthin, a value-added carotenoid with broad applications. Nevertheless, poor understanding of astaxanthin synthesis has limited engineering of this alga for rational improvements. RESULTS To reveal the molecular mechanism underlying astaxanthin accumulation in C. zofingiensis, here we conducted an integrated analysis by combining the time-resolved transcriptomes and carotenoid profiling in response to nitrogen deprivation (ND). A global response was triggered for C. zofingiensis to cope with the ND stress. Albeit the little variation in total carotenoid content, individual carotenoids responded differentially to ND: the primary carotenoids particularly lutein and β-carotene decreased, while the secondary carotenoids increased considerably, with astaxanthin and canthaxanthin being the most increased ones. The carotenogenesis pathways were reconstructed: ND had little effect on the carbon flux to carotenoid precursors, but stimulated astaxanthin biosynthesis while repressing lutein biosynthesis, thereby diverting the carotenoid flux from primary carotenoids to secondary carotenoids particularly astaxanthin. Comparison between C. zofingiensis and Haematococcus pluvialis revealed the distinctive mechanism of astaxanthin synthesis in C. zofingiensis. Furthermore, potential bottlenecks in astaxanthin synthesis were identified and possible engineering strategies were proposed for the alga. CONCLUSIONS Collectively, these findings shed light on distinctive mechanism of carotenogenesis for astaxanthin biosynthesis in C. zofingiensis, identify key functional enzymes and regulators with engineering potential and will benefit rational manipulation of this alga for improving nutritional traits.
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Affiliation(s)
- Yu Zhang
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing, 100871 China
| | - Meicheng Shi
- 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
| | - Yaping Kou
- 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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