1
|
Sui J, Cui Y, Zhang J, Li S, Zhao Y, Bai M, Feng G, Wu H. Enhanced biomass production and harvesting efficiency of Chlamydomonas reinhardtii under high-ammonium conditions by powdered oyster shell. BIORESOURCE TECHNOLOGY 2024; 403:130904. [PMID: 38801957 DOI: 10.1016/j.biortech.2024.130904] [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: 04/07/2024] [Revised: 05/23/2024] [Accepted: 05/24/2024] [Indexed: 05/29/2024]
Abstract
Chlamydomonas reinhardtii prefers ammonium (NH4+) as a nitrogen source, but its late-stage growth under high-NH4+ concentrations (0.5 ∼ 1 g/L) is retarded due to medium acidification. In this study, oyster shell powders were shown to increase the tolerance of C. reinhardtii to NH4+ supplementation at 0.7 g/L in TAP medium in 1-L bubble-column bioreactors, resulting in a 22.9 % increase in biomass production, 62.1 % rise in unsaturated fatty acid accumulation, and 19.2 % improvement in harvesting efficiency. Powdered oyster shell mitigated medium acidification (pH 7.2-7.8) and provided dissolved inorganic carbon up to 8.02 × 103 μmol/L, facilitating a 76.3 % NH4+ consumption, release of up to 189 mg/L of Ca2+, a 42.1 % reduction in ζ-potential and 27.7 % increase in flocculation activity of microalgae cells. This study highlights a promising approach to utilize powdered oyster shell as a liming agent, supplement carbon source, and bio-flocculant for enhancing biomass production and microalgae harvesting in NH4+-rich environments.
Collapse
Affiliation(s)
- Jikang Sui
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
| | - Yuxuan Cui
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
| | - Jinku Zhang
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
| | - Shiyang Li
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
| | - Yue Zhao
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
| | - Mingkai Bai
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China
| | - Guangxin Feng
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China.
| | - Haohao Wu
- State Key Laboratory of Marine Food Processing & Safety Control, College of Food Science and Engineering, Ocean University of China, 5 Yushan Road, Qingdao, Shandong Province 266003, China.
| |
Collapse
|
2
|
LaPanse AJ, Krishnan A, Dennis G, Karns DAJ, Dahlin LR, Van Wychen S, Burch TA, Guarnieri MT, Weissman JC, Posewitz MC. Proximate biomass characterization of the high productivity marine microalga Picochlorum celeri TG2. PLANT PHYSIOLOGY AND BIOCHEMISTRY : PPB 2024; 207:108364. [PMID: 38232496 DOI: 10.1016/j.plaphy.2024.108364] [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: 09/01/2023] [Revised: 12/23/2023] [Accepted: 01/10/2024] [Indexed: 01/19/2024]
Abstract
Microalgae are compelling renewable resources with applications including biofuels, bioplastics, nutrient supplements, and cosmetic products. Picochlorum celeri is an alga with high industrial interest due to exemplary outdoor areal biomass productivities in seawater. Detailed proximate analysis is needed in multiple environmental conditions to understand the dynamic biomass compositions of P. celeri, and how these compositions might be leveraged in biotechnological applications. In this study, biomass characterization of P. celeri was performed under nutrient-replete, nitrogen-restricted, and hyper-saline conditions. Nutrient-replete cultivation of P. celeri resulted in protein-rich biomass (∼50% ash-free dry weight) with smaller carbohydrate (∼12% ash-free dry weight) and lipid (∼11% ash-free dry weight) partitions. Gradual nitrogen depletion elicited a shift from proteins to carbohydrates (∼50% ash-free dry weight, day 3) as cells transitioned into the production of storage metabolites. Importantly, dilutions in nitrogen-restricted 40 parts per million (1.43 mM nitrogen) media generated high-carbohydrate (∼50% ash-free dry weight) biomass without substantially compromising biomass productivity (36 g ash-free dry weight m-2 day-1) despite decreased chlorophyll (∼2% ash-free dry weight) content. This strategy for increasing carbohydrate content allowed for the targeted production of polysaccharides, which could potentially be utilized to produce fuels, oligosaccharides, and bioplastics. Cultivation at 2X sea salts resulted in a shift towards carbohydrates from protein, with significantly increased levels of the amino acid proline, which putatively acts as an osmolyte. A detailed understanding of the biomass composition of P. celeri in nutrient-replete, nitrogen-restricted, and hyper saline conditions informs how this strain can be useful in the production of biotechnological products.
Collapse
Affiliation(s)
- Alaina J LaPanse
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA.
| | - Anagha Krishnan
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Galen Dennis
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Devin A J Karns
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Lukas R Dahlin
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Stefanie Van Wychen
- Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Tyson A Burch
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Michael T Guarnieri
- Biosciences Center, National Renewable Energy Laboratory, Golden, CO, 80401, USA
| | - Joseph C Weissman
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| | - Matthew C Posewitz
- Department of Chemistry, Colorado School of Mines, Golden, CO, 80401, USA
| |
Collapse
|
3
|
Shitanaka T, Higa L, Bryson AE, Bertucci C, Vande Pol N, Lucker B, Khanal SK, Bonito G, Du ZY. Flocculation of oleaginous green algae with Mortierella alpina fungi. BIORESOURCE TECHNOLOGY 2023; 385:129391. [PMID: 37364649 DOI: 10.1016/j.biortech.2023.129391] [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: 05/08/2023] [Revised: 06/22/2023] [Accepted: 06/23/2023] [Indexed: 06/28/2023]
Abstract
Microalgae are promising sources of valuable bioproducts such as biofuels, food, and nutraceuticals. However, harvesting microalgae is challenging due to their small size and low biomass concentrations. To address this challenge, bio-flocculation of starchless mutants of Chlamydomonas reinhardtii (sta6/sta7) was investigated with Mortierella alpina, an oleaginous fungus with high concentrations of arachidonic acid (ARA). Triacylglycerides (TAG) reached 85 % of total lipids in sta6 and sta7 through a nitrogen regime. Scanning electron microscopy determined cell-wall attachment and extra polymeric substances (EPS) to be responsible for flocculation. An algal-fungal biomass ratio around 1:1 (three membranes) was optimal for bio-flocculation (80-85 % flocculation efficiency in 24 h). Nitrogen-deprived sta6/sta7 were flocculated with strains of M. alpina (NVP17b, NVP47, and NVP153) with aggregates exhibiting fatty acid profiles similar to C. reinhardtii, with ARA (3-10 % of total fatty acids). This study showcases M. alpina as a strong bio-flocculation candidate for microalgae and advances a mechanistic understanding of algal-fungal interaction.
Collapse
Affiliation(s)
- Ty Shitanaka
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Lauren Higa
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Abigail E Bryson
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Conor Bertucci
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Natalie Vande Pol
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States
| | - Ben Lucker
- Trait Biosciences, Los Alamos, NM 87544, United States
| | - Samir Kumar Khanal
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States; Department of Civil and Environmental Engineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States
| | - Gregory Bonito
- Department of Plant, Soil and Microbial Sciences, Michigan State University, East Lansing, MI 48824, United States.
| | - Zhi-Yan Du
- Department of Molecular Biosciences & Bioengineering, University of Hawai'i at Mānoa, Honolulu, HI 96822, United States.
| |
Collapse
|
4
|
Gonzalez DI, Ynalvez RA. Comparison of the effects of nitrogen-, sulfur- and combined nitrogen- and sulfur-deprivations on cell growth, lipid bodies and gene expressions in Chlamydomonas reinhardtii cc5373-sta6. BMC Biotechnol 2023; 23:35. [PMID: 37684579 PMCID: PMC10492388 DOI: 10.1186/s12896-023-00808-3] [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: 11/12/2022] [Accepted: 08/29/2023] [Indexed: 09/10/2023] Open
Abstract
BACKGROUND Biofuel research that aims to optimize growth conditions in microalgae is critically important. Chlamydomonas reinhardtii is a green microalga that offers advantages for biofuel production research. This study compares the effects of nitrogen-, sulfur-, and nitrogen and sulfur- deprivations on the C. reinhardtii starchless mutant cc5373-sta6. Specifically, it compares growth, lipid body accumulation, and expression levels of acetyl-CoA carboxylase (ACC) and phosphoenolpyruvate carboxylase (PEPC). RESULTS Among nutrient-deprived cells, TAP-S cells showed significantly higher total chlorophyll, cell density, and protein content at day 6 (p < 0.05). Confocal analysis showed a significantly higher number of lipid bodies in cells subjected to nutrient deprivation than in the control over the course of six days; N deprivation for six days significantly increased the size of lipid bodies (p < 0.01). In comparison with the control, significantly higher ACC expression was observed after 8 and 24 h of NS deprivation and only after 24 h with N deprivation. On the other hand, ACC and PEPC expression at 8 and 24 h of S deprivation was not significantly different from that in the control. A significantly lower PEPC expression was observed after 8 h of N and NS deprivation (p < 0.01), but a significantly higher PEPC expression was observed after 24 h (p < 0.01). CONCLUSIONS Based on our findings, it would be optimum to cultivate cc5373-sta6 cells in nutrient deprived conditions (-N, -S or -NS) for four days; whereby there is cell growth, and both a high number of lipid bodies and a larger size of lipid bodies produced.
Collapse
Affiliation(s)
- David I Gonzalez
- Department of Biological Science, Vanderbilt University, 465 21st Ave S, Nashville, TN, 37240, USA
| | - Ruby A Ynalvez
- Department of Biology and Chemistry, Texas A&M International University, 5201 University Blvd, Laredo, TX, 78041, USA.
| |
Collapse
|
5
|
Action of 2,6-Dichloro-1,4-benzoquinone on the O2-Evolving Activity of Photosystem II in Chlamydomonas reinhardtii Cells with and without Cell Wall: Inhibitory Effect of Its Oxidized Form. Cells 2023; 12:cells12060907. [PMID: 36980248 PMCID: PMC10046965 DOI: 10.3390/cells12060907] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Revised: 03/01/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
Chlamydomonas reinhardtii is a widely used object in studies on green algae concerning both photosynthesis aspects and possible biotechnological approaches. The measurement of the maximum O2 evolution by photosystem II (PSII) in living algal cells in the presence of artificial acceptors is one of the commonly used methods for determining the photosynthetic apparatus state or its change as compared to a control, parent strain, etc., because PSII is the most sensitive component of the thylakoid membrane. The present study shows the need to use low concentrations of 2,6-dichloro-1,4-benzoquinone (DCBQ) paired with potassium ferricyanide (FeCy) for achieving the maximum O2 evolution rate, while a DCBQ concentration above certain threshold results in strong suppression of O2 evolution. The required DCBQ concentration depends on the presence of the cell wall and should be exactly ~0.1 mM or in the range of 0.2–0.4 mM for cells with and without a cell wall, respectively. The inhibition effect is caused, probably, by a higher content of DCBQ in the oxidized form inside cells; this depends on the presence of the cell wall, which influences the efficiency of DCBQ diffusion into and out of the cell, where it is maintained by FeCy in the oxidized state. The possible mechanism of DCBQ inhibition action is discussed.
Collapse
|
6
|
Yao H, Dahal S, Yang L. Novel context-specific genome-scale modelling explores the potential of triacylglycerol production by Chlamydomonas reinhardtii. Microb Cell Fact 2023; 22:13. [PMID: 36650525 PMCID: PMC9847032 DOI: 10.1186/s12934-022-02004-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Accepted: 12/17/2022] [Indexed: 01/19/2023] Open
Abstract
Gene expression data of cell cultures is commonly measured in biological and medical studies to understand cellular decision-making in various conditions. Metabolism, affected but not solely determined by the expression, is much more difficult to measure experimentally. Finding a reliable method to predict cell metabolism for expression data will greatly benefit metabolic engineering. We have developed a novel pipeline, OVERLAY, that can explore cellular fluxomics from expression data using only a high-quality genome-scale metabolic model. This is done through two main steps: first, construct a protein-constrained metabolic model (PC-model) by integrating protein and enzyme information into the metabolic model (M-model). Secondly, overlay the expression data onto the PC-model using a novel two-step nonconvex and convex optimization formulation, resulting in a context-specific PC-model with optionally calibrated rate constants. The resulting model computes proteomes and intracellular flux states that are consistent with the measured transcriptomes. Therefore, it provides detailed cellular insights that are difficult to glean individually from the omic data or M-model alone. We apply the OVERLAY to interpret triacylglycerol (TAG) overproduction by Chlamydomonas reinhardtii, using time-course RNA-Seq data. We show that OVERLAY can compute C. reinhardtii metabolism under nitrogen deprivation and metabolic shifts after an acetate boost. OVERLAY can also suggest possible 'bottleneck' proteins that need to be overexpressed to increase the TAG accumulation rate, as well as discuss other TAG-overproduction strategies.
Collapse
Affiliation(s)
- Haoyang Yao
- grid.410356.50000 0004 1936 8331Department of Chemical Engineering, Queen’s University, 19 Division St, Kingston, K7L 2N9 Canada
| | - Sanjeev Dahal
- grid.410356.50000 0004 1936 8331Department of Chemical Engineering, Queen’s University, 19 Division St, Kingston, K7L 2N9 Canada
| | - Laurence Yang
- grid.410356.50000 0004 1936 8331Department of Chemical Engineering, Queen’s University, 19 Division St, Kingston, K7L 2N9 Canada
| |
Collapse
|
7
|
Shokravi H, Heidarrezaei M, Shokravi Z, Ong HC, Lau WJ, Din MFM, Ismail AF. Fourth generation biofuel from genetically modified algal biomass for bioeconomic development. J Biotechnol 2022; 360:23-36. [PMID: 36272575 DOI: 10.1016/j.jbiotec.2022.10.010] [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: 07/11/2021] [Revised: 09/03/2022] [Accepted: 10/17/2022] [Indexed: 12/12/2022]
Abstract
Biofuels from microalgae have promising potential for a sustainable bioeconomy. Algal strains' oil content and biomass yield are the most influential cost drivers in the fourth generation biofuel (FGB) production. Genetic modification is the key to improving oil accumulation and biomass yield, consequently developing the bioeconomy. This paper discusses current practices, new insights, and emerging trends in genetic modification and their bioeconomic impact on FGB production. It was demonstrated that enhancing the oil and biomass yield could significantly improve the probability of economic success and the net present value of the FGB production process. The techno-economic and socioeconomic burden of using genetically modified (GM) strains and the preventive control strategies on the bioeconomy of FGB production is reviewed. It is shown that the fully lined open raceway pond could cost up to 25% more than unlined ponds. The cost of a plastic hoop air-supported greenhouse covering cultivation ponds is estimated to be US 60,000$ /ha. The competitiveness and profitability of large-scale cultivation of GM biomass are significantly locked to techno-economic and socioeconomic drivers. Nonetheless, it necessitates further research and careful long-term follow-up studies to understand the mechanism that affects these parameters the most.
Collapse
Affiliation(s)
- Hoofar Shokravi
- Faculty of Civil Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
| | - Mahshid Heidarrezaei
- Faculty of Chemical & Energy Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia; Institute of Bioproduct Development (IBD), Universiti Teknologi Malaysia, Johor Bahru 81310, Malaysia
| | - Zahra Shokravi
- Department of Microbiology, Faculty of Basic Science, Islamic Azad University, Science and Research Branch of Tehran, Markazi, 1477893855, Iran
| | - Hwai Chyuan Ong
- Future Technology Research Center, National Yunlin University of Science and Technology, 123 University Road, Section 3, Douliou, Yunlin 64002, Taiwan.
| | - Woei Jye Lau
- Faculty of Chemical & Energy Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia; Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| | - Mohd Fadhil Md Din
- Centre for Environmental Sustainability and Water Security (IPASA), School of Civil Engineering, Faculty of Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia
| | - Ahmad Fauzi Ismail
- Faculty of Chemical & Energy Engineering, Universiti Teknologi Malaysia, 81310 Johor Bahru, Johor, Malaysia; Advanced Membrane Technology Research Centre (AMTEC), Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia
| |
Collapse
|
8
|
Li X, Lan C, Li X, Hu Z, Jia B. A review on design-build-test-learn cycle to potentiate progress in isoprenoid engineering of photosynthetic microalgae. BIORESOURCE TECHNOLOGY 2022; 363:127981. [PMID: 36130687 DOI: 10.1016/j.biortech.2022.127981] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2022] [Revised: 09/10/2022] [Accepted: 09/12/2022] [Indexed: 06/15/2023]
Abstract
Currently, the generation of isoprenoid factories in microalgae relies on two strategies: 1) enhanced production of endogenous isoprenoids; or 2) production of heterologous terpenes by metabolic engineering. Nevertheless, low titers and productivity are still a feature of isoprenoid biotechnology and need to be addressed. In this context, the mechanisms underlying isoprenoid biosynthesis in microalgae and its relationship with central carbon metabolism are reviewed. Developments in microalgal biotechnology are discussed, and a new approach of integrated "design-build-test-learn" cycle is advocated to the trends, challenges and prospects involved in isoprenoid engineering. The emerging and promising strategies and tools are discussed for microalgal engineering in the future. This review encourages a systematic engineering perspective aimed at potentiating progress in isoprenoid engineering of photosynthetic microalgae.
Collapse
Affiliation(s)
- Xiangyu Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China; College of Physics and Optoelectronic Engineering, Shenzhen University, Shenzhen 518060, China
| | - Chengxiang Lan
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Xinyi Li
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Zhangli Hu
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China
| | - Bin Jia
- Guangdong Technology Research Center for Marine Algal Bioengineering, Guangdong Provincial Key Laboratory for Plant Epigenetics, Shenzhen Engineering Laboratory for Marine Algal Biotechnology, Longhua Innovation Institute for Biotechnology, College of Life Sciences and Oceanography, Shenzhen University, Shenzhen 518060, China.
| |
Collapse
|
9
|
Microalgae-Based PUFAs for Food and Feed: Current Applications, Future Possibilities, and Constraints. JOURNAL OF MARINE SCIENCE AND ENGINEERING 2022. [DOI: 10.3390/jmse10070844] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Microalgae are currently considered an attractive source of highly valuable compounds for human and animal consumption, including polyunsaturated fatty acids (PUFAs). Several microalgae-derived compounds, such as ω-3 fatty acids, pigments, and whole dried biomasses are available on the market and are mainly produced by culturing microalgae in open ponds, which can be achieved with low setup and maintenance costs with respect to enclosed systems. However, open tanks are more susceptible to bacterial and other environmental contamination, do not guarantee a high reproducibility of algal biochemical profiles and productivities, and constrain massive cultivation to a limited number of species. Genetic engineering techniques have substantially improved over the last decade, and several model microalgae have been successfully modified to promote the accumulation of specific value-added compounds. However, transgenic strains should be cultured in closed photobioreactors (PBRs) to minimize risks of contamination of aquatic environments with allochthonous species; in addition, faster growth rates and higher yields of compounds of interest can be achieved in PBRs compared to open ponds. In this review, we present information collected about the major microalgae-derived commodities (with a special focus on PUFAs) produced at industrial scale, as well genetically-engineered microalgae to increase PUFA production. We also critically analyzed the main bottlenecks that make large-scale production of algal commodities difficult, as well as possible solutions to overcome the main problems and render the processes economically and environmentally safe.
Collapse
|
10
|
Abstract
Economical production of photosynthetic organisms requires the use of natural day/night cycles. These induce strong circadian rhythms that lead to transient changes in the cells, requiring complex modeling to capture. In this study, we coupled times series transcriptomic data from the model green alga Chlamydomonas reinhardtii to a metabolic model of the same organism in order to develop the first transient metabolic model for diurnal growth of algae capable of predicting phenotype from genotype. We first transformed a set of discrete transcriptomic measurements (D. Strenkert, S. Schmollinger, S. D. Gallaher, P. A. Salomé, et al., Proc Natl Acad Sci U S A 116:2374–2383, 2019, https://doi.org/10.1073/pnas.1815238116) into continuous curves, producing a complete database of the cell’s transcriptome that can be interrogated at any time point. We also decoupled the standard biomass formation equation to allow different components of biomass to be synthesized at different times of the day. The resulting model was able to predict qualitative phenotypical outcomes of a starchless mutant. We also extended this approach to simulate all single-knockout mutants and identified potential targets for rational engineering efforts to increase productivity. This model enables us to evaluate the impact of genetic and environmental changes on the growth, biomass composition, and intracellular fluxes for diurnal growth. IMPORTANCE We have developed the first transient metabolic model for diurnal growth of algae based on experimental data and capable of predicting phenotype from genotype. This model enables us to evaluate the impact of genetic and environmental changes on the growth, biomass composition and intracellular fluxes of the model green alga, Chlamydomonas reinhardtii. The availability of this model will enable faster and more efficient design of cells for production of fuels, chemicals, and pharmaceuticals.
Collapse
|
11
|
Crucial carotenogenic genes elevate hyperaccumulation of both fucoxanthin and β-carotene in Phaeodactylum tricornutum. ALGAL RES 2022. [DOI: 10.1016/j.algal.2022.102691] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
|
12
|
Song I, Kim S, Kim J, Oh H, Jang J, Jeong SJ, Baek K, Shin WS, Sim SJ, Jin E. Macular pigment-enriched oil production from genome-edited microalgae. Microb Cell Fact 2022; 21:27. [PMID: 35183173 PMCID: PMC8858528 DOI: 10.1186/s12934-021-01736-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2021] [Accepted: 12/30/2021] [Indexed: 12/03/2022] Open
Abstract
Background The photosynthetic microorganism Chlamydomonas reinhardtii has been approved as generally recognized as safe (GRAS) recently, this can excessively produce carotenoid pigments and fatty acids. Zeaxanthin epoxidase (ZEP), which converts zeaxanthin to violaxanthin, and ADP-glucose pyrophosphorylase (AGP). These are key regulating genes for the xanthophyll and starch pathways in C. reinhardtii respectively. In this study, to produce macular pigment-enriched microalgal oil, we attempted to edit the AGP gene as an additional knock-out target in the zep mutant as a parental strain. Results Using a sequential CRISPR-Cas9 RNP-mediated knock-out method, we generated double knock-out mutants (dZAs), in which both the ZEP and AGP genes were deleted. In dZA1, lutein (2.93 ± 0.22 mg g−1 DCW: dried cell weight), zeaxanthin (3.12 ± 0.30 mg g−1 DCW), and lipids (450.09 ± 25.48 mg g−1 DCW) were highly accumulated in N-deprivation condition. Optimization of the culture medium and process made it possible to produce pigments and oil via one-step cultivation. This optimization process enabled dZAs to achieve 81% higher oil productivity along with similar macular pigment productivity, than the conventional two-step process. The hexane/isopropanol extraction method was developed for the use of macular pigment-enriched microalgal oil for food. As a result, 196 ± 20.1 mg g−1 DCW of edible microalgal oil containing 8.42 ± 0.92 mg g−1 lutein of oil and 7.69 ± 1.03 mg g−1 zeaxanthin of oil was produced. Conclusion Our research showed that lipids and pigments are simultaneously induced in the dZA strain. Since dZAs are generated by introducing pre-assembled sgRNA and Cas9-protein into cells, antibiotic resistance genes or selective markers are not inserted into the genome of dZA, which is advantageous for applying dZA mutant to food. Therefore, the enriched macular pigment oil extracted from improved strains (dZAs) can be further applied to various food products and nutraceuticals. Supplementary Information The online version contains supplementary material available at 10.1186/s12934-021-01736-7.
Collapse
|
13
|
Latest Expansions in Lipid Enhancement of Microalgae for Biodiesel Production: An Update. ENERGIES 2022. [DOI: 10.3390/en15041550] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Research progress on sustainable and renewable biofuel has gained motion over the years, not just due to the rapid reduction of dwindling fossil fuel supplies but also due to environmental and potential energy security issues as well. Intense interest in microalgae (photosynthetic microbes) as a promising feedstock for third-generation biofuels has grown over recent years. Fuels derived from algae are now considered sustainable biofuels that are promising, renewable, and clean. Therefore, selecting the robust species of microalgae with substantial features for quality biodiesel production is the first step in the way of biofuel production. A contemporary investigation is more focused on several strategies and techniques to achieve higher biomass and triglycerides in microalgae. The improvement in lipid enhancement in microalgae species by genetic manipulation approaches, such as metabolic or genetic alteration, and the use of nanotechnology are the most recent ways of improving the production of biomass and lipids. Hence, the current review collects up-to-date approaches for microalgae lipid increase and biodiesel generation. The strategies for high biomass and high lipid yield are discussed. Additionally, various pretreatment procedures that may aid in lipid harvesting efficiency and improve lipid recovery rate are described.
Collapse
|
14
|
Füßl M, König AC, Eirich J, Hartl M, Kleinknecht L, Bohne AV, Harzen A, Kramer K, Leister D, Nickelsen J, Finkemeier I. Dynamic light- and acetate-dependent regulation of the proteome and lysine acetylome of Chlamydomonas. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2022; 109:261-277. [PMID: 34709689 DOI: 10.1111/tpj.15555] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Revised: 10/19/2021] [Accepted: 10/22/2021] [Indexed: 06/13/2023]
Abstract
The green alga Chlamydomonas reinhardtii is one of the most studied microorganisms in photosynthesis research and for biofuel production. A detailed understanding of the dynamic regulation of its carbon metabolism is therefore crucial for metabolic engineering. Post-translational modifications can act as molecular switches for the control of protein function. Acetylation of the ɛ-amino group of lysine residues is a dynamic modification on proteins across organisms from all kingdoms. Here, we performed mass spectrometry-based profiling of proteome and lysine acetylome dynamics in Chlamydomonas under varying growth conditions. Chlamydomonas liquid cultures were transferred from mixotrophic (light and acetate as carbon source) to heterotrophic (dark and acetate) or photoautotrophic (light only) growth conditions for 30 h before harvest. In total, 5863 protein groups and 1376 lysine acetylation sites were identified with a false discovery rate of <1%. As a major result of this study, our data show that dynamic changes in the abundance of lysine acetylation on various enzymes involved in photosynthesis, fatty acid metabolism, and the glyoxylate cycle are dependent on acetate and light. Exemplary determination of acetylation site stoichiometries revealed particularly high occupancy levels on K175 of the large subunit of RuBisCO and K99 and K340 of peroxisomal citrate synthase under heterotrophic conditions. The lysine acetylation stoichiometries correlated with increased activities of cellular citrate synthase and the known inactivation of the Calvin-Benson cycle under heterotrophic conditions. In conclusion, the newly identified dynamic lysine acetylation sites may be of great value for genetic engineering of metabolic pathways in Chlamydomonas.
Collapse
Affiliation(s)
- Magdalena Füßl
- Plant Proteomics, Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, DE-50829, Germany
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 7, Muenster, DE-48149, Germany
| | - Ann-Christine König
- Plant Proteomics, Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, DE-50829, Germany
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
- Helmholtz Zentrum München, German Research Center for Environmental Health, Research Unit Protein Science, Heidemannstr. 1, Munich, DE-80939, Germany
| | - Jürgen Eirich
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 7, Muenster, DE-48149, Germany
| | - Markus Hartl
- Plant Proteomics, Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, DE-50829, Germany
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
- Mass Spectrometry Facility, Max Perutz Labs, University of Vienna, Vienna Biocenter (VBC), Dr. Bohr-Gasse 7, Vienna, AT-1030, Austria
| | - Laura Kleinknecht
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
| | - Alexandra-Viola Bohne
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
| | - Anne Harzen
- Plant Proteomics, Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, DE-50829, Germany
| | - Katharina Kramer
- Plant Proteomics, Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, DE-50829, Germany
| | - Dario Leister
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
| | - Jörg Nickelsen
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
| | - Iris Finkemeier
- Plant Proteomics, Max Planck Institute for Plant Breeding Research, Carl von Linné Weg 10, Cologne, DE-50829, Germany
- Faculty of Biology, Ludwig-Maximilians-University, Grosshaderner Strasse 2-4, Munich, DE-82152, Germany
- Plant Physiology, Institute of Plant Biology and Biotechnology, University of Muenster, Schlossplatz 7, Muenster, DE-48149, Germany
| |
Collapse
|
15
|
Santin A, Russo MT, Ferrante MI, Balzano S, Orefice I, Sardo A. Highly Valuable Polyunsaturated Fatty Acids from Microalgae: Strategies to Improve Their Yields and Their Potential Exploitation in Aquaculture. Molecules 2021; 26:7697. [PMID: 34946780 PMCID: PMC8707597 DOI: 10.3390/molecules26247697] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 12/14/2021] [Accepted: 12/15/2021] [Indexed: 11/16/2022] Open
Abstract
Microalgae have a great potential for the production of healthy food and feed supplements. Their ability to convert carbon into high-value compounds and to be cultured in large scale without interfering with crop cultivation makes these photosynthetic microorganisms promising for the sustainable production of lipids. In particular, microalgae represent an alternative source of polyunsaturated fatty acids (PUFAs), whose consumption is related to various health benefits for humans and animals. In recent years, several strategies to improve PUFAs' production in microalgae have been investigated. Such strategies include selecting the best performing species and strains and the optimization of culturing conditions, with special emphasis on the different cultivation systems and the effect of different abiotic factors on PUFAs' accumulation in microalgae. Moreover, developments and results obtained through the most modern genetic and metabolic engineering techniques are described, focusing on the strategies that lead to an increased lipid production or an altered PUFAs' profile. Additionally, we provide an overview of biotechnological applications of PUFAs derived from microalgae as safe and sustainable organisms, such as aquafeed and food ingredients, and of the main techniques (and their related issues) for PUFAs' extraction and purification from microalgal biomass.
Collapse
Affiliation(s)
- Anna Santin
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Monia Teresa Russo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Maria Immacolata Ferrante
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Sergio Balzano
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Department of Marine Microbiology and Biogeochemistry, Netherland Institute for Sea Research, Landsdiep 4, 1793 AB Texel, The Netherlands
| | - Ida Orefice
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
| | - Angela Sardo
- Stazione Zoologica Anton Dohrn, Villa Comunale, 80121 Naples, Italy; (A.S.); (M.T.R.); (S.B.); (I.O.)
- Istituto di Scienze Applicate e Sistemi Intelligenti “Eduardo Caianiello”, Via Campi Flegrei 34, 80078 Pozzuoli, Italy
| |
Collapse
|
16
|
Iwai M, Yamada-Oshima Y, Asami K, Kanamori T, Yuasa H, Shimojima M, Ohta H. Recycling of the major thylakoid lipid MGDG and its role in lipid homeostasis in Chlamydomonas reinhardtii. PLANT PHYSIOLOGY 2021; 187:1341-1356. [PMID: 34618048 PMCID: PMC8566231 DOI: 10.1093/plphys/kiab340] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2021] [Accepted: 06/24/2021] [Indexed: 06/01/2023]
Abstract
Monogalactosyldiacylglycerol (MGDG), the most abundant lipid in thylakoid membranes, is involved in photosynthesis and chloroplast development. MGDG lipase has an important role in lipid remodeling in Chlamydomonas reinhardtii. However, the process related to turnover of the lysogalactolipid that results from MGDG degradation, monogalactosylmonoacylglycerol (MGMG), remains to be clarified. Here we identified a homolog of Arabidopsis thaliana lysophosphatidylcholine acyltransferase (LPCAT) and characterized two independent knockdown (KD) alleles in C. reinhardtii. The enzyme designated as C. reinhardtiiLysolipid Acyltransferase 1 (CrLAT1) has a conserved membrane-bound O-acyl transferase domain. LPCAT from Arabidopsis has a key role in deacylation of phosphatidylcholine (PC). Chlamydomonas reinhardtii, however, lacks PC, and thus we hypothesized that CrLAT1 has some other important function in major lipid flow in this organism. In the CrLAT1 KD mutants, the amount of MGMG was increased, but triacylglycerols (TAGs) were decreased. The proportion of more saturated 18:1 (9) MGDG was lower in the KD mutants than in their parental strain, CC-4533. In contrast, the proportion of MGMG has decreased in the CrLAT1 overexpression (OE) mutants, and the proportion of 18:1 (9) MGDG was higher in the OE mutants than in the empty vector control cells. Thus, CrLAT1 is involved in the recycling of MGDG in the chloroplast and maintains lipid homeostasis in C. reinhardtii.
Collapse
Affiliation(s)
- Masako Iwai
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Yui Yamada-Oshima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Kota Asami
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Takashi Kanamori
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hideya Yuasa
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Mie Shimojima
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| | - Hiroyuki Ohta
- School of Life Science and Technology, Tokyo Institute of Technology, Yokohama 226-8501, Japan
| |
Collapse
|
17
|
CRISPR/Cas9 disruption of glucan synthase in Nannochloropsis gaditana attenuates accumulation of β-1,3-glucose oligomers. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102385] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|
18
|
A critical perspective on the scope of interdisciplinary approaches used in fourth-generation biofuel production. ALGAL RES 2021. [DOI: 10.1016/j.algal.2021.102436] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
|
19
|
Intra-Ramanome Correlation Analysis Unveils Metabolite Conversion Network from an Isogenic Population of Cells. mBio 2021; 12:e0147021. [PMID: 34465024 PMCID: PMC8406334 DOI: 10.1128/mbio.01470-21] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
To reveal the dynamic features of cellular systems, such as the correlation among phenotypes, a time or condition series set of samples is typically required. Here, we propose intra-ramanome correlation analysis (IRCA) to achieve this goal from just one snapshot of an isogenic population, via pairwise correlation among the cells of the thousands of Raman peaks in single-cell Raman spectra (SCRS), i.e., by taking advantage of the intrinsic metabolic heterogeneity among individual cells. For example, IRCA of Chlamydomonas reinhardtii under nitrogen depletion revealed metabolite conversions at each time point plus their temporal dynamics, such as protein-to-starch conversion followed by starch-to-triacylglycerol (TAG) conversion, and conversion of membrane lipids to TAG. Such among-cell correlations in SCRS vanished when the starch-biosynthesis pathway was knocked out yet were fully restored by genetic complementation. Extension of IRCA to 64 microalgal, fungal, and bacterial ramanomes suggests the IRCA-derived metabolite conversion network as an intrinsic metabolic signature of isogenic cellular population that is reliable, species-resolved, and state-sensitive. The high-throughput, low cost, excellent scalability, and general extendibility of IRCA suggest its broad applications.
Collapse
|
20
|
Parkes R, Archer L, Gee DM, Smyth TJ, Gillespie E, Touzet N. Differential responses in EPA and fucoxanthin production by the marine diatom Stauroneis sp. under varying cultivation conditions. Biotechnol Prog 2021; 37:e3197. [PMID: 34337902 DOI: 10.1002/btpr.3197] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2021] [Revised: 07/06/2021] [Accepted: 07/23/2021] [Indexed: 01/03/2023]
Abstract
There has been an increasing drive toward better valorising raw biological materials in the context of the sustainability of bio-based industries and the circular economy. As such, microalgae hold the ability to biosynthesise valuable metabolites, which are sought after within the bioenergy, pharmaceuticals, cosmetics or nutrition sectors. Owing to their bioactivities, the xanthophyll pigment fucoxanthin and the omega-3 polyunsaturated fatty acid eicosapentaenoic acid (EPA) have fostered increasing interests in terms of sustainably refining them from natural sources, such as microalgae. Together with the suitability of individual species to industrial cultivation, a key challenge resides in optimizing the yields of these compounds within the microalgal biomass they are retrieved from. The marine diatom Stauroneis sp. LACW24 was batch cultivated into its stationary phase of growth prior to being subjected at high cell density (1 × 106 cells mL-1 ) to seven different regimes of light exposure in replenished medium and under nutritional limitation (silica and nitrate) for 12 days. The highest EPA proportions and yields were obtained under blue LED in f/2 medium (16.5% and 4.8 mg g-1 , respectively), double the values obtained under red LED illumination. The fucoxanthin yield was the highest when cells were subjected to blue LEDs (5.9 mg g-1 ), a fourfold increase compared to the nitrogen-limited treatment under white LEDs. These results indicate that a two-stage approach to the batch cultivation of this diatom can be used for enhancing the production of the high-value metabolites fucoxanthin and EPA post-stationary phase.
Collapse
Affiliation(s)
- Rachel Parkes
- School of Science, Department of Environmental Science, Centre for Environmental Research, Sustainability and Innovation, Institute of Technology Sligo, Sligo, Ireland
| | - Lorraine Archer
- Algal Innovation Centre, Department of Plant Sciences, University of Cambridge, Cambridge, UK
| | | | - Thomas J Smyth
- School of Science, Department of Health and Nutritional Sciences, Cellular Health and Toxicology Research Group (CHAT), Institute of Technology Sligo, Sligo, Ireland
| | - Eoin Gillespie
- School of Science, Department of Environmental Science, Centre for Environmental Research, Sustainability and Innovation, Institute of Technology Sligo, Sligo, Ireland
| | - Nicolas Touzet
- School of Science, Department of Environmental Science, Centre for Environmental Research, Sustainability and Innovation, Institute of Technology Sligo, Sligo, Ireland
| |
Collapse
|
21
|
Fatty Acid Production and Direct Acyl Transfer through Polar Lipids Control TAG Biosynthesis during Nitrogen Deprivation in the Halotolerant Alga Dunaliella tertiolecta. Mar Drugs 2021; 19:md19070368. [PMID: 34202376 PMCID: PMC8304655 DOI: 10.3390/md19070368] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Revised: 06/10/2021] [Accepted: 06/23/2021] [Indexed: 12/31/2022] Open
Abstract
The aims of this work were to evaluate the contribution of the free fatty acid (FA) pool to triacylglyceride (TAG) biosynthesis and to try to characterize the mechanism by which FA are assimilated into TAG in the green alga Dunaliella tertiolecta. A time-resolved lipidomic analysis showed that nitrogen (N) deprivation induces a redistribution of total lipidome, particularly of free FA and major polar lipid (PL), in parallel to enhanced accumulation of polyunsaturated TAG. The steady-state concentration of the FA pool, measured by prolonged 14C-bicarbonate pre-labeling, showed that N deprivation induced a 50% decrease in total FA level within the first 24 h and up to 85% after 96 h. The abundance of oleic acid increased from 50 to 70% of total free FA while polyunsaturated FA (PUFA) disappeared under N deprivation. The FA flux, measured by the rate of incorporation of 14C-palmitic acid (PlA), suggests partial suppression of phosphatidylcholine (PC) acyl editing and an enhanced turnover of the FA pool and of total digalactosyl-diacylglycerol (DGDG) during N deprivation. Taken together, these results imply that FA biosynthesis is a major rate-controlling stage in TAG biosynthesis in D. tertiolecta and that acyl transfer through PL such as PC and DGDG is the major FA assimilation pathway into TAG in that alga and possibly in other green microalgae. Increasing the availability of FA could lead to enhanced TAG biosynthesis and to improved production of high-value products from microalgae.
Collapse
|
22
|
Chen H, Wang Q. Regulatory mechanisms of lipid biosynthesis in microalgae. Biol Rev Camb Philos Soc 2021; 96:2373-2391. [PMID: 34101323 DOI: 10.1111/brv.12759] [Citation(s) in RCA: 40] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 05/26/2021] [Accepted: 05/27/2021] [Indexed: 02/01/2023]
Abstract
Microalgal lipids are highly promising feedstocks for biofuel production. Microalgal lipids, especially triacylglycerol, and practical applications of these compounds have received increasing attention in recent years. For the commercial use of microalgal lipids to be feasible, many fundamental biological questions must be addressed based on detailed studies of algal biology, including how lipid biosynthesis occurs and is regulated. Here, we review the current understanding of microalgal lipid biosynthesis, with a focus on the underlying regulatory mechanisms. We also present possible solutions for overcoming various obstacles to understanding the basic biology of microalgal lipid biosynthesis and the practical application of microalgae-based lipids. This review will provide a theoretical reference for both algal researchers and decision makers regarding the future directions of microalgal research, particularly pertaining to microalgal-based lipid biosynthesis.
Collapse
Affiliation(s)
- Hui Chen
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| | - Qiang Wang
- State Key Laboratory of Crop Stress Adaptation and Improvement, School of Life Sciences, Henan University, Kaifeng, 475004, China
| |
Collapse
|
23
|
Rawat J, Gupta PK, Pandit S, Prasad R, Pande V. Current perspectives on integrated approaches to enhance lipid accumulation in microalgae. 3 Biotech 2021; 11:303. [PMID: 34194896 DOI: 10.1007/s13205-021-02851-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Accepted: 05/19/2021] [Indexed: 11/30/2022] Open
Abstract
In recent years, research initiatives on renewable bioenergy or biofuels have been gaining momentum, not only due to fast depletion of finite reserves of fossil fuels but also because of the associated concerns for the environment and future energy security. In the last few decades, interest is growing concerning microalgae as the third-generation biofuel feedstock. The CO2 fixation ability and conversion of it into value-added compounds, devoid of challenging food and feed crops, make these photosynthetic microorganisms an optimistic producer of biofuel from an environmental point of view. Microalgal-derived fuels are currently being considered as clean, renewable, and promising sustainable biofuel. Therefore, most research targets to obtain strains with the highest lipid productivity and a high growth rate at the lowest cultivation costs. Different methods and strategies to attain higher biomass and lipid accumulation in microalgae have been extensively reported in the previous research, but there are fewer inclusive reports that summarize the conventional methods with the modern techniques for lipid enhancement and biodiesel production from microalgae. Therefore, the current review focuses on the latest techniques and advances in different cultivation conditions, the effect of different abiotic and heavy metal stress, and the role of nanoparticles (NPs) in the stimulation of lipid accumulation in microalgae. Techniques such as genetic engineering, where particular genes associated with lipid metabolism, are modified to boost lipid synthesis within the microalgae, the contribution of "Omics" in metabolic pathway studies. Further, the contribution of CRISPR/Cas9 system technique to the production of microalgae biofuel is also briefly described.
Collapse
Affiliation(s)
- Jyoti Rawat
- Department of Biotechnology, Sir J. C. Bose Technical Campus Bhimtal, Kumaun University, Nainital, Uttarakhand 263136 India
| | - Piyush Kumar Gupta
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Knowledge Park III, Greater Noida, Uttar Pradesh 201310 India
| | - Soumya Pandit
- Department of Life Sciences, School of Basic Sciences and Research, Sharda University, Knowledge Park III, Greater Noida, Uttar Pradesh 201310 India
| | - Ram Prasad
- Department of Botany, Mahatma Gandhi Central University, Motihari, Bihar 845801 India
| | - Veena Pande
- Department of Biotechnology, Sir J. C. Bose Technical Campus Bhimtal, Kumaun University, Nainital, Uttarakhand 263136 India
| |
Collapse
|
24
|
Enhancing carbohydrate repartitioning into lipid and carotenoid by disruption of microalgae starch debranching enzyme. Commun Biol 2021; 4:450. [PMID: 33837247 PMCID: PMC8035404 DOI: 10.1038/s42003-021-01976-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Accepted: 03/11/2021] [Indexed: 02/01/2023] Open
Abstract
Light/dark cycling is an inherent condition of outdoor microalgae cultivation, but is often unfavorable for lipid accumulation. This study aims to identify promising targets for metabolic engineering of improved lipid accumulation under outdoor conditions. Consequently, the lipid-rich mutant Chlamydomonas sp. KOR1 was developed through light/dark-conditioned screening. During dark periods with depressed CO2 fixation, KOR1 shows rapid carbohydrate degradation together with increased lipid and carotenoid contents. KOR1 was subsequently characterized with extensive mutation of the ISA1 gene encoding a starch debranching enzyme (DBE). Dynamic time-course profiling and metabolomics reveal dramatic changes in KOR1 metabolism throughout light/dark cycles. During light periods, increased flux from CO2 through glycolytic intermediates is directly observed to accompany enhanced formation of small starch-like particles, which are then efficiently repartitioned in the next dark cycle. This study demonstrates that disruption of DBE can improve biofuel production under light/dark conditions, through accelerated carbohydrate repartitioning into lipid and carotenoid.
Collapse
|
25
|
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.
Collapse
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
| |
Collapse
|
26
|
Morales-Sánchez D, Schulze PSC, Kiron V, Wijffels RH. Temperature-Dependent Lipid Accumulation in the Polar Marine Microalga Chlamydomonas malina RCC2488. FRONTIERS IN PLANT SCIENCE 2020; 11:619064. [PMID: 33424911 PMCID: PMC7785989 DOI: 10.3389/fpls.2020.619064] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2020] [Accepted: 11/30/2020] [Indexed: 05/31/2023]
Abstract
The exploration of cold-adapted microalgae offers a wide range of biotechnological applications that can be used for human, animal, and environmental benefits in colder climates. Previously, when the polar marine microalga Chlamydomonas malina RCC2488 was cultivated under both nitrogen replete and depleted conditions at 8°C, it accumulated lipids and carbohydrates (up to 32 and 49%, respectively), while protein synthesis decreased (up to 15%). We hypothesized that the cultivation temperature had a more significant impact on lipid accumulation than the nitrogen availability in C. malina. Lipid accumulation was tested at three different temperatures, 4, 8, and 15°C, under nitrogen replete and depleted conditions. At 4°C under the nitrogen replete condition C. malina had the maximal biomass productivity (701.6 mg L-1 day-1). At this condition, protein content was higher than lipids and carbohydrates. The lipid fraction was mainly composed of polyunsaturated fatty acids (PUFA) in the polar lipid portion, achieving the highest PUFA productivity (122.5 mg L-1 day-1). At this temperature, under nitrogen deficiency, the accumulation of carbohydrates and neutral lipids was stimulated. At 8 and 15°C, under both nitrogen replete and depleted conditions, the lipid and carbohydrate content were higher than at 4°C, and the nitrogen stress condition did not affect the algal biochemical composition. These results suggest that C. malina is a polar marine microalga with a favorable growth temperature at 4°C and is stressed at temperatures ≥8°C, which directs the metabolism to the synthesis of lipids and carbohydrates. Nevertheless, C. malina RCC2488 is a microalga suitable for PUFA production at low temperatures with biomass productivities comparable with mesophilic strains.
Collapse
Affiliation(s)
- Daniela Morales-Sánchez
- The Norwegian College of Fishery Science, Faculty of Biosciences, Fisheries and Economics, UiT – The Arctic University of Norway, Tromsø, Norway
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Peter S. C. Schulze
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
- Green Colab – Associação Oceano Verde, University of Algarve, Faro, Portugal
| | - Viswanath Kiron
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
| | - Rene H. Wijffels
- Faculty of Biosciences and Aquaculture, Nord University, Bodø, Norway
- Bioprocess Engineering, AlgaePARC, Wageningen University, Wageningen, Netherlands
| |
Collapse
|
27
|
Ganie AH, Pandey R, Kumar MN, Chinnusamy V, Iqbal M, Ahmad A. Metabolite Profiling and Network Analysis Reveal Coordinated Changes in Low-N Tolerant and Low-N Sensitive Maize Genotypes under Nitrogen Deficiency and Restoration Conditions. PLANTS 2020; 9:plants9111459. [PMID: 33137957 PMCID: PMC7716227 DOI: 10.3390/plants9111459] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 10/20/2020] [Accepted: 10/25/2020] [Indexed: 11/16/2022]
Abstract
Nitrogen (N), applied in the form of a nitrogenous fertilizer, is one of the main inputs for agricultural production. Food production is closely associated with the application of N. However, the application of nitrogenous fertilizers to agricultural fields is associated with heavy production of nitrous oxide because agricultural crops can only utilize 30-40% of applied N, leaving behind unused 60-70% N in the environment. The global warming effect of this greenhouse gas is approximately 300 times more than of carbon dioxide. Under the present scenario of climate change, it is critical to maintain the natural balance between food production and environmental sustainability by targeting traits responsible for improving nitrogen-use-efficiency (NUE). Understanding of the molecular mechanisms behind the metabolic alterations due to nitrogen status needs to be addressed. Additionally, mineral nutrient deficiencies and their associated metabolic networks have not yet been studied well. Given this, the alterations in core metabolic pathways of low-N tolerant (LNT) and low-N sensitive (LNS) genotypes of maize under N-deficiency and their efficiency of recovering the changes upon resupplying N were investigated by us, using the GC-MS and LC-MS based metabolomic approach. Significant genotype-specific changes were noted in response to low-N. The N limitation affected the whole plant metabolism, most significantly the precursors of primary metabolic pathways. These precursors may act as important targets for improving the NUE. Limited availability of N reduced the levels of N-containing metabolites, organic acids and amino acids, but soluble sugars increased. Major variations were encountered in LNS, as compared to LNT. This study has revealed potential metabolic targets in response to the N status, which are indeed the prospective targets for crop improvement.
Collapse
Affiliation(s)
| | - Renu Pandey
- Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India; (R.P.); (M.N.K.); (V.C.)
| | - M. Nagaraj Kumar
- Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India; (R.P.); (M.N.K.); (V.C.)
| | - Viswanathan Chinnusamy
- Division of Plant Physiology, Indian Agricultural Research Institute, New Delhi 110012, India; (R.P.); (M.N.K.); (V.C.)
| | - Muhammad Iqbal
- Department of Botany, Jamia Hamdard, New Delhi 110062, India; (A.H.G.); (M.I.)
| | - Altaf Ahmad
- Department of Botany, Faculty of Life Sciences, Aligarh Muslim University, Aligarh 202002, India
- Correspondence: ; Tel.: +00-91-9999886334
| |
Collapse
|
28
|
Azaman SNA, Wong DCJ, Tan SW, Yusoff FM, Nagao N, Yeap SK. De novo transcriptome analysis of Chlorella sorokiniana: effect of glucose assimilation, and moderate light intensity. Sci Rep 2020; 10:17331. [PMID: 33060668 PMCID: PMC7562877 DOI: 10.1038/s41598-020-74410-4] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 10/01/2020] [Indexed: 02/01/2023] Open
Abstract
Chlorella can produce an unusually wide range of metabolites under various nutrient availability, carbon source, and light availability. Glucose, an essential molecule for the growth of microorganisms, also contributes significantly to the metabolism of various metabolic compounds produced by Chlorella. In addition, manipulation of light intensity also induces the formation of secondary metabolites such as pigments, and carotenoids in Chlorella. This study will focus on the effect of glucose addition, and moderate light on the regulation of carotenoid, lipid, starch, and other key metabolic pathways in Chlorella sorokiniana. To gain knowledge about this, we performed transcriptome profiling on C. sorokiniana strain NIES-2168 in response to moderate light stress supplemented with glucose under mixotrophic conditions. A total of 60,982,352 raw paired-end (PE) reads 100 bp in length was obtained from both normal, and mixotrophic samples of C. sorokiniana. After pre-processing, 93.63% high-quality PE reads were obtained, and 18,310 predicted full-length transcripts were assembled. Differential gene expression showed that a total of 937, and 1124 genes were upregulated, and downregulated in mixotrophic samples, respectively. Transcriptome analysis revealed that the mixotrophic condition caused upregulation of genes involved in carotenoids production (specifically lutein biosynthesis), fatty acid biosynthesis, TAG accumulation, and the majority of the carbon fixation pathways. Conversely, starch biosynthesis, sucrose biosynthesis, and isoprenoid biosynthesis were downregulated. Novel insights into the pathways that link the enhanced production of valuable metabolites (such as carotenoids in C. sorokiniana) grown under mixotrophic conditions is presented.
Collapse
Affiliation(s)
- Siti Nor Ani Azaman
- Centre of Foundation Studies for Agricultural Sciences, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- Aquatic Animal Health and Therapeutics Laboratory (AquaHealth), Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Darren C J Wong
- Ecology and Evolution, Research School of Biology, The Australian National University, Canberra, ACT, 2600, Australia
| | - Sheau Wei Tan
- Laboratory of Vaccine and Biomolecules (VacBio), Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Fatimah M Yusoff
- International Institute of Aquaculture and Aquatic Sciences (I-AQUAS), Universiti Putra Malaysia, Port Dickson, Negeri Sembilan, Malaysia
- Department of Aquaculture, Faculty of Agriculture, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
| | - Norio Nagao
- Aquatic Animal Health and Therapeutics Laboratory (AquaHealth), Institute of Bioscience, Universiti Putra Malaysia, Serdang, Selangor, Malaysia
- , 102 Naname-go, Shinkamigoto-cho, Minami Matsuura-Gun, Nagasaki, 857-4214, Japan
| | - Swee Keong Yeap
- China-ASEAN College of Marine Sciences, Xiamen University Malaysia, Sepang, Selangor, Malaysia.
| |
Collapse
|
29
|
Puzanskiy RK, Romanyuk DA, Kirpichnikova AA, Shishova MF. Alteration in the Expression of Genes Encoding Primary Metabolism Enzymes and Plastid Transporters during the Culture Growth of Chlamydomonas reinhardtii. Mol Biol 2020. [DOI: 10.1134/s0026893320040147] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
30
|
Genetic Impairment of Cellulose Biosynthesis Increases Cell Wall Fragility and Improves Lipid Extractability from Oleaginous Alga Nannochloropsis salina. Microorganisms 2020; 8:microorganisms8081195. [PMID: 32781613 PMCID: PMC7464416 DOI: 10.3390/microorganisms8081195] [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: 07/03/2020] [Revised: 07/31/2020] [Accepted: 08/05/2020] [Indexed: 01/03/2023] Open
Abstract
In microalgae, photosynthesis provides energy and sugar phosphates for the biosynthesis of storage and structural carbohydrates, lipids, and nitrogenous proteins. The oleaginous alga Nannochloropsis salina does not preferentially partition photoassimilates among cellulose, chrysolaminarin, and lipids in response to nitrogenous nutrient deprivation. In the present study, we investigated whether genetic impairment of the cellulose synthase gene (CesA) expression would lead to protein accumulation without the accumulation of storage C polymers in N. salina. Three cesA mutants were generated by the CRISPR/Cas9 approach. Cell wall thickness and cellulose content were reduced in the cesA1 mutant, but not in cesA2 or cesA4 cells. CesA1 mutation resulted in a reduction of chrysolaminarin and neutral lipid contents, by 66.3% and 37.1%, respectively, but increased the soluble protein content by 1.8-fold. Further, N. salina cells with a thinned cell wall were susceptible to mechanical stress, resulting in a 1.7-fold enhancement of lipid extractability. Taken together, the previous and current studies strongly suggest the presence of a controlling mechanism that regulates photoassimilate partitioning toward C and N metabolic pathways as well as the cellulose metabolism as a potential target for cost-effective microalgal cell disruption and as a useful protein production platform.
Collapse
|
31
|
Xu F, Pan J. Potassium channel KCN11 is required for maintaining cellular osmolarity during nitrogen starvation to control proper cell physiology and TAG accumulation in Chlamydomonas reinhardtii. BIOTECHNOLOGY FOR BIOFUELS 2020; 13:129. [PMID: 32699552 PMCID: PMC7372795 DOI: 10.1186/s13068-020-01769-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/11/2020] [Indexed: 06/11/2023]
Abstract
BACKGROUND Nitrogen (N) starvation in algae induces a variety of structural and metabolic changes including accumulation of triacylglycerol (TAG). Given the promising prospect of using algae as feedstock for biofuel production, accumulation of TAG upon N starvation becomes an ideal system to study TAG biosynthesis. Under nitrogen-depleted conditions, algae also accumulate compatible solutes such as sugar and certain amino acids, which is expected to elevate osmolarity in the cytoplasm. However, how osmoregulation is maintained and how it impacts on carbon metabolism, especially TAG accumulation under N starvation, are not well understood. RESULTS We show here that potassium channel KCN11 localized in the contractile vacuole (CV) mediates osmoregulation during N starvation and loss of KCN11 profoundly affects cell physiology and TAG biosynthesis. KCN11 level is increased and the CV pulsation is accelerated. Loss of KCN11 induces aberrant CV cycle, inhibition of cell growth, increase of cell size, inhibition of chlorophyll loss and TAG accumulation. These effects are rescued by addition of sucrose to raise osmolarity in the culture medium, indicating that osmoregulation is required for cell adaptation to N starvation. Metabolomic analysis shows reduction of acetyl-CoA and accumulation of glyceraldehyde-3-phosphate in kcn11 mutant relative to the control under N starvation, indicating that defects in acetyl-CoA biosynthesis and some metabolic steps from glyceraldehyde-3-phosphate to TAG contribute to the decreased TAG accumulation due to loss of osmoregulation. CONCLUSIONS This work provides novel insight of osmoregulation during N starvation in the control of cell physiology and metabolism especially TAG accumulation. According to these findings, we propose that osmolarity should be carefully monitored during the industrial production of biodiesel.
Collapse
Affiliation(s)
- Feifei Xu
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Department of Anesthesiology and Perioperative Medicine, Xijing Hospital, The Fourth Military Medical University, Xi’an, Shaanxi China
| | - Junmin Pan
- MOE Key Laboratory of Protein Sciences, School of Life Sciences, Tsinghua University, Beijing, China
- Laboratory for Marine Biology and Biotechnology, Qingdao National Laboratory for Marine Science and Technology, Qingdao, Shandong China
| |
Collapse
|
32
|
Upadhyaya S, Agrawal S, Gorakshakar A, Rao BJ. TOR kinase activity in Chlamydomonas reinhardtii is modulated by cellular metabolic states. FEBS Lett 2020; 594:3122-3141. [PMID: 32677084 DOI: 10.1002/1873-3468.13888] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Revised: 11/28/2019] [Accepted: 11/28/2019] [Indexed: 12/25/2022]
Abstract
Target of rapamycin (TOR) kinase is a sensor and a central integrator of internal and external metabolic cues. However, in algae and in higher plants, the components of TOR kinase signaling are yet to be characterized. Here, we establish an assay system to study TOR kinase activity in Chlamydomonas reinhardtii using the phosphorylation status of its putative downstream target, CrS6K. Using this assay, we probe the modulation of cellular TOR kinase activity under various physiological states such as photoautotrophy, heterotrophy, mixotrophy, and nitrogen (N) starvation. Importantly, we uncover that excess acetate in the medium leads to high cellular reactive oxygen species levels, triggering autophagy and a concomitant drop in TOR kinase activity in a dose-dependent manner, thus leading to a N-starvation-like cellular phenotype, even when nitrogen is present.
Collapse
Affiliation(s)
- Shivani Upadhyaya
- Department of Biological Sciences, Tata Institute of Fundamental Research (TIFR), Mumbai, India
| | - Shreya Agrawal
- Max Planck Institute of Molecular Plant Physiology, Potsdam, Germany
| | - Anmol Gorakshakar
- School of Biosciences and Technology, VIT University, Vellore, India
| | | |
Collapse
|
33
|
Rapid and Positive Effect of Bicarbonate Addition on Growth and Photosynthetic Efficiency of the Green Microalgae Chlorella Sorokiniana (Chlorophyta, Trebouxiophyceae). APPLIED SCIENCES-BASEL 2020. [DOI: 10.3390/app10134515] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Bicarbonate ions are the primary source of inorganic carbon for autotrophic organisms living in aquatic environments. In the present study, we evaluated the short-term (hours) effects of sodium bicarbonate (NaHCO3) addition on the growth and photosynthetic efficiency of the green algae Chlorella sorokiniana (211/8k). Bicarbonate was added to nonaxenic cultures at concentrations of 1, 2, and 3 g L−1 leading to a significant increase in biomass especially at the highest salt concentration (3 g L−1) and also showing a bactericidal and bacteriostatic effect that helped to keep a reduced microbial load in the algal culture. Furthermore, bicarbonate stimulated the increase in cellular content of chlorophyll a, improving the photosynthetic performance of cells. Since microalgae of genus Chlorella spp. show great industrial potential for the production of biofuels, nutraceuticals, cosmetics, health, and dietary supplements and the use of bicarbonate as a source of inorganic carbon led to short-term responses in Chlorella sorokiniana, this method represents a valid alternative not only to the insufflation of carbon dioxide for the intensive cultures but also for the production of potentially bioactive compounds in a short period.
Collapse
|
34
|
Sarkar S, Manna MS, Bhowmick TK, Gayen K. Priority-based multiple products from microalgae: review on techniques and strategies. Crit Rev Biotechnol 2020; 40:590-607. [DOI: 10.1080/07388551.2020.1753649] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Affiliation(s)
- Sambit Sarkar
- Department of Chemical Engineering, National Institute of Technology Agartala, Agartala, India
| | - Mriganka Sekhar Manna
- Department of Chemical Engineering, National Institute of Technology Agartala, Agartala, India
| | - Tridib Kumar Bhowmick
- Department of Bioengineering, National Institute of Technology Agartala, Agartala, India
| | - Kalyan Gayen
- Department of Chemical Engineering, National Institute of Technology Agartala, Agartala, India
| |
Collapse
|
35
|
Chang KS, Kim J, Park H, Hong SJ, Lee CG, Jin E. Enhanced lipid productivity in AGP knockout marine microalga Tetraselmis sp. using a DNA-free CRISPR-Cas9 RNP method. BIORESOURCE TECHNOLOGY 2020; 303:122932. [PMID: 32058903 DOI: 10.1016/j.biortech.2020.122932] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2019] [Revised: 01/28/2020] [Accepted: 01/28/2020] [Indexed: 06/10/2023]
Abstract
A marine green microalga, Tetraselmis sp., has been studied for the production of biomass and lipids in seawater culture. Since carbohydrate and lipid biosynthesis are competitive metabolic pathways, we attempted to increase lipid synthesis in Tetraselmis by inhibiting carbohydrate synthesis. The main regulatory enzyme in the starch synthesis pathway is ADP-glucose pyrophosphorylase (AGP). AGP loss-of-function mutants were developed using the CRISPR-Cas9 ribonucleoprotein (RNP) delivery system. AGP mutants showed a slight decrease in growth. However, the lipid content in two AGP mutants was significantly enhanced by 2.7 and 3.1 fold (21.1% and 24.1% of DCW), respectively, compared to that in the wild type (7.68% of DCW) under nitrogen starvation. This study is an example of metabolic engineering by genetic editing using the CRISPR-Cas9 RNP method in marine green microalgae. Consequently, starchless Tetraselmis mutants might be considered potential producers of lipids in seawater cultures.
Collapse
Affiliation(s)
- Kwang Suk Chang
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Jongrae Kim
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea
| | - Hanwool Park
- Department of Marine Science & Biological Engineering, Marine Bioenergy R&D Consortium, Inha University, Inchon 22212, Republic of Korea
| | - Seong-Joo Hong
- Department of Marine Science & Biological Engineering, Marine Bioenergy R&D Consortium, Inha University, Inchon 22212, Republic of Korea
| | - Choul-Gyun Lee
- Department of Marine Science & Biological Engineering, Marine Bioenergy R&D Consortium, Inha University, Inchon 22212, Republic of Korea
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul 04763, Republic of Korea.
| |
Collapse
|
36
|
Torres-Tiji Y, Fields FJ, Mayfield SP. Microalgae as a future food source. Biotechnol Adv 2020; 41:107536. [PMID: 32194145 DOI: 10.1016/j.biotechadv.2020.107536] [Citation(s) in RCA: 171] [Impact Index Per Article: 42.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2019] [Revised: 02/25/2020] [Accepted: 03/02/2020] [Indexed: 02/08/2023]
Abstract
One of the key challenges that we face in the 21st century is the need to feed an ever-increasing human population with increasingly limited natural resources. Even today it is estimated that roughly 1 out of 9 people in the world are undernourished, of which the most important factor is protein-energy malnutrition. By establishing microalgae as a new food and feed platform, we have the opportunity to increase the supply of these essential products to address global demands in a more efficient and environmentally sustainable way. Many types of algae are nutritionally complete foods, their yields outperform most plant crops, and there is a growing set of tools to develop improved strains of algae. Similar improvements were achieved in traditional crops through thousands of years of breeding and strain selection, whereas with the newest genetic engineering tools and advanced strain selection techniques, similar changes can be implemented in microalgae in just a few years. Here we describe different strategies that could be used to enhance the nutritional content, productivity, and organoleptic traits of algae to help drive development of this new crop. Clearly developing more efficient, sustainable, and nutritious foods and feed would be an enormous benefit for the planet, and algae represents an opportunity to develop a new crop that would complement traditional agriculture, and one that could potential result in a more efficient means to meet the world's food and feed supply.
Collapse
Affiliation(s)
- Yasin Torres-Tiji
- The California Center for Algae Biotechnology, University of California, San Diego, La Jolla, CA, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.
| | - Francis J Fields
- The California Center for Algae Biotechnology, University of California, San Diego, La Jolla, CA, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA
| | - Stephen P Mayfield
- The California Center for Algae Biotechnology, University of California, San Diego, La Jolla, CA, USA; Division of Biological Sciences, University of California, San Diego, La Jolla, CA, USA.
| |
Collapse
|
37
|
Arif M, Bai Y, Usman M, Jalalah M, Harraz FA, Al-Assiri MS, Li X, Salama ES, Zhang C. Highest accumulated microalgal lipids (polar and non-polar) for biodiesel production with advanced wastewater treatment: Role of lipidomics. BIORESOURCE TECHNOLOGY 2020; 298:122299. [PMID: 31706891 DOI: 10.1016/j.biortech.2019.122299] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 10/16/2019] [Accepted: 10/17/2019] [Indexed: 06/10/2023]
Abstract
Microalgal lipids consist of non-polar and polar lipids. Triacyleglyceride (TAG), a non-polar lipid, is convertible to biodiesel, whereas glycolipids and phospholipids are polar and not convertible to biodiesel owing to their high degree of unsaturation (polyunsaturated fatty acids), which makes the production process insufficient and expensive. In this review, microalgal species that contain the highest lipid content (≥40%) in the literature till 2019 are highlighted. The differentiation between non-polar and polar lipids and the limitations in the conversion of polar lipids to biodiesel are reported. The basic and advanced factors contributing to the accumulation of lipids convertible to biodiesel is discussed. Microalgal species including Scenedesmus obliquus, Ourococcus multisporus, Chlamydomonas pitschmannii, Micractinium reisseri, and Botryococcus braunii with high lipid content are potential candidates for biomass/biodiesel production and nutrient removal from wastewater. Application of lipidomics and transcriptomics to manipulate the lipid associated gene acetyl-CoA synthetase in microalgae improves the accumulative lipid content.
Collapse
Affiliation(s)
- Muhammad Arif
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, PR China; Department of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou 730000, Gansu, PR China
| | - Yanrui Bai
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, PR China
| | - Muhammad Usman
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, PR China; Department of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou 730000, Gansu, PR China
| | - Mohammed Jalalah
- Promising Center for Sensors and Electronic Devices (PCSED) Najran University, Najran 11001, Saudi Arabia
| | - Farid A Harraz
- Promising Center for Sensors and Electronic Devices (PCSED) Najran University, Najran 11001, Saudi Arabia; Nanomaterials and Nanotechnology Department, Central Metallurgical Research and Development Institute (CMRDI), P.O. 87 Helwan, Cairo 11421, Egypt
| | - M S Al-Assiri
- Promising Center for Sensors and Electronic Devices (PCSED) Najran University, Najran 11001, Saudi Arabia
| | - Xiangkai Li
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, PR China
| | - El-Sayed Salama
- Department of Occupational and Environmental Health, School of Public Health, Lanzhou University, Lanzhou 730000, Gansu, PR China
| | - Chunjiang Zhang
- School of Life Sciences, Lanzhou University, Lanzhou 730000, Gansu Province, PR China.
| |
Collapse
|
38
|
Cooper RO, Cressler CE. Characterization of key bacterial species in the Daphnia magna microbiota using shotgun metagenomics. Sci Rep 2020; 10:652. [PMID: 31959775 PMCID: PMC6971282 DOI: 10.1038/s41598-019-57367-x] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2019] [Accepted: 12/24/2019] [Indexed: 12/28/2022] Open
Abstract
The keystone zooplankton Daphnia magna has recently been used as a model system for understanding host-microbiota interactions. However, the bacterial species present and functions associated with their genomes are not well understood. In order to understand potential functions of these species, we combined 16S rRNA sequencing and shotgun metagenomics to characterize the whole-organism microbiota of Daphnia magna. We assembled five potentially novel metagenome-assembled genomes (MAGs) of core bacteria in Daphnia magna. Genes involved in host colonization and immune system evasion were detected across the MAGs. Some metabolic pathways were specific to some MAGs, including sulfur oxidation, nitrate reduction, and flagellar assembly. Amino acid exporters were identified in MAGs identified as important for host fitness, and pathways for key vitamin biosynthesis and export were identified across MAGs. In total, our examination of functions in these MAGs shows a diversity of nutrient acquisition and metabolism pathways present that may benefit the host, as well as genomic signatures of host association and immune system evasion.
Collapse
Affiliation(s)
- Reilly O Cooper
- School of Biological Sciences, University of Nebraska, Lincoln, NE, USA.
| | | |
Collapse
|
39
|
Xiang T, Lehnert E, Jinkerson RE, Clowez S, Kim RG, DeNofrio JC, Pringle JR, Grossman AR. Symbiont population control by host-symbiont metabolic interaction in Symbiodiniaceae-cnidarian associations. Nat Commun 2020; 11:108. [PMID: 31913264 PMCID: PMC6949306 DOI: 10.1038/s41467-019-13963-z] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Accepted: 12/11/2019] [Indexed: 01/28/2023] Open
Abstract
In cnidarian-Symbiodiniaceae symbioses, algal endosymbiont population control within the host is needed to sustain a symbiotic relationship. However, the molecular mechanisms that underlie such population control are unclear. Here we show that a cnidarian host uses nitrogen limitation as a primary mechanism to control endosymbiont populations. Nitrogen acquisition and assimilation transcripts become elevated in symbiotic Breviolum minutum algae as they reach high-densities within the sea anemone host Exaiptasia pallida. These same transcripts increase in free-living algae deprived of nitrogen. Symbiotic algae also have an elevated carbon-to-nitrogen ratio and shift metabolism towards scavenging nitrogen from purines relative to free-living algae. Exaiptasia glutamine synthetase and glutamate synthase transcripts concomitantly increase with the algal endosymbiont population, suggesting an increased ability of the host to assimilate ammonium. These results suggest algal growth and replication in hospite is controlled by access to nitrogen, which becomes limiting for the algae as their population within the host increases. The relationship between the coral animal and symbiotic algae is essential to coral health, and researchers are turning to Exaiptasia, a model cnidarian system, to study this relationship mechanistically. Here the authors find that endosymbiotic algae become limited by nitrogen at high population densities and provide the host with high levels of fixed carbon.
Collapse
Affiliation(s)
- Tingting Xiang
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA. .,Department of Biological Sciences, University of North Carolina at Charlotte, Charlotte, NC, 28223, USA.
| | - Erik Lehnert
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Robert E Jinkerson
- Department of Chemical and Environmental Engineering, University of California, Riverside, CA, 92521, USA
| | - Sophie Clowez
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Rick G Kim
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| | - Jan C DeNofrio
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - John R Pringle
- Department of Genetics, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Arthur R Grossman
- Department of Plant Biology, Carnegie Institution for Science, Stanford, CA, 94305, USA
| |
Collapse
|
40
|
Shahid A, Rehman AU, Usman M, Ashraf MUF, Javed MR, Khan AZ, Gill SS, Mehmood MA. Engineering the metabolic pathways of lipid biosynthesis to develop robust microalgal strains for biodiesel production. Biotechnol Appl Biochem 2020; 67:41-51. [DOI: 10.1002/bab.1812] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 09/03/2019] [Indexed: 01/29/2023]
Affiliation(s)
- Ayesha Shahid
- Bioenergy Research CenterDepartment of Bioinformatics and BiotechnologyGovernment College University Faisalabad Faisalabad Pakistan
| | - Abd ur Rehman
- Bioenergy Research CenterDepartment of Bioinformatics and BiotechnologyGovernment College University Faisalabad Faisalabad Pakistan
| | - Muhammad Usman
- Bioenergy Research CenterDepartment of Bioinformatics and BiotechnologyGovernment College University Faisalabad Faisalabad Pakistan
| | - Muhammad Umer Farooq Ashraf
- Bioenergy Research CenterDepartment of Bioinformatics and BiotechnologyGovernment College University Faisalabad Faisalabad Pakistan
| | - Muhammad Rizwan Javed
- Bioenergy Research CenterDepartment of Bioinformatics and BiotechnologyGovernment College University Faisalabad Faisalabad Pakistan
| | - Aqib Zafar Khan
- State Key Laboratory of Microbial MetabolismJoint International Research Laboratory of Metabolic & Developmental Sciences of Ministry of Education, School of Life Science and BiotechnologyShanghai Jiao Tong University Shanghai People's Republic of China
| | - Saba Shahid Gill
- Department of Plant and Environmental SciencesNew Mexico State University Las Cruces NM USA
| | - Muhammad Aamer Mehmood
- Bioenergy Research CenterDepartment of Bioinformatics and BiotechnologyGovernment College University Faisalabad Faisalabad Pakistan
- School of BioengineeringSichuan University of Science & Engineering Zigong People's Republic of China
| |
Collapse
|
41
|
Dixit R, Singh S, Singh A. Effect of nitrogen deficiency on the physiology and biochemical composition of microalga Scenedesmus rotundus-MG910488. J Basic Microbiol 2019; 60:158-172. [PMID: 31692003 DOI: 10.1002/jobm.201900383] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2019] [Revised: 10/12/2019] [Accepted: 10/18/2019] [Indexed: 11/06/2022]
Abstract
The present investigation ascertains the impact of gradient concentrations of sodium nitrate on the physiology and biochemical composition of isolated microalga Scenedesmus rotundus-MG910488. The concentrations of nitrate were selected as 0, 3.5, 7.0, 10.5, 14.0, and 17.6 mM/L in BG11 medium. The lower concentrations of nitrogen were found to be significantly decreasing the cell count and photosynthetic activity in the microalga as well as changing cell morphology. The amount of biomass, its productivity and lipid yield were significantly affected. The highest biomass of 689.15 ± 14.27 mg/L was achieved in the concentration of 17.6 mM/L with the biomass productivity of 38.28 ± 0.78 mg/L. The highest lipid accumulation of 41.46 ± 1.94% dry-cell weight was obtained at a concentration of 3.5 mM/L, whereas the lowest lipid accumulation of 29.22 ± 1.65% at the concentration of 17.6 mM/L sodium nitrate. The fatty acid composition determines the quality of the fuel, so the characterization of fatty acid methyl esters (FAMEs) was performed by GC, and the assessment of methyl esters of fatty acid confirmed the existence of palmitic acid, oleic acid, and linoleic acid, which are essential components suitable for biodiesel production. FTIR confirms the presence of FAME components by estimating the bending and stretching of functional groups.
Collapse
Affiliation(s)
- Rishibha Dixit
- Algal Biotechnology Laboratory, Department of P.G. Studies and Research in Biological Science, Rani Durgavati University, Jabalpur, India
| | - Surendra Singh
- Algal Biotechnology Laboratory, Department of P.G. Studies and Research in Biological Science, Rani Durgavati University, Jabalpur, India
| | - Ajeet Singh
- Discipline of Chemistry, Indian Institute of Technology Indore, Indore, India
| |
Collapse
|
42
|
Park S, Nguyen THT, Jin E. Improving lipid production by strain development in microalgae: Strategies, challenges and perspectives. BIORESOURCE TECHNOLOGY 2019; 292:121953. [PMID: 31405625 DOI: 10.1016/j.biortech.2019.121953] [Citation(s) in RCA: 43] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2019] [Revised: 07/31/2019] [Accepted: 08/01/2019] [Indexed: 05/16/2023]
Abstract
Over the past decade, the number of original articles and reviews presenting microalgae as a promising feedstock for biodiesel has increased tremendously. Many improvements of microalgae have been achieved through selection and strain development for industrial applications. However, the large-scale production of lipids for commercialization is not yet realistic because the production is still much more expensive than that of agricultural products. This review summarizes recent research on the induction of lipid biosynthesis in microalgae and the various strategies of genetic and metabolic engineering for enhancing lipid production. Strain engineering targets are proposed based on these strategies. To address current limitations of strain engineering for lipid production, this review provides insights on recent engineering strategies based on molecular tools and methods, and also discusses further perspectives.
Collapse
Affiliation(s)
- Seunghye Park
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea
| | - Thu Ha Thi Nguyen
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea
| | - EonSeon Jin
- Department of Life Science, Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea.
| |
Collapse
|
43
|
Upadhyaya S, Rao BJ. Reciprocal regulation of photosynthesis and mitochondrial respiration by TOR kinase in Chlamydomonas reinhardtii. PLANT DIRECT 2019; 3:e00184. [PMID: 31832599 PMCID: PMC6854518 DOI: 10.1002/pld3.184] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Revised: 10/21/2019] [Accepted: 10/29/2019] [Indexed: 05/03/2023]
Abstract
While the role of TOR kinase in the chloroplast biogenesis and transcriptional regulation of photosynthesis is well documented in Arabidopsis, the functional relevance of this metabolic sensor kinase in chloroplast-mitochondria cross talk is unknown. Using Chlamydomonas reinhardtii as the model system, we demonstrate the role of TOR kinase in the regulation of chloroplast and mitochondrial functions: We show that TOR kinase inhibition impairs the maintenance of high ETR associated with PSII and low NPQ and inhibits efficient state transitions between PSII and PSI. While compromised photosynthetic functions are observed in TOR kinase inhibited cells, same conditions lead to augmentation in mitochondrial basal respiration rate by twofold and concomitantly a rise in ATP production. Interestingly, such upregulated mitochondrial functions in TOR-inhibited cells are mediated by fragmented mitochondria via upregulating COXIIb and downregulating Hxk1 and AOX1 protein levels. We propose that TOR kinase may act as a sensor that counter-regulates chloroplast versus mitochondrial functions in a normal C. reinhardtii cell.
Collapse
Affiliation(s)
- Shivani Upadhyaya
- Department of Biological SciencesTata Institute of Fundamental Research (TIFR)MumbaiIndia
| | - Basuthkar Jagadeeshwar Rao
- Indian Institute of Science Education and Research (IISER) TirupatiTransit Campus: Sree Rama Engineering CollegeTirupatiIndia
| |
Collapse
|
44
|
Burlacot A, Peltier G, Li-Beisson Y. Subcellular Energetics and Carbon Storage in Chlamydomonas. Cells 2019; 8:E1154. [PMID: 31561610 PMCID: PMC6830334 DOI: 10.3390/cells8101154] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2019] [Revised: 09/19/2019] [Accepted: 09/24/2019] [Indexed: 01/09/2023] Open
Abstract
Microalgae have emerged as a promising platform for production of carbon- and energy- rich molecules, notably starch and oil. Establishing an economically viable algal biotechnology sector requires a holistic understanding of algal photosynthesis, physiology, cell cycle and metabolism. Starch/oil productivity is a combined effect of their cellular content and cell division activities. Cell growth, starch and fatty acid synthesis all require carbon building blocks and a source of energy in the form of ATP and NADPH, but with a different requirement in ATP/NADPH ratio. Thus, several cellular mechanisms have been developed by microalgae to balance ATP and NADPH supply which are essentially produced by photosynthesis. Major energy management mechanisms include ATP production by the chloroplast-based cyclic electron flow and NADPH removal by water-water cycles. Furthermore, energetic coupling between chloroplast and other cellular compartments, mitochondria and peroxisome, is increasingly recognized as an important process involved in the chloroplast redox poise. Emerging literature suggests that alterations of energy management pathways affect not only cell fitness and survival, but also influence biomass content and composition. These emerging discoveries are important steps towards diverting algal photosynthetic energy to useful products for biotechnological applications.
Collapse
Affiliation(s)
- Adrien Burlacot
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| | - Gilles Peltier
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| | - Yonghua Li-Beisson
- Aix Marseille Univ, CEA, CNRS, Institut de Biosciences et Biotechnologies Aix-Marseille, CEA Cadarache CEDEX, 13108 Saint Paul-Lez-Durance, France.
| |
Collapse
|
45
|
Overexpression of malic enzyme isoform 2 in Chlamydomonas reinhardtii PTS42 increases lipid production. ACTA ACUST UNITED AC 2019. [DOI: 10.1016/j.biteb.2019.100239] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
|
46
|
Wu M, Zhang H, Sun W, Li Y, Hu Q, Zhou H, Han D. Metabolic plasticity of the starchless mutant of Chlorella sorokiniana and mechanisms underlying its enhanced lipid production revealed by comparative metabolomics analysis. ALGAL RES 2019. [DOI: 10.1016/j.algal.2019.101587] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
|
47
|
Osorio H, Jara C, Fuenzalida K, Rey-Jurado E, Vásquez M. High-efficiency nuclear transformation of the microalgae Nannochloropsis oceanica using Tn5 Transposome for the generation of altered lipid accumulation phenotypes. BIOTECHNOLOGY FOR BIOFUELS 2019; 12:134. [PMID: 31168324 PMCID: PMC6545213 DOI: 10.1186/s13068-019-1475-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/18/2018] [Accepted: 05/23/2019] [Indexed: 06/09/2023]
Abstract
BACKGROUND One of the major problems in the production of lipids for biotechnological purposes using microalgae is maintaining a high productivity of these molecules without reducing cellular biomass. High production rates are usually obtained by cultivating microalgae under different stress conditions. However, many of these changes usually result in lower biomass productivity. Therefore, the optimization of the culture conditions and genetic modification techniques in these organisms is needed to generate robust new strains for profitable economic use. RESULTS In this work, we describe a new strategy for random mutation of genomic DNA in the microalgae Nannochloropsis oceanica by insertion of a Transposome complex Tn5. This complex contains an antibiotic-resistance cassette commanded by a CMV viral promoter that allows high efficiency of transformation and the generation of mutants. This strategy, complemented with a large-scale identification and selection system for mutants, such as flow cytometry with cell selection, allowed us to obtain clonal cultures of mutants with altered phenotypes in the accumulation of intracellular lipids. The characterization of some of these mutants uncovered new genes that are likely to be involved in the regulation of lipid synthesis, revealing possible cellular responses that influence the intracellular homeostasis of lipids. CONCLUSION The strategies proposed here are easy to implement in different types of microalgae and provide a promising scenario for improving biotechnological applications.
Collapse
Affiliation(s)
- Hector Osorio
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O´Higgins 340, Santiago, Chile
| | - Carol Jara
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O´Higgins 340, Santiago, Chile
| | - Karen Fuenzalida
- Departamento de Fisiología, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O´Higgins 340, Santiago, Chile
| | - Emma Rey-Jurado
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O´Higgins 340, Santiago, Chile
| | - Mónica Vásquez
- Departamento de Genética Molecular y Microbiología, Pontificia Universidad Católica de Chile, Avenida Libertador Bernardo O´Higgins 340, Santiago, Chile
| |
Collapse
|
48
|
Kong F, Yamaoka Y, Ohama T, Lee Y, Li-Beisson Y. Molecular Genetic Tools and Emerging Synthetic Biology Strategies to Increase Cellular Oil Content in Chlamydomonas reinhardtii. PLANT & CELL PHYSIOLOGY 2019; 60:1184-1196. [PMID: 30715500 DOI: 10.1093/pcp/pcz022] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2018] [Accepted: 01/18/2019] [Indexed: 05/26/2023]
Abstract
Microalgae constitute a highly diverse group of eukaryotic and photosynthetic microorganisms that have developed extremely efficient systems for harvesting and transforming solar energy into energy-rich molecules such as lipids. Although microalgae are considered to be one of the most promising platforms for the sustainable production of liquid oil, the oil content of these organisms is naturally low, and algal oil production is currently not economically viable. Chlamydomonas reinhardtii (Chlamydomonas) is an established algal model due to its fast growth, high transformation efficiency, and well-understood physiology and to the availability of detailed genome information and versatile molecular tools for this organism. In this review, we summarize recent advances in the development of genetic manipulation tools for Chlamydomonas, from gene delivery methods to state-of-the-art genome-editing technologies and fluorescent dye-based high-throughput mutant screening approaches. Furthermore, we discuss practical strategies and toolkits that enhance transgene expression, such as choice of expression vector and background strain. We then provide examples of how advanced genetic tools have been used to increase oil content in Chlamydomonas. Collectively, the current literature indicates that microalgal oil content can be increased by overexpressing key enzymes that catalyze lipid biosynthesis, blocking lipid degradation, silencing metabolic pathways that compete with lipid biosynthesis and modulating redox state. The tools and knowledge generated through metabolic engineering studies should pave the way for developing a synthetic biological approach to enhance lipid productivity in microalgae.
Collapse
Affiliation(s)
- Fantao Kong
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian, China
| | - Yasuyo Yamaoka
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
| | - Takeshi Ohama
- School of Environmental Science and Engineering, Kochi University of Technology (KUT), Tosayamada, Kochi, Japan
| | - Youngsook Lee
- Department of Integrative Bioscience & Biotechnology, Pohang University of Science and Technology, Pohang, Korea
- Department of Life Science, Pohang University of Science and Technology, Pohang, Korea
| | - Yonghua Li-Beisson
- Aix-Marseille Univ., CEA, CNRS, BIAM, UMR7265, CEA Cadarache, Saint-Paul-lez Durance F, France
| |
Collapse
|
49
|
|
50
|
Zhang YT, Jiang JY, Shi TQ, Sun XM, Zhao QY, Huang H, Ren LJ. Application of the CRISPR/Cas system for genome editing in microalgae. Appl Microbiol Biotechnol 2019; 103:3239-3248. [PMID: 30877356 DOI: 10.1007/s00253-019-09726-x] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2018] [Revised: 02/25/2019] [Accepted: 02/25/2019] [Indexed: 12/12/2022]
Abstract
Microalgae are arguably the most abundant single-celled eukaryotes and are widely distributed in oceans and freshwater lakes. Moreover, microalgae are widely used in biotechnology to produce bioenergy and high-value products such as polyunsaturated fatty acids (PUFAs), bioactive peptides, proteins, antioxidants and so on. In general, genetic editing techniques were adapted to increase the production of microalgal metabolites. The main genome editing tools available today include zinc finger nucleases (ZFNs), transcriptional activator-like effector nucleases (TALENs), and the clustered regularly interspaced short palindromic repeats (CRISPR)/Cas nuclease system. Due to its high genome editing efficiency, the CRISPR/Cas system is emerging as the most important genome editing method. In this review, we summarized the available literature on the application of CRISPR/Cas in microalgal genetic engineering, including transformation methods, strategies for the expression of Cas9 and sgRNA, the CRISPR/Cas9-mediated gene knock-in/knock-out strategies, and CRISPR interference expression modification strategies.
Collapse
Affiliation(s)
- Yu-Ting Zhang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Jia-Yi Jiang
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Tian-Qiong Shi
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Xiao-Man Sun
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - Quan-Yu Zhao
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
| | - He Huang
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- School of Pharmaceutical Sciences, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China
- State Key Laboratory of Materials-Oriented Chemical Engineering, Nanjing Tech University, No. 5 Xinmofan Road, Nanjing, 210009, People's Republic of China
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, Wenyuan Road, Nanjing, 210023, People's Republic of China
| | - Lu-Jing Ren
- College of Biotechnology and Pharmaceutical Engineering, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China.
- Jiangsu National Synergetic Innovation Center for Advanced Materials (SICAM), No. 30 South Puzhu Road, Nanjing, 211816, People's Republic of China.
| |
Collapse
|