Production of kertinases using chicken feathers as substrate by a novel multifunctional strain of Pseudomonas stutzeri and its dehairing application

In this study, keratinolytic potential of a Sodium Dodecyl Sulfate (SDS) degrading strain of Pseudomonas stutzeri strain K4 was evaluated. Strain K4 completely metabolized 1% (w/v) chicken feathers after 72 h of incubation with production of 784.2 µg/ml of soluble protein and 42 U/ml of keratinase. Scanning Electron Microscopy (SEM) analysis of chicken feathers indicated damage on the surface of feathers. Activity staining for keratinase showed presence of five keratinases (26–76 kDa) during growth with chicken feathers. Optimum pH and temperature for crude keratinase was found to be pH-8 and 40 °C respectively. Crude keratinase showed activation in presence of metal ions such as Mg2+ (39%), Mn2+ (28%), Na+ (20.8%), solvents such as isopropanol (30.7%), glycerol (28.2%), reducing agents such as β- mercaptoethanol (70%), chelating agents such as EDTA (25.3%) and anionic detergent SDS (37.8%), respectively. Crude keratinases showed high substrate specificity for keratin and chicken feathers, low specificity for collagen and hair, respectively. Dehairing of goat skin by employing crude ketainase preparation (40 U/ml) indicated complete dehairing after 20 h of incubation. Enzymatic dehairing was superior over chemical dehairing, as no damage to skin and hairs were observed. This is the first report of a novel strain of P. stutzeri exhibiting excellent dehairing activity; results indicate that purification of keratinases prior to dehairing was not required.