A comparative study of production of hydrophobin like proteins (HYD-LPs) in submerged liquid and solid state fermentation from white rot fungus Pleurotus ostreatus

Abstract Hydrophobins are small, surface-active, cysteine-rich proteins produced by filamentous fungi. They are able to assemble spontaneously into amphipathic monolayers at hydrophobic-hydrophilic interfaces. They have a specific property of producing stable foam. Hydrophobins isolated from edible mushrooms like Pleurotus ostreatus can be used industrially for various purposes like food foams, biosurfactants, biosensors, flavor stabilizers, pharmaceutical formulations, drug delivery systems and many more. In consideration with industrial importance of the protein, the objective of this research work was to improve yield of the process. In this study Pleurotus ostreatus was grown in submerged liquid fermentation (SLF) using Yeast maltose and glucose (YMG) medium supplemented with 100 mg/L of Tryptophan and also grown in solid state fermentation (SSF) on agro-industrial waste oil cakes of coconut and sesame obtained from local market. Moisture content of SSF process was maintained at 75%. Class I Hydrophobin like proteins (HYD-LPs) were purified using Trifluroacetic acid (TFA). Sesame oil cake gave higher yield of HYD-LPs (3.85 mg/g of biomass) as compared to yield of HYD-LPs isolated from YMG submerged liquid medium (1.86 mg/g of biomass). Production in SSF was 2 fold higher than SLF. This huge difference in yields of hydrophobins underlines the suitability of solid substrate fermentation process along with addition of oil cakes to improve the yields.