Antioxidant and antibacterial activities of a polysaccharide produced by Chaetomium globosum CGMCC 6882

In the present work, a Gynostemma pentaphyllum herb endophytic fungus of Chaetomium globosum CGMCC 6882 polysaccharide produced from tapioca starch (GCP-TS) with submerged fermentation was analyzed. GCP-TS contains rhamnose, glucosamine, galactose, glucose, mannose, and glucuronic acid in the molar ratio of 6.29: 0.55: 1.12: 22.93: 10.94: 3.54. Its weight-average molecular weight, number-average molecular weight and polydispersity were 4.73 × 104 Da, 4.29 × 104 Da and 1.103, respectively. Antioxidant results showed that GCP-TS had a concentration-dependent scavenging ability against DPPH radical, superoxide anion, hydroxyl radical, and ABTS radical. The corresponding scavenging capacities of GCP-TS aqueous solution at the concentration of 1.0 mg/mL were 45.11 ± 2.52, 43.58 ± 1.97, 36.27 ± 2.48, and 34.39 ± 2.06 %, respectively. Antibacterial activities of GCP-TS against Staphylococcus aureus and Escherichia coli were enhanced with the increase in its concentration, and its bacteriostatic activity against S. aureus was stronger than that against E. coli.