NATURAL PRODUCT RESEARCH AND DEVELOPMENT ›› 2023, Vol. 35 ›› Issue (2): 221-230.doi: 10.16333/j.1001-6880.2023.2.005

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Screening,identification and fermentation condition optimization of Bacillus with high cellulase production

YANG Yan-hong1*,ZHANG Hao-bo2,YAO Xin-yi2,HE Xi2,WANG Zhe2   

  1. 1School of Pharmacy & Bioengineering,Chongqing University of Technology,Chongqing 400054,China;2Chongqing Yucai Secondary School,Chongqing 400050,China
  • Online:2023-02-28 Published:2023-03-02

Abstract:

Cellulose is the most widespread and cheapest raw material for biomass energy production.Screening of high-activity-cellulase-producing strain is the key to the development and utilization of cellulose energy.Congo red-CMC plate was used to screen cellulase-producing strains.The strains were identified by morphological,physiological,biochemical characteristics and 16S rDNA sequence analysis.The optimal fermentation conditions of strain AF1 were screened by orthogonal experiments.Five cellulase-producing strains with high activity were obtained and identified as two strains of Bacillus subtilis and three strains of Bacillus amyloliquefaciens.The ratio of the hydrolytic circle diameter and colony diameter of the five strains was more than 4.5,and AF1 was the maximum reaching to 8.04.The optimal solid fermentation medium for AF1 strain was:corn straw powder 20 g,NaCl 0.4 g,CaCl2 0.2 g,bran 32 g,twain 80 0.2 g,peptone 0.7 g,(NH4)2SO4 0.8 g,KH2PO4 0.5g,MgSO4·7H2O 0.04 g,molasses 0.4 g,twain 20 0.4 g,water 115 mL;The optimal physical and chemical fermentation conditions were as follows:temperature 30°C,pH 6.5,inoculum amount 1.5%(OD600=1.0).And under these optimal conditions,the maximum α-amylase activity is obtained 26.904 U/g after 42 h,which could provide strain source for cellulase preparation research and bio-energy development.

Key words: cellulase, 16S rDNA, strain identification, Bacillus, fermentation conditions

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