Abstract:
Bacillus sp. FK14 produced an extracellular keratinase in a medium containing feather meal as asubstrate at pH 7.5, 37?C and 150 rpm. The keratinase was purified by ultrafiltraton (YM10), 40 %ammonium sulfate fractionation and two columns of anion exchange chromatography (DEAESepharose). After purification, the keratinase exhibited high specific activity (104 U/mg) with 41purificaton fold and 105 % yield. The enzyme was monomeric and had a molecular mass of 35000Da. The enzyme had optimum pH and optimum temperature of 8.5 and 60 ?C, respectively. Theenzyme was stable over the pH range between 7 - 9 and stable up to 37?C. The enzyme activity wasinhibited by PMSF, EDTA and Iodoacetamide at 96 %, 62 % and 22 %, respectively. It is indicatedthat the enzyme is a serine protease. The enzyme was stimulated by most metal ions except Fe3+andhad the highest relative activity with Mn2+ and Al3+. Keratinase was capable of hydrolysing bothsoluble proteins and insoluble proteins. It hydrolysed soluble proteins ; casein, gelatin, BSA andelastin, with relative activity of 100 %, 79.5 %, 76.5 % and 3.6 %, respectively. It also hydrolysedinsoluble proteins ; collagen type I, human nail, keratin azure, chicken feather and human hair, withrelative activity of 35.6 %, 16.35 %, 9.0 %, 5.1 % and 2.8 %, respectively. This keratinase digestedchicken feather, human hair and keratin azure more effective than Trypsin and digested the keratinsubstrates similar to Subtilisin Carlsberg.