Biochemical and Structural Characterization of a Detergent Stable Alkaline Serine Keratinase from Paenibacillus Woosongensis TKB2: A Potential Additive for Laundry Detergent

A monomeric alkaline keratinolytic serine protease with a molecular weight 190.24 kDa was purified from Paenibacillus woosongensis TKB2 in submerged fermentation using waste chicken feather as substrate. The purified keratinase was highest activity at pH 9.0 and 50 °C, requiring Mo+ for increasing fourfold enzyme activities, showed substrate specificity for keratin powder. The Km and Vmax for the enzyme was 1.4 mg/ml and 251.1 U/ml respectively. An initial analysis of the circular dichroism spectrum in the ultraviolet range revealed that the protease is predominantly an α-helix structure. In the presence of 7 mg/ml (w/v) detergents, the protease was active and retained 40–90 % activity. Therefore, it may have a possible application in laundry formulations. The keratinase combined with detergent was able to destain blood, fruit juice and turmeric stained cloth within 30 min without damaging the fabric structure and strength.