Screening of Cellulose-Degrading Bacteria and Optimization of Enzyme-Production Conditions

Bacteria,which could effectively degrade the cellulose,was isolated and screened from the rotting straw soil.The classification of this bacteria and its optimal enzyme production conditions were determined.The sodium carboxymethyl cellulose hydrolysis circle method,filter paper disintegration,enzyme activity determination method were used to screen bacteria strains.The effects of straw length,incubation time,nitrogen sources,nitrogen dosage and pH value on enzyme production were inverstigated in straw enzyme production medium.Two strong degradation ability strains were isolated,which were named XY2 and XY6 respectively.Through the 16 S rRNA sequence analysis,strain XY2 belongs to the Burkholderia mimosarum;strain XY6 belongs to the Enterobacter.The optimal enzyme production conditions for strain XY2 is 30 ℃,pH 6.0,4 cm straw segment as the carbon source,0.5% ammonium sulfate as the nitrogen source;for strain XY6,the optimal enzyme production conditions is 30 ℃,pH 6.0 for rice straw or 8.0 for wheat straw,4 cm straw segment as the carbon source.And 5‰ sodium nitrate for rice straw or ammonium sulfate as the nitrogen source for wheat straw.The enzyme activities changed a little in a week.