Biodegradation of feather waste by keratinase produced from newly isolated Bacillus licheniformis ALW1 (original) (raw)

Journal of Genetic Engineering and Biotechnology

Abstract

Isolation and identification of newly microbial sources able to utilize keratinous wastes is the target to begin this research. Optimization of the medium composition and fermentation conditions was performed to maximize the production of keratinase and the properties of the produced crude keratinase were also carried out. Among ten microbial isolates screened for keratinase production, isolate identified as B. licheniformis ALW1 secreted a significant amount of keratinase (25.2 U/ml) under static condition. The optimization studies indicated that the medium consisted of (g/l): feather 10.0; NaCl 0.5; KH2PO4 0.7; K2HPO4 1.4; MgSO4.7H2O 0.1; galactose 1.0; corn steep liquor 9.2 at initial pH 6.0 with 5 % inoculum size and incubated at 42°C for four days under static condition increase the production of keratinase to 72.2 U/ml (2.9 fold). The crude extracellular keratinase was optimally active at pH 8.0 and temperature 65°C with 0.7 % soluble keratin as substrate. The produced B. licheniformis ALW1 keratinase exhibited a good stability over pH range from 7 to 9 and over a temperature range 50°C - 60°C for almost 90 min. The crude enzyme solution was able to degrade native feather up to 63% in redox free system.

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