Improving product yields on D-glucose in Escherichia coli via knockout of pgi and zwf and feeding of supplemental carbon sources.

The use of lignocellulosic biomass as a feedstock for microbial fermentation processes presents an opportunity for increasing the yield of bioproducts derived directly from glucose. Lignocellulosic biomass consists of several fermentable sugars, including glucose, xylose, and arabinose. In this study, we investigate the ability of an E. coli Δpgi Δzwf mutant to consume alternative carbon sources (xylose, arabinose, and glycerol) for growth while reserving glucose for product formation. Deletion of pgi and zwf was found to eliminate catabolite repression as well as the ability of E. coli to consume glucose for biomass formation. In addition, the yield from glucose of the bioproduct D-glucaric acid was significantly increased in a Δpgi Δzwf strain.