Screening of a Thermostable Cellulase-secreting Bacillus from High Temperature Daqu

The Bacillus that can produce cellulase is isolated and purified from the high temperature Daqu,based on the analysis of 16SrDNA and some biochemical and physiological characteristics,this strain was identified as Bacillus cereus Frankland.The shake flask liquid fermentation was taken to determine the endo-cellulase activity(260.32 u·mL-1),and exo-cellulase activity(87.22 u·mL-1),the solid state fermentation was taken to determine the endo-cellulase activity(556.64 u·mL-1)and exo-cellulase activity(121.47 u·mL-1).High heat and pH stability of cellulase activity are observed at temperature lower than 60 ℃ and pH4～8.After the response surface method optimization,the cellulase activity of solid state fermentation increased to 1 643.27 u·mL-1.