P93: Fermentation of Sugar Mixtures found in Lignocellulosic Hydrolysate using Substrate-Selective Escherichia coli

 We report on substrate-selective uptake as an approach for the simultaneous consumption of sugars found in biomass hydrolysates.  Substrate-selective uptake involves using a consortium of strains of a single microbial species which by virtue of gene knockouts are each limited to consuming a single carbon source.  Comparing growth rate of E. coli strains, we observed that wild type E. coli W showed generally the fastest growth on carbohydrates. The triple-knockout strain W glk ptsG manZ (KD777) consumed 7 g/L L-arabinose or D-xylose within 5.5 h, and subsequently consumed glucose only slowly.  The presence of glucose did affect the utilization of D-galactose by KD777.  Similar results were obtained with W glk ptsG manZ crr (KD915), which slowly consumed glucose despite the elimination of both Enzyme IIA and IIB of the glucose-specific phosphotransferase system. Results with additional knockouts in MG1655 (including ptsI, bglF, fruA, galP and galK) were also investigated.