Biotechnology Bulletin ›› 2014, Vol. 0 ›› Issue (9): 164-170.

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Screening,Identification of a Cellulase-producing Bacterium Strain and Its Enzyme-producing Conditions

Chai Xiujuan, Li Caolong, Kong Dezhen, Cui Zhenglong, Wang Aiying   

  1. College of Life Science,Shihezi University,Xinjiang 834000
  • Received:2014-04-15 Online:2014-09-15 Published:2014-09-07

Abstract: One cellulose producing strains C-8 were isolated from Xinjiang turpan area soil samples. According to morphology, biochemical and physiological characterization, and 16S rRNA sequence analysis, C-8 was identified as Bacillus sp. The celluloses produced by C-8 could hydrolyze cellulose, the optimum pH and temperature were 4.0 and 40℃, also it has good thermal stability and pH stability. In order to improve the ability of cellulose producing strain C-8, the fermentation conditions were optimized using response surface method. It was to screen out the effects of the main effect of enzyme production condition factors using Plackett-Burman Design, the steepest ascent experiment approximation maximum response area, and optimize fermentation conditions by Response Surface Box-Behnken. The results showed that the initial pH, CMC-Na% and culture tempinduedrature was the main influencing factor. The response of three factors was, obtained, and the optimal conditions for the initiation of pH8.0, CMC-Na%2.5%, culture temperature 28℃. Under the optimum condition, the activity of cellulose was up to 193.89 U/mL, and the enzyme activity was increased by 2.35 times compare to previous optimization.

Key words: Bacillus sp. , Cellulose , Response surface analysis, Fermentation optimization