FOOD SCIENCE ›› 2009, Vol. 30 ›› Issue (11): 158-162.doi: 10.7506/spkx1002-6630-200911035

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Separation and Identification of A Chymosin Producing Bacterium from Soil of Yak Grazing District in Tianzhu Country of Gansu Province

SONG Xi,GAN Bo-zhong*,HE Xiao-ling,ZHANG Wei-bing,LI Fan,LIU Xing-long   

  1. College of Food Science and Engineering, Gansu Agricultural University, Analysis and Research Center of Gansu Agricultural University, Lanzhou 730070, China
  • Received:2008-10-09 Revised:2009-01-10 Online:2009-06-01 Published:2010-12-29
  • Contact: GAN Bo-zhong E-mail:ganbz@126.com

Abstract:

An efficient chymosin producing strain, D3.11, was screened out from 18 bacterial strains isolated from the soil of yak grazing district in Tianzhu County of Gansu Province, China, using casein medium, whose chymosin and proteolysis activities were 89.56 SU/ml and 21.27 U/ml after 72 h shaking fermentation (140 r/min) at 37℃ in bran medium, respectively. This strain was identified as Bacillus licheniformis by the means of bacterial morphological feature observation, physiological and biochemical characteristics measurement and 16S rDNA sequence analysis. Furthermore, the growth and enzyme production curves of this strain were plotted.

Key words: chymosin, bacterium, separation and identification, 16S rDNA, Bacillus licheniformis

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