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Slocombe SP, Zúñiga-Burgos T, Chu L, Mehrshahi P, Davey MP, Smith AG, Camargo-Valero MA, Baker A. Overexpression of PSR1 in Chlamydomonas reinhardtii induces luxury phosphorus uptake. FRONTIERS IN PLANT SCIENCE 2023; 14:1208168. [PMID: 37575910 PMCID: PMC10413257 DOI: 10.3389/fpls.2023.1208168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Accepted: 05/23/2023] [Indexed: 08/15/2023]
Abstract
Remediation using micro-algae offers an attractive solution to environmental phosphate (PO4 3-) pollution. However, for maximum efficiency, pre-conditioning of algae to induce 'luxury phosphorus (P) uptake' is needed. To replicate this process, we targeted the global regulator PSR1 (Myb transcription factor: Phosphate Starvation Response 1) for over-expression in algae. Manipulating a single gene (PSR1) drove uptake of both PO4 3- and a Mg2+ counter-ion leading to increased PolyP granule size, raising P levels 4-fold to 8% dry cell weight, and accelerated removal of PO4 3- from the medium. Examination of the gene expression profile showed that the P-starvation response was mimicked under P-replete conditions, switching on luxury uptake. Hyper-accumulation of P depended on a feed-forward mechanism, where a small set of 'Class I' P-transporter genes were activated despite abundant external PO4 3- levels. The transporters drove a reduction in external PO4 3- levels, permitting more genes to be expressed (Class II), leading to more P-uptake. Our data pointed toward a PSR1-independent mechanism for detection of external PO4 3- which suppressed Class II genes. This model provided a plausible mechanism for P-overplus where prior P-starvation elevates PSR1 and on P-resupply causes luxury P-uptake. This is because the Class I genes, which include P-transporter genes, are not suppressed by the excess PO4 3-. Taken together, these discoveries facilitate a bio-circular approach of recycling nutrients from wastewater back to agriculture.
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Affiliation(s)
- Stephen P. Slocombe
- School of Molecular and Cellular Biology, Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Tatiana Zúñiga-Burgos
- School of Molecular and Cellular Biology, Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
- BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds, United Kingdom
| | - Lili Chu
- School of Molecular and Cellular Biology, Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
| | - Payam Mehrshahi
- Department of Plant Sciences, Cambridge University, Cambridge, United Kingdom
| | - Matthew P. Davey
- Department of Plant Sciences, Cambridge University, Cambridge, United Kingdom
| | - Alison G. Smith
- Department of Plant Sciences, Cambridge University, Cambridge, United Kingdom
| | - Miller Alonso Camargo-Valero
- BioResource Systems Research Group, School of Civil Engineering, University of Leeds, Leeds, United Kingdom
- Departamento de Ingeniería Química, Universidad Nacional de Colombia, Manizales, Colombia
| | - Alison Baker
- School of Molecular and Cellular Biology, Centre for Plant Sciences and Astbury Centre for Structural Molecular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, United Kingdom
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Penhaul Smith J, Hughes A, McEvoy L, Day J. Use of crude glycerol for mixotrophic culture of Phaeodactylum tricornutum. ALGAL RES 2023. [DOI: 10.1016/j.algal.2022.102929] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
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Rawat D, Sharma U, Poria P, Finlan A, Parker B, Sharma RS, Mishra V. Iron-dependent mutualism between Chlorella sorokiniana and Ralstonia pickettii forms the basis for a sustainable bioremediation system. ISME COMMUNICATIONS 2022; 2:83. [PMID: 36407791 PMCID: PMC9476460 DOI: 10.1038/s43705-022-00161-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/09/2021] [Revised: 06/15/2022] [Accepted: 07/14/2022] [Indexed: 01/11/2023]
Abstract
Phototrophic communities of autotrophic microalgae and heterotrophic bacteria perform complex tasks of nutrient acquisition and tackling environmental stress but remain underexplored as a basis for the bioremediation of emerging pollutants. In industrial monoculture designs, poor iron uptake by microalgae limits their productivity and biotechnological efficacy. Iron supplementation is expensive and ineffective because iron remains insoluble in an aqueous medium and is biologically unavailable. However, microalgae develop complex interkingdom associations with siderophore-producing bacteria that help solubilize iron and increase its bioavailability. Using dye degradation as a model, we combined environmental isolations and synthetic ecology as a workflow to design a simplified microbial community based on iron and carbon exchange. We established a mutualism between the previously non-associated alga Chlorella sorokiniana and siderophore-producing bacterium Ralstonia pickettii. Siderophore-mediated increase in iron bioavailability alleviated Fe stress for algae and increased the reductive iron uptake mechanism and bioremediation potential. In exchange, C. sorokiniana produced galactose, glucose, and mannose as major extracellular monosaccharides, supporting bacterial growth. We propose that extracellular iron reduction by ferrireductase is crucial for azoreductase-mediated dye degradation in microalgae. These results demonstrate that iron bioavailability, often overlooked in cultivation, governs microalgal growth, enzymatic processes, and bioremediation potential. Our results suggest that phototrophic communities with an active association for iron and carbon exchange have the potential to overcome challenges associated with micronutrient availability, while scaling up bioremediation designs.
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Affiliation(s)
- Deepak Rawat
- Bioresources & Environmental Biotechnology Laboratory, Department of Environmental Studies, University of Delhi, Delhi, 110007 India
- Department of Biochemical Engineering, Bernard Katz Building, University College London, Gower Street, London, WC1E 6BT UK
- Department of Environmental Studies, Janki Devi Memorial College, University of Delhi, Delhi, 110060 India
| | - Udita Sharma
- Bioresources & Environmental Biotechnology Laboratory, Department of Environmental Studies, University of Delhi, Delhi, 110007 India
| | - Pankaj Poria
- Bioresources & Environmental Biotechnology Laboratory, Department of Environmental Studies, University of Delhi, Delhi, 110007 India
| | - Arran Finlan
- Department of Biochemical Engineering, Bernard Katz Building, University College London, Gower Street, London, WC1E 6BT UK
| | - Brenda Parker
- Department of Biochemical Engineering, Bernard Katz Building, University College London, Gower Street, London, WC1E 6BT UK
| | - Radhey Shyam Sharma
- Bioresources & Environmental Biotechnology Laboratory, Department of Environmental Studies, University of Delhi, Delhi, 110007 India
- Delhi School of Climate Change & Sustainability, Institute of Eminence, University of Delhi, Delhi, 110007 India
| | - Vandana Mishra
- Bioresources & Environmental Biotechnology Laboratory, Department of Environmental Studies, University of Delhi, Delhi, 110007 India
- Centre for Interdisciplinary Studies on Mountain & Hill Environment, University of Delhi, Delhi, 110007 India
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Xiang Q, Wei X, Yang Z, Xie T, Zhang Y, Li D, Pan X, Liu X, Zhang X, Yao C. Acclimation to a broad range of nitrate strength on a euryhaline marine microalga Tetraselmis subcordiformis for photosynthetic nitrate removal and high-quality biomass production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2021; 781:146687. [PMID: 33812104 DOI: 10.1016/j.scitotenv.2021.146687] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Revised: 03/19/2021] [Accepted: 03/19/2021] [Indexed: 06/12/2023]
Abstract
Industrial wastewaters usually possess a wide range of nitrate strength. Microalgae-based nitrate-rich wastewater treatment could realize nitrate recovery along with CO2 sequestration for sustainable biomass production, but the low tolerance of the microalgal strains to high-strength nitrate restricted the treatment process. The present study comprehensively evaluated a euryhaline marine microalga Tetraselmis subcordiformis for photosynthetic nitrate removal and biomass production in synthetic wastewater with a broad range of nitrate strength (0.24-7.0 g NO3--N/L). This alga could acclimate to high nitrate strength up to 3.5 g NO3--N/L (HN) without compromising biomass production. Nitrate could be completely removed within four days when low nitrate (0.24 g NO3--N/L, LN) was loaded. The maximum nitrate removal rate of 331 mg N/L/day and specific nitrate removal rate of 360 mg N/day/g cell was obtained under medium nitrate condition (1.8 g NO3--N/L, MN). High-nitrate stress under 7.0 g NO3--N/L (SHN) caused an increased light energy dissipation while decreased the density of photosystem II active reaction center, which partially protect the cells from photodamage and contributed to their acclimation to SHN. The algae also enhanced amino acid/fatty acid proportions essential for maintaining intracellular redox states to cope with the stress caused by LN or SHN. HN and SHN was in favor of protein accumulation and maintenance with enhanced proportion of essential amino acids, which entitled the algal biomass to be of high quality for animal feed applied in livestock graziery and aquaculture. LN facilitated productive starch and lipid accumulation with good quality for biofuels production. The nitrate removal rate and biomass productivity exceeded most of the microalgae reported in literature under similar conditions, which highlighted Tetraselmis subcordiformis as a potent strain for flexible nitrate-rich wastewater remediation coupled with fast CO2 bio-mitigation and high-quality biomass production for sustainable algal biorefinery.
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Affiliation(s)
- Qi Xiang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xiaolong Wei
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Zezhou Yang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Tonghui Xie
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Yongkui Zhang
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Defu Li
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China
| | - Xuerong Pan
- Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, Sichuan 610213, China
| | - Xiaolong Liu
- Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, Sichuan 610213, China
| | - Xiang Zhang
- Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu, Sichuan 610213, China
| | - Changhong Yao
- Department of Pharmaceutical & Biological Engineering, School of Chemical Engineering, Sichuan University, Chengdu, Sichuan 610065, China.
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Gray A, Krolikowski M, Fretwell P, Convey P, Peck LS, Mendelova M, Smith AG, Davey MP. Remote sensing reveals Antarctic green snow algae as important terrestrial carbon sink. Nat Commun 2020; 11:2527. [PMID: 32433543 PMCID: PMC7239900 DOI: 10.1038/s41467-020-16018-w] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 04/02/2020] [Indexed: 12/25/2022] Open
Abstract
We present the first estimate of green snow algae community biomass and distribution along the Antarctic Peninsula. Sentinel 2 imagery supported by two field campaigns revealed 1679 snow algae blooms, seasonally covering 1.95 × 106 m2 and equating to 1.3 × 103 tonnes total dry biomass. Ecosystem range is limited to areas with average positive summer temperatures, and distribution strongly influenced by marine nutrient inputs, with 60% of blooms less than 5 km from a penguin colony. A warming Antarctica may lose a majority of the 62% of blooms occupying small, low-lying islands with no high ground for range expansion. However, bloom area and elevation were observed to increase at lower latitudes, suggesting that parallel expansion of bloom area on larger landmasses, close to bird or seal colonies, is likely. This increase is predicted to outweigh biomass lost from small islands, resulting in a net increase in snow algae extent and biomass as the Peninsula warms. Snow algae bloom along the coast of Antarctica and are likely to be biogeochemically important. Here, the authors produced the first map of such blooms, show that they are driven by warmer temperatures and proximity to birds and mammals, and are likely to increase given projected climate changes.
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Affiliation(s)
- Andrew Gray
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK. .,NERC Field Spectroscopy Facility, Edinburgh, EH3 9FE, UK.
| | - Monika Krolikowski
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Peter Fretwell
- British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, UK
| | - Peter Convey
- British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, UK
| | - Lloyd S Peck
- British Antarctic Survey, NERC, Madingley Road, Cambridge, CB3 0ET, UK
| | - Monika Mendelova
- University of Edinburgh, School of GeoSciences, Edinburgh, EH8 9XP, UK
| | - Alison G Smith
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK
| | - Matthew P Davey
- Department of Plant Sciences, University of Cambridge, Downing Street, Cambridge, CB2 3EA, UK.
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Song Z, Lye GJ, Parker BM. Morphological and biochemical changes in Phaeodactylum tricornutum triggered by culture media: Implications for industrial exploitation. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101822] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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