Effect of Desaturase Gene Overexpression on Fatty Acid Synthesis in Escherichia coli

Abstract

In order to obtain efficient engineered strains for oil production, the desaturase gene from Bacillus subtilis HB1310, an endophytic bacterium isolated from walnut, was expressed in Escherichia coli BL21 (DE3), the single-gene-expression strains BL21(DE3)/pET-de1 and BL21(DE3)/pET-de2 and the co-expression strain BL21(DE3)/pET-de were constructed. The results showed that the desaturase gene was highly expressed in E. coli BL21(DE3), and the desaturase activities of the three engineered strains were higher than that of the wild-type strain after induction for up to 60 h, and they reached their maximum after 24 h, which were enhanced by 1.38, 1.48 and 1.75 times compared with that of the wild-type strain at the same time point, respectively. The overexpression of exogenous desaturase gene led to changes in oil yield and fatty acid components in E. coli. The oil yields of the engineered strains were significantly improved compared with that of the wild-type strain, and reached 0.57, 0.58 and 0.72 g/L after 24 h, respectively. The contents of saturated fatty acids were increased by 72.26%, 66.93% and 123.21%, respectively, and unsaturated fatty acids by 112.18%, 44.18% and 134.30%, respectively in the engineered strains compared with the wild-type strain. This study provides a valuable strain source for the development and application of engineered bacteria for oil production.

Keywords

• desaturase; overexpression; co-expression; escherichia coli; fatty acids