Metabolic engineering of Escherichia coli to produce succinate from woody hydrolysate under anaerobic conditions.

It is of great economic interest to produce succinate from low-grade carbon sources, e.g., lignocellulosic biomass hydrolysate, which mainly contains glucose and xylose. Inactivation of the glucose uptake system PtsG was evaluated for succinate production from xylose-rich feedstocks. Strains with integration of succinate production modules into the chromosome of Escherichia coli were then constructed. These strains have better succinate production performance from xylose-rich feedstocks than strain FZ560 harboring pHL413KF1. Glucose utilization was enhanced in FZ661T by manipulation of the gal operon to allow efficient use of the high-concentration glucose in woody biomass hydrolysate. Up to 906.7 mM (107.0 g/L) succinate was produced from mixed sugars in fed-batch fermentation and more than 461.7 mM (54.5 g/L) succinate was produced from woody hydrolysate in a batch fermentation. In this study, FZ661T was able to produce succinate from woody hydrolysate in minimal medium efficiently, making it attractive for industrial applications in succinate production.