Optimization of growth conditions for mycelial yield and exopolysaccharride production by Pleurotus ostreatus cultivated in Nigeria

Optimum culture condition for mycelia and exopolysaccharides production (EPS) by Pleurotus ostreatus in submerged liquid culture was investigated. The optimum temperature for mycelia yield and exopolysaccharide production was 25 and 15 degrees C in day 14 with yields of 1.40 g/ml and 2700 mg/l respectively. Optimum pH was found to be 8 with respective yields of 2.5 g/ml and 2665 mg/l in day 12 for mycelia and EPS mannitol (9.75 g/litre) and raffinose stimulated the highest mycelia growth (3.0 g/ml) and EPS production (3000 mg/l) at day 14 respectively. Mycelia yield (2.10 g/ml) and EPS production (2700 mg/l) was optimally supported by urea. Glycine (1.0 g) and leucine (1.0 g) supported optimum production of mycelia yield (2.5 g/ml) and EPS concentration (2925 mg/l) respectively while folic acid and ascorbic acid induced the moderate mycelia yield and EPS concentration respectively. These results have shown that significant improvement in mycelia yield and EPS production by P. ostreatus could be enhanced through submerged cultivation under appropriate optimized conditions.