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Canini D, Ceschi E, Perozeni F. Toward the Exploitation of Sustainable Green Factory: Biotechnology Use of Nannochloropsis spp. BIOLOGY 2024; 13:292. [PMID: 38785776 PMCID: PMC11117969 DOI: 10.3390/biology13050292] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/24/2024] [Revised: 04/19/2024] [Accepted: 04/24/2024] [Indexed: 05/25/2024]
Abstract
Securing food, energy, and raw materials for a growing population is one of the most significant challenges of our century. Algae play a central role as an alternative to plants. Wastewater and flue gas can secure nutrients and CO2 for carbon fixation. Unfortunately, algae domestication is necessary to enhance biomass production and reduce cultivation costs. Nannochloropsis spp. have increased in popularity among microalgae due to their ability to accumulate high amounts of lipids, including PUFAs. Recently, the interest in the use of Nannochloropsis spp. as a green bio-factory for producing high-value products increased proportionally to the advances of synthetic biology and genetic tools in these species. In this review, we summarized the state of the art of current nuclear genetic manipulation techniques and a few examples of their application. The industrial use of Nannochloropsis spp. has not been feasible yet, but genetic tools can finally lead to exploiting this full-of-potential microalga.
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Affiliation(s)
| | | | - Federico Perozeni
- Department of Biotechnology, University of Verona, 37134 Verona, Italy; (D.C.); (E.C.)
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2
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Liang W, Wei L, Wang Q, You W, Poetsch A, Du X, Lv N, Xu J. Knocking Out Chloroplastic Aldolases/Rubisco Lysine Methyltransferase Enhances Biomass Accumulation in Nannochloropsis oceanica under High-Light Stress. Int J Mol Sci 2024; 25:3756. [PMID: 38612566 PMCID: PMC11012178 DOI: 10.3390/ijms25073756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2024] [Revised: 03/10/2024] [Accepted: 03/12/2024] [Indexed: 04/14/2024] Open
Abstract
Rubisco large-subunit methyltransferase (LSMT), a SET-domain protein lysine methyltransferase, catalyzes the formation of trimethyl-lysine in the large subunit of Rubisco or in fructose-1,6-bisphosphate aldolases (FBAs). Rubisco and FBAs are both vital proteins involved in CO2 fixation in chloroplasts; however, the physiological effect of their trimethylation remains unknown. In Nannochloropsis oceanica, a homolog of LSMT (NoLSMT) is found. Phylogenetic analysis indicates that NoLSMT and other algae LSMTs are clustered in a basal position, suggesting that algal species are the origin of LSMT. As NoLSMT lacks the His-Ala/ProTrp triad, it is predicted to have FBAs as its substrate instead of Rubisco. The 18-20% reduced abundance of FBA methylation in NoLSMT-defective mutants further confirms this observation. Moreover, this gene (nolsmt) can be induced by low-CO2 conditions. Intriguingly, NoLSMT-knockout N. oceanica mutants exhibit a 9.7-13.8% increase in dry weight and enhanced growth, which is attributed to the alleviation of photoinhibition under high-light stress. This suggests that the elimination of FBA trimethylation facilitates carbon fixation under high-light stress conditions. These findings have implications in engineering carbon fixation to improve microalgae biomass production.
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Affiliation(s)
- Wensi Liang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Wuxin You
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
| | - Ansgar Poetsch
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
| | - Xuefeng Du
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Nana Lv
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels, Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (W.L.)
- University of Chinese Academy of Sciences, Beijing 100049, China
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3
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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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Krishnan A, Cano M, Karns DA, Burch TA, Likhogrud M, Aqui M, Bailey S, Verruto J, Lambert W, Kuzminov F, Naghipor M, Wang Y, Ebmeier CC, Weissman JC, Posewitz MC. Simultaneous CAS9 editing of cp SRP43, LHCA6, and LHCA7 in Picochlorum celeri lowers chlorophyll levels and improves biomass productivity. PLANT DIRECT 2023; 7:e530. [PMID: 37711644 PMCID: PMC10497401 DOI: 10.1002/pld3.530] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/03/2023] [Accepted: 08/17/2023] [Indexed: 09/16/2023]
Abstract
High cellular pigment levels in dense microalgal cultures contribute to excess light absorption. To improve photosynthetic yields in the marine microalga Picochlorum celeri, CAS9 gene editing was used to target the molecular chaperone cpSRP43. Depigmented strains (>50% lower chlorophyll) were generated, with proteomics showing attenuated levels of most light harvesting complex (LHC) proteins. Gene editing generated two types of cpSRP43 transformants with distinct lower pigment phenotypes: (i) a transformant (Δsrp43) with both cpSRP43 diploid alleles modified to encode non-functional polypeptides and (ii) a transformant (STR30309) with a 3 nt in-frame insertion in one allele at the CAS9 cut site (non-functional second allele), leading to expression of a modified cpSRP43. STR30309 has more chlorophyll than Δsrp43 but substantially less than wild type. To further decrease light absorption by photosystem I in STR30309, CAS9 editing was used to stack in disruptions of both LHCA6 and LHCA7 to generate STR30843, which has higher (5-24%) productivities relative to wild type in solar-simulating bioreactors. Maximal productivities required frequent partial harvests throughout the day. For STR30843, exemplary diel bioreactor yields of ~50 g m-2 day-1 were attained. Our results demonstrate diel productivity gains in P. celeri by lowering pigment levels.
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Affiliation(s)
- Anagha Krishnan
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Melissa Cano
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Devin A. Karns
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Tyson A. Burch
- Department of ChemistryColorado School of MinesGoldenColoradoUSA
| | - Maria Likhogrud
- ExxonMobil Technology and Engineering CompanyAnnandaleNew JerseyUSA
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Leister D. Enhancing the light reactions of photosynthesis: Strategies, controversies, and perspectives. MOLECULAR PLANT 2023; 16:4-22. [PMID: 35996755 DOI: 10.1016/j.molp.2022.08.005] [Citation(s) in RCA: 16] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Revised: 07/26/2022] [Accepted: 08/16/2022] [Indexed: 06/15/2023]
Abstract
Photosynthesis is central to life on Earth, employing sunlight, water, and carbon dioxide to produce chemical energy and oxygen. It is generally accepted that boosting its efficiency offers one promising way to increase crop yields under agronomically realistic conditions. Since the components, structure, and regulatory mechanisms of the light reactions of photosynthesis are well understood, concepts for enhancing the process have been suggested and partially tested. These approaches vary in complexity, from targeting single components to comprehensive redesign of the whole process on the scales from single cells or tissues to whole canopies. Attempts to enhance light utilization per leaf, by decreasing pigmentation, increasing levels of photosynthetic proteins, prolonging the lifespan of the photosynthetic machinery, or massive reconfiguration of the photosynthetic machinery and the incorporation of nanomaterials, are discussed in this review first. Secondly, strategies intended to optimize the acclimation of photosynthesis to changes in the environment are presented, including redesigning mechanisms to dissipate excess excitation energy (e.g., non-photochemical quenching) or reduction power (e.g., flavodiiron proteins). Moreover, schemes for improving acclimation, inspired by natural or laboratory-induced adaptation, are introduced. However, all these endeavors are still in an early exploratory phase and/or have not resulted in the desired outcome, largely because photosynthesis is embedded within large networks of closely interacting cellular and metabolic processes, which can vary among species and even cultivars. This explains why integrated, systems-wide approaches are required to achieve the breakthroughs required for effectively increasing crop yields.
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Affiliation(s)
- Dario Leister
- Plant Molecular Biology, Faculty of Biology, Ludwig-Maximilians-University (LMU) Munich, Martinsried-Planegg, D-82152 Munich, Germany.
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Barahona E, Isidro ES, Sierra-Heras L, Álvarez-Melcón I, Jiménez-Vicente E, Buesa JM, Imperial J, Rubio LM. A directed genome evolution method to enhance hydrogen production in Rhodobacter capsulatus. Front Microbiol 2022; 13:991123. [PMID: 36090091 PMCID: PMC9449697 DOI: 10.3389/fmicb.2022.991123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/09/2022] [Indexed: 11/13/2022] Open
Abstract
Nitrogenase-dependent H2 production by photosynthetic bacteria, such as Rhodobacter capsulatus, has been extensively investigated. An important limitation to increase H2 production using genetic manipulation is the scarcity of high-throughput screening methods to detect possible overproducing mutants. Previously, we engineered R. capsulatus strains that emitted fluorescence in response to H2 and used them to identify mutations in the nitrogenase Fe protein leading to H2 overproduction. Here, we used ultraviolet light to induce random mutations in the genome of the engineered H2-sensing strain, and fluorescent-activated cell sorting to detect and isolate the H2-overproducing cells from libraries containing 5 × 105 mutants. Three rounds of mutagenesis and strain selection gradually increased H2 production up to 3-fold. The whole genomes of five H2 overproducing strains were sequenced and compared to that of the parental sensor strain to determine the basis for H2 overproduction. No mutations were present in well-characterized functions related to nitrogen fixation, except for the transcriptional activator nifA2. However, several mutations mapped to energy-generating systems and to carbon metabolism-related functions, which could feed reducing power or ATP to nitrogenase. Time-course experiments of nitrogenase depression in batch cultures exposed mismatches between nitrogenase protein levels and their H2 and ethylene production activities that suggested energy limitation. Consistently, cultivating in a chemostat produced up to 19-fold more H2 than the corresponding batch cultures, revealing the potential of selected H2 overproducing strains.
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Affiliation(s)
- Emma Barahona
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Elisa San Isidro
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Laura Sierra-Heras
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Inés Álvarez-Melcón
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Emilio Jiménez-Vicente
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - José María Buesa
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Juan Imperial
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
| | - Luis M. Rubio
- Centro de Biotecnología y Genómica de Plantas, Universidad Politécnica de Madrid (UPM), Instituto Nacional de Investigación y Tecnología Agraria y Alimentaria (INIA-CSIC), Madrid, Spain
- Departamento de Biotecnología-Biología Vegetal, Escuela Técnica Superior de Ingeniería Agronómica, Alimentaria y de Biosistemas, Universidad Politécnica de Madrid, Madrid, Spain
- *Correspondence: Luis M. Rubio,
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An increase in the membrane lipids recycling by PDAT overexpression stimulates the accumulation of triacylglycerol in Nannochloropsis gaditana. J Biotechnol 2022; 357:28-37. [PMID: 35931238 DOI: 10.1016/j.jbiotec.2022.07.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 07/18/2022] [Accepted: 07/30/2022] [Indexed: 11/23/2022]
Abstract
Oleaginous microalgae represent potential feedstocks for the sustainable production of lipids thanks to their ability to accumulate triacylglycerols (TAGs). TAG accumulation in several algal species is strongly induced under specific conditions such as nutrient deprivation and high light which, however, also negatively impact growth. Genetic modification of lipogenic pathways can potentially enhance TAG accumulation without negatively affecting growth, avoiding the trade-off between biomass and lipids productivity. In this study, the phospholipid: diacylglycerol acyltransferase (PDAT), an enzyme involved in membrane lipid recycling, was overexpressed in the seawater alga Nannochloropsis gaditana. PDAT overexpression induced increased TAG content in actively growing algae cultures while no effects were observed in conditions naturally stimulating strong lipid accumulation such as high light and nitrogen starvation. The increase of TAG content was confirmed also in a strain cultivated in industrially relevant conditions even though PDAT overexpression, if too strong, the gene overexpression becomes detrimental for growth in the longer term. Results overall suggest that genetic modulation of the PDAT gene represents a promising strategy to increase microalgae lipids content by minimizing negative effects on biomass productivity.
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Random Mutagenesis as a Promising Tool for Microalgal Strain Improvement towards Industrial Production. Mar Drugs 2022; 20:md20070440. [PMID: 35877733 PMCID: PMC9318807 DOI: 10.3390/md20070440] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 06/27/2022] [Accepted: 06/27/2022] [Indexed: 02/06/2023] Open
Abstract
Microalgae have become a promising novel and sustainable feedstock for meeting the rising demand for food and feed. However, microalgae-based products are currently hindered by high production costs. One major reason for this is that commonly cultivated wildtype strains do not possess the robustness and productivity required for successful industrial production. Several strain improvement technologies have been developed towards creating more stress tolerant and productive strains. While classical methods of forward genetics have been extensively used to determine gene function of randomly generated mutants, reverse genetics has been explored to generate specific mutations and target phenotypes. Site-directed mutagenesis can be accomplished by employing different gene editing tools, which enable the generation of tailor-made genotypes. Nevertheless, strategies promoting the selection of randomly generated mutants avoid the introduction of foreign genetic material. In this paper, we review different microalgal strain improvement approaches and their applications, with a primary focus on random mutagenesis. Current challenges hampering strain improvement, selection, and commercialization will be discussed. The combination of these approaches with high-throughput technologies, such as fluorescence-activated cell sorting, as tools to select the most promising mutants, will also be discussed.
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Cecchin M, Cazzaniga S, Martini F, Paltrinieri S, Bossi S, Maffei ME, Ballottari M. Astaxanthin and eicosapentaenoic acid production by S4, a new mutant strain of Nannochloropsis gaditana. Microb Cell Fact 2022; 21:117. [PMID: 35710482 PMCID: PMC9204945 DOI: 10.1186/s12934-022-01847-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Accepted: 06/01/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND Astaxanthin is a ketocarotenoid with high antioxidant power used in different fields as healthcare, food/feed supplementation and as pigmenting agent in aquaculture. Primary producers of astaxanthin are some species of microalgae, unicellular photosynthetic organisms, as Haematococcus lacustris. Astaxanthin production by cultivation of Haematococcus lacustris is costly due to low biomass productivity, high risk of contamination and the requirement of downstream extraction processes, causing an extremely high price on the market. Some microalgae species are also primary producers of omega-3 fatty acids, essential nutrients for humans, being related to cardiovascular wellness, and required for visual and cognitive development. One of the main well-known producers of omega-3 fatty eicosapentaenoic acid (EPA) is the marine microalga Nannochloropsis gaditana (named also Microchloropsis gaditana): this species has been already approved by the Food and Drug Administration (FDA) for human consumption and it is characterized by a fast grow phenotype. RESULTS Here we obtained by chemical mutagenesis a Nannochloropsis gaditana mutant strain, called S4, characterized by increased carotenoid to chlorophyll ratio. S4 strain showed improved photosynthetic activity, increased lipid productivity and increased ketocarotenoids accumulation, producing not only canthaxanthin but also astaxanthin, usually found only in traces in the WT strain. Ketocarotenoids produced in S4 strain were extractible in different organic solvents, with the highest efficiency observed upon microwaves pre-treatment followed by methanol extraction. By cultivation of S4 strain at different irradiances it was possible to produce up to 1.3 and 5.2 mgL-1 day-1 of ketocarotenoids and EPA respectively, in a single cultivation phase, even in absence of stressing conditions. Genome sequencing of S4 strain allowed to identify 199 single nucleotide polymorphisms (SNP): among the mutated genes, mutations in a carotenoid oxygenase gene and in a glutamate synthase gene could explain the different carotenoids content and the lower chlorophylls content, respectively. CONCLUSIONS By chemical mutagenesis and selection of strain with increased carotenoids to chlorophyll ratio it was possible to isolate a new Nannochloropsis gaditana strain, called S4 strain, characterized by increased lipids and ketocarotenoids accumulation. S4 strain can thus be considered as novel platform for ketocarotenoids and EPA production for different industrial applications.
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Affiliation(s)
- Michela Cecchin
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Stefano Cazzaniga
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Flavio Martini
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Stefania Paltrinieri
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134, Verona, Italy
| | - Simone Bossi
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Unità di Fisiologia Vegetale, Università di Torino, Via Quarello 15/a, 10135, Turin, Italy
| | - Massimo E Maffei
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Unità di Fisiologia Vegetale, Università di Torino, Via Quarello 15/a, 10135, Turin, Italy
| | - Matteo Ballottari
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134, Verona, Italy.
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Bonnefond H, Lie Y, Lacour T, Saint-Jean B, Carrier G, Pruvost E, Talec A, Bernard O, Sciandra A. Dynamical Darwinian selection of a more productive strain of Tisochrysis lutea. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102743] [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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11
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Hosseinkhani N, McCauley JI, Ralph PJ. Key challenges for the commercial expansion of ingredients from algae into human food products. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102696] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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12
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Perin G, Gambaro F, Morosinotto T. Knowledge of Regulation of Photosynthesis in Outdoor Microalgae Cultures Is Essential for the Optimization of Biomass Productivity. FRONTIERS IN PLANT SCIENCE 2022; 13:846496. [PMID: 35444673 PMCID: PMC9014180 DOI: 10.3389/fpls.2022.846496] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Microalgae represent a sustainable source of biomass that can be exploited for pharmaceutical, nutraceutical, cosmetic applications, as well as for food, feed, chemicals, and energy. To make microalgae applications economically competitive and maximize their positive environmental impact, it is however necessary to optimize productivity when cultivated at a large scale. Independently from the final product, this objective requires the optimization of biomass productivity and thus of microalgae ability to exploit light for CO2 fixation. Light is a highly variable environmental parameter, continuously changing depending on seasons, time of the day, and weather conditions. In microalgae large scale cultures, cell self-shading causes inhomogeneity in light distribution and, because of mixing, cells move between different parts of the culture, experiencing abrupt changes in light exposure. Microalgae evolved multiple regulatory mechanisms to deal with dynamic light conditions that, however, are not adapted to respond to the complex mixture of natural and artificial fluctuations found in large-scale cultures, which can thus drive to oversaturation of the photosynthetic machinery, leading to consequent oxidative stress. In this work, the present knowledge on the regulation of photosynthesis and its implications for the maximization of microalgae biomass productivity are discussed. Fast mechanisms of regulations, such as Non-Photochemical-Quenching and cyclic electron flow, are seminal to respond to sudden fluctuations of light intensity. However, they are less effective especially in the 1-100 s time range, where light fluctuations were shown to have the strongest negative impact on biomass productivity. On the longer term, microalgae modulate the composition and activity of the photosynthetic apparatus to environmental conditions, an acclimation response activated also in cultures outdoors. While regulation of photosynthesis has been investigated mainly in controlled lab-scale conditions so far, these mechanisms are highly impactful also in cultures outdoors, suggesting that the integration of detailed knowledge from microalgae large-scale cultivation is essential to drive more effective efforts to optimize biomass productivity.
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Kselíková V, Singh A, Bialevich V, Čížková M, Bišová K. Improving microalgae for biotechnology - From genetics to synthetic biology - Moving forward but not there yet. Biotechnol Adv 2021; 58:107885. [PMID: 34906670 DOI: 10.1016/j.biotechadv.2021.107885] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Revised: 11/28/2021] [Accepted: 12/07/2021] [Indexed: 12/28/2022]
Abstract
Microalgae are a diverse group of photosynthetic organisms that can be exploited for the production of different compounds, ranging from crude biomass and biofuels to high value-added biochemicals and synthetic proteins. Traditionally, algal biotechnology relies on bioprospecting to identify new highly productive strains and more recently, on forward genetics to further enhance productivity. However, it has become clear that further improvements in algal productivity for biotechnology is impossible without combining traditional tools with the arising molecular genetics toolkit. We review recent advantages in developing high throughput screening methods, preparing genome-wide mutant libraries, and establishing genome editing techniques. We discuss how algae can be improved in terms of photosynthetic efficiency, biofuel and high value-added compound production. Finally, we critically evaluate developments over recent years and explore future potential in the field.
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Affiliation(s)
- Veronika Kselíková
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic; Faculty of Science, University of South Bohemia, 37005 České Budějovice, Czech Republic
| | - Anjali Singh
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic
| | - Vitali Bialevich
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic
| | - Mária Čížková
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic
| | - Kateřina Bišová
- Institute of Microbiology of the Czech Academy of Sciences, Centre Algatech, Laboratory of Cell Cycles of Algae, 379 81 Třeboň, Czech Republic.
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Ben-Sheleg A, Khozin-Godberg I, Yaakov B, Vonshak A. Characterization of Nannochloropsis oceanica Rose Bengal Mutants Sheds Light on Acclimation Mechanisms to High Light When Grown in Low Temperature. PLANT & CELL PHYSIOLOGY 2021; 62:1478-1493. [PMID: 34180533 PMCID: PMC8600018 DOI: 10.1093/pcp/pcab094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/14/2021] [Revised: 06/23/2021] [Accepted: 06/27/2021] [Indexed: 06/13/2023]
Abstract
A barrier to realizing Nannochloropsis oceanica's potential for omega-3 eicosapentaenoic acid (EPA) production is the disparity between conditions that are optimal for growth and those that are optimal for EPA biomass content. A case in point is temperature: higher content of polyunsaturated fatty acid, and especially EPA, is observed in low-temperature (LT) environments, where growth rates are often inhibited. We hypothesized that mutant strains of N. oceanica resistant to the singlet-oxygen photosensitizer Rose Bengal (RB) would withstand the oxidative stress conditions that prevail in the combined stressful environment of high light (HL; 250 μmol photons m-2 s-1) and LT (18°C). This growth environment caused the wild-type (WT) strain to experience a spike in lipid peroxidation and an inability to proliferate, whereas growth and homeostatic reactive oxygen species levels were observed in the mutant strains. We suggest that the mutant strains' success in this environment can be attributed to their truncated photosystem II antennas and their increased ability to diffuse energy in those antennas as heat (non-photosynthetic quenching). As a result, the mutant strains produced upward of four times more EPA than the WT strain in this HL-LT environment. The major plastidial lipid monogalactosyldiacylglycerol was a likely target for oxidative damage, contributing to the photosynthetic inhibition of the WT strain. A mutation in the NO10G01010.1 gene, causing a subunit of the 2-oxoisovalerate dehydrogenase E1 protein to become non-functional, was determined to be the likely source of tolerance in the RB113 mutant strain.
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Affiliation(s)
- 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-Godberg
- 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
| | - Beery Yaakov
- 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
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15
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Perin G, Fletcher T, Sagi-Kiss V, Gaboriau DCA, Carey MR, Bundy JG, Jones PR. Calm on the surface, dynamic on the inside. Molecular homeostasis of Anabaena sp. PCC 7120 nitrogen metabolism. PLANT, CELL & ENVIRONMENT 2021; 44:1885-1907. [PMID: 33608943 DOI: 10.1111/pce.14034] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Revised: 02/12/2021] [Accepted: 02/13/2021] [Indexed: 06/12/2023]
Abstract
Nitrogen sources are all converted into ammonium/ia as a first step of assimilation. It is reasonable to expect that molecular components involved in the transport of ammonium/ia across biological membranes connect with the regulation of both nitrogen and central metabolism. We applied both genetic (i.e., Δamt mutation) and environmental treatments to a target biological system, the cyanobacterium Anabaena sp PCC 7120. The aim was to both perturb nitrogen metabolism and induce multiple inner nitrogen states, respectively, followed by targeted quantification of key proteins, metabolites and enzyme activities. The absence of AMT transporters triggered a substantial whole-system response, affecting enzyme activities and quantity of proteins and metabolites, spanning nitrogen and carbon metabolisms. Moreover, the Δamt strain displayed a molecular fingerprint indicating nitrogen deficiency even under nitrogen replete conditions. Contrasting with such dynamic adaptations was the striking near-complete lack of an externally measurable altered phenotype. We conclude that this species evolved a highly robust and adaptable molecular network to maintain homeostasis, resulting in substantial internal but minimal external perturbations. This analysis provides evidence for a potential role of AMT transporters in the regulatory/signalling network of nitrogen metabolism and the existence of a novel fourth regulatory mechanism controlling glutamine synthetase activity.
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Affiliation(s)
- Giorgio Perin
- Department of Life Sciences, Imperial College London, London, UK
| | - Tyler Fletcher
- Complex Carbohydrate Research Center and Department of Chemistry, University of Georgia, Athens, Georgia, USA
| | - Virag Sagi-Kiss
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - David C A Gaboriau
- Facility for Imaging by Light Microscopy, NHLI, Imperial College London, London, UK
| | - Mathew R Carey
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Jacob G Bundy
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Patrik R Jones
- Department of Life Sciences, Imperial College London, London, UK
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Guardini Z, Dall’Osto L, Barera S, Jaberi M, Cazzaniga S, Vitulo N, Bassi R. High Carotenoid Mutants of Chlorella vulgaris Show Enhanced Biomass Yield under High Irradiance. PLANTS 2021; 10:plants10050911. [PMID: 34062906 PMCID: PMC8147269 DOI: 10.3390/plants10050911] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 04/26/2021] [Accepted: 04/27/2021] [Indexed: 12/30/2022]
Abstract
Microalgae represent a carbon-neutral source of bulk biomass, for extraction of high-value compounds and production of renewable fuels. Due to their high metabolic activity and reproduction rates, species of the genus Chlorella are highly productive when cultivated in photobioreactors. However, wild-type strains show biological limitations making algal bioproducts expensive compared to those extracted from other feedstocks. Such constraints include inhomogeneous light distribution due to high optical density of the culture, and photoinhibition of the surface-exposed cells. Thus, the domestication of algal strains for industry makes it increasingly important to select traits aimed at enhancing light-use efficiency while withstanding excess light stress. Carotenoids have a crucial role in protecting against photooxidative damage and, thus, represent a promising target for algal domestication. We applied chemical mutagenesis to Chlorella vulgaris and selected for enhanced tolerance to the carotenoid biosynthesis inhibitor norflurazon. The NFR (norflurazon-resistant) strains showed an increased carotenoid pool size and enhanced tolerance towards photooxidative stress. Growth under excess light revealed an improved carbon assimilation rate of NFR strains with respect to WT. We conclude that domestication of Chlorella vulgaris, by optimizing both carotenoid/chlorophyll ratio and resistance to photooxidative stress, boosted light-to-biomass conversion efficiency under high light conditions typical of photobioreactors. Comparison with strains previously reported for enhanced tolerance to singlet oxygen, reveals that ROS resistance in Chlorella is promoted by at least two independent mechanisms, only one of which is carotenoid-dependent.
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17
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Microalgae with a truncated light-harvesting antenna to maximize photosynthetic efficiency and biomass productivity: Recent advances and current challenges. Process Biochem 2021. [DOI: 10.1016/j.procbio.2021.03.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
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18
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Incorporating a molecular antenna in diatom microalgae cells enhances photosynthesis. Sci Rep 2021; 11:5209. [PMID: 33664413 PMCID: PMC7933240 DOI: 10.1038/s41598-021-84690-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Accepted: 02/03/2021] [Indexed: 11/22/2022] Open
Abstract
Diatom microalgae have great industrial potential as next-generation sources of biomaterials and biofuels. Effective scale-up of their production can be pursued by enhancing the efficiency of their photosynthetic process in a way that increases the solar-to-biomass conversion yield. A proof-of-concept demonstration is given of the possibility of enhancing the light absorption of algae and of increasing their efficiency in photosynthesis by in vivo incorporation of an organic dye which acts as an antenna and enhances cells’ growth and biomass production without resorting to genetic modification. A molecular dye (Cy5) is incorporated in Thalassiosira weissflogii diatom cells by simply adding it to the culture medium and thus filling the orange gap that limits their absorption of sunlight. Cy5 enhances diatoms’ photosynthetic oxygen production and cell density by 49% and 40%, respectively. Cy5 incorporation also increases by 12% the algal lipid free fatty acid (FFA) production versus the pristine cell culture, thus representing a suitable way to enhance biofuel generation from algal species. Time-resolved spectroscopy reveals Förster Resonance Energy Transfer (FRET) from Cy5 to algal chlorophyll. The present approach lays the basis for non-genetic tailoring of diatoms’ spectral response to light harvesting, opening up new ways for their industrial valorization.
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Super-Earths, M Dwarfs, and Photosynthetic Organisms: Habitability in the Lab. Life (Basel) 2020; 11:life11010010. [PMID: 33374408 PMCID: PMC7823553 DOI: 10.3390/life11010010] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2020] [Revised: 12/18/2020] [Accepted: 12/18/2020] [Indexed: 11/26/2022] Open
Abstract
In a few years, space telescopes will investigate our Galaxy to detect evidence of life, mainly by observing rocky planets. In the last decade, the observation of exoplanet atmospheres and the theoretical works on biosignature gasses have experienced a considerable acceleration. The most attractive feature of the realm of exoplanets is that 40% of M dwarfs host super-Earths with a minimum mass between 1 and 30 Earth masses, orbital periods shorter than 50 days, and radii between those of the Earth and Neptune (1–3.8 R⊕). Moreover, the recent finding of cyanobacteria able to use far-red (FR) light for oxygenic photosynthesis due to the synthesis of chlorophylls d and f, extending in vivo light absorption up to 750 nm, suggests the possibility of exotic photosynthesis in planets around M dwarfs. Using innovative laboratory instrumentation, we exposed different cyanobacteria to an M dwarf star simulated irradiation, comparing their responses to those under solar and FR simulated lights. As expected, in FR light, only the cyanobacteria able to synthesize chlorophyll d and f could grow. Surprisingly, all strains, both able or unable to use FR light, grew and photosynthesized under the M dwarf generated spectrum in a similar way to the solar light and much more efficiently than under the FR one. Our findings highlight the importance of simulating both the visible and FR light components of an M dwarf spectrum to correctly evaluate the photosynthetic performances of oxygenic organisms exposed under such an exotic light condition.
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20
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A fluorescence-based approach to screen for productive chemically mutagenized strains of Desmodesmus armatus. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.102028] [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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21
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Hwangbo M, Chu KH. Recent advances in production and extraction of bacterial lipids for biofuel production. THE SCIENCE OF THE TOTAL ENVIRONMENT 2020; 734:139420. [PMID: 32464391 DOI: 10.1016/j.scitotenv.2020.139420] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2020] [Revised: 04/24/2020] [Accepted: 05/11/2020] [Indexed: 06/11/2023]
Abstract
Lipid-based biofuel is a clean and renewable energy that has been recognized as a promising replacement for petroleum-based fuels. Lipid-based biofuel can be made from three different types of intracellular biolipids; triacylglycerols (TAGs), wax esters (WEs), and polyhydroxybutyrate (PHB). Among many lipid-producing prokaryotes and eukaryotes, biolipids from prokaryotes have been recently highlighted due to simple cultivation of lipid-producing prokaryotes and their ability to accumulate high biolipid contents. However, the cost of lipid-based biofuel production remains high, in part, because of high cost of lipid extraction processes. This review summarizes the production mechanisms of these different types of biolipids from prokaryotes and extraction methods for these biolipids. Traditional and improved physical/chemical approaches for biolipid extraction remain costly, and these methods are summarized and compared in this review. Recent advances in biological lipid extraction including phage-based cell lysis or secretion of biolipids are also discussed. These new techniques are promising for bacterial biolipids extraction. Challenges and future research needs for cost-effective lipid extraction are identified in this review.
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Affiliation(s)
- Myung Hwangbo
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA
| | - Kung-Hui Chu
- Zachry Department of Civil and Environmental Engineering, Texas A&M University, College Station, TX 77843-3136, USA.
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Han X, Song X, Li F, Lu Y. Improving lipid productivity by engineering a control-knob gene in the oleaginous microalga Nannochloropsis oceanica. Metab Eng Commun 2020; 11:e00142. [PMID: 32995270 PMCID: PMC7516279 DOI: 10.1016/j.mec.2020.e00142] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Revised: 08/06/2020] [Accepted: 08/19/2020] [Indexed: 01/08/2023] Open
Abstract
Nannochloropsis spp. are promising industrial microalgae for scalable oil production and the lipid production can be boosted by nutrient starvation and high irradiance. However, these stimuli halt growth, thereby decreasing overall productivity. In this study, we created transgenic N. oceanica where AtDXS gene encoding 1-deoxy-D-xylulose 5-phosphate synthase (DXS) derived from Arabidopsis thaliana was overexpressed in vivo. Compared with the wild type (WT), engineered Nannochloropsis showed a higher CO2 absorption capacity and produced more biomass, lipids, and carbohydrates with more robust growth in either preferred conditions or various stressed conditions (low light, high light, nitrogen starvation, and trace element depletion). Specifically, relative to the WT, lipid production increased by ~68.6% in nitrogen depletion (~1.08 g L−1) and ~110.6% in high light (~1.15 g L−1) in the transgenic strains. As for neutral lipid (triacylglycerol, TAG), the engineered strains produced ~93.2% more in nitrogen depletion (~0.77 g L−1) and ~148.6% more in high light (~0.80 g L−1) than the WT. These values exceed available records in engineered industrial microalgae. Therefore, engineering control-knob genes could modify multiple biological processes simultaneously and enable efficient carbon partitioning to lipid biosynthesis with elevated biomass productivity. It could be further exploited for simultaneous enhancement of growth property and oil productivity in more industrial microalgae. An oil-rich strain Nannochloropsis AtDXSoe3 was genetically created. AtDXSoe3 produces ~110.6% more total lipids than wild-type stain. AtDXSoe3 produces ~148.6% more neutral lipid than wild-type stain. AtDXSoe3 exceeds documented engineered microalgae in oil production. Crucial algal traits could be improved by engineering a single ‘control knob’ gene.
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Affiliation(s)
- Xiao Han
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Oceanology, Hainan University, Haikou, 570228, Hainan Province, China
| | - Xiaojin Song
- Shandong Provincial Key Laboratory of Energy Genetics, CAS Key Laboratory of Biofuels, Qingdao Engineering Laboratory of Single Cell Oil, Shandong Engineering Laboratory of Single Cell Oil, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, 266101, Shandong, China
| | - Falan Li
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Oceanology, Hainan University, Haikou, 570228, Hainan Province, China
| | - Yandu Lu
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Oceanology, Hainan University, Haikou, 570228, Hainan Province, China
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23
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Harnessing the Power of Mutagenesis and Adaptive Laboratory Evolution for High Lipid Production by Oleaginous Microalgae and Yeasts. SUSTAINABILITY 2020. [DOI: 10.3390/su12125125] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Oleaginous microalgae and yeasts represent promising candidates for large-scale production of lipids, which can be utilized for production of drop-in biofuels, nutraceuticals, pigments, and cosmetics. However, low lipid productivity and costly downstream processing continue to hamper the commercial deployment of oleaginous microorganisms. Strain improvement can play an essential role in the development of such industrial microorganisms by increasing lipid production and hence reducing production costs. The main means of strain improvement are random mutagenesis, adaptive laboratory evolution (ALE), and rational genetic engineering. Among these, random mutagenesis and ALE are straight forward, low-cost, and do not require thorough knowledge of the microorganism’s genetic composition. This paper reviews available mutagenesis and ALE techniques and screening methods to effectively select for oleaginous microalgae and yeasts with enhanced lipid yield and understand the alterations caused to metabolic pathways, which could subsequently serve as the basis for further targeted genetic engineering.
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24
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Cecchin M, Berteotti S, Paltrinieri S, Vigliante I, Iadarola B, Giovannone B, Maffei ME, Delledonne M, Ballottari M. Improved lipid productivity in Nannochloropsis gaditana in nitrogen-replete conditions by selection of pale green mutants. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:78. [PMID: 32336989 PMCID: PMC7175523 DOI: 10.1186/s13068-020-01718-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/24/2019] [Accepted: 04/15/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Nannochloropsis gaditana is a photosynthetic unicellular microalgae considered one of the most interesting marine algae to produce biofuels and food additive due to its rapid growth rate and high lipid accumulation. Although microalgae are attractive platforms for solar energy bioconversion, the overall efficiency of photosynthesis is reduced due to the steep light gradient in photobioreactors. Moreover, accumulation of lipids in microalgae for biofuels production is usually induced in a two-phase cultivation process by nutrient starvation, with additional time and costs associated. In this work, a biotechnological approach was directed for the isolation of strains with improved light penetration in photobioreactor combined with increased lipids productivity. RESULTS Mutants of Nannochloropsis gaditana were obtained by chemical mutagenesis and screened for having both a reduced chlorophyll content per cell and increased affinity for Nile red, a fluorescent dye which binds to cellular lipid fraction. Accordingly, one mutant, called e8, was selected and characterized for having a 30% reduction of chlorophyll content per cell and an almost 80% increase of lipid productivity compared to WT in nutrient-replete conditions, with C16:0 and C18:0 fatty acids being more than doubled in the mutant. Whole-genome sequencing revealed mutations in 234 genes in e8 mutant among which there is a non-conservative mutation in the dgd1 synthase gene. This gene encodes for an enzyme involved in the biosynthesis of DGDG, one of the major lipids found in the thylakoid membrane and it is thus involved in chloroplast biogenesis. Lipid biosynthesis is strongly influenced by light availability in several microalgae species, including Nannochloropsis gaditana: reduced chlorophyll content per cell and more homogenous irradiance in photobioreactor is at the base for the increased lipid productivity observed in the e8 mutant. CONCLUSIONS The results herein obtained presents a promising strategy to produce algal biomass enriched in lipid fraction to be used for biofuel and biodiesel production in a single cultivation process, without the additional complexity of the nutrient starvation phase. Genome sequencing and identification of the mutations introduced in e8 mutant suggest possible genes responsible for the observed phenotypes, identifying putative target for future complementation and biotechnological application.
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Affiliation(s)
- Michela Cecchin
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Silvia Berteotti
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Stefania Paltrinieri
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Ivano Vigliante
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Unità di Fisiologia Vegetale, Università di Torino, Via Quarello 15/a, 10135 Turin, Italy
| | - Barbara Iadarola
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Barbara Giovannone
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Massimo E. Maffei
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Unità di Fisiologia Vegetale, Università di Torino, Via Quarello 15/a, 10135 Turin, Italy
| | - Massimo Delledonne
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
| | - Matteo Ballottari
- Dipartimento di Biotecnologie, Università degli Studi di Verona, Strada le Grazie 15, 37134 Verona, Italy
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Zhang Y, Wang H, Yang R, Wang L, Yang G, Liu T. Genetic Transformation of Tribonema minus, a Eukaryotic Filamentous Oleaginous Yellow-Green Alga. Int J Mol Sci 2020; 21:ijms21062106. [PMID: 32204356 PMCID: PMC7139823 DOI: 10.3390/ijms21062106] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 03/14/2020] [Accepted: 03/18/2020] [Indexed: 11/25/2022] Open
Abstract
Eukaryotic filamentous yellow-green algae from the Tribonema genus are considered to be excellent candidates for biofuels and value-added products, owing to their ability to grow under autotrophic, mixotrophic, and heterotrophic conditions and synthesize large amounts of fatty acids, especially unsaturated fatty acids. To elucidate the molecular mechanism of fatty acids and/or establish the organism as a model strain, the development of genetic methods is important. Towards this goal, here, we constructed a genetic transformation method to introduce exogenous genes for the first time into the eukaryotic filamentous alga Tribonema minus via particle bombardment. In this study, we constructed pSimple-tub-eGFP and pEASY-tub-nptⅡ plasmids in which the green fluorescence protein (eGFP) gene and the neomycin phosphotransferase Ⅱ-encoding G418-resistant gene (nptⅡ) were flanked by the T. minus-derived tubulin gene (tub) promoter and terminator, respectively. The two plasmids were introduced into T. minus cells through particle-gun bombardment under various test conditions. By combining agar and liquid selecting methods to exclude the pseudotransformants under long-term antibiotic treatment, plasmids pSimple-tub-eGFP and pEASY-tub- nptⅡ were successfully transformed into the genome of T. minus, which was verified using green fluorescence detection and the polymerase chain reaction, respectively. These results suggest new possibilities for efficient genetic engineering of T. minus for future genetic improvement.
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Affiliation(s)
- Yan Zhang
- Key Laboratory of Biofuels, Key Laboratory of Shandong Energy Biological Genetic Resources, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (Y.Z.); (L.W.)
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Hui Wang
- Key Laboratory of Biofuels, Key Laboratory of Shandong Energy Biological Genetic Resources, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (Y.Z.); (L.W.)
- Correspondence: (H.W.); (T.L.); Tel.: +86-0532-80662735 (H.W. & T.L.)
| | - Ruigang Yang
- College of Liberal arts and Sciences, National University of Defense Technology, Changsha 410073, China;
| | - Lihao Wang
- Key Laboratory of Biofuels, Key Laboratory of Shandong Energy Biological Genetic Resources, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (Y.Z.); (L.W.)
| | - Guanpin Yang
- College of Marine Life Sciences, Ocean University of China, Qingdao 266061, China;
| | - Tianzhong Liu
- Key Laboratory of Biofuels, Key Laboratory of Shandong Energy Biological Genetic Resources, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101, China; (Y.Z.); (L.W.)
- Correspondence: (H.W.); (T.L.); Tel.: +86-0532-80662735 (H.W. & T.L.)
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26
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Ryu AJ, Kang NK, Jeon S, Hur DH, Lee EM, Lee DY, Jeong BR, Chang YK, Jeong KJ. Development and characterization of a Nannochloropsis mutant with simultaneously enhanced growth and lipid production. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:38. [PMID: 32158502 PMCID: PMC7057510 DOI: 10.1186/s13068-020-01681-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Accepted: 02/13/2020] [Indexed: 05/24/2023]
Abstract
BACKGROUND The necessity to develop high lipid-producing microalgae is emphasized for the commercialization of microalgal biomass, which is environmentally friendly and sustainable. Nannochloropsis are one of the best industrial microalgae and have been widely studied for their lipids, including high-value polyunsaturated fatty acids (PUFAs). Many reports on the genetic and biological engineering of Nannochloropsis to improve their growth and lipid contents have been published. RESULTS We performed insertional mutagenesis in Nannochloropsis salina, and screened mutants with high lipid contents using fluorescence-activated cell sorting (FACS). We isolated a mutant, Mut68, which showed improved growth and a concomitant increase in lipid contents. Mut68 exhibited 53% faster growth rate and 34% higher fatty acid methyl ester (FAME) contents after incubation for 8 days, resulting in a 75% increase in FAME productivity compared to that in the wild type (WT). By sequencing the whole genome, we identified the disrupted gene in Mut68 that encoded trehalose-6-phosphate (T6P) synthase (TPS). TPS is composed of two domains: TPS domain and T6P phosphatase (TPP) domain, which catalyze the initial formation of T6P and dephosphorylation to trehalose, respectively. Mut68 was disrupted at the TPP domain in the C-terminal half, which was confirmed by metabolic analyses revealing a great reduction in the trehalose content in Mut68. Consistent with the unaffected N-terminal TPS domain, Mut68 showed moderate increase in T6P that is known for regulation of sugar metabolism, growth, and lipid biosynthesis. Interestingly, the metabolic analyses also revealed a significant increase in stress-related amino acids, including proline and glutamine, which may further contribute to the Mut68 phenotypes. CONCLUSION We have successfully isolated an insertional mutant showing improved growth and lipid production. Moreover, we identified the disrupted gene encoding TPS. Consistent with the disrupted TPP domain, metabolic analyses revealed a moderate increase in T6P and greatly reduced trehalose. Herein, we provide an excellent proof of concept that the selection of insertional mutations via FACS can be employed for the isolation of mutants with improved growth and lipid production. In addition, trehalose and genes encoding TPS will provide novel targets for chemical and genetic engineering, in other microalgae and organisms as well as Nannochloropsis.
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Affiliation(s)
- Ae Jin Ryu
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Nam Kyu Kang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Present Address: Carl. R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL USA
| | - Seungjib Jeon
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Dong Hoon Hur
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Eun Mi Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Do Yup Lee
- Department of Agricultural Biotechnology, Seoul National University, Seoul, 08826 Republic of Korea
| | - Byeong-ryool Jeong
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Present Address: School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919 Korea
- Present Address: Single-Cell Center, Qingdao Institute of BioEnergy and Bioprocess Technology (QIBEBT), Qingdao, 266101 Shandong China
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Advanced Biomass R&D Center (ABC), KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
| | - Ki Jun Jeong
- Department of Chemical and Biomolecular Engineering, Korea Advanced Institute of Science and Technology (KAIST), 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
- Institute for the BioCentury, KAIST, 291 Daehak-ro, Yuseong-gu, Daejeon, 34141 Republic of Korea
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Vecchi V, Barera S, Bassi R, Dall’Osto L. Potential and Challenges of Improving Photosynthesis in Algae. PLANTS 2020; 9:plants9010067. [PMID: 31947868 PMCID: PMC7020468 DOI: 10.3390/plants9010067] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 12/24/2019] [Accepted: 12/30/2019] [Indexed: 11/16/2022]
Abstract
Sunlight energy largely exceeds the energy required by anthropic activities, and therefore its exploitation represents a major target in the field of renewable energies. The interest in the mass cultivation of green microalgae has grown in the last decades, as algal biomass could be employed to cover a significant portion of global energy demand. Advantages of microalgal vs. plant biomass production include higher light-use efficiency, efficient carbon capture and the valorization of marginal lands and wastewaters. Realization of this potential requires a decrease of the current production costs, which can be obtained by increasing the productivity of the most common industrial strains, by the identification of factors limiting biomass yield, and by removing bottlenecks, namely through domestication strategies aimed to fill the gap between the theoretical and real productivity of algal cultures. In particular, the light-to-biomass conversion efficiency represents one of the major constraints for achieving a significant improvement of algal cell lines. This review outlines the molecular events of photosynthesis, which regulate the conversion of light into biomass, and discusses how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. This review highlights the most recent results in the manipulation of the fundamental mechanisms of algal photosynthesis, which revealed that a significant yield enhancement is feasible. Moreover, metabolic engineering of microalgae, focused upon the development of renewable fuel biorefineries, has also drawn attention and resulted in efforts for enhancing productivity of oil or isoprenoids.
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Affiliation(s)
| | | | | | - Luca Dall’Osto
- Correspondence: ; Tel.: +39-045-8027806; Fax: +39-045-8027929
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Bellan A, Bucci F, Perin G, Alboresi A, Morosinotto T. Photosynthesis Regulation in Response to Fluctuating Light in the Secondary Endosymbiont Alga Nannochloropsis gaditana. PLANT & CELL PHYSIOLOGY 2020; 61:41-52. [PMID: 31511895 DOI: 10.1093/pcp/pcz174] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 09/03/2019] [Indexed: 06/10/2023]
Abstract
In nature, photosynthetic organisms are exposed to highly dynamic environmental conditions where the excitation energy and electron flow in the photosynthetic apparatus need to be continuously modulated. Fluctuations in incident light are particularly challenging because they drive oversaturation of photosynthesis with consequent oxidative stress and photoinhibition. Plants and algae have evolved several mechanisms to modulate their photosynthetic machinery to cope with light dynamics, such as thermal dissipation of excited chlorophyll states (non-photochemical quenching, NPQ) and regulation of electron transport. The regulatory mechanisms involved in the response to light dynamics have adapted during evolution, and exploring biodiversity is a valuable strategy for expanding our understanding of their biological roles. In this work, we investigated the response to fluctuating light in Nannochloropsis gaditana, a eukaryotic microalga of the phylum Heterokonta originating from a secondary endosymbiotic event. Nannochloropsis gaditana is negatively affected by light fluctuations, leading to large reductions in growth and photosynthetic electron transport. Exposure to light fluctuations specifically damages photosystem I, likely because of the ineffective regulation of electron transport in this species. The role of NPQ, also assessed using a mutant strain specifically depleted of this response, was instead found to be minor, especially in responding to the fastest light fluctuations.
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Affiliation(s)
- Alessandra Bellan
- Department of Biology, University of Padova, Via U. Bassi 58/B, Padova 35121, Italy
| | - Francesca Bucci
- Department of Biology, University of Padova, Via U. Bassi 58/B, Padova 35121, Italy
| | - Giorgio Perin
- Department of Biology, University of Padova, Via U. Bassi 58/B, Padova 35121, Italy
| | - Alessandro Alboresi
- Department of Biology, University of Padova, Via U. Bassi 58/B, Padova 35121, Italy
| | - Tomas Morosinotto
- Department of Biology, University of Padova, Via U. Bassi 58/B, Padova 35121, Italy
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Economic feasibility and long-term sustainability criteria on the path to enable a transition from fossil fuels to biofuels. Curr Opin Biotechnol 2019; 57:175-182. [DOI: 10.1016/j.copbio.2019.04.004] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2018] [Revised: 03/31/2019] [Accepted: 04/16/2019] [Indexed: 12/19/2022]
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30
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Perin G, Bellan A, Bernardi A, Bezzo F, Morosinotto T. The potential of quantitative models to improve microalgae photosynthetic efficiency. PHYSIOLOGIA PLANTARUM 2019; 166:380-391. [PMID: 30578540 DOI: 10.1111/ppl.12915] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2018] [Revised: 12/14/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
The massive increase in carbon dioxide concentration in the atmosphere driven by human activities is causing huge negative consequences and new sustainable sources of energy, food and materials are highly needed. Algae are unicellular photosynthetic microorganisms that can provide a highly strategic contribution to this challenge as alternative source of biomass to complement crops cultivation. Algae industrial cultures are commonly limited by light availability, and biomass accumulation is strongly dependent on their photon-to-biomass conversion efficiency. Investigation of algae photosynthetic metabolism is thus strategic for the generation of more efficient strains with higher productivity. Algae are cultivated at industrial scale in conditions highly different from the natural niches they adapted to and strains development efforts must fully consider the seminal influence on productivity of regulatory mechanism of photosynthesis as well as of cultivation parameters like cells concentration, light distribution in the culture, mixing, nutrients and carbon dioxide availability. In this review we will focus in particular on how mathematical models can account for the complex influence of all environmental parameters and can be exploited for development of improved algae strains.
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Affiliation(s)
- Giorgio Perin
- Department of Biology, University of Padova, Via Ugo Bassi 58/B 35131, Padova, Italy
| | - Alessandra Bellan
- Department of Biology, University of Padova, Via Ugo Bassi 58/B 35131, Padova, Italy
| | - Andrea Bernardi
- Department of Industrial Engineering, University of Padova, Via Marzolo 9 35131, Padova, Italy
- Centre for Process Systems Engineering, Department of Chemical Engineering, Imperial College London, SW7 2AZ, London, UK
| | - Fabrizio Bezzo
- Department of Industrial Engineering, University of Padova, Via Marzolo 9 35131, Padova, Italy
| | - Tomas Morosinotto
- Department of Biology, University of Padova, Via Ugo Bassi 58/B 35131, Padova, Italy
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He Y, Wang X, Wei H, Zhang J, Chen B, Chen F. Direct enzymatic ethanolysis of potential Nannochloropsis biomass for co-production of sustainable biodiesel and nutraceutical eicosapentaenoic acid. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:78. [PMID: 30992715 PMCID: PMC6449970 DOI: 10.1186/s13068-019-1418-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Accepted: 03/27/2019] [Indexed: 05/24/2023]
Abstract
BACKGROUND Marine microalga Nannochloropsis is a promising source for the production of renewable and sustainable biodiesel in replacement of depleting petroleum. Other than biodiesel, Nannochloropsis is a green and potential resource for the commercial production of nutraceutical eicosapentaenoic acid (EPA, C20:5). In recent studies, low-value biodiesel can be achieved by transesterification of Nannochloropsis biomass. However, it is undoubtedly wasteful to produce microalgal biodiesel containing EPA from nutritional and economical aspects. A new strategy was addressed and exploited to produce low-value bulky biodiesel along with EPA enrichment via enzymatic ethanolysis of Nannochloropsis biomass with a specific lipase. RESULTS Cellulase pretreatment on Nannochloropsis sp. biomass significantly improved the biodiesel conversion by direct ethanolysis with five enzymes from Candida antarctica (CALA and CALB), Thermomyces lanuginosus (TL), Rhizomucor miehei (RM), and Aspergillus oryzae (PLA). Among these five biocatalysts, CALA was the best suitable enzyme to yield high biodiesel conversion and effectively enrich EPA. After optimization, the maximum biodiesel conversion (46.53-48.57%) was attained by CALA at 8:1 ethanol/biomass ratio (v/w) in 10-15% water content with 10% lipase weight at 35 °C for 72 h. Meanwhile, EPA (60.81%) was highly enriched in microalgae NPLs (neutral lipids and polar lipids), increasing original EPA levels by 1.51-fold. Moreover, this process was re-evaluated with two Nannochloropsis species (IMET1 and Salina 537). Under the optimized conditions, the biodiesel conversions of IMET1 and Salina 537 by CALA were 63.41% and 54.33%, respectively. EPA contents of microalgal NPLs were 50.06% for IMET1 and 53.73% for Salina 537. CONCLUSION CALA was the potential biocatalyst to discriminate against EPA in the ethanolysis of Nannochloropsis biomass. The biodiesel conversion and EPA enrich efficiency of CALA were greatly dependent on lipidic class and fatty acid compositions of Nannochloropsis biomass. CALA-catalyzed ethanolysis with Nannochloropsis biomass was a promising approach for co-production of low-value biodiesel and high-value microalgae products rich in EPA.
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Affiliation(s)
- Yongjin He
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
- Key Laboratory of Feed Biotechnology, The Ministry of Agriculture of the People’s Republic of China, Beijing, 100081 China
- College of Life Science, Fujian Normal University, Fuzhou, 350117 China
| | - Xiaofei Wang
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
| | - Hehong Wei
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
| | - Jianzhi Zhang
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
| | - Bilian Chen
- College of Life Science, Fujian Normal University, Fuzhou, 350117 China
| | - Feng Chen
- BIC-ESAT, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Food & Bioresource Engineering, College of Engineering, Peking University, Beijing, 100871 China
- Institute for Advanced Study, Shenzhen University, Shenzhen, 518000 China
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Dall’Osto L, Cazzaniga S, Guardini Z, Barera S, Benedetti M, Mannino G, Maffei ME, Bassi R. Combined resistance to oxidative stress and reduced antenna size enhance light-to-biomass conversion efficiency in Chlorella vulgaris cultures. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:221. [PMID: 31534480 PMCID: PMC6745798 DOI: 10.1186/s13068-019-1566-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/22/2019] [Accepted: 09/07/2019] [Indexed: 05/20/2023]
Abstract
BACKGROUND Microalgae are efficient producers of lipid-rich biomass, making them a key component in developing a sustainable energy source, and an alternative to fossil fuels. Chlorella species are of special interest because of their fast growth rate in photobioreactors. However, biological constraints still cast a significant gap between the high cost of biofuel and cheap oil, thus hampering perspective of producing CO2-neutral biofuels. A key issue is the inefficient use of light caused by its uneven distribution in the culture that generates photoinhibition of the surface-exposed cells and darkening of the inner layers. Efficient biofuel production, thus, requires domestication, including traits which reduce optical density of cultures and enhance photoprotection. RESULTS We applied two steps of mutagenesis and phenotypic selection to the microalga Chlorella vulgaris. First, a pale-green mutant (PG-14) was selected, with a 50% reduction of both chlorophyll content per cell and LHCII complement per PSII, with respect to WT. PG-14 showed a 30% increased photon conversion into biomass efficiency vs. WT. A second step of mutagenesis of PG-14, followed by selection for higher tolerance to Rose Bengal, led to the isolation of pale-green genotypes, exhibiting higher resistance to singlet oxygen (strains SOR). Growth in photobioreactors under high light conditions showed an enhanced biomass production of SOR strains with respect to PG-14. When compared to WT strain, biomass yield of the pale green + sor genotype was enhanced by 68%. CONCLUSIONS Domestication of microalgae like Chlorella vulgaris, by optimizing both light distribution and ROS resistance, yielded an enhanced carbon assimilation rate in photobioreactor.
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Affiliation(s)
- Luca Dall’Osto
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Stefano Cazzaniga
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Zeno Guardini
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Simone Barera
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Manuel Benedetti
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Giuseppe Mannino
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Unità di Fisiologia Vegetale, Università di Torino, Via Quarello 15/a, 10135 Turin, Italy
| | - Massimo E. Maffei
- Dipartimento di Scienze della Vita e Biologia dei Sistemi, Unità di Fisiologia Vegetale, Università di Torino, Via Quarello 15/a, 10135 Turin, Italy
| | - Roberto Bassi
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
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Benedetti M, Vecchi V, Barera S, Dall’Osto L. Biomass from microalgae: the potential of domestication towards sustainable biofactories. Microb Cell Fact 2018; 17:173. [PMID: 30414618 PMCID: PMC6230293 DOI: 10.1186/s12934-018-1019-3] [Citation(s) in RCA: 103] [Impact Index Per Article: 17.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Accepted: 10/31/2018] [Indexed: 12/22/2022] Open
Abstract
Interest in bulk biomass from microalgae, for the extraction of high-value nutraceuticals, bio-products, animal feed and as a source of renewable fuels, is high. Advantages of microalgal vs. plant biomass production include higher yield, use of non-arable land, recovery of nutrients from wastewater, efficient carbon capture and faster development of new domesticated strains. Moreover, adaptation to a wide range of environmental conditions evolved a great genetic diversity within this polyphyletic group, making microalgae a rich source of interesting and useful metabolites. Microalgae have the potential to satisfy many global demands; however, realization of this potential requires a decrease of the current production costs. Average productivity of the most common industrial strains is far lower than maximal theoretical estimations, suggesting that identification of factors limiting biomass yield and removing bottlenecks are pivotal in domestication strategies aimed to make algal-derived bio-products profitable on the industrial scale. In particular, the light-to-biomass conversion efficiency represents a major constraint to finally fill the gap between theoretical and industrial productivity. In this respect, recent results suggest that significant yield enhancement is feasible. Full realization of this potential requires further advances in cultivation techniques, together with genetic manipulation of both algal physiology and metabolic networks, to maximize the efficiency with which solar energy is converted into biomass and bio-products. In this review, we draft the molecular events of photosynthesis which regulate the conversion of light into biomass, and discuss how these can be targeted to enhance productivity through mutagenesis, strain selection or genetic engineering. We outline major successes reached, and promising strategies to achieving significant contributions to future microalgae-based biotechnology.
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Affiliation(s)
- Manuel Benedetti
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Valeria Vecchi
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Simone Barera
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
| | - Luca Dall’Osto
- Dipartimento di Biotecnologie, Università di Verona, Strada Le Grazie 15, 37134 Verona, Italy
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Poliner E, Farré EM, Benning C. Advanced genetic tools enable synthetic biology in the oleaginous microalgae Nannochloropsis sp. PLANT CELL REPORTS 2018; 37:1383-1399. [PMID: 29511798 DOI: 10.1007/s00299-018-2270-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2017] [Accepted: 02/26/2018] [Indexed: 05/16/2023]
Abstract
Nannochloropsis is a genus of fast-growing microalgae that are regularly used for biotechnology applications. Nannochloropsis species have a high triacylglycerol content and their polar lipids are rich in the omega-3 long-chain polyunsaturated fatty acid, eicosapentaenoic acid. Placed in the heterokont lineage, the Nannochloropsis genus has a complex evolutionary history. Genome sequences are available for several species, and a number of transcriptomic datasets have been produced, making this genus a facile model for comparative genomics. There is a growing interest in Nannochloropsis species as models for the study of microalga lipid metabolism and as a chassis for synthetic biology. Recently, techniques for gene stacking, and targeted gene disruption and repression in the Nannochloropsis genus have been developed. These tools enable gene-specific, mechanistic studies and have already allowed the engineering of improved Nannochloropsis strains with superior growth, or greater bioproduction.
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Affiliation(s)
- Eric Poliner
- Cell and Molecular Biology Program, Michigan State University, East Lansing, MI, USA
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA
| | - Eva M Farré
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA
| | - Christoph Benning
- MSU-DOE Plant Research Laboratory, Michigan State University, East Lansing, MI, USA.
- Department of Plant Biology, Michigan State University, East Lansing, MI, USA.
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, USA.
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Thiriet-Rupert S, Carrier G, Trottier C, Eveillard D, Schoefs B, Bougaran G, Cadoret JP, Chénais B, Saint-Jean B. Identification of transcription factors involved in the phenotype of a domesticated oleaginous microalgae strain of Tisochrysis lutea. ALGAL RES 2018. [DOI: 10.1016/j.algal.2017.12.011] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Perin G, Simionato D, Bellan A, Carone M, Occhipinti A, Maffei ME, Morosinotto T. Cultivation in industrially relevant conditions has a strong influence on biological properties and performances of Nannochloropsis gaditana genetically modified strains. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.10.013] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Sharon-Gojman R, Leu S, Zarka A. Antenna size reduction and altered division cycles in self-cloned, marker-free genetically modified strains of Haematococcus pluvialis. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.09.015] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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38
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Kwon S, Kang NK, Koh HG, Shin SE, Lee B, Jeong BR, Chang YK. Enhancement of biomass and lipid productivity by overexpression of a bZIP transcription factor in Nannochloropsis salina. Biotechnol Bioeng 2017; 115:331-340. [PMID: 28976541 DOI: 10.1002/bit.26465] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 09/11/2017] [Accepted: 09/29/2017] [Indexed: 11/12/2022]
Abstract
Microalgae are considered as excellent platforms for biomaterial production that can replace conventional fossil fuel-based fuels and chemicals. Genetic engineering of microalgae is prerequisite to maximize production of materials and to reduce costs for the production. Transcription factors (TFs) are emerging as key regulators of metabolic pathways to enhance production of molecules for biofuels and other materials. TFs with the basic leucine zipper (bZIP) domain have been known as stress regulators and are associated with lipid metabolism in plants. We overexpressed a bZIP TF, NsbZIP1, in Nannochloropsis salina, and found that transformants showed enhanced growth with concomitant increase in lipid contents. The improved phenotypes were also notable under stress conditions including N limitation and high salt. To understand the mechanism underlying improved phenotypes, we analyzed expression patterns of predicted target genes involved in lipid metabolism via quantitative RT-PCR, confirming increases transcript levels. NsbZIP1 appeared to be one of type C bZIPs in plants that has been known to regulate lipid metabolism under stress. Taken together, we demonstrated that NsbZIP1 could improve both growth and lipid production, and TF engineering can serve as an excellent genetic engineering tool for production of biofuels and biomaterials in microalgae.
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Affiliation(s)
- Sohee Kwon
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea
| | - Nam Kyu Kang
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea
| | - Hyun Gi Koh
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea
| | - Sung-Eun Shin
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea
| | - Bongsoo Lee
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea
| | - Byeong-Ryool Jeong
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea
| | - Yong Keun Chang
- Department of Chemical and Biomolecular Engineering, Daejeon, Republic of Korea.,Advanced Biomass R&D Center (ABC), Yuseong-gu, Daejeon, Republic of Korea
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Wei L, Wang Q, Xin Y, Lu Y, Xu J. Enhancing photosynthetic biomass productivity of industrial oleaginous microalgae by overexpression of RuBisCO activase. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.07.023] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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40
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A mathematical model to guide genetic engineering of photosynthetic metabolism. Metab Eng 2017; 44:337-347. [DOI: 10.1016/j.ymben.2017.11.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 10/18/2017] [Accepted: 11/05/2017] [Indexed: 01/13/2023]
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Banerjee A, Banerjee C, Negi S, Chang JS, Shukla P. Improvements in algal lipid production: a systems biology and gene editing approach. Crit Rev Biotechnol 2017; 38:369-385. [DOI: 10.1080/07388551.2017.1356803] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Avik Banerjee
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, India
| | - Chiranjib Banerjee
- Department of Environmental Science and Engineering, Indian Institute of Technology (Indian School of Mines), Dhanbad, India
| | | | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Tainan, Taiwan
| | - Pratyoosh Shukla
- Department of Microbiology, Enzyme Technology and Protein Bioinformatics Laboratory, Maharshi Dayanand University, Rohtak, India
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Chukhutsina VU, Fristedt R, Morosinotto T, Croce R. Photoprotection strategies of the alga Nannochloropsis gaditana. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2017; 1858:544-552. [DOI: 10.1016/j.bbabio.2017.05.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2017] [Revised: 05/03/2017] [Accepted: 05/07/2017] [Indexed: 01/02/2023]
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43
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Beacham TA, Sweet JB, Allen MJ. Large scale cultivation of genetically modified microalgae: A new era for environmental risk assessment. ALGAL RES 2017. [DOI: 10.1016/j.algal.2017.04.028] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
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44
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Remmers IM, Martens DE, Wijffels RH, Lamers PP. Dynamics of triacylglycerol and EPA production in Phaeodactylum tricornutum under nitrogen starvation at different light intensities. PLoS One 2017; 12:e0175630. [PMID: 28403203 PMCID: PMC5389818 DOI: 10.1371/journal.pone.0175630] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 03/29/2017] [Indexed: 01/02/2023] Open
Abstract
Lipid production in microalgae is highly dependent on the applied light intensity. However, for the EPA producing model-diatom Phaeodactylum tricornutum, clear consensus on the impact of incident light intensity on lipid productivity is still lacking. This study quantifies the impact of different incident light intensities on the biomass, TAG and EPA yield on light in nitrogen starved batch cultures of P. tricornutum. The maximum biomass concentration and maximum TAG and EPA contents were found to be independent of the applied light intensity. The lipid yield on light was reduced at elevated light intensities (>100 μmol m-2 s-1). The highest TAG yield on light (112 mg TAG molph-1) was found at the lowest light intensity tested (60 μmol m-2 s-1), which is still relatively low to values reported in literature for other algae. Furthermore, mass balance analysis showed that the EPA fraction in TAG may originate from photosynthetic membrane lipids.
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Affiliation(s)
- Ilse M. Remmers
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
- * E-mail:
| | - Dirk E. Martens
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
| | - René H. Wijffels
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
- Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Packo P. Lamers
- Bioprocess Engineering & AlgaePARC, Wageningen University and Research, Wageningen, The Netherlands
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Wei L, Xin Y, Wang Q, Yang J, Hu H, Xu J. RNAi-based targeted gene knockdown in the model oleaginous microalgae Nannochloropsis oceanica. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2017; 89:1236-1250. [PMID: 28188644 DOI: 10.1111/tpj.13411] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/02/2016] [Accepted: 10/24/2016] [Indexed: 05/09/2023]
Abstract
Microalgae are promising feedstock for renewable fuels such as biodiesel, yet development of industrial oleaginous strains has been hindered by the paucity and inefficiency of reverse genetics tools. Here we established an efficient RNAi-based targeted gene-knockdown method for Nannochloropsis spp., which are emerging model organisms for industrial microalgal oil production. The method achieved a 40-80% success rate in Nannochloropsis oceanica strain IMET1. When transcript level of one carbonic anhydrase (CA) was inhibited by 62-83% via RNAi, mutant cells exhibited photosynthetic oxygen evolution (POE) rates that were 68-100% higher than wild-type (WT) at pH 6.0, equivalent to WT at pH 8.2, yet 39-45% lower than WT at pH 9.0. Moreover, the mutant POE rates were negatively correlated with the increase of culture pH, an exact opposite of WT. Thus, a dynamic carbon concentration mechanism (CCM) that is highly sensitive to pH homeostasis was revealed, where the CA inhibition likely partially abrogated the mechanism that normally deactivates CCM under a high level of dissolved CO2 . Extension of the method to another sequenced N. oceanica strain of CCMP 1779 demonstrated comparable performance. Finally, McrBC-PCR followed by bisulfite sequencing revealed that the gene knockdown is mediated by the CG, CHG and CHH types of DNA methylation at the coding region of the targeted gene. The efficiency, robustness and general applicability of this reverse genetics approach suggested the possibility of large-scale RNAi-based gene function screening in industrial microalgae.
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Affiliation(s)
- Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Juan Yang
- University of Chinese Academy of Sciences, Beijing, 100049, China
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China
| | - Hanhua Hu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
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Dolch LJ, Rak C, Perin G, Tourcier G, Broughton R, Leterrier M, Morosinotto T, Tellier F, Faure JD, Falconet D, Jouhet J, Sayanova O, Beaudoin F, Maréchal E. A Palmitic Acid Elongase Affects Eicosapentaenoic Acid and Plastidial Monogalactosyldiacylglycerol Levels in Nannochloropsis. PLANT PHYSIOLOGY 2017; 173:742-759. [PMID: 27895203 PMCID: PMC5210741 DOI: 10.1104/pp.16.01420] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2016] [Accepted: 11/24/2016] [Indexed: 05/03/2023]
Abstract
Nannochloropsis species are oleaginous eukaryotes containing a plastid limited by four membranes, deriving from a secondary endosymbiosis. In Nannochloropsis, thylakoid lipids, including monogalactosyldiacylglycerol (MGDG), are enriched in eicosapentaenoic acid (EPA). The need for EPA in MGDG is not understood. Fatty acids are de novo synthesized in the stroma, then converted into very-long-chain polyunsaturated fatty acids (FAs) at the endoplasmic reticulum (ER). The production of MGDG relies therefore on an EPA supply from the ER to the plastid, following an unknown process. We identified seven elongases and five desaturases possibly involved in EPA production in Nannochloropsis gaditana Among the six heterokont-specific saturated FA elongases possibly acting upstream in this pathway, we characterized the highly expressed isoform Δ0-ELO1 Heterologous expression in yeast (Saccharomyces cerevisiae) showed that NgΔ0-ELO1 could elongate palmitic acid. Nannochloropsis Δ0-elo1 mutants exhibited a reduced EPA level and a specific decrease in MGDG In NgΔ0-elo1 lines, the impairment of photosynthesis is consistent with a role of EPA-rich MGDG in nonphotochemical quenching control, possibly providing an appropriate MGDG platform for the xanthophyll cycle. Concomitantly with MGDG decrease, the level of triacylglycerol (TAG) containing medium chain FAs increased. In Nannochloropsis, part of EPA used for MGDG production is therefore biosynthesized by a channeled process initiated at the elongation step of palmitic acid by Δ0-ELO1, thus acting as a committing enzyme for galactolipid production. Based on the MGDG/TAG balance controlled by Δ0-ELO1, this study also provides novel prospects for the engineering of oleaginous microalgae for biotechnological applications.
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Affiliation(s)
- Lina-Juana Dolch
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.);
| | - Camille Rak
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.);
| | - Giorgio Perin
- Padua Algae Research Laboratory, Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy (G.P., T.M.)
- Padua Algae Research Laboratory, Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy (G.P., T.M.);
| | - Guillaume Tourcier
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.);
| | - Richard Broughton
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (R.B., O.S., F.B.)
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (R.B., O.S., F.B.);
| | - Marina Leterrier
- Fermentalg, 4 Rue Rivière, 33500, Libourne, France (M.L.); and
- Fermentalg, 4 Rue Rivière, 33500, Libourne, France (M.L.); and
| | - Tomas Morosinotto
- Padua Algae Research Laboratory, Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy (G.P., T.M.)
- Padua Algae Research Laboratory, Department of Biology, University of Padova, Via U. Bassi 58/B, 35121 Padova, Italy (G.P., T.M.);
| | - Frédérique Tellier
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France (J.-D.F.)
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France (J.-D.F.)
| | - Jean-Denis Faure
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France (J.-D.F.)
- Institut Jean-Pierre Bourgin, INRA, AgroParisTech, CNRS, Université Paris-Saclay, 78000, Versailles, France (J.-D.F.)
| | - Denis Falconet
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.);
| | - Juliette Jouhet
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.);
| | - Olga Sayanova
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (R.B., O.S., F.B.)
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (R.B., O.S., F.B.);
| | - Frédéric Beaudoin
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (R.B., O.S., F.B.)
- Biological Chemistry and Crop Protection Department, Rothamsted Research, Harpenden, Hertfordshire, AL5 2JQ, United Kingdom (R.B., O.S., F.B.);
| | - Eric Maréchal
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.)
- Laboratoire de Physiologie Cellulaire et Végétale, Unité mixte de recherche 5168 CNRS - CEA - Université Grenoble 1, Institut de Recherche en Sciences et Technologies pour le Vivant, CEA Grenoble, 17 rue des Martyrs, 38054, Grenoble Cedex 9, France (L.-J.D., C.R., G.T., D.F., J.J., E.M.);
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Wang Q, Lu Y, Xin Y, Wei L, Huang S, Xu J. Genome editing of model oleaginous microalgae Nannochloropsis spp. by CRISPR/Cas9. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2016; 88:1071-1081. [PMID: 27538728 DOI: 10.1111/tpj.13307] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Revised: 08/04/2016] [Accepted: 08/05/2016] [Indexed: 05/18/2023]
Abstract
Microalgae are promising feedstock for biofuels yet mechanistic probing of their cellular network and industrial strain development have been hindered by lack of genome-editing tools. Nannochloropsis spp. are emerging model microalgae for scalable oil production and carbon sequestration. Here we established a CRISPR/Cas9-based precise genome-editing approach for the industrial oleaginous microalga Nannochloropsis oceanica, using nitrate reductase (NR; g7988) as example. A new screening procedure that compares between restriction enzyme-digested nested PCR (nPCR) products derived from enzyme-digested and not-digested genomic DNA of transformant pools was developed to quickly, yet reliably, detect genome-engineered mutants. Deep sequencing of nPCR products directly amplified from pooled genomic DNA revealed over an 1% proportion of 5-bp deletion mutants and a lower frequency of 12-bp deletion mutants, with both types of editing precisely located at the targeted site. The isolated mutants, in which precise deletion of five bases caused a frameshift in NR translation, grow normally under NH4 Cl but fail to grow under NaNO3 , and thus represent a valuable chassis strain for transgenic-strain development. This demonstration of CRISPR/Cas9-based genome editing in industrial microalgae opens many doors for microalgae-based biotechnological applications.
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Affiliation(s)
- Qintao Wang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Yandu Lu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- State Key Laboratory of Marine Resource Utilization in South China Sea, College of Oceanology, Hainan University, 570228, Haikou, Hainan, China
| | - Yi Xin
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Li Wei
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
| | - Shi Huang
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jian Xu
- Single-Cell Center, CAS Key Laboratory of Biofuels and Shandong Key Laboratory of Energy Genetics, Qingdao Institute of BioEnergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao, Shandong, 266101, China
- University of Chinese Academy of Sciences, Beijing, 100049, China
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Alboresi A, Perin G, Vitulo N, Diretto G, Block M, Jouhet J, Meneghesso A, Valle G, Giuliano G, Maréchal E, Morosinotto T. Light Remodels Lipid Biosynthesis in Nannochloropsis gaditana by Modulating Carbon Partitioning between Organelles. PLANT PHYSIOLOGY 2016; 171:2468-82. [PMID: 27325666 PMCID: PMC4972283 DOI: 10.1104/pp.16.00599] [Citation(s) in RCA: 66] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/14/2016] [Accepted: 06/20/2016] [Indexed: 05/18/2023]
Abstract
The seawater microalga Nannochloropsis gaditana is capable of accumulating a large fraction of reduced carbon as lipids. To clarify the molecular bases of this metabolic feature, we investigated light-driven lipid biosynthesis in Nannochloropsis gaditana cultures combining the analysis of photosynthetic functionality with transcriptomic, lipidomic and metabolomic approaches. Light-dependent alterations are observed in amino acid, isoprenoid, nucleic acid, and vitamin biosynthesis, suggesting a deep remodeling in the microalgal metabolism triggered by photoadaptation. In particular, high light intensity is shown to affect lipid biosynthesis, inducing the accumulation of diacylglyceryl-N,N,N-trimethylhomo-Ser and triacylglycerols, together with the up-regulation of genes involved in their biosynthesis. Chloroplast polar lipids are instead decreased. This situation correlates with the induction of genes coding for a putative cytosolic fatty acid synthase of type 1 (FAS1) and polyketide synthase (PKS) and the down-regulation of the chloroplast fatty acid synthase of type 2 (FAS2). Lipid accumulation is accompanied by the regulation of triose phosphate/inorganic phosphate transport across the chloroplast membranes, tuning the carbon metabolic allocation between cell compartments, favoring the cytoplasm, mitochondrion, and endoplasmic reticulum at the expense of the chloroplast. These results highlight the high flexibility of lipid biosynthesis in N. gaditana and lay the foundations for a hypothetical mechanism of regulation of primary carbon partitioning by controlling metabolite allocation at the subcellular level.
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Affiliation(s)
- Alessandro Alboresi
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Giorgio Perin
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Nicola Vitulo
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Gianfranco Diretto
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Maryse Block
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Juliette Jouhet
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Andrea Meneghesso
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Giorgio Valle
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Giovanni Giuliano
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Eric Maréchal
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
| | - Tomas Morosinotto
- PAR-Lab_Padua Algae Research Laboratory, Department of Biology (A.A., G.P., A.M., T.M.), and Innovative Biotechnologies Interdepartmental Research Center (CRIBI; N.V., G.V.), University of Padova, 35121 Padova, Italy;Laboratoire de Biologie Cellulaire et Végétale, UMR 5168 CNRS, CEA, INRA, Université Grenoble Alpes, BIG, CEA-Grenoble, 38054 Grenoble, Cedex 9, France (M.B., J.J., E.M.);Department of Biotechnology, University of Verona, 37134 Verona, Italy (N.V.); andItalian National Agency for New Technologies, Energy, and Sustainable Economic Development (ENEA), Casaccia Research Centre, 00123 Roma, Italy (G.D., G.G.)
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