Screening and Characterisation of Keratin-Degrading Bacillus sp. from Feather Waste

Abstract

Aim: This study focuses on the screening and characterisation of keratin-degrading Bacillus species from feather waste. Methods: Nine bacteria were isolated from feather waste obtained from a poultry layout at Egbeda local government secretariat, Ibadan, Nigeria. These bacteria were grown in basal medium with feather as primary source of carbon, nitrogen, sulfur and energy. Feather degrading bacteria were screened for both proteolytic activity and keratin degradation on skimmed milk agar and keratin azure medium respectively. They were also screened for their ability to degrade other keratin substrates such as hair and nail. Results: Three of the isolates with higher feather degradation levels also showed high proteolytic activity and release of azure dye. They were selected and identified phenotypically and genotypically using 16S rRNA sequencing as Bacillus licheniformis-K51, Bacillus subtilis-K50 and Bacillus sp.-K53. The bacteria were capable of degrading other keratin-containing substrates such as nail and hair. Bacillus subtilis-K50 and Bacillus licheniformis-K51 showed significant difference (P) in degradation among the three different keratin sources used yielding higher degradation with feather as keratin source with respective optical densities of 0.07 and 0.11 followed by hair and least in nails with optical densities of 0.05 and 0.07 respectively. Highest degradation of all the three keratin substrates was observed in Bacillus licheniformis-K51. Conclusion: The three isolated bacteria possess the ability to degrade keratin and utilize feather as keratin substrate. As a result, these can be considered as potential candidates for degradation and utilization of feather keratin.