ABSTRACT
Aims: Polysaccharide of Pleurotus ostreatus is one of the fungal polysaccharide which has been widely studied, produced by extracting the fruiting body. An alternative method for producing polysaccharide of P. ostreatus directly from the mycelia instead of the fruiting body is through submerged culture. This study was aimed to determine the optimum submerged culture conditions for producing biomass and intracellular polysaccharide of the oyster mushroom. Methodology and results: P. ostreatus BPPTCC 6017 was collected from traditional mushroom farm in West Java, Indonesia. Submerged fermentation was conducted in 1000 mL medium (2 L flask). Four variables were tested: temperature, pH, agitation, and fermentation time, using central composite design of the response surface methodology. Mycelial biomass produced, was extracted to obtain water-soluble and alkali-soluble polysaccharide. Experimental data obtained were fitted to a second-order polynomial equation using multiple regression analysis and also analysed by appropriate statistical methods. The 3-D response surface plots derived from the mathematical models were applied to determine the optimum conditions: temperature 27.89 °C, initial pH medium 5.49, agitation 124.08 rpm, and fermentation time 11.44 days. The predicted results of the models were 33.75 g/L mycelia, 0.33 g/L water-soluble polysaccharide, and 0.64 g/L alkali-soluble polysaccharide. Those results were then verified on the optimum conditions, and produced 32.00±1.25 g/L mycelia, 0.29±0.01 g/L water-soluble polysaccharide and 0.60±0.02 g/L alkali-soluble polysaccharide, were close to the theoretical predictions. Conclusion, significance and impact study: The present study was a first effort to assess and obtain the optimum conditions for producing the biomass and polysaccharides of the strain P. ostreatus BPPTCC 6017 using submerged fermentation