PARTIAL PURIFICATION AND CHARACTERIZATION OF A KERATINOLYTIC ENZYME FROM PSYCHROBACTER PULMONIS AND ITS APPLICATIONS

Abstract

This study focused on isolating and characterizing bacteria that produce the keratinase enzyme. Enrichment technique was employed using natural sources, including chicken feathers, soil, and compost. Screening was performed on 14 soil isolates, and the most efficient isolates were selected. Hydrolysis zones were observed on agar-based media at 30°C for 72 hours. Through morphological, cultural, biochemical, and molecular characterization, the potent keratinolytic isolate was identified as Psychrobacter pulmonis. The optimum pH and temperature for bacterial growth and enzyme activity were 7 and 30°C, respectively. Keratinolytic activity was detected during growth in liquid basal media containing 1% of the feathers, which were completely degraded within 8-9 days. The crude keratinase was partially purified by 40% ammonium sulfate precipitation at pH 7. SDS-PAGE analysis revealed a single band, indicating a pure enzyme with a molecular weight of 63 kDa. The total protein concentration in the concentrated keratinase was 3.8 mg/ml, which was 12.7 times higher than the crude keratinase based on the Bradford assay.