Production and characterization of surfactant-stable fungal keratinase from <Emphasis Type="Italic">Gibberella intermedia</Emphasis> CA3-1 with application potential in detergent industry

Surfactant-stable keratinases with good properties are promising candidates for extensive applications in detergent industries. A novel fungal keratinase-producing strain, Gibberella intermedia CA3-1, is described in this study. The keratinase production medium was optimized and composed of 10 g L^?1 of wool powder, 5 g L^?1 of tryptone, 10 g L^?1 of maltodextrin and 0.5 g L^?1 of NaCl. Keratinase activity was increased up to 109 U mL^?1 from 15 U mL^?1 by culture optimization. The optimal reaction pH and temperature of the enzyme were 9.0 and 60°C, respectively. The keratinase activity could be improved by sodium dodecyl sulphate (SDS), and it remained stable in the presence of several surfactants and commercial detergents. G. intermedia keratinase was proved to completely remove blood stains from cotton cloth when combined with detergents. These findings indicate that this fungal keratinase is a promising catalyst for the application in detergent industry. To our knowledge, this is the first report on keratinase production by Gibberella genus.