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Thepsuthammarat K, Reungsang A, Plangklang P. Microalga Coelastrella sp. Cultivation on Unhydrolyzed Molasses-Based Medium towards the Optimization of Conditions for Growth and Biomass Production under Mixotrophic Cultivation. Molecules 2023; 28:molecules28083603. [PMID: 37110836 PMCID: PMC10145047 DOI: 10.3390/molecules28083603] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 04/18/2023] [Accepted: 04/18/2023] [Indexed: 04/29/2023] Open
Abstract
Improving biomass production with the utilization of low-cost substrate is a crucial approach to overcome the hindrance of high cost in developing large-scale microalgae production. The microalga Coelastrella sp. KKU-P1 was mixotrophically cultivated using unhydrolyzed molasses as a carbon source, with the key environmental conditions being varied in order to maximize biomass production. The batch cultivation in flasks achieved the highest biomass production of 3.81 g/L, under an initial pH 5.0, a substrate to inoculum ratio of 100:3, an initial total sugar concentration of 10 g/L, and a sodium nitrate concentration of 1.5 g/L with continuous light illumination at 23.7 W/m2. The photobioreactor cultivation results indicated that CO2 supplementation did not improve biomass production. An ambient concentration of CO2 was sufficient to promote the mixotrophic growth of the microalga as indicated by the highest biomass production of 4.28 g/L with 33.91% protein, 46.71% carbohydrate, and 15.10% lipid. The results of the biochemical composition analysis suggest that the microalgal biomass obtained is promising as a source of essential amino acids and pigments as well as saturated and monounsaturated fatty acids. This research highlights the potential for bioresource production via microalgal mixotrophic cultivation using untreated molasses as a low-cost raw material.
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Affiliation(s)
- Kamolwan Thepsuthammarat
- Graduate School, Khon Kaen University, Khon Kaen 40002, Thailand
- Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand
| | - Alissara Reungsang
- Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand
- Research Group for Development of Microbial Hydrogen Production Process from Biomass, Khon Kaen University, Khon Kaen 40002, Thailand
- Academy of Science, Royal Society of Thailand, Bangkok 10300, Thailand
| | - Pensri Plangklang
- Department of Biotechnology, Faculty of Technology, Khon Kaen University, Khon Kaen 40002, Thailand
- Research Group for Development of Microbial Hydrogen Production Process from Biomass, Khon Kaen University, Khon Kaen 40002, Thailand
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Liu X, Wei L, Zhang J, Zhu K, Zhang H, Hua G, Cheng H. Effects of sulfate ions on growth and lipid synthesis of Scenedesmus obliquus in synthetic wastewater with various carbon-to-nitrogen ratios altered by different ammonium and nitrate additions. BIORESOURCE TECHNOLOGY 2021; 341:125766. [PMID: 34416659 DOI: 10.1016/j.biortech.2021.125766] [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: 07/22/2021] [Revised: 08/06/2021] [Accepted: 08/10/2021] [Indexed: 06/13/2023]
Abstract
Producing biodiesel from microalgae is a promising strategy to upgrade energy structure. In this study, effects of sulfate (SO42-) on lipid synthesis of Scenedesmus obliquus (S. obliquus) cultivated in synthetic wastewater with different carbon to nitrogen (C/N) ratios regulated by ammonium (NH4+-N) and nitrate (NO3--N), separately, were investigated. The results shown that SO42- could dramatically increase cell growth preferring to NH4+-N supply. And SO42- addition could improve its carbon and nitrogen utilization potential for boosting lipid productivity leading α-linolenic acid (C18:3n3) to occupy a dominant component (38.96%) in NH4+-N group at a C/N ratio of 7.5. Additionally, SO42- could enhance the enrichment and expression of up-regulated genes annotated in key enzymes such as GK, GNPAT, CRLS, plc and DEGS involved in glycerolipid, glycerophospholipid and sphingolipid metabolic pathways, resulting in carbon metabolism enhancement and sulfatide accumulation. This study brings a comprehensive view towards nutritional regulation of lipid synthesis in microalgae.
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Affiliation(s)
- Xiang Liu
- College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China.
| | - Lin Wei
- College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China
| | - Jin Zhang
- School of Civil Engineering, Yantai University, Yantai 264005, China
| | - Kongsong Zhu
- College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China
| | - Heng Zhang
- College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China
| | - Guofen Hua
- College of Agricultural Science and Engineering, Hohai University, Nanjing 210098, China
| | - Haomiao Cheng
- School of Environmental Science and Engineering, Yangzhou University, Yangzhou 225127, China
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3
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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.
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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
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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.
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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
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Chen HH, Xue LL, Liang MH, Jiang JG. Intervention of triethylamine on Dunaliella tertiolecta reveals metabolic insights into triacylglycerol accumulation. ALGAL RES 2020. [DOI: 10.1016/j.algal.2020.101876] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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6
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Comparative performance and emission studies of the CI engine with Nodularia Spumigena microalgae biodiesel versus different vegetable oil derived biodiesel. SN APPLIED SCIENCES 2020. [DOI: 10.1007/s42452-020-2697-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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Suresh A, Pan C, Ng WJ. Sodium azide inhibition of microbial activities and impact on sludge floc destabilization. CHEMOSPHERE 2020; 244:125452. [PMID: 31821925 DOI: 10.1016/j.chemosphere.2019.125452] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/26/2019] [Revised: 11/19/2019] [Accepted: 11/22/2019] [Indexed: 06/10/2023]
Abstract
Absence of sludge deflocculation under prolonged (24 h or longer) conditions with dissolved oxygen (DO) less than 0.5 mg L⁻1 was recently reported. The reduced aerobic microbial activity, was speculated, had been compensated by the activity of other bacterial (i.e. facultative) communities. To assess such a compensation mechanism and to better evaluate impact of overall microbial activity on the flocculation process, SBR sludge samples were inhibited by using sodium azide under various DO conditions. Sludge deflocculated only in the presence of sodium azide, regardless of DO conditions. This was linked to sodium azide's inhibitory effects on the microbes as indicated by the reduced ammonium and DOC removals. Extracellular potassium level in the mixed liquor of azide spiked samples also indicated simultaneous cell lysis. Fluorescence excitation emission matrix (FEEM) analysis of the extracted bound EPS and fluorescence quenching based interaction studies indicated sodium azide had interacted with the EPS components, and especially with the bound EPS proteins. The impact of such interactions on reduced floc stability needs consideration. This study confirmed the importance of overall microbial activity in the biological flocculation process and the role of bacterial communities, other than the aerobes, in mitigating deflocculation under low DO conditions.
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Affiliation(s)
- Akshaykumar Suresh
- Nanyang Environment & Water Research Institute, Interdisciplinary Graduate School, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore
| | - Chaozhi Pan
- Environmental Bio-innovations Group (EBiG), School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Ave, 639798, Singapore
| | - Wun Jern Ng
- Environmental Bio-innovations Group (EBiG), School of Civil and Environmental Engineering, Nanyang Technological University, N1-01a-29, 50 Nanyang Ave, 639798, Singapore.
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8
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Sun XM, Ren LJ, Zhao QY, Zhang LH, Huang H. Application of chemicals for enhancing lipid production in microalgae-a short review. BIORESOURCE TECHNOLOGY 2019; 293:122135. [PMID: 31540787 DOI: 10.1016/j.biortech.2019.122135] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Revised: 09/04/2019] [Accepted: 09/05/2019] [Indexed: 05/05/2023]
Abstract
Microalgae have attracted great attention as a promising sustainable resource for biofuel production. In studies aiming to improve lipid accumulation, many key enzymes involved in lipid biosynthesis were identified and confirmed, but genetic engineering remains a challenge in most species of microalgae. In an alternative approach, various chemical modulators can be used to directly regulate the lipid biosynthesis pathway, with similar effects to gene overexpression and interference approaches, including improving the precursor supply and blocking competing pathways. The produced lipid can be protected from being converted into other metabolites by the chemicals such as lipase inhibitors. In addition, a few chemicals were also demonstrated to greatly influence cell growth and lipid accumulation by indirect regulation of the lipid biosynthesis pathway, such as increasing cell permeability or regulating oxidative stress. Thus, adding chemical modulators can be a useful alternative strategy for improving lipid accumulation in large-scale cultivation of microalgae.
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Affiliation(s)
- Xiao-Man Sun
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, Jiangsu Province, China
| | - Lu-Jing Ren
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
| | - Quan-Yu Zhao
- Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
| | - Li-Hui Zhang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, Jiangsu Province, China.
| | - He Huang
- School of Food Science and Pharmaceutical Engineering, Nanjing Normal University, 2 Xuelin Road, Qixia District, Nanjing, Jiangsu Province, China; Jiangsu National Synergetic Innovation Center for Advanced Materials, State Key Laboratory of Materials-Oriented Chemical Engineering, College of Biotechnology and Pharmaceutical Engineering, School of Pharmacy, Nanjing Tech University, No. 30 South Puzhu Road, Nanjing 211816, China
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9
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Sijil PV, Adki VR, Sarada R, Chauhan VS. Strategies for enhancement of alpha-linolenic acid rich lipids in Desmodesmus sp. without compromising the biomass production. BIORESOURCE TECHNOLOGY 2019; 294:122215. [PMID: 31610489 DOI: 10.1016/j.biortech.2019.122215] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2019] [Revised: 09/26/2019] [Accepted: 09/26/2019] [Indexed: 06/10/2023]
Abstract
The indigenous freshwater microalga Desmodesmus sp. produces ALA rich lipids (about 23%). The phytohormones (DAH and KIN; 0.5 mg L-1) increased the biomass yield and lipid content of microalga by 1.4-1.7 fold. Mixotrophic cultivation (500 mM glucose and 100 mM sodium acetate) enhanced the biomass yield and lipid content by 1.8-2.7 fold. The sodium azide (1.0 mM) led to a 1.5 fold and 1.7 fold enhancement in the lipid content and ALA fraction of total fatty acids, respectively without affecting the biomass yield. The low temperature (5 °C) as the second stage of cultivation enhanced the ALA fraction of total fatty acids by 1.2-1.5 fold for untreated, phytohormone supplemented and mixotrophic cultures, without affecting the biomass yield. These cultivation strategies could, therefore, be used for enhancement of ALA rich lipids in microalgae without compromising the biomass production.
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Affiliation(s)
- P V Sijil
- Plant Cell Biotechnology (PCBT) Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru 570 020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - Vinaya R Adki
- Plant Cell Biotechnology (PCBT) Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru 570 020, India
| | - R Sarada
- Plant Cell Biotechnology (PCBT) Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru 570 020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India
| | - V S Chauhan
- Plant Cell Biotechnology (PCBT) Department, CSIR-Central Food Technological Research Institute (CFTRI), Mysuru 570 020, India; Academy of Scientific and Innovative Research (AcSIR), Ghaziabad 201 002, India.
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Chen HH, Xue LL, Liang MH, Jiang JG. Sodium azide intervention, salinity stress and two-step cultivation of Dunaliella tertiolecta for lipid accumulation. Enzyme Microb Technol 2019; 127:1-5. [PMID: 31088611 DOI: 10.1016/j.enzmictec.2019.04.008] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Revised: 04/02/2019] [Accepted: 04/10/2019] [Indexed: 12/28/2022]
Abstract
A two-step strategy was employed to culture Dunaliella tertiolecta, an oleaginous unicellular green alga, combined by the salt stress and sodium azide intervention, to observe their effects on its lipid accumulation. When the algae cultured at different salt concentrations reached the logarithmic growth phase, sodium azide was added. The results showed that the addition of sodium azide significantly increased the lipid content and had no significant effect on cell biomass. The lipid yield and single cell lipid content under 50 μM sodium azide increased by 10.4% and 21.7%. Under the two-step culture condition, combining of the treatment of 50 μM sodium azide and 2.5 M salt stress, the total lipid productivity and single-cell lipid content were 10% and 70.5% higher than that of the control. It seemed that sodium azide and salinity might have a synergistic effect on the lipid accumulation of D. tertiolecta. It can be concluded that sodium azide is an effective inducer of lipid accumulation in D. tertiolecta, and two-stage cultivation is a feasible way to improve lipid accumulation in microalgae.
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Affiliation(s)
- Hao-Hong Chen
- College of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China
| | - Lu-Lu Xue
- College of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China; Industrial Crops Research Institute, Henan Academy of Agricultural Sciences, Zhengzhou, 45002, China
| | - Ming-Hua Liang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
| | - Jian-Guo Jiang
- College of Food Science and Engineering, South China University of Technology, Guangzhou, 510640, China.
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Effects of triethylamine on the expression patterns of two G3PDHs and lipid accumulation in Dunaliella tertiolecta. Enzyme Microb Technol 2019; 127:17-21. [PMID: 31088612 DOI: 10.1016/j.enzmictec.2019.04.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Revised: 03/20/2019] [Accepted: 04/04/2019] [Indexed: 12/17/2022]
Abstract
Glycerol-3-phosphate (G3P) is the important precursors for triacylglycerol synthesis, while glycerol-3-phosphate dehydrogenase (GPDH) determines the formation of G3P. In this study, two GDPH genes, Dtgdp1 and Dtgdp2 were isolated and identified from Dunaliella tertiolecta. The full-length Dtgdp1 and Dtgdp2 CDS were 2016 bp and 2094 bp, which encoded two putative protein sequences of 671 and 697 amino acids with predicted molecular weights of 73.64 kDa and 76.73 kDa, respectively. DtGDP1 and DtGDP2 both had a close relationship with those of algal and higher plants. DtGDP1 shared two conserved superfamily (A1 and A2) and four signature motifs (I-IV), and the DtGDP2 showed six signature domains (from motif I to VI) and DAO_C conserved family. Our previous work showed that the triethylamine intervention could greatly increase the triacylglycerol content (up to 80%) of D. tertiolecta. This study aims to investigate the effect of triethylamine on GPDH expression. Results showed that, when treated by triethylamine at 100 ppm and 150 ppm, the expression levels of Dtgdp1 and Dtgpd2 were increased to 5.121- and 56.964-fold compared with the control, respectively. Triethylamine seemed to enhance lipid metabolic flow by inducing the expressions of Dtgdp1 and Dtgdp2 to increase the lipid content, which provides a new insight into the desired pathway of lipid synthesis in algae through genetic engineering.
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Two-Stage Cultivation of Dunaliella tertiolecta with Glycerol and Triethylamine for Lipid Accumulation: a Viable Way To Alleviate the Inhibitory Effect of Triethylamine on Biomass. Appl Environ Microbiol 2019; 85:AEM.02614-18. [PMID: 30552184 DOI: 10.1128/aem.02614-18] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 11/29/2018] [Indexed: 11/20/2022] Open
Abstract
Microalgae are promising alternatives for sustainable biodiesel production. Previously, it was found that 100 ppm triethylamine greatly enhanced lipid production and lipid content per cell of Dunaliella tertiolecta by 20% and 80%, respectively. However, triethylamine notably reduced biomass production and pigment contents. In this study, a two-stage cultivation with glycerol and triethylamine was attempted to improve cell biomass and lipid accumulation. At the first stage with 1.0 g/liter glycerol addition, D. tertiolecta cells reached the late log phase in a shorter time due to rapid cell growth, leading to the highest cell biomass (1.296 g/liter) for 16 days. However, the increased glycerol concentrations with glycerol addition decreased the lipid content. At the second-stage cultivation with 100 ppm triethylamine, the highest lipid concentration and lipid weight content were 383.60 mg/liter and 37.7% of dry cell weight (DCW), respectively, in the presence of 1.0 g/liter glycerol, which were 27.36% and 72.51% higher than those of the control group, respectively. Besides, the addition of glycerol alleviated the inhibitory effect of triethylamine on cell morphology, algal growth, and pigment accumulation in D. tertiolecta The results indicated that two-stage cultivation is a viable way to improve lipid yield in microalgae.IMPORTANCE Microalgae are promising alternatives for sustainable biodiesel production. Two-stage cultivation with glycerol and triethylamine enhanced the lipid productivity of Dunaliella tertiolecta, indicating that two-stage cultivation is an efficient strategy for biodiesel production from microalgae. It was found that glycerol significantly enhanced cell biomass of D. tertiolecta, and the presence of glycerol alleviated the inhibitory effect of triethylamine on algal growth. Glycerol, the major byproduct from biodiesel production, was used for the biomass accumulation of D. tertiolecta at the first stage of cultivation. Triethylamine, as a lipid inducer, was used for lipid accumulation at the second stage of cultivation. Two-stage cultivation with glycerol and triethylamine enhanced lipid productivity and alleviated the inhibitory effect of triethylamine on the algal growth of D. tertiolecta, which is an efficient strategy for lipid production from D. tertiolecta.
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Liang MH, Wang L, Wang Q, Zhu J, Jiang JG. High-value bioproducts from microalgae: Strategies and progress. Crit Rev Food Sci Nutr 2018; 59:2423-2441. [PMID: 29676930 DOI: 10.1080/10408398.2018.1455030] [Citation(s) in RCA: 53] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Microalgae have been considered as alternative sustainable resources for high-value bioproducts such as lipids (especially triacylglycerides [TAGs]), polyunsaturated fatty acids (PUFAs), and carotenoids, due to their relatively high photosynthetic efficiency, no arable land requirement, and ease of scale-up. It is of great significance to exploit microalgae for the production of high-value bioproducts. How to improve the content or productivity of specific bioproducts has become one of the most urgent challenges. In this review, we will describe high-value bioproducts from microalgae and their biosynthetic pathways (mainly for lipids, PUFAs, and carotenoids). Recent progress and strategies for the enhanced production of bioproducts from microalgae are also described in detail, and these strategies take advantages of optimized cultivation conditions with abiotic stress, chemical stress (addition of metabolic precursors, phytohormones, chemical inhibitors, and chemicals inducing oxidative stress response), and molecular approaches such as metabolic engineering, transcriptional engineering, and gene disruption strategies (mainly RNAi, antisense RNA, miRNA-based knockdown, and CRISPR/Cas9).
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Affiliation(s)
- Ming-Hua Liang
- a College of Food Science and Engineering, South China University of Technology , Guangzhou , China
| | - Ling Wang
- b School of Biotechnology, Jiangsu University of Science and Technology , Zhenjiang , China
| | - Qiming Wang
- c College of Bioscience and Biotechnology, Hunan Agricultural University , Changsha , China
| | - Jianhua Zhu
- b School of Biotechnology, Jiangsu University of Science and Technology , Zhenjiang , China.,c College of Bioscience and Biotechnology, Hunan Agricultural University , Changsha , China.,d Department of Plant Science and Landscape Architecture, University of Maryland , College Park , Maryland , USA
| | - Jian-Guo Jiang
- a College of Food Science and Engineering, South China University of Technology , Guangzhou , China
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Chen B, Wan C, Mehmood MA, Chang JS, Bai F, Zhao X. Manipulating environmental stresses and stress tolerance of microalgae for enhanced production of lipids and value-added products-A review. BIORESOURCE TECHNOLOGY 2017; 244:1198-1206. [PMID: 28601395 DOI: 10.1016/j.biortech.2017.05.170] [Citation(s) in RCA: 138] [Impact Index Per Article: 19.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Revised: 05/25/2017] [Accepted: 05/26/2017] [Indexed: 05/12/2023]
Abstract
Microalgae have promising potential to produce lipids and a variety of high-value chemicals. Suitable stress conditions such as nitrogen starvation and high salinity could stimulate synthesis and accumulation of lipids and high-value products by microalgae, therefore, various stress-modification strategies were developed to manipulate and optimize cultivation processes to enhance bioproduction efficiency. On the other hand, advancements in omics-based technologies have boosted the research to globally understand microalgal gene regulation under stress conditions, which enable further improvement of production efficiency via genetic engineering. Moreover, integration of multi-omics data, synthetic biology design, and genetic engineering manipulations exhibits a tremendous potential in the betterment of microalgal biorefinery. This review discusses the process manipulation strategies and omics studies on understanding the regulation of metabolite biosynthesis under various stressful conditions, and proposes genetic engineering of microalgae to improve bioproduction via manipulating stress tolerance.
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Affiliation(s)
- Bailing Chen
- State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chun Wan
- School of Life Science and Biotechnology, Dalian University of Technology, Dalian 116024, China
| | - Muhammad Aamer Mehmood
- State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China; Bioenergy Research Centre, Department of Bioinformatics & Biotechnology, Government College University Faisalabad, Faisalabad 38000, Pakistan
| | - Jo-Shu Chang
- Department of Chemical Engineering, National Cheng Kung University, Taiwan; Research Center for Energy Technology and Strategy, National Cheng Kung University, Taiwan
| | - Fengwu Bai
- State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xinqing Zhao
- State Key Laboratory of Microbial Metabolism and School of Life Science and Biotechnology, Shanghai Jiao Tong University, Shanghai 200240, China.
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Burch AR, Franz AK. Combined nitrogen limitation and hydrogen peroxide treatment enhances neutral lipid accumulation in the marine diatom Phaeodactylum tricornutum. BIORESOURCE TECHNOLOGY 2016; 219:559-565. [PMID: 27529521 DOI: 10.1016/j.biortech.2016.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Revised: 08/02/2016] [Accepted: 08/04/2016] [Indexed: 05/03/2023]
Abstract
Exogenous application of dilute hydrogen peroxide (H2O2) increases neutral lipid production in Phaeodactylum tricornutum. Exposing early stationary phase cultures of P. tricornutum to 0.25-2mM H2O2 increases the amount of neutral lipids per biomass (mg/mg) by >100% at 24h post H2O2 treatment as determined upon lipid extraction and analysis using a neutral lipid assay. H2O2 treatment increased the total levels of neutral lipids harvested up to 50%, from 64mg/L to 96mg/L, demonstrating its possible effectiveness as a pre-harvest strategy to enhance the biofuel feedstock potential of P. tricornutum. The effects of H2O2 on biomass are concentration dependent; increasing concentrations of H2O2 reduce the levels of isolated biomass. Analysis of combined stressors demonstrates that H2O2 treatment exhibits synergistic effects to enhance neutral lipid production under nitrogen-depleted, but not phosphorus-depleted conditions, suggesting that the effects of hydrogen peroxide on lipid production are influenced by environmental nitrogen levels.
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Affiliation(s)
- Andrew R Burch
- Department of Chemistry, One Shields Avenue, University of California, Davis, CA 95616, United States; Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, CA 95616, United States
| | - Annaliese K Franz
- Department of Chemistry, One Shields Avenue, University of California, Davis, CA 95616, United States; Biochemistry, Molecular, Cellular and Developmental Biology Graduate Group, University of California, Davis, CA 95616, United States.
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Wu S, Meng Y, Cao X, Xue S. Regulatory mechanisms of oxidative species and phytohormones in marine microalgae Isochrysis zhangjiangensis under nitrogen deficiency. ALGAL RES 2016. [DOI: 10.1016/j.algal.2016.05.025] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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Avidan O, Pick U. Acetyl-CoA synthetase is activated as part of the PDH-bypass in the oleaginous green alga Chlorella desiccata. JOURNAL OF EXPERIMENTAL BOTANY 2015; 66:7287-98. [PMID: 26357883 PMCID: PMC4765794 DOI: 10.1093/jxb/erv424] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
In a recent study, it has been shown that biosynthesis of triacylglycerol (TAG) in the oleaginous green alga Chlorella desiccata is preceded by a large increase in acetyl-coenzyme A (Ac-CoA) levels and by upregulation of plastidic pyruvate dehydrogenase (ptPDH). It was proposed that the capacity to accumulate high TAG critically depends on enhanced production of Ac-CoA. In this study, two alternative Ac-CoA producers-plastidic Ac-CoA synthase (ptACS) and ATP citrate lyase (ACL)-are shown to be upregulated prior to TAG accumulation under nitrogen deprivation in the oleaginous species C. desiccata, but not in the moderate TAG accumulators Dunaliella tertiolecta and Chlamydomonas reinhardtii. Measurements of endogenous acetate production and of radiolabelled acetate incorporation into lipids are consistent with the upregulation of ptACS, but suggest that its contribution to the overall TAG biosynthesis is negligible. Induction of ACS and production of endogenous acetate are correlated with activation of alcohol dehydrogenase, suggesting that the upregulation of ptACS is associated with activation of PDH-bypass in C. desiccata. It is proposed that activation of the PDH-bypass in C. desiccata is needed to enable a high rate of lipid biosynthesis under nitrogen deprivation by controlling the level of pyruvate reaching ptPHD and/or mtPDH. This may be an important parameter for massive TAG accumulation in microalgae.
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Affiliation(s)
- Omri Avidan
- Department of Biological Chemistry, The Weizmann institute of Science, Rehovot 76100, Israel
| | - Uri Pick
- Department of Biological Chemistry, The Weizmann institute of Science, Rehovot 76100, Israel
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