Efficient biosynthesis of anticancer polysaccharide by a mutant Chaetomium globosum ALE20 via non-sterilized...

The sterilization process, due to its immense energy consumption, high facilities investment, and loss of raw materials by caramelization, during industrial production has drawn much attention. In this study, a methanol-resistant mutant strain, Chaetomium globosum ALE20, was obtained following 20 cycles of adaptive laboratory evolution process. The titer of anticancer polysaccharide (GCP-M) from C. globosum ALE20 reached 9.2 g/L with glycerol as sole carbon source using non-sterilized and fed-batch fermentation strategy. This titer represents a 200% increase compared with the 3.3 g/L attained with batch fermentation. The GCP-M monosaccharide was comprised of galactose, glucose, mannose and glucuronic acid, in a molar ratio of 3.83:66.37:3.26:1.95, respectively, and its weight-average molecular weight and polydispersity were 3.796 × 10⁴ Da and 1.060, respectively. This work presents an ideal alternative and safer fermentation process without sterilization, and a useful approach for enhancing industrial production.