Overexpression of glycosyltransferase genes enhance the production of extracellular polysaccharides in Cordyceps militaris

This study aimed to increase the production of extracellular polysaccharides in Cordyceps militaris by overexpressing polysaccharide transferase genes, including alpha-1,2-mannosyltransferase (Kre5), alpha-1,3-mannosyltransferase (CMT1), alpha-1,6-mannosyltransferase subunit (A16), and alpha-1,2-mannosyltransferase (A12) genes. The research data showed that, except for the CM-CMT1 strain, the extracellular polysaccharides (EPS) content of the other seven recombinant strains was higher than that of the wild-type strain, indicating that overexpression of key enzyme genes increased polysaccharide production. Among the single-gene recombinant strains, the CM-Kre5 strain had the highest EPS production, reaching 3.27 ± 0.18 g/L, which was 23.3% higher than that of the CM-WT strain, indicating that the Kre5 gene had the greatest impact on Cordyceps militaris polysaccharide biosynthesis. Among the combination gene recombinant strains, the CM-Kre5-CMT1-A16 strain had the highest EPS production, reaching 4.22 ± 0.35 g/L, which was 59.2% higher than that of the CM-WT strain, indicating that gene combination expression can further increase Cordyceps militaris polysaccharide production. Therefore, this study provides a new way for the development of EPSs and their downstream products in Cordyceps militaris.