Engineering Xylose Metabolism and Coutilization with Glucose in Corynebacterium glutamicum for Efficient Microbial Cell Factories

Xylose, an important sugar component of lignocellulosic biomass, is often inefficiently utilized due to limitations in its transport and metabolic pathways. This study aimed to enhance the xylose metabolism in Corynebacterium glutamicum through metabolic engineering and transcriptional regulation strategies. First, the xylose assimilation pathway was constructed by the heterologous expression of xylose isomerase (XylA) and xylulose kinase (XylB), which improved the strain's xylose metabolic capability. Transcriptomic analysis identified IolT2 as a potential xylose transporter. Furthermore, the introduction of the Escherichia coli xylose-specific transporter XylE enhanced xylose transport and reduced the inhibitory effect of glucose on xylose metabolism. The strain WTABE_ALE6, selected through adaptive laboratory evolution, exhibited improved xylose utilization efficiency, supporting its ability to coutilize glucose and xylose in mixed-sugar fermentation. This study provides insights into optimizing the xylose utilization and glucose-xylose coutilization in C. glutamicum, which may facilitate the conversion of lignocellulosic biomass and the production of biobased chemicals.