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Vera-Vives AM, Michelberger T, Morosinotto T, Perin G. Assessment of photosynthetic activity in dense microalgae cultures using oxygen production. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 208:108510. [PMID: 38471244 DOI: 10.1016/j.plaphy.2024.108510] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 02/12/2024] [Accepted: 03/06/2024] [Indexed: 03/14/2024]
Abstract
Microalgae are photosynthetic microorganisms playing a pivotal role in primary production in aquatic ecosystems, sustaining the entry of carbon in the biosphere. Microalgae have also been recognized as sustainable source of biomass to complement crops. For this objective they are cultivated in photobioreactors or ponds at high cell density to maximize biomass productivity and lower the cost of downstream processes. Photosynthesis depends on light availability, that is often not constant over time. In nature, sunlight fluctuates over diurnal cycles and weather conditions. In high-density microalgae cultures of photobioreactors outdoors, on top of natural variations, microalgae are subjected to further complexity in light exposure. Because of the high-density cells experience self-shading effects that heavily limit light availability in most of the mass culture volume. This limitation strongly affects biomass productivity of industrial microalgae cultivation plants with important implications on economic feasibility. Understanding how photosynthesis responds to cell density is informative to assess functionality in the inhomogeneous light environment of industrial photobioreactors. In this work we exploited a high-sensitivity Clark electrode to measure microalgae photosynthesis and compare cultures with different densities, using Nannochloropsis as model organism. We observed that cell density has a substantial impact on photosynthetic activity, and demonstrated the reduction of the cell's light-absorption capacity by genetic modification is a valuable strategy to increase photosynthetic functionality on a chlorophyll-basis of dense microalgae cultures.
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Affiliation(s)
| | - Tim Michelberger
- Department of Biology, University of Padova, 35131, Padova, Italy
| | | | - Giorgio Perin
- Department of Biology, University of Padova, 35131, Padova, Italy.
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Tsai TY, Chien YL, Zheng YY, Li YC, Chen JC, Su RC, Ben-Sheleg A, Khozin-Goldberg I, Vonshak A, Lee TM. Modification in the ascorbate-glutathione cycle leads to a better acclimation to high light in the rose Bengal resistant mutant of Nannochloropsis oceanica. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108326. [PMID: 38237421 DOI: 10.1016/j.plaphy.2023.108326] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 12/27/2023] [Accepted: 12/28/2023] [Indexed: 03/16/2024]
Abstract
Understanding how to adapt outdoor cultures of Nannochloropsis oceanica to high light (HL) is vital for boosting productivity. The N. oceanica RB2 mutant, obtained via ethyl methanesulfonate mutagenesis, was chosen for its tolerance to Rose Bengal (RB), a singlet oxygen (1O2) generator. Compared to the wild type (WT), the RB2 mutant showed higher resilience to excess light conditions. Analyzing the ascorbate-glutathione cycle (AGC), involving ascorbate peroxidases (APX, EC 1.11.1.11), dehydroascorbate reductase (DHAR, EC 1.8.5.1), and glutathione reductase (GR, EC 1.8.1.7), in the RB2 mutant under HL stress provided valuable insights. At 250 μmol photon m-2 s-1 (HL), the WT strain displayed superoxide anion radicals (O2▪-) and hydrogen peroxide (H2O2) accumulation, increased lipid peroxidation, and cell death compared to normal light (NL) conditions (50 μmol photon m-2 s-1). The RB2 mutant didn't accumulate O2▪- and H2O2 after HL exposure, and exhibited increased APX, DHAR, and GR activities and transcript levels compared to WT and remained consistent after HL treatment. Although the RB2 mutant had a smaller ascorbate (AsA) pool than the WT, its ability to regenerate dehydroascorbate (DHA) increased post HL exposure, indicated by a higher AsA/DHA ratio. Additionally, under HL conditions, the RB2 mutant displayed an improved glutathione (GSH) regeneration rate (GSH/GSSG ratio) without changing the GSH pool size. Remarkably, H2O2 or menadione (a O2▪- donor) treatment induced cell death in the WT strain but not in the RB2 mutant. These findings emphasize the essential role of AGC in the RB2 mutant of Nannochloropsis in handling photo-oxidative stress.
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Affiliation(s)
- Tsung-Yu Tsai
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Yi-Lin Chien
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Yu-Yun Zheng
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Yu-Chia Li
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan
| | - Jen-Chih Chen
- Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan
| | - Ruey-Chih Su
- Department of Life Science, Fu-Jen University, New Taipei City 242, Taiwan
| | - Avraham Ben-Sheleg
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion 8499000, Israel
| | - Inna Khozin-Goldberg
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion 8499000, Israel.
| | - Avigad Vonshak
- Microalgal Biotechnology Laboratory, The French Associates Institute for Agriculture and Biotechnology of Drylands, Jacob Blaustein Institute for Desert Research, Ben-Gurion University of the Negev, Sede-Boqer Campus, Midreshet Ben-Gurion 8499000, Israel.
| | - Tse-Min Lee
- Department of Marine Biotechnology and Resources, National Sun Yat-sen University, Kaohsiung 804, Taiwan; Institute of Biotechnology, National Taiwan University, Taipei 106, Taiwan; Doctoral Degree Program in Marine Biotechnology, National Sun Yat-sen University, Kaohsiung 804, Taiwan.
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Caprara CDSC, Mathias TK, Santos MDFC, D’Oca MGM, D’Oca CDRM, Roselet F, Abreu PC, Ramos DF. Application of 1H HR-MAS NMR-Based Metabolite Fingerprinting of Marine Microalgae. Metabolites 2023; 13:metabo13020202. [PMID: 36837821 PMCID: PMC9965007 DOI: 10.3390/metabo13020202] [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: 01/05/2023] [Revised: 01/22/2023] [Accepted: 01/24/2023] [Indexed: 01/31/2023] Open
Abstract
Natural products from the marine environment as well as microalgae, have been known for the complexity of the metabolites they produce due to their adaptability to different environmental conditions, which has been an inexhaustible source of several bioactive properties, such as antioxidant, anti-tumor, and antimicrobial. This study aims to characterize the main metabolites of three species of microalgae (Nannochloropsis oceanica, Chaetoceros muelleri, and Conticribra weissflogii), which have important applications in the biofuel and nutrition industries, by 1H High-resolution magic angle spinning nuclear magnetic resonance (1H HR-MAS NMR), a method which is non-destructive, is highly reproducible, and requires minimal sample preparation. Even though the three species were found in the same ecosystem and a superior production of lipid compounds was observed, important differences were identified in relation to the production of specialized metabolites. These distinct properties favor the use of these compounds as leaders in the development of new bioactive compounds, especially against environmental, human, and animal pathogens (One Health), and demonstrate their potential in the development of alternatives for aquaculture.
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Affiliation(s)
| | - Tatiane Ksyvickas Mathias
- NMR Laboratory, NMR Center, Departamento de Química, Universidade Federal do Paraná, Curitiba 81530-900, PR, Brazil
| | - Maria de Fátima C. Santos
- NMR Laboratory, NMR Center, Departamento de Química, Universidade Federal do Paraná, Curitiba 81530-900, PR, Brazil
| | - Marcelo G. M. D’Oca
- NMR Laboratory, NMR Center, Departamento de Química, Universidade Federal do Paraná, Curitiba 81530-900, PR, Brazil
| | - Caroline Da R. M. D’Oca
- NMR Laboratory, NMR Center, Departamento de Química, Universidade Federal do Paraná, Curitiba 81530-900, PR, Brazil
| | - Fabio Roselet
- Laboratório de Produção de Microalgas (LPM), Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Rio Grande 96210-030, RS, Brazil
| | - Paulo Cesar Abreu
- Laboratório de Produção de Microalgas (LPM), Instituto de Oceanografia, Universidade Federal do Rio Grande (FURG), Rio Grande 96210-030, RS, Brazil
| | - Daniela Fernandes Ramos
- Laboratório de Desenvolvimento de Novos Fármacos (LADEFA), Universidade Federal do Rio Grande (FURG), Rio Grande 96200-400, RS, Brazil
- Núcleo de Desenvolvimento de Novos Fármacos—NUDEFA, Rua General Osório, s/n°, Campus Saúde, 2° andar, Rio Grande 96200-400, RS, Brazil
- Correspondence: ; Tel.: +55-53-3237-4634
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