Engineered harbors xylose isomerase and xylose transporter improves co-fermentation of xylose and glucose for ethanol production.

cannot assimilate xylose, second to glucose derived from lignocellulosic biomass. Here, the engineered strains INV-XI and INV-XI/XT were constructed using and to co-utilize xylose and glucose, achieving economic viability and sustainable production of fuels. The xylose utilization rate of INV-XI/XT was 2.3-fold higher than that of INV-XI, indicating that overexpressing could further enhance xylose utilization. In mixed sugar media, a small amount of glucose enhanced the consumption of xylose by INV-XI/XT. Transcriptome analysis showed that glucose increased the upregulation of acetate of coenzyme A synthetase (), alcohol dehydrogenase (), and transketolase gene expression in INV-XI/XT, further promoting xylose utilization and ethanol yield. The highest ethanol titer of 2.91 g/L with a yield of 0.29 g/g at 96 h by INV-XI/XT was 56.9% and 63.0% of the theoretical ethanol yield from glucose and xylose, respectively. These results showed overexpression of and is a promising strategy for improving xylose and glucose conversion to ethanol. Although the ability of strain INV-XI/XT to produce ethanol was not very satisfactory, glucose was discovered to influence xylose utilization in strain INV-XI/XT. Altering the glucose concentration is a promising strategy to improve the xylose and glucose co-utilization.