The aim of this study was to isolate chicken feather-degrading bacteria with high keratinolytic activity and to investigate cultural conditions affecting keratinolytic enzyme production by a selected isolate. A chicken feather-degrading bacterial strain CH3 was isolated from poultry wastes. Isolate CH3 degraded whole chicken feather completely within 3 days. On the basis of phenotypical and 16S rDNA studies, isolate CH3 was identified as Bacillus thuringiensis CH3. This strain is the first B. thuringiensis described as a feather degrader. The bacterium grew with an optimum at pH 8.0 and 37℃, where maximum keratinolytic activity was also observed. The composition of optimal medium for keratinolytic enzyme production was feather 0.1%, sucrose 0.7%, casein 0.3%, K2HPO4 0.03%, KH2PO4 0.04%, MgCl2 0.01% and NaCl 0.05%, respectively. The keratinolytic enzyme had a pH and temperature optima 9.0 and 45℃, respectively. The keratinolytic activity was inhibited ethylenediaminetetraacetic acid, phenylmethylsulfonyl fluoride, and metal ions like Hg2+, Cu2+ and Zn2+. The enzyme activated by Fe2+, dithiothreitol and 2-mercaptoethanol.

• Jung Chul Kim(Department of Microbiology, Pusan National University)
• Min Ju Kim(Department of Microbiology, Pusan National University)
• Hyeng Sik Son(Department of Microbiology, Pusan National University)
• Eun Youn Ryu(Department of Microbiology, Pusan National University)
• Seong Yun Jeong(Korea BIO-IT Foundry Center, Pusan National University)
• Mi A Kim(Korea BIO-IT Foundry Center, Pusan National University)
• Geun Tae Park(Research & University-Industry Cooperation, Pusan National University)
• Hong Joo Son(School of Applied Life Science, Pusan National University)
• Sang Joon Lee(Department of Microbiology, Pusan National University) Corresponding Author