Characterization of a new HUP plus Phaeodactylum tricornutum strain having improved production of eicosapentaenoic acid

BACKGROUND: Eicosapentaenoic acid (EPA, 20:5) is an essential fatty acid of the omega-3 family and its importance for prevention and treatment of several disorders has been documented. Phaeodactylum tricornutum is a prominent candidate as an EPA producer. In several microalgal species the mixotrophic growth allows improvement of cell growth and EPA production, although P. tricornutum does not have glucose transporter proteins, limiting glucose assimilation. In the present study, the growth and EPA production of P. tricornutum UTEX 646 and its transformant T-HUP*(8), in which the glucose transporter hup1 gene was expressed, was evaluated under mixotrophic cultivation using glucose as carbon source. RESULTS: Insertion of the gene hup1 in the T-HUP*(8) strain allowed an increase in the glucose uptake of 4.4-fold compared to the glucose consumption observed in the wild type strain. In T-HUP*(8) the lipid content and productivity were 42% and 63% higher than in the wild type; these differences were reflected in the EPA concentration, which was enhanced up to twofold in cultivation of T-HUP*(8) strain. The improvement observed in lipid and EPA production in the strain T-HUP*(8) can be explained by increases of 2.97-, 5.71-, and 9.44-fold in the relative expression of the genes acc1, me1, and ptd5, respectively. CONCLUSION: Increase in glucose consumption in cultivation of the P. tricornutum T-HUP*(8) strain caused metabolic changes that increased the lipid content and EPA specific concentration, making this strain a good candidate for improved EPA production.(c) 2023 The Authors. Journal of Chemical Technology and Biotechnology published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry (SCI).