Biosynthesis of chondroitin in engineered Corynebacterium glutamicum .

Chondroitin, the precursor of chondroitin sulfate, which is an important polysaccharide, has drawn significant attention due to its applications in many fields. In the present study, a heterologous biosynthesis pathway of chondroitin was designed in a GRAS (generally recognized as safe) strain C. glutamicum . CgkfoC and CgkfoA genes with host codon preference were synthesized and driven by promoter P tac , which was confirmed as a strong promoter via GFPuv reporter assessment. In a lactate dehydrogenase ( ldh ) deficient host, intracellular chondroitin titer increased from 0.25 to 0.88 g/L compared with that in a wild type host. Moreover, precursor enhancement via overexpressing precursor synthesizing gene ugdA further improved chondroitin titers to 1.09 g/L. Chondroitin production reached 1.91 g/L with the engineered strain C. glutamicum ΔL- Cg CAU in a 5-L fed-batch fermentation with a single distribution Mw of 186 kDa. This work provides an alternative, safe and novel means of producing chondroitin for industrial applications.