Purification and biochemical characterization of two novel extracellular keratinases with feather-degradation and hide-dehairing potential

Two novel extracellular keratinases were produced by Actinomadura keratinilytica strain Cpt20. Both enzymes purified to homogeneity using heat-treatment (60 °C for 30 min) and ammonium sulfate salt fractionation (40 %–70 %), followed anion-exchange chromatography with fast protein liquid (FPLC) system. The keratinases, designated as KERA-71 KERB-19, are monomeric named according their molecular masses of 71 kDa 19 kDa, respectively, estimated via sodium dodecyl polyacrylamide gel electrophoresis (SDS-PAGE), zymography, high-performance (HPLC). N-terminal residues both exhibited high identity other keratinases. Their hydrolytic activities significantly inhibited phenylmethylsulfonyl fluoride (PMSF) di-iodopropyl fluorophosphates (DFP), classifying them in the serine proteases family. While was ideally active at 50 pH 8, KERB-19 illustrated optimum activity 40 7. thermo-activity thermo-stability improved 10 mM Ca2+. Interestingly, displayed broader substrate specificity, higher catalytic efficiency (kcat/Km), a degree hydrolysis (DH) than actinobacterial including KERDZ, KERAK-29, Actinase E, KERAB. effective keratinase potential, illustrating possibility be used process keratin-containing wastes valorization leather industry.