The use of mushroom hydrolysate from waste bag-log as the nitrogen source to mycelium biomass and exopolysaccharide production in Pleurotus eryngii cultivation

In this study, Pleurotus eryngii head part waste in a bag-log was collected and processed to yield mushroom hydrolysate powder (MHP). To test its stimulatory effect, a P. eryngii submerged culture was conducted. The prepared MHP (1.6%) and glucose (2%) were found to be the best sources for both mycelial biomass and EPS productions. A specific growth rate of 0.68 day(-1), and a specific EPS yield of 9.55 g/g-dry-cell-weight were obtained under these conditions. It was also found that MHP gave higher mycelial biomass growth rate (2.05 g/L/day), and EPS yield (92 mg/L) than those of yeast extract. In 5-L fermentation with MHP as nitrogen source, high mycelial biomass growth rate (2.44 g/L/day) and EPS yield (312 mg/L) were obtained. In the solid state culture, P. eryngii hyphae growth rate in MHP agar (6.43 +/- 0.21 mm/day) was better than that in PDA (4.57 +/- 0.23 mm/day). By using PCA and cluster analysis, the major amino acids of MHP displayed a close similarity to those of P. eryngii mycelial hydrolysate powder (PEMHP). (C) 2012 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.