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Journal of Zhejiang University SCIENCE B 2008 Vol.9 No.1 P.60~67


Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis

Author(s):  Cheng-gang CAI, Bing-gan LOU, Xiao-dong ZHENG

Affiliation(s):  College of Food Science and Biosystem Engineering, Zhejiang University, Hangzhou 310029, China; more

Corresponding email(s):   bglou@zju.edu.cn

Key Words:  Bacillus subtilis, Keratin, Keratin degradation, Keratinase production, N-methyl-N&prime, -nitro-N-nitrosoguanidine (MNNG) mutagenesis

Cheng-gang CAI, Bing-gan LOU, Xiao-dong ZHENG. Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis[J]. Journal of Zhejiang University Science B, 2008, 9(1): 60~67.

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author="Cheng-gang CAI, Bing-gan LOU, Xiao-dong ZHENG",
journal="Journal of Zhejiang University Science B",
publisher="Zhejiang University Press & Springer",

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%T Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis
%A Cheng-gang CAI
%A Bing-gan LOU
%A Xiao-dong ZHENG
%J Journal of Zhejiang University SCIENCE B
%V 9
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%@ 1673-1581
%D 2008
%I Zhejiang University Press & Springer
%DOI 10.1631/jzus.B061620

T1 - Keratinase production and keratin degradation by a mutant strain of Bacillus subtilis
A1 - Cheng-gang CAI
A1 - Bing-gan LOU
A1 - Xiao-dong ZHENG
J0 - Journal of Zhejiang University Science B
VL - 9
IS - 1
SP - 60
EP - 67
%@ 1673-1581
Y1 - 2008
PB - Zhejiang University Press & Springer
ER -
DOI - 10.1631/jzus.B061620

A new feather-degrading bacterium was isolated from a local feather waste site and identified as Bacillus subtilis based on morphological, physiochemical, and phylogenetic characteristics. Screening for mutants with elevated keratinolytic activity using N-methyl-N&prime;-nitro-N-nitrosoguanidine mutagenesis resulted in a mutant strain KD-N2 producing keratinolytic activity about 2.5 times that of the wild-type strain. The mutant strain produced inducible keratinase in different substrates of feathers, hair, wool and silk under submerged cultivation. Scanning electron microscopy studies showed the degradation of feathers, hair and silk by the keratinase. The optimal conditions for keratinase production include initial pH of 7.5, inoculum size of 2% (v/v), age of inoculum of 16 h, and cultivation at 23 °C. The maximum keratinolytic activity of KD-N2 was achieved after 30 h. Essential amino acids like threonine, valine, methionine as well as ammonia were produced when feathers were used as substrates. Strain KD-N2, therefore, shows great promise of finding potential applications in keratin hydrolysis and keratinase production.

Darkslateblue:Affiliate; Royal Blue:Author; Turquoise:Article


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