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Nikitashina V, Stettin D, Pohnert G. Metabolic adaptation of diatoms to hypersalinity. PHYTOCHEMISTRY 2022; 201:113267. [PMID: 35671808 DOI: 10.1016/j.phytochem.2022.113267] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 05/20/2022] [Accepted: 05/29/2022] [Indexed: 06/15/2023]
Abstract
Microalgae are important primary producers and form the basis for the marine food web. As global climate changes, so do salinity levels that algae are exposed to. A metabolic response of algal cells partly alleviates the resulting osmotic stress. Some metabolites involved in the response are well studied, but the full metabolic implications of adaptation remain unclear. Improved analytical methodology provides an opportunity for additional insight. We can now follow responses to stress in major parts of the metabolome and derive comprehensive charts of the resulting metabolic re-wiring. In this study, we subjected three species of diatoms to high salinity conditions and compared their metabolome to controls in an untargeted manner. The three well-investigated species with sequenced genomes Phaeodactylum tricornutum, Thalassiosira pseudonana, and Skeletonema marinoi were selected for our survey. The microalgae react to salinity stress with common adaptations in the metabolome by amino acid up-regulation, production of saccharides, and inositols. But also species-specific dysregulation of metabolites is common. Several metabolites previously not connected with osmotic stress reactions are identified, including 4-hydroxyproline, pipecolinic acid, myo-inositol, threonic acid, and acylcarnitines. This expands our knowledge about osmoadaptation and calls for further functional characterization of metabolites and pathways in algal stress physiology.
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Affiliation(s)
- Vera Nikitashina
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Daniel Stettin
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University Jena, 07743, Jena, Germany
| | - Georg Pohnert
- Institute for Inorganic and Analytical Chemistry, Bioorganic Analytics, Friedrich Schiller University Jena, 07743, Jena, Germany.
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Dhanker R, Kumar R, Tiwari A, Kumar V. Diatoms as a biotechnological resource for the sustainable biofuel production: a state-of-the-art review. Biotechnol Genet Eng Rev 2022; 38:111-131. [PMID: 35343391 DOI: 10.1080/02648725.2022.2053319] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
The greenhouse gas emission from fossil fuel and higher economic cost in its transportation are stimulating scientists to explore biomass energy production at the local level. In the present review, the authors have explored the prospects of commercial-scale biofuels production from the microalgal group, diatoms. Insights on suitability of mass cultivation systems for large-scale production of diatoms have been deliberated based on published literature. Diatoms can proliferate extracting nutrients from the wastewater and the same biomass can be harvested for biofuel production. Residues can be further utilized for the formation of other bioproducts and biofertilizers. The residual applications of diatoms from mass culture are estimated to compensate for the additional costs incurred in the removal of impurities. Well-planned research is required to optimize the commercial-scale production of biofuels from diatoms. The aim of this review is therefore, to demonstrate the economically feasible, hygienically safe cultivation of diatoms on nutrients from wastewater, limitations in using diatoms for biofuel production, and how these limitations can be shorted out for optimum utilization of diatom for biofuel production.
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Affiliation(s)
- Raunak Dhanker
- Department of Basic and Applied Sciences, School of Engineering and Sciences, GD Goenka University, Gurugram, Haryana, India
| | - Ram Kumar
- Ecosystem Research Laboratory, Department of Environmental Science, School of Earth, Biological and Environmental Sciences, Central University of South Bihar, Fatehpur, Gaya, Bihar, India
| | - Archana Tiwari
- Diatom Research Laboratory, Amity Institute of Biotechnology, Amity University, Noida, Uttar Pradesh, India
| | - Vineet Kumar
- Division, CSIR-National Environmental Engineering Research Institute (CSIR-NEERI)Waste Re-processing, Nehru Marg, Nagpur, Maharashtra, India
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Fal S, Aasfar A, Rabie R, Smouni A, Arroussi HEL. Salt induced oxidative stress alters physiological, biochemical and metabolomic responses of green microalga Chlamydomonas reinhardtii. Heliyon 2022; 8:e08811. [PMID: 35118209 PMCID: PMC8792077 DOI: 10.1016/j.heliyon.2022.e08811] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2021] [Revised: 12/05/2021] [Accepted: 01/18/2022] [Indexed: 12/17/2022] Open
Abstract
Salinity is one of the most significant environmental factors limiting microalgal biomass productivity. In the present study, the model microalga Chlamydomonas reinhardtii (C. reinhardtii) was exposed to 200 mM NaCl for eight days to explore the physiological, biochemical and metabolomic changes. C. reinhradtii exhibited a significant decrease in growth rate, and Chl a and Chl b levels. 200 mM NaCl induced ROS generation in C. reinhardtii with increase in H2O2 content. This caused lipid peroxidation with increase in MDA levels. C. reinhardtii also exhibited an increase in carbohydrate and lipid accumulation under 200 mM NaCl conditions as storage molecules in cells to maintain microalgal survival. In addition, NaCl stress increased the content of carotenoids, polyphenols and osmoprotectant molecules such as proline. SOD and APX activities decreased, while ROS-scavenger enzymes (POD and CAT) decreased. Metabolomic response showed an accumulation of the major molecules implicated in membrane remodelling and stress resistance such oleic acid (40.29%), linolenic acid (19.29%), alkanes, alkenes and phytosterols. The present study indicates the physiological, biochemical and metabolomic responses of C. reinhardtii to salt stress.
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Affiliation(s)
- Soufiane Fal
- Green Biotechnology Laboratory, Moroccan Foundation for Advanced Science, Innovation and Research (MASCIR), Rabat Design Center, Rue Mohamed Al Jazouli – Madinat Al Irfane, Rabat, Morocco
- Plant Physiology and Biotechnology Team, Center of Plant and Microbial Biotechnology, Biodiversity and Environment, Faculty of Sciences, Mohammed V University in Rabat, Morocco
| | - Abderahim Aasfar
- Green Biotechnology Laboratory, Moroccan Foundation for Advanced Science, Innovation and Research (MASCIR), Rabat Design Center, Rue Mohamed Al Jazouli – Madinat Al Irfane, Rabat, Morocco
| | - Reda Rabie
- Green Biotechnology Laboratory, Moroccan Foundation for Advanced Science, Innovation and Research (MASCIR), Rabat Design Center, Rue Mohamed Al Jazouli – Madinat Al Irfane, Rabat, Morocco
- University Sidi Mohamed Ben Abdellah, Faculty of Sciences and Techniques of Fez, Laboratory of Applied Organic Chemistry, Fez, Morocco
| | - Abelaziz Smouni
- Plant Physiology and Biotechnology Team, Center of Plant and Microbial Biotechnology, Biodiversity and Environment, Faculty of Sciences, Mohammed V University in Rabat, Morocco
| | - Hicham EL. Arroussi
- Green Biotechnology Laboratory, Moroccan Foundation for Advanced Science, Innovation and Research (MASCIR), Rabat Design Center, Rue Mohamed Al Jazouli – Madinat Al Irfane, Rabat, Morocco
- Agrobiosciences Program, University Mohamed 6 Polytechnic (UM6P), Ben-Guerir, Morocco
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Fernandes T, Cordeiro N. Microalgae as Sustainable Biofactories to Produce High-Value Lipids: Biodiversity, Exploitation, and Biotechnological Applications. Mar Drugs 2021; 19:md19100573. [PMID: 34677472 PMCID: PMC8540142 DOI: 10.3390/md19100573] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2021] [Revised: 10/09/2021] [Accepted: 10/11/2021] [Indexed: 12/04/2022] Open
Abstract
Microalgae are often called “sustainable biofactories” due to their dual potential to mitigate atmospheric carbon dioxide and produce a great diversity of high-value compounds. Nevertheless, the successful exploitation of microalgae as biofactories for industrial scale is dependent on choosing the right microalga and optimum growth conditions. Due to the rich biodiversity of microalgae, a screening pipeline should be developed to perform microalgal strain selection exploring their growth, robustness, and metabolite production. Current prospects in microalgal biotechnology are turning their focus to high-value lipids for pharmaceutic, nutraceutic, and cosmetic products. Within microalgal lipid fraction, polyunsaturated fatty acids and carotenoids are broadly recognized for their vital functions in human organisms. Microalgal-derived phytosterols are still an underexploited lipid resource despite presenting promising biological activities, including neuroprotective, anti-inflammatory, anti-cancer, neuromodulatory, immunomodulatory, and apoptosis inductive effects. To modulate microalgal biochemical composition, according to the intended field of application, it is important to know the contribution of each cultivation factor, or their combined effects, for the wanted product accumulation. Microalgae have a vital role to play in future low-carbon economy. Since microalgal biodiesel is still costly, it is desirable to explore the potential of oleaginous species for its high-value lipids which present great global market prospects.
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Affiliation(s)
- Tomásia Fernandes
- Laboratory of Bioanalysis, Biomaterials, and Biotechnology (LB3), Faculty of Exact Sciences and Engineering, University of Madeira, Campus Universitário da Penteada, 9020-105 Funchal, Portugal;
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, 4450-208 Matosinhos, Portugal
| | - Nereida Cordeiro
- Laboratory of Bioanalysis, Biomaterials, and Biotechnology (LB3), Faculty of Exact Sciences and Engineering, University of Madeira, Campus Universitário da Penteada, 9020-105 Funchal, Portugal;
- Interdisciplinary Centre of Marine and Environmental Research (CIIMAR), University of Porto, 4450-208 Matosinhos, Portugal
- Correspondence:
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Overexpression of Key Sterol Pathway Enzymes in Two Model Marine Diatoms Alters Sterol Profiles in Phaeodactylum tricornutum. Pharmaceuticals (Basel) 2020; 13:ph13120481. [PMID: 33371196 PMCID: PMC7766473 DOI: 10.3390/ph13120481] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Revised: 12/15/2020] [Accepted: 12/16/2020] [Indexed: 12/26/2022] Open
Abstract
Sterols are a class of triterpenoid molecules with diverse functional roles in eukaryotic cells, including intracellular signaling and regulation of cell membrane fluidity. Diatoms are a dominant eukaryotic phytoplankton group that produce a wide diversity of sterol compounds. The enzymes 3-hydroxy-3-methyl glutaryl CoA reductase (HMGR) and squalene epoxidase (SQE) have been reported to be rate-limiting steps in sterol biosynthesis in other model eukaryotes; however, the extent to which these enzymes regulate triterpenoid production in diatoms is not known. To probe the role of these two metabolic nodes in the regulation of sterol metabolic flux in diatoms, we independently over-expressed two versions of the native HMGR and a conventional, heterologous SQE gene in the diatoms Thalassiosira pseudonana and Phaeodactylum tricornutum. Overexpression of these key enzymes resulted in significant differential accumulation of downstream sterol pathway intermediates in P. tricornutum. HMGR-mVenus overexpression resulted in the accumulation of squalene, cycloartenol, and obtusifoliol, while cycloartenol and obtusifoliol accumulated in response to heterologous NoSQE-mVenus overexpression. In addition, accumulation of the end-point sterol 24-methylenecholesta-5,24(24’)-dien-3β-ol was observed in all P. tricornutum overexpression lines, and campesterol increased three-fold in P. tricornutum lines expressing NoSQE-mVenus. Minor differences in end-point sterol composition were also found in T. pseudonana, but no accumulation of sterol pathway intermediates was observed. Despite the successful manipulation of pathway intermediates and individual sterols in P. tricornutum, total sterol levels did not change significantly in transformed lines, suggesting the existence of tight pathway regulation to maintain total sterol content.
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Sethi D, Butler TO, Shuhaili F, Vaidyanathan S. Diatoms for Carbon Sequestration and Bio-Based Manufacturing. BIOLOGY 2020; 9:E217. [PMID: 32785088 PMCID: PMC7464044 DOI: 10.3390/biology9080217] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/24/2020] [Revised: 08/03/2020] [Accepted: 08/05/2020] [Indexed: 12/12/2022]
Abstract
Carbon dioxide (CO2) is a major greenhouse gas responsible for climate change. Diatoms, a natural sink of atmospheric CO2, can be cultivated industrially in autotrophic and mixotrophic modes for the purpose of CO2 sequestration. In addition, the metabolic diversity exhibited by this group of photosynthetic organisms provides avenues to redirect the captured carbon into products of value. These include lipids, omega-3 fatty acids, pigments, antioxidants, exopolysaccharides, sulphated polysaccharides, and other valuable metabolites that can be produced in environmentally sustainable bio-manufacturing processes. To realize the potential of diatoms, expansion of our knowledge of carbon supply, CO2 uptake and fixation by these organisms, in conjunction with ways to enhance metabolic routing of the fixed carbon to products of value is required. In this review, current knowledge is explored, with an evaluation of the potential of diatoms for carbon capture and bio-based manufacturing.
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Affiliation(s)
- Deepak Sethi
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
| | - Thomas O. Butler
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
| | - Faqih Shuhaili
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
- School of Bioprocess Engineering, Universiti Malaysia Perlis (UniMAP), Arau 02600, Perlis, Malaysia
| | - Seetharaman Vaidyanathan
- Department of Chemical and Biological Engineering, The University of Sheffield, Sheffield S1 3JD, UK; (F.S.); (S.V.)
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