Screening for a new Streptomyces strain capable of efficient keratin degradation.
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 degrees C to 55 degrees 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.
Chao
Ya-Peng
YP
State Key Laboratories of Transducer Technology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China. chaoyp@sun.im.ac.cn
Xie
Fu-Hong
FH
Yang
Jing
J
Lu
Jing-Hua
JH
Qian
Shi-Jun
SJ
D000818:Animals; D005241:Feathers / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007633:Keratins / Q000378:metabolism*; D010447:Peptide Hydrolases / Q000378:metabolism; D012867:Skin / Q000378:metabolism; D013302:Streptomyces / Q000201:enzymology / Q000378:metabolism*; D013379:Substrate Specificity; D013696:Temperature
D007633:Keratins; D010447:Peptide Hydrolases; C035855:keratinase