Isolation and characterization of a newly keratinase producing Bacillus sp N1 from tofu liquid waste

Abstract

Keratinase is one of important industrial enzyme. The enzyme is produced by wide range of microbes. Microbial diversity offers keratinase diversity as well. Tofu liquid waste is rich with protein and a good natural environment for microorganism which produced extracellular protein hydrolases. This work reports our work on an isolation of a newly keratinase producing bacterium from tofu liquid waste. A keratinase producing bacterium was isolated in four steps: microbial enrichment using chicken feather to elevate population of keratinase producing microorganism, selection of protease producing microorganism by growing it on skim-milk agar medium following by securing colonies with proteolitic index above 3, selection of keratinase producing microorganism in chicken feather liquid medium, and selection of keratinase producing microorganism with highest keratinase activity. Species of a selected microorganism was identified base on 16S rRNA gene sequence. the isolate was identified as Bacillus sp with maximum sequence identity of 89% compare to the available sequence on the data base. Bacillus sp is capable to produce extracellular keratinase under 1% feather keratin substrate. Furthermore characterization showed that the enzyme exhibits potential ability to dehair goat skin with better dehaired surface profile.