Characterisation and bioactivity of protein-bound polysaccharides from submerged-culture fermentation of Coriolus versicolor Wr-74 and ATCC-20545 strains

The protein-bound polysaccharides of Coriolus versicolor (CPS) have been reported to stimulate overall immune functions against cancers and various infectious diseases by activating specific cell functions. A New Zealand isolate (Wr-74) and a patented strain (ATCC-20545) of C. versicolor were compared in this study. The fruit bodies of both strains were grown for visual verification. Both strains were grown in submerged-culture using an airlift fermentor with milk permeate as the base medium supplemented with glucose, yeast extract and salt. Metabolic profiles of both strains obtained over 7-day fermentation showed very similar trends in terms of biomass production (8.9-10.6 mg/ml), amounts of extracellular polysaccharide (EPS) from the culture medium (1150-1132 mu g/ml), and intracellular polysaccharide (IPS) from the mycelium (80-100 mu g/ml). Glucose was the dominant sugar in both EPS and IPS, and the polymers each consisted of three molecular weight fractions ranging from 2 x 10(6) to 3 x 10(3) Da. Both the EPS and IPS were able to significantly induce cytokine production (interleukin 12 and gamma interferon) in murine splenocytes in vitro. Highest levels of interleukin 12 (291 pg/ml) and gamma interferon (6,159 pg/ml) were obtained from samples containing Wr-74 IPS (0.06 mu g/ml) and ATCC 20545 IPS (0.1 mu g/ml), respectively. The results indicated that lower levels of EPS and IPS generally resulted in higher immune responses than did higher polymer concentrations.