Overexpression of transketolase relieves xylA repression and enhances xylose utilization in Saccharomyces cerevisiae during mixed sugar fermentation

To overcome the bottleneck of inefficient xylose utilization in lignocellulosic bioethanol production, we constructed a recombinant Saccharomyces cerevisiae strain (INVSc-xylA-Xltr1p-TKL1) by overexpressing the transketolase gene TKL1. This engineering strategy significantly enhanced xylose consumption by 33%, upregulated xylose isomerase (xylA) expression, and improved the sugar-to-ethanol conversion rate to 0.43 g/g (93.5% theoretical yield for xylose). These findings demonstrate that TKL1 overexpression effectively alleviates metabolic repression and advances co-utilization of glucose/xylose for efficient biofuel production.