Exopolysaccharide production with high antibacterial efficiency from Lentinus edodes using sheep wool protein hydrolysate

Abstract

Peptones are one of the most expensive components of culture media. This study was performed to produce exopolysaccharide (EPS) and mycelial biomass from the edible mushroom Lentinus edodes by using the peptone prepared from waste sheep wool. Wool peptone I (WPI) was prepared by HCl hydrolysis and NaOH neutralization and wool peptone II (WPII) by NaOH hydrolysis and HCl neutralization. The efficiency of wool peptones in EPS and mycelia production was compared with commercial tryptone peptone (TP) and proteose peptone (PP). Protein contents of TP, PP, WPI, and WPII were measured as 83.4, 83.7, 53.6, and 66.7 g/100 g, and their ash contents as 7.4, 10.3, 41.2, and 30.4 g/100 g, respectively. Compared to TP and PP, WPI and WPII were found to be richer in minerals, especially Na and Cl. At the optimal peptone concentration, relatively higher mycelial biomass concentrations were achieved in the presence of commercial peptones. Conversely, wool peptones, especially WPI, were found to be more favorable for EPS synthesis. In WPI, WPII, PP, and TP-based cultures, the maximum concentrations of produced EPS were determined as 0.55, 0.41, 0.35, and 0.21 g/L, respectively. It was determined that EPS samples produced in the presence of wool peptones had lower molecular weight but higher antibacterial activity. This is the first report on usability of wool protein hydrolysate as peptone source for production of mycelial biomass and polysaccharides from mushrooms including L. edodes.