Construction of a Novel Recombinant Escherichia coli Strain Capable of Simultaneously Utilizing Glucose and Xylose

Abstract

Lignocellulose-derived carbon sources are attractive to produce valuable biofuels and biochemicals. Despite many approaches have been intensively attempted for the production of valuable bioproducts in Escherichia coli, there still problems remaining such as carbon catabolite repression (CCR). Since non-engineered E. coli cannot simultaneously utilize glucose and xylose, it leads to longer fermentation times and lower productivities. Recently, we have found the enhanced glucose-xylose co-fermenting strains by using xylose metabolic operon with constitutive promoters, in order to exclude CCR in E. coli. Further, we performed adaptive evolution to strengthen the xylose metabolism mediated by the synthetic promoters. Analysis of whole genome re-sequencing of the adapted E. coli strains showed that four mutations were found in each adapted strain resulting in metabolic changes. Consequently we confirmed the significance of these mutations for xylose metabolism by using precise genome engineering tools. This study would be helpful to design an efficient platform strain for valuable bioproducts from lignocellulosic biomass containing large amount of glucose and xylose.