Exploring the function of acyltransferase and domain replacement in order to change the polyunsaturated fatty acid profile of Schizochytrium sp.

Omega-3 fatty acids have received considerable attention due to their substantial health benefits. The aim of this study was to investigate the roles of acyltransferase (AT) domain and replace it for regulating fatty acid profile in Schizochytrium sp. Herein, Schizochytrium sp. was engineered via gene deletion of AT and replacement of the native AT with its homologue, Shew-AT domain from Shewanella sp. The docosahexaenoic acid (DHA) content in total fatty acids of the AT deficient strain observably decreased from 49.52% to 35.2% and the strain exhibited a low growth rate. Replacement with the Shew-AT gene recovered the cell growth and led to a high DHA content, with 3.7 times more eicosapentaenoic acid (EPA). This study will expand knowledge for synthesis of polyunsaturated fatty acid and facilitate the design of microbes with high yields of omega-3 fatty acids as a source of these valuable compounds for nutritional improvement.