Antioxidant properties of exopolysaccharides (EPS) and intracellular polysaccharides (IPS) obtained respectively from mycelia and filtrates of submerged culture by Armillaria mellea in a 20-L stirred tank bioreactor were investigated. Effective production of EPS and IPS is available by submerged culture of A. mellea with respective number average molecular weights and protein/polysaccharide ratios as 7.68×106 Da and 7.68% as well as 5.65×106 Da and 5.26%. Both EPS and IPS exhibit powerful antioxidant activities by conjugated diene method, chelating effect on ferrous ions and scavenging effect on superoxide anion, as evidenced by their quite low EC50 values (< 5 mg/mL). Results confirmed that fermented A. mellea polysaccharides are potential antioxidant sources of both healthy medicine and food industries.Key words: Armillaria mellea, intracellular polysaccharide, exopolysaccharide, antioxidant activity
