The Preliminary Study On The Isolation And Identification Of Cellulose-producing Bacteria From Silage, Optimization Of Cultural Conditions And Enzyme-producing Conditions And Enzyme Property

This study has isolated a cellulose-producing Bacillus sp. ws-6, and optimized the fermental conditions and enzyme-producing conditions, and did a preliminary research on the enzyme property. The results are as follows:Isolation and identification of strains 6 CMCase producing strains are isolated from silage in Wusu. Among them, the ws-6 strain has highest level of CMCase activity. Through the observation of the morphology, the physiological and biochemical identification and the 16S rDNA sequencing analysis, the strain was identified as Bacillus licheniformis. The optimum pH for the bacteria is 5.0 7.0, the optimal growth temperature is 35℃, its CMCase activity is up to 2.55 U/mL.Enzyme Producing Conditions and Enzyme Properties of the Strain Through the screening and orthogonal design experiments of the carbon, nitrogen and trace elements, the most suitable components of medium for strain ws-6 to produce CMCase are found to be as follows (g / L): glucose 15 g, CMC-Na 5 g, yeast extract 15 g , KH₂PO₄ 0.5g, NaCl 5g. The optimal initial pH for enzyme-producing fermentation is 6.5, the optimal temperature is 35℃when cultivating in 250 mL conical bottle with 30 mL medium.The preliminary study on the enzyme properties of strain ws-6 indicate that the optimal pH for the enzyme is 5.0, the optimal temperature is 50℃, the optimal concentration of substrate is 0.6%, the optimal time for reaction is 20 min.Optimization of fermental condition Through the screening and orthogonal design experiments of the carbon, nitrogen and trace elements, the most suitable components of medium for strain's fermentation are found to be as follows (g / L): sucrose 60 g, peptone 30 g, NaCl 30 g, K₂HPO₄ 2 g, MgSO4 1 g, FeSO4 0.02 g, MnSO4 0.01 g. The research on fermental condition indicate that the optimal initial pH of fermentation is 5.5, the optimal temperature is 35℃with the optimal volume of liquid medium is 10 mL in 250 mL conical bottle. The strain ws-6's living barteria has reached 6.58×10¹⁰ CFU·mL(-1) after the optimization of the components of medium and cultivating condition.