scholarly journals Increasing lipid productivity in Chlamydomonas by engineering lipid catabolism using the CRISPR-Cas9 system

2020 ◽  
Author(s):  
Thu Ha Thi Nguyen ◽  
Seunghye Park ◽  
Jooyeon Jeong ◽  
Ye Sol Shin ◽  
Sang Jun Sim ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Cell Growth ◽  
Lipid Accumulation ◽  
Sustainable Energy ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Energy Sources ◽  
Lipid Catabolism ◽  
Oleaginous Microalgae ◽  
Knockout Mutants

Abstract Background Currently, most of the attention in renewable energy industry is focused on the development of alternative, sustainable energy sources. Microalgae are a promising feedstock for biofuel production in response to the energy crisis. The use of metabolic engineering to improve yields of biofuel-related lipid components in microalgae, without affecting cell growth, is now a promising approach to develop more sustainable energy sources and to make this approach more economically feasible. Results The CRISPR-Cas9 system was successfully applied to generate a target-specific knockout of the ELT gene in Chlamydomonas reinhardtii . The target gene encodes an enzyme involved in lipid catabolism, in which the knockout phenotype impacts fatty acid degradation. As a result, the knockout mutants show up to 28.52% increased total lipid accumulation in comparison with the wild-type strain. This is also accompanied by a shift in the fatty acid composition with an increase of up to 27.2% in the C18:1 proportion. These changes do not significantly impact cell growth. Conclusion This study provides useful insights for the improvement of the oleaginous microalgae strain for biodiesel production. The acquired elt mutants showed improved lipid accumulation and productivity without compromising the growth rate.

scholarly journals Molecular Mechanism of Lipid Accumulation and Metabolism of Oleaginous Chlorococcum sphacosum GD from Soil under Salt Stress

2021 ◽  
Vol 22 (3) ◽  
pp. 1304
Author(s):  
Hang Su ◽  
Jia Feng ◽  
Junping Lv ◽  
Qi Liu ◽  
Fangru Nan ◽  
...  
Keyword(s):  
Salt Stress ◽  
Fatty Acid ◽  
Lipid Content ◽  
Salt Concentration ◽  
Lipid Accumulation ◽  
Transcriptome Sequencing ◽  
High Throughput Sequencing ◽  
Lipid Production ◽  
Biodiesel Production ◽  
Oleaginous Microalgae

The oleaginous microalgae species Chlorococcum sphacosum GD is a promising feedstock for biodiesel production from soil. However, its metabolic mechanism of lipid production remains unclear. In this study, the lipid accumulation and metabolism mechanisms of Chlorococcum sphacosum GD were analyzed under salt stress based on transcriptome sequencing. The biomass and lipid content of the alga strain were determined under different NaCl concentrations, and total RNA from fresh cells were isolated and sequenced by HiSeq 2000 high throughput sequencing technology. As the salt concentration increased in culture medium, the algal lipid content increased but the biomass decreased. Following transcriptome sequencing by assembly and splicing, 24,128 unigenes were annotated, with read lengths mostly distributed in the 200–300 bp interval. Statistically significant differentially expressed unigenes were observed in different experimental groups, with 2051 up-regulated genes and 1835 down-regulated genes. The lipid metabolism pathway analysis showed that, under salt stress, gene-related fatty acid biosynthesis (ACCase, KASII, KAR, HAD, FATA) was significantly up-regulated, but some gene-related fatty acid degradation was significantly down-regulated. The comprehensive results showed that salt concentration can affect the lipid accumulation and metabolism of C. sphacosum GD, and the lipid accumulation is closely related to the fatty acid synthesis pathway.

scholarly journals Lipid accumulation of Chlorella sp. TLD6B from the Taklimakan Desert under salt stress

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11525
Author(s):  
Hong Li ◽  
Jun Tan ◽  
Yun Mu ◽  
Jianfeng Gao
Keyword(s):  
Salt Stress ◽  
Fatty Acid ◽  
Lipid Accumulation ◽  
Large Scale ◽  
Fatty Acid Biosynthesis ◽  
High Salinity ◽  
Raw Material ◽  
Biodiesel Production ◽  
Taklimakan Desert ◽  
Acid Biosynthesis

Chlorella has become an important raw material for biodiesel production in recent years, and Chlorella sp. TLD6B, a species with high lipid concentrations and high salt and drought tolerance, has been cultivated on a large scale. To explore the lipid accumulation of Chlorella sp. TLD6B and its relationship to external NaCl concentrations, we performed physiological measurements and genome-wide gene expression profiling under different levels of salt stress. Chlorella sp. TLD6B was able to tolerate high levels of salt stress (0.8 M NaCl addition). Lipid concentrations initially increased and then decreased as salt stress increased and were highest under the addition of 0.2 M NaCl. Comparative transcriptomic analysis revealed that salt stress enhanced the expression of genes related to sugar metabolism and fatty acid biosynthesis (the ACCases BC and BCCP, KAS II, and GPDHs involved in TAG synthesis), thereby promoting lipid accumulation under the addition of 0.2 M NaCl. However, high salinity inhibited cell growth. Expression of three SADs, whose encoded products function in unsaturated fatty acid biosynthesis, was up-regulated under high salinity (0.8 M NaCl addition). This research clarifies the relationship between salt tolerance and lipid accumulation and promotes the utilization of Chlorella sp. TLD6B.

scholarly journals Biodiesel Production From Lignocellulosic Biomass Using Oleaginous Microbes: Prospects for Integrated Biofuel Production

2021 ◽  
Vol 12 ◽  
Author(s):  
Anjani Devi Chintagunta ◽  
Gaetano Zuccaro ◽  
Mahesh Kumar ◽  
S. P. Jeevan Kumar ◽  
Vijay Kumar Garlapati ◽  
...  
Keyword(s):  
Vegetable Oils ◽  
Circular Economy ◽  
Edible Oils ◽  
Lipid Extraction ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Oleaginous Microalgae ◽  
Waste Oils ◽  
Lignocellulosic Substrates ◽  
Liquid Biofuel

Biodiesel is an eco-friendly, renewable, and potential liquid biofuel mitigating greenhouse gas emissions. Biodiesel has been produced initially from vegetable oils, non-edible oils, and waste oils. However, these feedstocks have several disadvantages such as requirement of land and labor and remain expensive. Similarly, in reference to waste oils, the feedstock content is succinct in supply and unable to meet the demand. Recent studies demonstrated utilization of lignocellulosic substrates for biodiesel production using oleaginous microorganisms. These microbes accumulate higher lipid content under stress conditions, whose lipid composition is similar to vegetable oils. In this paper, feedstocks used for biodiesel production such as vegetable oils, non-edible oils, oleaginous microalgae, fungi, yeast, and bacteria have been illustrated. Thereafter, steps enumerated in biodiesel production from lignocellulosic substrates through pretreatment, saccharification and oleaginous microbe-mediated fermentation, lipid extraction, transesterification, and purification of biodiesel are discussed. Besides, the importance of metabolic engineering in ensuring biofuels and biorefinery and a brief note on integration of liquid biofuels have been included that have significant importance in terms of circular economy aspects.

scholarly journals Catalysts for Biodiesel Production: A Review

2021 ◽  
Vol 33 (9) ◽  
pp. 1985-1999
Author(s):  
K.A.V. Miyuranga ◽  
D. Thilakarathne ◽  
Udara S.P.R. Arachchige ◽  
R.A. Jayasinghe ◽  
N.A. Weerasekara
Keyword(s):  
Energy Demand ◽  
Fossil Fuels ◽  
Reaction Rate ◽  
Fossil Fuel ◽  
Sustainable Energy ◽  
Biodiesel Production ◽  
Energy Sources ◽  
World Population ◽  
Economic Issues ◽  
The World

As the world population and modernization increase, energy demand increases. One of the non-sustainable energy sources is fossil fuels. However, fossil fuel consumption raises various environmental and economic issues. Most of the studies focus on sustainable energy sources, which can replace fossil fuel dependence. Biodiesel is an alternative sustainable fuel for diesel power. Biodiesel can produce through the transesterification process. Since the catalyst plays a significant role in the biodiesel yield during a defined reaction time, the addition of a catalyst can increases the reaction rate. This article is outlined the several catalysts used by multiple researchers over the years to increase biodiesel yields.

scholarly journals BIOFUELS FROM ALGAE AS A DIRECTION FOR THE DEVELOPMENT OF THE «GREEN» ECONOMY: THE CURRENT STATE AND PROSPECTS

2021 ◽  
pp. 21-36
Author(s):  
Hanna SHEVCHUK
Keyword(s):  
Alternative Energy ◽  
Alternative Fuels ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Basic Knowledge ◽  
Energy Sources ◽  
Third Generation ◽  
Current State ◽  
Algae Biofuel ◽  
The Impact

The article describes environmental aspects of the impact of traditional energy sources on the environment. It is substantiated that energy needs and environmental problems lead to the search for alternative renewable fuels. A comparative analysis of the structure of general supply between traditional and alternative energy sources is done. The current state of production and use of traditional fuels and prospects for the production of biofuels in Ukraine are analyzed. The projected structure of the use of traditional and alternative fuels according to the Energy Strategy of Ukraine until 2035 «Safety, energy efficiency, competitiveness» is presented. The classification of biofuels is provided depending on raw materials: first, second and third generation. Unlike biofuels from crops such as sugar cane and corn (first-generation biofuels), as well as animal and vegetable wastes (second-generation), algae-derived fuels (third-generation biofuels) have many benefits. In particular, this is a greater potential for biofuel production compared to previous systems: a variety of possible fuels (biodiesel, bioethanol, biobutanol, biogas and even jet fuel); flexible production technologies. Algae cultivation technologies have been studied: especially cultivation in open reservoirs or in more advanced closed ponds and bioreactors. It is substantiated that algae are most often used for biodiesel production; a comparison of different technologies for its production is made. The foreign experience of algae biofuel production and its usage by various automobile companies and enterprises, as well as the prospects of algae biofuel production in Ukraine are presented. Despite the prospects for the production of the third-generation biofuels, there we think, that the issue of investigation has been not been studied properly by scientists and Ukrainian producers don’t have basic knowledge.

scholarly journals Genome-scale metabolic modelling underscores the potential of Cutaneotrichosporon oleaginosus ATCC 20509 as a cell factory for biofuel production

2020 ◽  
Author(s):  
Nhung TT Pham ◽  
Maarten Reijnders ◽  
Maria Suarez-Diez ◽  
Bart Nijsse ◽  
Jan Springer ◽  
...  
Keyword(s):  
Carbon Source ◽  
Lipid Accumulation ◽  
Crude Glycerol ◽  
Unsaturated Fatty Acids ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Cell Factory ◽  
A Genome ◽  
Wide Range ◽  
Genome Scale

Abstract Background: Cutaneotrichosporon oleaginosus ATCC 20509 is a fast growing oleaginous basidiomycete yeast that is able to grow in a wide range of low-cost carbon sources including crude glycerol, a byproduct of biodiesel production. When glycerol is used as a carbon source, this yeast can accumulate more than 50% lipids (w/w) with high concentrations of mono-unsaturated fatty acids. Results: To increase our understanding of this yeast and to provide a knowledge base for further industrial use, a FAIR re-annotated genome was used to build a genome-scale, constraint-based metabolic model containing 1553 reactions involving 1373 metabolites in 11 compartments. A new description of the biomass synthesis reaction was introduced to account for massive lipid accumulation in conditions with high carbon to nitrogen (C/N) ratio in the media. This condition-specific biomass objective function is shown to better predict conditions with high lipid accumulation using glucose, fructose, sucrose, xylose, ethanol and glycerol as sole carbon source. Conclusion: Contributing to the economic viability of biodiesel as renewable fuel, C. oleaginosus ATCC 20509 can effectively convert crude glycerol waste streams in lipids as a potential bioenergy source. Performance simulations are essential to identify optimal production conditions and to develop and fine tune a cost-effective production process. Our model suggests ATP-citrate lyase as a target for overexpression to further improve lipid production.

scholarly journals Genome-scale metabolic modelling underscores the potential of Cutaneotrichosporon oleaginosus ATCC 20509 as a cell factory for biofuel production

2020 ◽  
Author(s):  
Nhung TT Pham ◽  
Maarten Reijnders ◽  
Maria Suarez-Diez ◽  
Bart Nijsse ◽  
Jan Springer ◽  
...  
Keyword(s):  
Lipid Accumulation ◽  
Crude Glycerol ◽  
Lipid Production ◽  
Biodiesel Production ◽  
Biofuel Production ◽  
Cell Factory ◽  
Atp Citrate Lyase ◽  
A Genome ◽  
Wide Range ◽  
Genome Scale

Abstract Background: Cutaneotrichosporon oleaginosus ATCC 20509 is a fast growing oleaginous basidiomycete yeast that is able to grow in a wide range of low-cost carbon sources including crude glycerol, a byproduct of biodiesel production. When glycerol is used as a carbon source, this yeast can accumulate more than 50% lipids (w/w) with high concentrations of mono-unsaturated fatty acids.Results: To increase our understanding of this yeast and to provide a knowledge base for further industrial use, a FAIR re-annotated genome was used to build a genome-scale, constraint-based metabolic model containing 1553 reactions involving 1373 metabolites in 11 compartments. A new description of the biomass synthesis reaction was introduced to account for massive lipid accumulation in conditions with high carbon to nitrogen (C/N) ratio in the media. This condition-specific biomass objective function is shown to better predict conditions with high lipid accumulation using glucose, fructose, sucrose, xylose, and glycerol as sole carbon source.Conclusion: Contributing to the economic viability of biodiesel as renewable fuel, C. oleaginosus ATCC 20509 can effectively convert crude glycerol waste streams in lipids as a potential bioenergy source. Performance simulations are essential to identify optimal production conditions and to develop and fine tune a cost-effective production process. Our model suggests ATP-citrate lyase as a possible target to further improve lipid production.

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