scholarly journals Overexpression of a type 2 diacylglycerol acyltransferase in the marine diatom Phaeodactylum tricornutum enhances lipid production and omega-3 Long Chain Polyunsaturated Fatty Acid content

2020 ◽  
Author(s):  
Richard P. Haslam ◽  
Mary L. Hamilton ◽  
Chloe K. Economou ◽  
Richard Smith ◽  
Kirsty L. Hassall ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Phaeodactylum Tricornutum ◽  
Lipid Production ◽  
Marine Diatom ◽  
Efficient Production ◽  
Omega 3 ◽  
Oleaginous Microalgae ◽  
Epa And Dha ◽  
Long Chain

Abstract Background: Oleaginous microalgae represent a valuable resource for the production of high value molecules. Considering the importance of omega-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health and nutrition the yields of high value eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) require significant improvement to meet demand, however, the current cost of production remains high. A promising approach is to metabolically engineer strains with enhanced levels of triacylglycerols (TAGs) enriched in EPA and DHA. Results: Recently we have engineered the marine diatom Phaeodactylum tricornutum to accumulate enhanced levels of DHA in TAG. To further improve the incorporation of omega-3 LC-PUFAs in TAG we focused our effort on the identification of a type 2 acyl-CoA:diacylglycerol acyltransferase (DGAT) capable of improving lipid production and the incorporation of DHA in TAG. DGAT is a key enzyme in lipid synthesis. Following a diatom based in vivo screen of candidate DGATs, a native P. tricornutum DGAT2B was taken forward for detailed characterisation. Expression of DGAT2B in P. tricornutum was confirmed by qRT-PCR and the transgenic strain grew successfully in comparison to wildtype. PtDGAT2B has broad substrate specificity with preferences for C16 and LC-PUFAs acyl groups. Moreover, the expression of DGAT2B resulted in higher lipid yields and enhanced levels of DHA in TAG. Furthermore, co-expression with a Δ5-elongase showed how iterative metabolic engineering can be used to increase DHA and TAG content, irrespective of nitrogen treatment.Conclusion: This study provides further insight into lipid metabolism in P. tricornutum and suggests a metabolic engineering approach for the efficient production of EPA and DHA in microalgae.

scholarly journals Overexpression of an endogenous type 2 diacylglycerol acyltransferase in the marine diatom Phaeodactylum tricornutum enhances lipid production and omega-3 Long Chain Polyunsaturated Fatty Acid content

2020 ◽  
Author(s):  
Richard P. Haslam ◽  
Mary L. Hamilton ◽  
Chloe K. Economou ◽  
Richard Smith ◽  
Kirsty L. Hassall ◽  
...  
Keyword(s):  
Metabolic Engineering ◽  
Phaeodactylum Tricornutum ◽  
Lipid Production ◽  
Marine Diatom ◽  
Efficient Production ◽  
Omega 3 ◽  
Oleaginous Microalgae ◽  
Epa And Dha ◽  
Long Chain

Abstract Background: Oleaginous microalgae represent a valuable resource for the production of high value molecules. Considering the importance of omega-3 long chain polyunsaturated fatty acids (LC-PUFAs) for human health and nutrition the yields of high value eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) require significant improvement to meet demand, however, the current cost of production remains high. A promising approach is to metabolically engineer strains with enhanced levels of triacylglycerols (TAGs) enriched in EPA and DHA.Results: Recently we have engineered the marine diatom Phaeodactylum tricornutum to accumulate enhanced levels of DHA in TAG. To further improve the incorporation of omega-3 LC-PUFAs in TAG we focused our effort on the identification of a type 2 acyl-CoA:diacylglycerol acyltransferase (DGAT) capable of improving lipid production and the incorporation of DHA in TAG. DGAT is a key enzyme in lipid synthesis. Following a diatom based in vivo screen of candidate DGATs, a native P. tricornutum DGAT2B was taken forward for detailed characterisation. Overexpression of the endogenous P. tricornutum DGAT2B was confirmed by qRT-PCR and the transgenic strain grew successfully in comparison to wildtype. PtDGAT2B has broad substrate specificity with preferences for C16 and LC-PUFAs acyl groups. Moreover, the overexpression of an endogenous DGAT2B resulted in higher lipid yields and enhanced levels of DHA in TAG. Furthermore, a combined overexpression of the endogenous DGAT2B and ectopic expression of a Δ5-elongase showed how iterative metabolic engineering can be used to increase DHA and TAG content, irrespective of nitrogen treatment.Conclusion: This study provides further insight into lipid metabolism in P. tricornutum and suggests a metabolic engineering approach for the efficient production of EPA and DHA in microalgae.

scholarly journals The Dark Side of Microalgae Biotechnology: A Heterotrophic Biorefinery Platform Directed to ω-3 Rich Lipid Production

2019 ◽  
Vol 7 (12) ◽  
pp. 670 ◽  
Author(s):  
Teresa Lopes da Silva ◽  
Patrícia Moniz ◽  
Carla Silva ◽  
Alberto Reis
Keyword(s):  
Low Cost ◽  
Lipid Production ◽  
Arable Land ◽  
Integrated System ◽  
Dark Side ◽  
Omega 3 ◽  
Niche Markets ◽  
Microalgal Biomass ◽  
Oleaginous Microalgae ◽  
Heterotrophic Microalgae

Microbial oils have been considered a renewable feedstock for bioenergy not competing with food crops for arable land, freshwater and biodiverse natural landscapes. Microalgal oils may also have other purposes (niche markets) besides biofuels production such as pharmaceutical, nutraceutical, cosmetic and food industries. The polyunsaturated fatty acids (PUFAs) obtained from oleaginous microalgae show benefits over other PUFAs sources such as fish oils, being odorless, and non-dependent on fish stocks. Heterotrophic microalgae can use low-cost substrates such as organic wastes/residues containing carbon, simultaneously producing PUFAs together with other lipids that can be further converted into bioenergy, for combined heat and power (CHP), or liquid biofuels, to be integrated in the transportation system. This review analyses the different strategies that have been recently used to cultivate and further process heterotrophic microalgae for lipids, with emphasis on omega-3 rich compounds. It also highlights the importance of studying an integrated process approach based on the use of low-cost substrates associated to the microalgal biomass biorefinery, identifying the best sustainability methodology to be applied to the whole integrated system.

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