Abstract

A novel bacterium, Bacillus licheniformis K-19, which produces a large amount of akeratinase that is extremely thermostable and has a broad resistance to pH, was isolated and characterized. The maximum amount of keratinase activity (about 224 Uml^-1) was produced at 37°C when the bacterium was cultured for 72 h in broth containing feather meal with initial pH of 7.5. The keratinase activity was observed over a wide range of temperatures (30 - 90°C) and pH values (pH 6 - 10). It was optimal at 60°C and pH 7.5 - 8 respectively. These results suggest potential biotechnological applications of this bacterium that involve hydrolysis of keratin, including the improvement of the nutritional properties of feathers (and other keratins) used as supplementary feedstuffs.

Key words: Bacillus licheniformis, chicken feather, keratin, keratinolytic protease.