Screening And Cultural Condition Optimization Of Cellulase Producing Strains And Its Enzymatic Properties

Cellulase, a kind of hydrolytic ferment is a complex enzyme system that containsendoglucanase, cellobiohydrolase and β-glucosidase.13bacterial strains with the activity of cellulase were obtained. A strain withhigh enzyme activity numbered XW-13was screened out. It’s an exoenzyme. ItsCMC enzyme activity is62.50U/ml, and its filter paperlyase is63.43U/ml.The fermentation condition experiment and orthogonal test shows that the bestsubstrate is: CMC-Na as carbon source, yeast as nitrogen source, KH₂PO₄and MgSO₄,pH7.0, inoculum concentration of5.0%,24hours.The enzymatic properties experiment shows that the suitable pH for reaction is7.0, and it has a stability between pH5.0to9.0with activity over60%. It it stablebelows20℃and it still has80%of its activity after kept at20℃for2hours. NH₄⁺,Na⁺, Fe²⁺, K⁺, Ca²⁺, Mn²⁺, Zn²⁺, Mg²⁺can promote the activity of cellulase at theconcentration of0.2mg/mL while Hg+and Cu²⁺can inhibit its activity.