Production of chondroitin by Corynebacterium glutamicum through co-utilization of glucose and xylose from corn straw.

Chondroitin sulfate (CS), a biopolymer with critical applications in osteoarthritis treatment and biomedical sectors, faces production challenges due to low yields and high costs. This study established a high-yield chondroitin (the major precursor of CS) production platform in Corynebacterium glutamicum for the simultaneous utilization of glucose and xylose from corn straw hydrolysate. Firstly, through codon optimization of genes encoding chondroitin synthase (KfoC) and UDP-N-acetylglucosamine-4-epimerase (KfoA), combined with tailoring metabolic pathways and medium components for chondroitin synthesis, yielded the high-titer strain CgC25. Fed-batch fermentation achieved a chondroitin titer of 9.59 ± 0.15 g/L in CgC25, the highest reported titer for medium molecular weight chondroitin to date. Next, the xylose metabolism module was optimized by reconstructing the xylose isomerase (XI) and Weimberg pathways using an RBS-library strategy, ultimately yielding a strain CgRXIW. Finally, integration of xylose metabolism and chondroitin synthesis modules enabled CgC25 to produce 6.64 ± 0.11 g/L chondroitin from corn stover hydrolysate. Integration of the xylose metabolism pathway with chondroitin synthesis modules enabled. This study establishes a glucose and xylose co-utilization mechanism in C. glutamicum, offering a scalable platform for cost-effective chondroitin production and the biosynthesis of high-value compounds from renewable feedstocks.