Screening of Alkaline Cellulase-producing Strains and Research on Enzymatic Characteristics

【Objective】Strain with alkaline CMCase-producing ablities was screened from compost heaps and identified.Studies were conducted on the strain and its enzymatic characters.【Method】Strain C73was screened primarily through Congo-red agar plates and secondly by flask fermentation.The strain was identified by morphism speculation and 16SrRNA sequence analysis.Enzymatic properties of optimal activity pH,pH stablity,optimal activity temperature and thermo-stablity as well as influence of metal ions,SDS and EDTA on the enzyme were determined throuth DNS method.【Result】The strain was rod-shaped,gram-positive,non-sporulating and could grow at pH 8.0~11.0,30~37℃.Fermentation with CMC media showed maxium cell growth and CMCase avtivity peaks were reached at 40hand 50h,with the pH of system decreased to 9.5.Optimal CMCase activity pH was 10.0,while the CMCase activity reached2.3U/mL.60%of CMCase activity was obtained at the pH range of 8.0~11.0.Optimal CMCase activity temperature was 60℃and 60%of residual CMCase activity was obtained after incubation at 30~80℃for 1h.The addition of Mn2+,Co2+and(NH4)2SO4strongly inhibited CMCase activities.【Conclusion】Strain C73exhibited higher alkaline CMCase activity,higher pH stablity and thermo-stablity and had a potential in industrial application.