Wu_2021_Bioresour.Technol_341_125873

Poly(3-hydroxybutyrate-co-lactate)[P(3HB-co-LA)], is a biodegradable and biocompatible bioplastic, and the monomeric composition of the copolymer plays an important role in affecting its mechanical properties. Corn stover hydrolysate (CSH), the waste by-product in agriculture, has been considered as an important carbon source for value-added biochemical production. Therefore, the effect of CSH on P(3HB-co-LA) biosynthesis was investigated in this study. Taking CSH as the carbon source, the lactate (LA) fraction in the copolymer reached 7.1 mol% by the engineered stain. The results of shake flask fermentation demonstrated that reducing the activity of electron transport system resulted in a higher LA fraction. Furthermore, we replaced the promoter of the key gene pct(th) with ldhA gene promoter, so that the expression of pct(th) gene could be dynamically modulated as well as the lactic acid content changed. This study suggests that CSH is a promising carbon source for the production of biodegradable P(3HB-co-LA).