Structural characterization and immunomodulatory activity of a polysaccharide produced by chaetomium globosum CGMCC 6882

Efficient utilization of cellulose resources is of great significance to environmental protection and to solve the crisis of global energy shortage. In the present work, a polysaccharide (CGP-TS) was successfully produced by Chaetomium globosum CGMCC 6882 from waste tobacco stalk via submerged fermentation. Chemical composition analysis showed that the carbohydrate and protein contents in CGP-TS were 92.55% ± 3.16% and 4.73% ± 1.04%, respectively. Structural characterization indicated that CGP-TS was not pectin and composed of rhamnose, arabinose, galactose, glucose and xylose in a molar ratio of 22.2166: 9.8269: 36.2455: 3.3111: 0.416, and its molecular weight was 613.235 kDa. In vitro bioactivity and potential application investigation showed that antioxidant activities of CGP-TS against DPPH, ABTS, hydroxyl and superoxide radicals were positively correlated to its concentration from 0.5 mg/mL to 2.5 mg/mL. Meanwhile, CGP-TS exhibited immunomodulatory activity via enhancing the phagocytic activity and promoting the cytokines (TNF-α, IL-1β, IL-6 and NO) release of RAW 264.7 macrophages.