scholarly journals Effect of nitrogen concentration on growth, lipid production and fatty acid profiles of the marine diatom Phaeodactylum tricornutum

2017 ◽  
Vol 51 (3) ◽  
pp. 190-197 ◽  
Author(s):  
Natthawut Yodsuwan ◽  
Shigeki Sawayama ◽  
Sarote Sirisansaneeyakul
Keyword(s):  
Fatty Acid ◽  
Phaeodactylum Tricornutum ◽  
Nitrogen Concentration ◽  
Lipid Production ◽  
Marine Diatom ◽  
Fatty Acid Profiles

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 Comparing EPA production and fatty acid profiles of three Phaeodactylum tricornutum strains under western Norwegian climate conditions

2018 ◽  
Vol 30 ◽  
pp. 11-22 ◽  
Author(s):  
Pia Steinrücken ◽  
Siv Kristin Prestegard ◽  
Jeroen Hendrik de Vree ◽  
Julia E. Storesund ◽  
Bernadette Pree ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Phaeodactylum Tricornutum ◽  
Fatty Acid Profiles ◽  
Climate Conditions

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 Characterization of a Novel Acyl-ACP Δ9 Desaturase Gene Responsible for Palmitoleic Acid Accumulation in a Diatom Phaeodactylum tricornutum

2020 ◽  
Vol 11 ◽  
Author(s):  
Baoling Liu ◽  
Yan Sun ◽  
Wei Hang ◽  
Xiaodan Wang ◽  
Jinai Xue ◽  
...  
Keyword(s):  
Fatty Acid ◽  
Phaeodactylum Tricornutum ◽  
Palmitoleic Acid ◽  
Acyl Chain ◽  
Marine Diatom ◽  
Dimensional Structure ◽  
Functional Domain ◽  
Dna Encoding ◽  
Practical Applications ◽  
Δ9 Desaturase

Palmitoleic acid (16:1Δ9) possesses a double bond at the seventh carbon atom from methyl end of the acyl chain and belongs to unusual ω-7 monounsaturated fatty acids with broad applications in food, pharmaceuticals, cosmetics, biofuel, and other industries. This high-value fatty acid accumulates up to >40% of total lipid in the marine diatom Phaeodactylum tricornutum. The present study was conducted to determine the key gene responsible for 16:1Δ9 biosynthesis in this unicellular alga. A new full-length cDNA and genomic DNA encoding acyl-ACP Δ9 desaturase (PtAAD) were isolated from P. tricornutum cells. Expression levels of PtAAD gene under normal and stress culture conditions were both positively correlated with 16:1Δ9 accumulation, implying its potential role for fatty acid determination. Functional complementation assay of a yeast mutant strain BY4839 evidenced that PtAAD could restore the synthesis of unsaturated fatty acid, especially generating high levels of 16:1Δ9. Further transient expression of PtAAD gene in Nicotiana benthamiana leaves was accompanied by the accumulation of 16:1Δ9, which was absent from control groups. Three-dimensional structure modeling studies showed that functional domain of PtAAD contained three variant amino acids (F160, A223, and L156), which may narrow the space shape of substrate-binding cavity to ensure the entry of 16:0-ACP. Consistent with this prediction, the mutated version of PtAAD gene (F160L, A223T, and L156M) in N. benthamiana systems failed to accumulate 16:1Δ9, but increased levels of 18:1Δ9. Taken together, PtAAD exhibits a strong enzymatic activity and substrate preference for 16:0-ACP, acting as the key player for high biosynthesis and accumulation of 16:1Δ9 in this alga. These findings provide new insights for better understanding the palmitoleic acid and oil biosynthetic mechanism in P. tricornutum, indicating that PtAAD gene may have practical applications for enriching palmitoleic acid and oil yield in other commercial oleaginous algae and crops.

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