Screening for a new Streptomyces strain capable of e cientkeratin degradation
CHAO Ya-peng , XIE Fu-hong , YANG Jing , LU Jing-hua , QIAN Shi-jun
DOI:
Received October 18, 2006,Revised December 25, 2006, Accepted , Available online
Volume 19,2007,Pages 1125-1128
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Keratinous wastes could be degraded by some microorganisms in nature. Native human foot skin (NHFS) was used as sole nitrogen
source to screen microorganisms with keratin-degrading capability. From approximately 200 strains, a strain of Streptomyces sp. strain
No.16 was found to possess the strongest keratinolytic activity, and the total activity in the culture was 110 KU/ml with specific activity
of 2870 KU/mg protein (KU: keratinase unit). Substrate specificity test indicated that the crude keratinase could degrade keratin azure,
human hair, cock feathers and collagen. The optimal pH of the crude keratinase ranged from 7.5 to 10 and the temperature ranged from
40°C to 55°C. Metal chelating agent ethylenediamine tetraacetic acid obviously stimulated the keratinolytic activity but suppressed
the proteolytic activity. To our knowledge, this is the first report on specific induction of keratinases by NHFS from an actinomycete.
Moreover, excellent characteristics of its crude keratinase may lead to the potential application in waste treatment and recovery, poultry
and leather industry, medicine, and cosmetic development.
