LAUSR

Abstract Sugar transporter-mediated sugar transport is the first rate-limiting step in the control of yeast metabolism. Almost all known wild-type sugar transporters do not have the ability to co-transport glucose and xylose, which makes yeast less available to mixed sugar substrates (e.g. lignocellulose hydrolysate) and leads to lower product titers. Here, we achieved co-utilization of glucose and xylose by the tolerant yeast Candida glycerinogenes and facilitated D -xylonate production through rational modification of the hexose transporter (transporter engineering). Specifically, a hexose transporter mutant CgHxt4.2A.S (CgHxt4K9A, N351S, K538A) with high membrane localization stability (MLS) and co-transport of glucose and xylose was obtained by functional characterization, homology modeling, molecular docking and rational mutagenesis. Ultimately, this mutant enhanced the utilization of sugars (especially xylose) by C. glycerinogenes and increased the titer of D -xylonate in sugarcane bagasse hydrolysate by 49.3%. Our study provides a promising strategy for the future efficient utilization of cheaper lignocellulosic hydrolysates by recombinant yeast for the production of high-value chemicals.