Keratinolytic activities of a new feather-degrading isolate of Bacillus cereus LAU 08 isolated from Nigerian soil

Abstract

A local strain of Bacillus cereus LAU 08 was isolated from a chicken-feather disposal site in Ogbomoso, Southwest Nigeria. Production of keratinase was induced using three sources of keratin, namely: hooves, horn, and feather, at a growth temperature of 37 °C. In each case, high titers were recorded for both keratinolytic and proteolytic activities. Maximum enzyme activities were obtained within 24–96 h of cultivation, depending on the keratin substrate used and the activity under study. While maximum keratinolytic activities of 67.9, 63.1, and 51.7 U ml −1 were obtained using enzymes induced by hooves, horn, and feather, respectively, proteolytic activities of 11 860, 820, and 126 U ml −1 were obtained using enzymes induced by feather, hooves, and horn, respectively. The optimal conditions for the keratinolytic activity were determined to be pH 7.0 and temperature of 50 °C; however, the enzyme displayed more than 50% activities within the broad range of pH 7–9 and temperature of 40–70 °C. In addition, the isolate was able to completely degrade a whole chicken feather within a period of 7 days at room temperature (30 ± 2 °C). B. cereus LAU 08 is therefore a promising strain for the management of chicken feather waste through biotechnological processes.