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Xu B, Zhang Q, Lu Z, Li Y, Zuo Y, Gan N, Zhan J, Song L. Production of eicosapentaenoic acid by Vacuoliviride crystalliferum under 20% CO 2 conditions. BIORESOURCE TECHNOLOGY 2024; 410:131307. [PMID: 39155016 DOI: 10.1016/j.biortech.2024.131307] [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: 05/29/2024] [Revised: 08/14/2024] [Accepted: 08/15/2024] [Indexed: 08/20/2024]
Abstract
Utilizing flue gas CO2 to co-produce eicosapentaenoic acid (EPA) with microalgae is considered an ideal approach for combating climate change and reducing cultivation costs. However, microalgal species that can efficiently produce EPA under high-CO2 conditions are scarce. This study identified that the eustigmatophycean strain Vacuoliviride crystalliferum demonstrates rapid growth under 20 % CO2 conditions (0.22 vvm), achieving a biomass concentration and productivity of 3.90 g/L and 229.26 mg/L/d, respectively. The EPA content and EPA productivity were found to be 4.28 % (w/w) and 9.80 mg/L/d, respectively. Additionally, an improved biomass concentration of 3.39 g/L and EPA content and productivity of 4.32 % (w/w) and 11.28 mg/L/d were obtained in a 30 L up-scaled cultivation system. Taken together, these findings suggest that V. crystalliferum is a promising candidate for integrating flue gas sequestration with EPA production.
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Affiliation(s)
- Baolin Xu
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China; University of Chinese Academy of Sciences, Beijing 100049, China
| | - Qi Zhang
- National Aquatic Biological Resource Center, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Zhe Lu
- Xiaoliang Research Station of Tropical Coastal Ecosystems, Key Laboratory of Vegetation Restoration and Management of Degraded Ecosystems, and Guangdong Provincial Key Laboratory of Applied Botany, South China Botanical Garden, Chinese Academy of Sciences, Guangzhou 510650, PR China
| | - Yanhua Li
- YANGTZE Eco-Environment Engineering Research Center, China Three Gorges Corporation, Wuhan 430014, China
| | - Yanxia Zuo
- State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Nanqing Gan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China
| | - Jiao Zhan
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
| | - Lirong Song
- Key Laboratory of Algal Biology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan 430072, China.
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2
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Montoya‐Arroyo A, Muñoz‐González A, Lehnert K, Frick K, Schmid‐Staiger U, Vetter W, Frank J. Monodopsis subterranea is a source of α-tocomonoenol, and its concentration, in contrast to α-tocopherol, is not affected by nitrogen depletion. Food Sci Nutr 2024; 12:1869-1879. [PMID: 38455160 PMCID: PMC10916641 DOI: 10.1002/fsn3.3880] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2023] [Revised: 11/12/2023] [Accepted: 11/15/2023] [Indexed: 03/09/2024] Open
Abstract
α-Tomonoenols (αT1) are tocochromanols structurally related to tocopherols (T) and tocotrienols (T3), the bioactive members of the vitamin E family. However, limited evidence exists regarding the sources and biosynthesis of tocomonoenols. Nitrogen depletion increases the content of α-tocopherol (αT), the main vitamin E congener, in microalgae, but little is known regarding its effect on other tocochromanols, such as tocomonoenols and tocotrienols. We therefore quantified the concentrations of T, T1, and T3, in freeze-dried biomass from nitrogen-sufficient, and nitrogen-depleted Monodopsis subterranea (Eustigmatophyceae). The identities of isomers of αT1 were confirmed by LC-MS and GC-MS. αT was the predominant tocochromanol (82% of total tocochromanols). αT1 was present in higher quantities than the sum of all T3 (6% vs. 1% of total tocochromanols). 11'-αT1 was the main αT1 isomer. Nitrogen depletion increased αT, but not αT1 or T3 in M. subterranea. In conclusion, nitrogen depletion increased the content of αT, the biologically most active form of vitamin E, in M. subterranea without affecting αT1 and T3 and could potentially be used as a strategy to enhance its nutritional value but not to increase αT1 content, indicating that αT1 accumulation is independent of that of αT in microalgae.
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Affiliation(s)
| | - Alejandra Muñoz‐González
- Institute of Nutritional Sciences (140b)University of HohenheimStuttgartGermany
- School of Food TechnologyUniversity of Costa RicaSan PedroCosta Rica
| | - Katja Lehnert
- Institute of Food Chemistry (170b)University of HohenheimStuttgartGermany
| | - Konstantin Frick
- Institute of Interfacial Process Engineering and Plasma TechnologyUniversity of StuttgartStuttgartGermany
| | - Ulrike Schmid‐Staiger
- Innovation Field Functional IngredientsFraunhofer Institute for Interfacial Engineering and Biotechnology IGBStuttgartGermany
| | - Walter Vetter
- Institute of Food Chemistry (170b)University of HohenheimStuttgartGermany
| | - Jan Frank
- Institute of Nutritional Sciences (140b)University of HohenheimStuttgartGermany
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3
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Kadam RV, Rani V, Padmavathy P, Shalini R, Selvi MJT, Narsale SA. Assessment of heavy metals and environmental stress conditions on the production potential of polyunsaturated fatty acids (PUFAs) in indigenous microalgae isolated from the Gulf of Mannar coastal waters. ENVIRONMENTAL MONITORING AND ASSESSMENT 2024; 196:301. [PMID: 38400851 DOI: 10.1007/s10661-024-12447-y] [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: 10/16/2023] [Accepted: 02/12/2024] [Indexed: 02/26/2024]
Abstract
The present study evaluated the effects of heavy metals, viz., lead, mercury, and cadmium, on growth, chlorophyll a, b, c, carotenoids, and PUFA content of marine microalgae Chlorella sp. and Cylindrotheca fusiformis. At 96-h exposure, the IC50 values for Hg2+, Pb2+, and Cd2+ were 0.85 mg/L, 2.4 mg/L, and 5.3 mg/L respectively, in Chlorella sp. In C. fusiformis, IC50 values for Hg2+, Pb2+, and Cd2+ were 0.5 mg/L, 1.2 mg/L, and 3 mg/L respectively. The pigment contents of both microalgae were significantly affected upon heavy metal exposure. In Chlorella sp. and C. fusiformis, the exposed concentrations of Hg2+ averagely decreased the PUFA content by 76.34% and 78.68%, respectively. Similarly, Pb2+-exposed concentrations resulted in 54.50% and 82.64% average reductions in PUFA content of Chlorella sp. and C. fusiformis, respectively. Cd2+-exposed concentrations showed 32.58% and 40.54% average reduction in PUFA content of Chlorella sp. and C. fusiformis, respectively. Among the environmental stress conditions, the dark treatment has increased total PUFA content by 6.63% in Chlorella sp. and 3.92% in C. fusiformis. It was observed that the 50% nitrogen starvation (two-stage) significantly improved the PUFA production from 26.47 ± 6.55% to 40.92 ± 10.74% in Chlorella sp. and from 11.23 ± 5.01 to 32.8 ± 14.17% in C. fusiformis. The toxicity for both microalgae was followed in the order Hg2+ > Pb2+ > Cd2+. Among the two species, Chlorella sp. has shown a high tolerance to heavy metals and can be effectively utilized in PUFA production.
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Affiliation(s)
- Rishikesh Venkatrao Kadam
- Department of Aquatic Environment Management, Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Thoothukudi, 628 008, Tamil Nadu, India
| | - V Rani
- Department of Aquatic Environment Management, Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Thoothukudi, 628 008, Tamil Nadu, India.
| | - P Padmavathy
- Department of Aquatic Environment Management, Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Thoothukudi, 628 008, Tamil Nadu, India
| | - R Shalini
- Department of Fish Quality Assurance and Management, Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Thoothukudi, 628 008, Tamil Nadu, India
| | - M J Thamarai Selvi
- Department of Aquatic Environment Management, Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Thoothukudi, 628 008, Tamil Nadu, India
| | - Swapnil Ananda Narsale
- Department of Fish Pathology and Health Management, Fisheries College and Research Institute, Tamil Nadu Dr. J. Jayalalithaa Fisheries University, Thoothukudi, 628 008, Tamil Nadu, India
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Ye Y, Liu M, Yu L, Sun H, Liu J. Nannochloropsis as an Emerging Algal Chassis for Light-Driven Synthesis of Lipids and High-Value Products. Mar Drugs 2024; 22:54. [PMID: 38393025 PMCID: PMC10890015 DOI: 10.3390/md22020054] [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: 12/23/2023] [Revised: 01/14/2024] [Accepted: 01/22/2024] [Indexed: 02/25/2024] Open
Abstract
In light of the escalating global energy crisis, microalgae have emerged as highly promising producers of biofuel and high-value products. Among these microalgae, Nannochloropsis has received significant attention due to its capacity to generate not only triacylglycerol (TAG) but also eicosapentaenoic acid (EPA) and valuable carotenoids. Recent advancements in genetic tools and the field of synthetic biology have revolutionized Nannochloropsis into a powerful biofactory. This comprehensive review provides an initial overview of the current state of cultivation and utilization of the Nannochloropsis genus. Subsequently, our review examines the metabolic pathways governing lipids and carotenoids, emphasizing strategies to enhance oil production and optimize carbon flux redirection toward target products. Additionally, we summarize the utilization of advanced genetic manipulation techniques in Nannochloropsis. Together, the insights presented in this review highlight the immense potential of Nannochloropsis as a valuable model for biofuels and synthetic biology. By effectively integrating genetic tools and metabolic engineering, the realization of this potential becomes increasingly feasible.
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Affiliation(s)
- Ying Ye
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
| | - Meijing Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Center for Algae Innovation & Engineering Research, School of Resources and Environment, Nanchang University, Nanchang 330031, China
| | - Lihua Yu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
| | - Han Sun
- Institute for Advanced Study, Shenzhen University, Shenzhen 518060, China
| | - Jin Liu
- Laboratory for Algae Biotechnology & Innovation, College of Engineering, Peking University, Beijing 100871, China; (Y.Y.); (M.L.); (L.Y.)
- Key Laboratory of Poyang Lake Environment and Resource Utilization, Ministry of Education, Center for Algae Innovation & Engineering Research, School of Resources and Environment, Nanchang University, Nanchang 330031, China
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Andriopoulos V, Kornaros M. LASSO Regression with Multiple Imputations for the Selection of Key Variables Affecting the Fatty Acid Profile of Nannochloropsis oculata. Mar Drugs 2023; 21:483. [PMID: 37755096 PMCID: PMC10533012 DOI: 10.3390/md21090483] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Revised: 08/28/2023] [Accepted: 08/31/2023] [Indexed: 09/28/2023] Open
Abstract
The marine microalga Nannochloropsis oculata has garnered significant interest as a potential source of lipids, both for biofuel and nutrition, containing significant amounts of C16:0, C16:1, and C20:5, n-3 (EPA) fatty acids (FA). Growth parameters such as temperature, pH, light intensity, and nutrient availability play a crucial role in the fatty acid profile of microalgae, with N. oculata being no exception. This study aims to identify key variables for the FA profile of N. oculata grown autotrophically. To that end, the most relevant literature data were gathered and combined with our previous work as well as with novel experimental data, with 121 observations in total. The examined variables were the percentages of C14:0, C16:0, C16:1, C18:1, C18:2, and C20:5, n-3 in total FAs, their respective ratios to C16:0, and the respective content of biomass in those fatty acids in terms of ash free dry weight. Many potential predictor variables were collected, while dummy variables were introduced to account for bias in the measured variables originating from different authors as well as for other parameters. The method of multiple imputations was chosen to handle missing data, with limits based on the literature and model-based estimation, such as using the software PHREEQC and residual modelling for the estimation of pH. To eliminate unimportant predictor variables, LASSO (Least Absolute Shrinkage and Selection Operator) regression analysis with a novel definition of optimal lambda was employed. LASSO regression identified the most relevant predictors while minimizing the risk of overfitting the model. Subsequently, stepwise linear regression with interaction terms was used to further study the effects of the selected predictors. After two rounds of regression, sparse refined models were acquired, and their coefficients were evaluated based on significance. Our analysis confirms well-known effects, such as that of temperature, and it uncovers novel unreported effects of aeration, calcium, magnesium, and manganese. Of special interest is the negative effect of aeration on polyunsaturated fatty acids (PUFAs), which is possibly related to the enzymatic kinetics of fatty acid desaturation under increased oxygen concentration. These findings contribute to the optimization of the fatty acid profile of N. oculata for different purposes, such as production of, high in PUFAs, food or feed, or production of, high in saturated and monounsaturated FA methyl esters (FAME), biofuels.
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Affiliation(s)
- Vasilis Andriopoulos
- Laboratory of Biochemical Engineering & Environmental Technology (LBEET), Department of Chemical Engineering, University of Patras, 26504 Patras, Greece;
- Institute of Circular Economy and Environment (ICEE), University of Patras’ Research and Development Center, 26504 Patras, Greece
| | - Michael Kornaros
- Laboratory of Biochemical Engineering & Environmental Technology (LBEET), Department of Chemical Engineering, University of Patras, 26504 Patras, Greece;
- Institute of Circular Economy and Environment (ICEE), University of Patras’ Research and Development Center, 26504 Patras, Greece
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6
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Guimarães BO, Villarreal-Toribio B, García-Barrera T, Arias-Borrego A, Gremmen P, Wijffels RH, Barbosa MJ, D'Adamo S. Effect of sulphur on selenium accumulation and speciation in Nannochloropsis oceanica. J Funct Foods 2022. [DOI: 10.1016/j.jff.2022.105215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2022] Open
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Wan Razali WA, Evans CA, Pandhal J. Comparative Proteomics Reveals Evidence of Enhanced EPA Trafficking in a Mutant Strain of Nannochloropsis oculata. Front Bioeng Biotechnol 2022; 10:838445. [PMID: 35646838 PMCID: PMC9134194 DOI: 10.3389/fbioe.2022.838445] [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: 12/17/2021] [Accepted: 03/29/2022] [Indexed: 01/23/2023] Open
Abstract
The marine microalga Nannochloropsis oculata is a bioproducer of eicosapentaenoic acid (EPA), a fatty acid. EPA is incorporated into monogalactosyldiacylglycerol within N. oculata thylakoid membranes, and there is a biotechnological need to remodel EPA synthesis to maximize production and simplify downstream processing. In this study, random mutagenesis and chemical inhibitor-based selection method were devised to increase EPA production and accessibility for improved extraction. Ethyl methanesulfonate was used as the mutagen with selective pressure achieved by using two enzyme inhibitors of lipid metabolism: cerulenin and galvestine-1. Fatty acid methyl ester analysis of a selected fast-growing mutant strain had a higher percentage of EPA (37.5% of total fatty acids) than the wild-type strain (22.2% total fatty acids), with the highest EPA quantity recorded at 68.5 mg/g dry cell weight, while wild-type cells had 48.6 mg/g dry cell weight. Label-free quantitative proteomics for differential protein expression analysis revealed that the wild-type and mutant strains might have alternative channeling pathways for EPA synthesis. The mutant strain showed potentially improved photosynthetic efficiency, thus synthesizing a higher quantity of membrane lipids and EPA. The EPA synthesis pathways could also have deviated in the mutant, where fatty acid desaturase type 2 (13.7-fold upregulated) and lipid droplet surface protein (LDSP) (34.8-fold upregulated) were expressed significantly higher than in the wild-type strain. This study increases the understanding of EPA trafficking in N. oculata, leading to further strategies that can be implemented to enhance EPA synthesis in marine microalgae.
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Affiliation(s)
- Wan Aizuddin Wan Razali
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom.,Faculty of Fisheries and Food Science, Universiti Malaysia Terengganu, Terengganu, Malaysia
| | - Caroline A Evans
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
| | - Jagroop Pandhal
- Department of Chemical and Biological Engineering, University of Sheffield, Sheffield, United Kingdom
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Heredia V, Marchal L, Gonçalves O, Pruvost J. Optimization of continuous TAG production by Nannochloropsis gaditana in solar-nitrogen-limited culture. Biotechnol Bioeng 2022; 119:1808-1819. [PMID: 35377482 DOI: 10.1002/bit.28097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 03/22/2022] [Accepted: 03/25/2022] [Indexed: 11/08/2022]
Abstract
Nitrogen limitation and changing solar conditions are both known to affect triacylglycerol (TAG) production in microalgae. This work investigates the optimization of TAG production with a continuous nitrogen-limited culture of Nannochloropsis gaditana in simulated day-night cycles. The effect of day-night cycles was firstly investigated in nitrogen-deprived condition (i.e. batch culture), emphasizing a significant change in mechanical resistance of the strain during the night. The concept of Released TAG, which shows how much of the TAG produced is actually recovered in the downstream stages, i.e. after cell disruption, was shown here of interest. For a maximum released TAG, the optimum harvesting time was suggested as being 4 hours into the night period, which minimizes the losses due to a too great cell mechanical resistance. The protocol for continuous nitrogen-limited culture was then optimized, and a continuous nitrogen addition was compared to a pulsed-addition. For the latter, nitrogen was supplied in a single pulse at the beginning of the light periods, while the bulk medium was supplied separately at a slow but constant dilution rate of 0.005 h - 1 . The pulse dose was calculated after the study of nitrogen consumption and TAG production/consumption during the day-night cycles. The estimated released TAG for the pulsed-addition of 1.4 ⋅ 1 0 - 3 kg/m 2 ⋅ d was found significantly higher than the one achieved in batch culture (0.3 ⋅ 1 0 - 3 kg/m 2 ⋅ d) but lower than for continuous nitrogen addition which obtained the highest released TAG of 3 ⋅ 1 0 - 3 kg/m 2 ⋅ d. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Vladimir Heredia
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
| | - Luc Marchal
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
| | - Olivier Gonçalves
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
| | - Jeremy Pruvost
- Université de Nantes, Oniris, GEPEA, UMR 6144 F-44600, Saint-Nazaire, France
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Short-term physiologic response of the green microalga Picochlorum sp. (BPE23) to supra-optimal temperature. Sci Rep 2022; 12:3290. [PMID: 35228560 PMCID: PMC8885816 DOI: 10.1038/s41598-022-06954-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2021] [Accepted: 02/08/2022] [Indexed: 11/09/2022] Open
Abstract
Photobioreactors heat up significantly during the day due to irradiation by sunlight. High temperatures affect cell physiology negatively, causing reduced growth and productivity. To elucidate the microalgal response to stressful supra-optimal temperature, we studied the physiology of Picochlorum sp. (BPE23) after increasing the growth temperature from 30 °C to 42 °C, whereas 38 °C is its optimal growth temperature. Cell growth, cell composition and mRNA expression patterns were regularly analyzed for 120 h after increasing the temperature. The supra-optimal temperature caused cell cycle arrest for 8 h, with concomitant changes in metabolic activity. Accumulation of fatty acids was observed during this period to store unspent energy which was otherwise used for growth. In addition, the microalgae changed their pigment and fatty acid composition. For example, palmitic acid (C16:0) content in the polar fatty acid fraction increased by 30%, hypothetically to reduce membrane fluidity to counteract the effect of increased temperature. After the relief of cell cycle arrest, the metabolic activity of Picochlorum sp. (BPE23) reduced significantly over time. A strong response in gene expression was observed directly after the increase in temperature, which was dampened in the remainder of the experiment. mRNA expression levels associated with pathways associated with genes acting in photosynthesis, carbon fixation, ribosome, citrate cycle, and biosynthesis of metabolites and amino acids were downregulated, whereas the proteasome, autophagy and endocytosis were upregulated.
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Heredia V, Pruvost J, Gonçalves O, Drouin D, Marchal L. Lipid recovery from Nannochloropsis gaditana using the wet pathway: Investigation of the operating parameters of bead milling and centrifugal extraction. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102318] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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High-throughput insertional mutagenesis reveals novel targets for enhancing lipid accumulation in Nannochloropsis oceanica. Metab Eng 2021; 66:239-258. [PMID: 33971293 DOI: 10.1016/j.ymben.2021.04.012] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/07/2021] [Accepted: 04/18/2021] [Indexed: 12/17/2022]
Abstract
The microalga Nannochloropsis oceanica is considered a promising platform for the sustainable production of high-value lipids and biofuel feedstocks. However, current lipid yields of N. oceanica are too low for economic feasibility. Gaining fundamental insights into the lipid metabolism of N. oceanica could open up various possibilities for the optimization of this species through genetic engineering. Therefore, the aim of this study was to discover novel genes associated with an elevated neutral lipid content. We constructed an insertional mutagenesis library of N. oceanica, selected high lipid mutants by five rounds of fluorescence-activated cell sorting, and identified disrupted genes using a novel implementation of a rapid genotyping procedure. One particularly promising mutant (HLM23) was disrupted in a putative APETALA2-like transcription factor gene. HLM23 showed a 40%-increased neutral lipid content, increased photosynthetic performance, and no growth impairment. Furthermore, transcriptome analysis revealed an upregulation of genes related to plastidial fatty acid biosynthesis, glycolysis and the Calvin-Benson-Bassham cycle in HLM23. Insights gained in this work can be used in future genetic engineering strategies for increased lipid productivity of Nannochloropsis.
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Guéguen N, Le Moigne D, Amato A, Salvaing J, Maréchal E. Lipid Droplets in Unicellular Photosynthetic Stramenopiles. FRONTIERS IN PLANT SCIENCE 2021; 12:639276. [PMID: 33968100 PMCID: PMC8100218 DOI: 10.3389/fpls.2021.639276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Accepted: 03/17/2021] [Indexed: 06/12/2023]
Abstract
The Heterokonta or Stramenopile phylum comprises clades of unicellular photosynthetic species, which are promising for a broad range of biotechnological applications, based on their capacity to capture atmospheric CO2 via photosynthesis and produce biomolecules of interest. These molecules include triacylglycerol (TAG) loaded inside specific cytosolic bodies, called the lipid droplets (LDs). Understanding TAG production and LD biogenesis and function in photosynthetic stramenopiles is therefore essential, and is mostly based on the study of a few emerging models, such as the pennate diatom Phaeodactylum tricornutum and eustigmatophytes, such as Nannochloropsis and Microchloropsis species. The biogenesis of cytosolic LD usually occurs at the level of the endoplasmic reticulum. However, stramenopile cells contain a complex plastid deriving from a secondary endosymbiosis, limited by four membranes, the outermost one being connected to the endomembrane system. Recent cell imaging and proteomic studies suggest that at least some cytosolic LDs might be associated to the surface of the complex plastid, via still uncharacterized contact sites. The carbon length and number of double bonds of the acyl groups contained in the TAG molecules depend on their origin. De novo synthesis produces long-chain saturated or monounsaturated fatty acids (SFA, MUFA), whereas subsequent maturation processes lead to very long-chain polyunsaturated FA (VLC-PUFA). TAG composition in SFA, MUFA, and VLC-PUFA reflects therefore the metabolic context that gave rise to the formation of the LD, either via an early partitioning of carbon following FA de novo synthesis and/or a recycling of FA from membrane lipids, e.g., plastid galactolipids or endomembrane phosphor- or betaine lipids. In this review, we address the relationship between cytosolic LDs and the complex membrane compartmentalization within stramenopile cells, the metabolic routes leading to TAG accumulation, and the physiological conditions that trigger LD production, in response to various environmental factors.
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Young DY, Shachar-Hill Y. Large fluxes of fatty acids from membranes to triacylglycerol and back during N-deprivation and recovery in Chlamydomonas. PLANT PHYSIOLOGY 2021; 185:796-814. [PMID: 33822218 PMCID: PMC8133548 DOI: 10.1093/plphys/kiaa071] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/23/2020] [Indexed: 06/12/2023]
Abstract
Microalgae accumulate triacylglycerol (TAG) during nutrient deprivation and break it down after nutrient resupply, and these processes involve dramatic shifts in cellular carbon allocation. Due to the importance of algae in the global carbon cycle, and the potential of algal lipids as feedstock for chemical and fuel production, these processes are of both ecophysiological and biotechnological importance. However, the metabolism of TAG is not well understood, particularly the contributions of fatty acids (FAs) from different membrane lipids to TAG accumulation and the fate of TAG FAs during degradation. Here, we used isotopic labeling time course experiments on Chlamydomonas reinhardtii to track FA synthesis and transfer between lipid pools during nitrogen (N)-deprivation and resupply. When cells were labeled before N-deprivation, total levels of label in cellular FAs were unchanged during subsequent N-deprivation and later resupply, despite large fluxes into and out of TAG and membrane lipid pools. Detailed analyses of FA levels and labeling revealed that about one-third of acyl chains accumulating in TAG during N-deprivation derive from preexisting membrane lipids, and in total, at least 45% of TAG FAs passed through membrane lipids at one point. Notably, most acyl chains in membrane lipids during recovery after N-resupply come from TAG. Fluxes of polyunsaturated FAs from plastidic membranes into TAG during N-deprivation were particularly noteworthy. These findings demonstrate a high degree of integration of TAG and membrane lipid metabolism and highlight a role for TAG in storage and supply of membrane lipid components.
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Affiliation(s)
- Danielle Yvonne Young
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
| | - Yair Shachar-Hill
- Department of Plant Biology, Michigan State University, East Lansing, Michigan, 48824, USA
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Producing Energy-Rich Microalgae Biomass for Liquid Biofuels: Influence of Strain Selection and Culture Conditions. ENERGIES 2021. [DOI: 10.3390/en14051246] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Energy-storage metabolites such as neutral lipids and carbohydrates are valuable compounds for liquid biofuel production. The aim of this work is to elucidate the main biological responses of two algae species known for their effective energy-rich compound accumulation in nitrogen limitation and day–night cycles: Nannochloropsis gaditana, a seawater species, and Parachlorella kessleri, a freshwater species. Lipid and carbohydrate production are investigated, as well as cell resistance to mechanical disruption for energy-rich compound release. Nitrogen-depleted N. gaditana showed only a low consumption of energy-storage molecules with a non-significant preference for neutral lipids (TAG) and carbohydrates in day–night cycles. However, it did accumulate significantly fewer carbohydrates than P. kessleri. Following this, the highest levels of productivity for N. gaditana in chemostat cultures at four levels of nitrogen limitation were found to be 3.4 and 2.2 × 10−3 kg/m2·d for carbohydrates and TAG, respectively, at 56%NO3 limitation. The cell disruption rate of N. gaditana decreased along with nitrogen limitation, from 75% (at 200%NO3) to 17% (at 13%NO3). In the context of potentially recoverable energy for biofuels, P. kessleri showed good potential for biodiesel and high potential for bioethanol; by contrast, N. gaditana was found to be more efficient for biodiesel production only.
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Lozano-Muñoz I, Muñoz S, Díaz NF, Medina A, Bazaes J, Riquelme C. Nutritional Enhancement of Farmed Salmon Meat via Non-GMO Nannochloropsis Gaditana: Eicosapentaenoic Acid (EPA, 20:5 n-3), Docosapentaenoic Acid (DPA, 22:5 n-3) and Vitamin D3 for Human Health. Molecules 2020; 25:E4615. [PMID: 33050537 PMCID: PMC7587176 DOI: 10.3390/molecules25204615] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 08/29/2020] [Accepted: 08/31/2020] [Indexed: 02/07/2023] Open
Abstract
Omega-3 long-chain polyunsaturated fatty acids (n-3 LC PUFAs) and vitamin D3 are essential components of human nutrition. A regular human diet is highly deficient in n-3 LC PUFAs. Fish like salmon are highly recommended in the human diet as they are a major source of high-value n-3 LC PUFAs and vitamin D3. The levels of these nutrients have been decreasing over the last few years in farmed salmon, whose production urgently needs sustainable sources of these nutrients. The microalga Nannochloropsis gaditana (NG) is known for its naturally high potential for the production of eicosapentaenoic (EPA, 20:5 n-3) fatty acid. A commercial diet for Atlantic salmon was supplemented with 1% and 10% of spray-dried NG grown under controlled conditions for a high EPA content. Salmon were harvested on day 49, following which, boneless and skinless salmon meat was recovered from fish and analyzed for the fatty acid profile, total fat, and vitamin D3. Vitamin D3, EPA, and docosapentaenoic fatty acid (DPA, 22:5 n-3) levels were significantly increased (p < 0.05) by supplementing the basal diet with 10% NG, thus, NG represents a novel, functional, natural ingredient and a sustainable source of n-3 LC-PUFAs that can raise the levels of healthy fats and vitamin D3 in farmed salmon meat.
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Affiliation(s)
- Ivonne Lozano-Muñoz
- Departamento de Producción Animal, Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago 8820000, Chile; (S.M.); (N.F.D.)
| | - Susana Muñoz
- Departamento de Producción Animal, Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago 8820000, Chile; (S.M.); (N.F.D.)
| | - Nelson F. Díaz
- Departamento de Producción Animal, Facultad de Ciencias Agronómicas, Universidad de Chile, Santiago 8820000, Chile; (S.M.); (N.F.D.)
| | - Alberto Medina
- Departamento de Acuicultura y Recursos Agroalimentarios, Universidad de Los Lagos, Osorno 5290000, Chile;
| | - Jazmín Bazaes
- Centro de Bioinnovación, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta 1240000, Chile; (J.B.); (C.R.)
| | - Carlos Riquelme
- Centro de Bioinnovación, Facultad de Ciencias del Mar y Recursos Biológicos, Universidad de Antofagasta, Antofagasta 1240000, Chile; (J.B.); (C.R.)
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16
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Proteomic and Transcriptomic Patterns during Lipid Remodeling in Nannochloropsis gaditana. Int J Mol Sci 2020; 21:ijms21186946. [PMID: 32971781 PMCID: PMC7554720 DOI: 10.3390/ijms21186946] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/16/2020] [Accepted: 09/17/2020] [Indexed: 12/24/2022] Open
Abstract
Nutrient limited conditions are common in natural phytoplankton communities and are often used to increase the yield of lipids from industrial microalgae cultivations. Here we studied the effects of bioavailable nitrogen (N) and phosphorus (P) deprivation on the proteome and transcriptome of the oleaginous marine microalga Nannochloropsis gaditana. Turbidostat cultures were used to selectively apply either N or P deprivation, controlling for variables including the light intensity. Global (cell-wide) changes in the proteome were measured using Tandem Mass Tag (TMT) and LC-MS/MS, whilst gene transcript expression of the same samples was quantified by Illumina RNA-sequencing. We detected 3423 proteins, where 1543 and 113 proteins showed significant changes in abundance in N and P treatments, respectively. The analysis includes the global correlation between proteomic and transcriptomic data, the regulation of subcellular proteomes in different compartments, gene/protein functional groups, and metabolic pathways. The results show that triacylglycerol (TAG) accumulation under nitrogen deprivation was associated with substantial downregulation of protein synthesis and photosynthetic activity. Oil accumulation was also accompanied by a diverse set of responses including the upregulation of diacylglycerol acyltransferase (DGAT), lipase, and lipid body associated proteins. Deprivation of phosphorus had comparatively fewer, weaker effects, some of which were linked to the remodeling of respiratory metabolism.
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17
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Huang JJ, Huang W, Li J, Li P, Cheung PCK. Potential advancement of ultraviolet-free solar radiation technology in enriching the nutrient composition and biodiesel feedstock production in marine green microalga Platymonas subcordiformis. ACTA ACUST UNITED AC 2020. [DOI: 10.1016/j.biteb.2020.100534] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
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18
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You W, Wei L, Gong Y, Hajjami ME, Xu J, Poetsch A. Integration of proteome and transcriptome refines key molecular processes underlying oil production in Nannochloropsis oceanica. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:109. [PMID: 32565907 PMCID: PMC7302151 DOI: 10.1186/s13068-020-01748-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Accepted: 06/08/2020] [Indexed: 05/03/2023]
Abstract
BACKGROUND Under nitrogen deficiency situation, Nannochloropsis spp. accumulate large amounts of lipids in the form of triacylglycerides (TAG). Mechanisms of this process from the perspective of transcriptome and metabolome have been obtained previously, yet proteome analysis is still sparse which hinders the analysis of dynamic adaption to nitrogen deficiency. Here, proteomes for 3 h, 6 h, 12 h, 24 h, 48 h and 10th day of nitrogen deplete (N-) and replete (N+) conditions were obtained and integrated with previous transcriptome data for N. oceanica. RESULTS Physiological adaptations to N- not apparent from transcriptome data were unveiled: (a) abundance of proteins related to photosynthesis only slightly decreased in the first 48 h, indicating that photosynthesis is still working efficiently, and protein amounts adjust gradually with reduction in chloroplast size. (b) Most proteins related to the TCA cycle were strongly upregulated after 48 h under N-, suggesting that respiration is enhanced after 48 h and that TCA cycle efflux supports the carbon required for lipid synthesis. (c) Proteins related to lipid accumulation via the Kennedy pathway increased their abundance at 48 h, synchronous with the previously reported diversification of fatty acids after 48 h. CONCLUSIONS This study adds a proteome perspective on the major pathways for TAG accumulation in Nannochloropsis spp. Temporal changes of proteome exhibited distinct adaptation phases that are usually delayed relative to transcriptomic responses. Notably, proteome data revealed that photosynthesis and carbon fixation are still ongoing even after 48 h of N-. Moreover, sometimes completely opposite trends in proteome and transcriptome demonstrate the relevance of underexplored post-transcriptional regulation for N- adaptation.
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Affiliation(s)
- Wuxin You
- 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 China
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - 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 China
- University of Chinese Academy of Science, Beijing, China
| | - Yanhai Gong
- 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 China
- University of Chinese Academy of Science, Beijing, China
| | - Mohamed El Hajjami
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
| | - 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 China
- University of Chinese Academy of Science, Beijing, China
| | - Ansgar Poetsch
- Department of Plant Biochemistry, Ruhr University Bochum, Bochum, Germany
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, 266237 China
- College of Marine Life Sciences, Ocean University of China, Qingdao, 266003 China
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19
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Xu J, Li T, Li CL, Zhu SN, Wang ZM, Zeng EY. Lipid accumulation and eicosapentaenoic acid distribution in response to nitrogen limitation in microalga Eustigmatos vischeri JHsu-01 (Eustigmatophyceae). ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101910] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
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20
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Canelli G, Neutsch L, Carpine R, Tevere S, Giuffrida F, Rohfritsch Z, Dionisi F, Bolten CJ, Mathys A. Chlorella vulgaris in a heterotrophic bioprocess: Study of the lipid bioaccessibility and oxidative stability. ALGAL RES 2020. [DOI: 10.1016/j.algal.2019.101754] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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21
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Qiu C, He Y, Huang Z, Li S, Huang J, Wang M, Chen B. Lipid extraction from wet Nannochloropsis biomass via enzyme-assisted three phase partitioning. BIORESOURCE TECHNOLOGY 2019; 284:381-390. [PMID: 30959375 DOI: 10.1016/j.biortech.2019.03.148] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 03/28/2019] [Accepted: 03/29/2019] [Indexed: 06/09/2023]
Abstract
A green and efficient enzyme assisted three phase partitioning (EA-TPP) process was firstly developed to extract microalgal lipids using wet Nannochloropsis sp. biomass. In the pretreatment of microalgal biomass by four hydrolytic enzymes, TPP obtained a higher TFAs lipid extraction efficiency by cellulase compared with the resting enzymes. After optimization by EA-TPP of the wet disrupted Nannochloropsis biomass (3 g), the maximum TFAs extraction yield (90.40%) was attained at 20% ammonium sulphate, 6-7 pH, 1:2 slurry/tert-butanol ratio and 70 °C for 2 h incubation time and two extraction cycles. Moreover, results also revealed that the lipidic species compositions of Nannochloropsis sp. biomass were greatly related with the EA-TPP parameters. In the laboratory scale for wet disrupted microalgae biomass, EA-TPP process achieved 88.70% TFAs extraction yield under the optimized conditions. In all, EA-TPP process could be a promising approach to extract microalgae lipids for food application using wet microalgae biomass.
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Affiliation(s)
- Changyang Qiu
- College of Life Science, Fujian Normal University, Fuzhou 350117, China
| | - Yongjin He
- College of Life Science, Fujian Normal University, Fuzhou 350117, China; Key Laboratory of Feed Biotechnology, The Ministry of Agriculture of the People's Republic of China, Beijing 100081, China
| | - Zicheng Huang
- College of Life Science, Fujian Normal University, Fuzhou 350117, China
| | - Shaofeng Li
- College of Life Science, Fujian Normal University, Fuzhou 350117, China
| | - Jian Huang
- College of Life Science, Fujian Normal University, Fuzhou 350117, China; Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou 350117, China
| | - Mingzi Wang
- College of Life Science, Fujian Normal University, Fuzhou 350117, China; Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou 350117, China
| | - Bilian Chen
- College of Life Science, Fujian Normal University, Fuzhou 350117, China; Engineering Research Center of Industrial Microbiology, Ministry of Education, Fujian Normal University, Fuzhou 350117, China.
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22
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Janssen JH, Wijffels RH, Barbosa MJ. Lipid Production in Nannochloropsis gaditana during Nitrogen Starvation. BIOLOGY 2019; 8:biology8010005. [PMID: 30626148 PMCID: PMC6466408 DOI: 10.3390/biology8010005] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 01/03/2019] [Indexed: 12/19/2022]
Abstract
The microalga Nannochloropsis gaditana is a natural producer of triacylglycerol (TAG) and the omega-3 fatty acid eicosapentaenoic acid (EPA). TAG accumulation is induced by nitrogen starvation. The biomass-specific photon supply rate used had an effect on EPA and TAG accumulation during nitrogen starvation as well as on the localization of EPA accumulation. Clear differences in TAG yield on light were found for different biomass-specific photon supply rates and light regimes during nitrogen starvation. De novo EPA synthesis or the translocation of EPA between lipid fractions might be limiting for EPA accumulation in TAG. Further studies are needed to fully understand EPA accumulation in TAG during nitrogen starvation. To elucidate the function of EPA in TAG nitrogen recovery, experiments are suggested. The overexpression of genes involved in de novo EPA synthesis and translocation is proposed to elucidate the exact metabolic routes involved in these processes during nitrogen starvation. This work addresses future opportunities to increase EPA accumulation.
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Affiliation(s)
- Jorijn H Janssen
- Bioprocess Engineering, AlgaePARC, Wageningen University and Research, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
| | - René H Wijffels
- Bioprocess Engineering, AlgaePARC, Wageningen University and Research, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
- Faculty of Biosciences and Aquaculture, Nord University, N-8049 Bodø, Norway.
| | - Maria J Barbosa
- Bioprocess Engineering, AlgaePARC, Wageningen University and Research, P.O. Box 16, 6700 AA Wageningen, The Netherlands.
- Department of Biology, University of Bergen, P.O. Box 7803, 5006 Bergen, Norway.
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