Transcriptomic response of the xylose-selective strain derived from E. coli BL21(DE3) growing on xylose or glucose

Different genetic engineering strategies have been proposed to obtain E. coli strains that selectively consume xylose. In this study, a previously reported strategy for obtaining a xylose-selective strain in E. coli K12 was applied to E. coli BL21 (DE3). While this approach resulted in the expected xylose-selective phenotype, a low xylose consumption rate was recorded when the strain was grown on a mixture of xylose and glucose. To enhance xylose consumption, a variant of the transcriptional activator XylR was expressed. The resulting strain not only exhibited an improved capacity to consume xylose but also slightly recovered the ability to consume glucose. The aim of the microarray analysis was to identify the transcriptional changes associated with glucose assimilation in the BL21(DE3) derived xylose-selective strain. The analysis compared the transcriptomic response of a xylose-selective strain (derived from BL21(DE3)) when growing in xylose or glucose against the wild-type strain BL21(DE3) growing in the respective sugar.