title: Screening for a new Streptomyces strain capable of efficient keratin degradation.
abstract: 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.
authors.affiliation: State Key Laboratories of Transducer Technology, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100080, China. chaoyp@sun.im.ac.cn
authors.forename: Ya-Peng
authors.initials: YP
authors.lastname: Chao
authors.forename: Fu-Hong
authors.initials: FH
authors.lastname: Xie
authors.forename: Jing
authors.initials: J
authors.lastname: Yang
authors.forename: Jing-Hua
authors.initials: JH
authors.lastname: Lu
authors.forename: Shi-Jun
authors.initials: SJ
authors.lastname: Qian
mesh_terms: 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
chemical_list: D007633:Keratins; D010447:Peptide Hydrolases; C035855:keratinase