Study On The Screening, Identification, Growth Condition And Cellulase Production Of A Cellulolytic Bacterium With High Performance

Cellulase producing microbes played important roles in the transferring of cellulose resource, improving the utility of food for animals and removing environmental pollutant. The screening and cellulase production study of cellulolytic micribes was the basis for the purpose.CMC medium was used in this study to isolate cellulose degrading bacteria. As a result, twelve strains were obtained from the soil, three strains of which, 8, E and F had higher cellulose activities which were 5.73 U/mL,13.07 U/mL and 15.60 U/mL, respecitively. Morphological and biophysical properties showed that strain F might be a strain of Bacillus subtilis. Furthermore, the 16S rRNA gene of F strain was coloned and sequenced, BLAST anaylysis about the sequence showed that F strain harbouring the gene was a Bacillus subtilis.Then, the cellulase yielding conditions of F strain were further studied. The study about the effects of different conditions such as temperature (25℃, 30℃, 37℃, 42℃, respecitvely) and PH(5.0, 6.0, 7.0, 8.0, respecitvely) on cellulase production showed that the optimal condition of cellulase production was 30℃and pH 7.0. When growing in the liquid medium under different concentration of Ca²⁺, Mg²⁺, and Mn²⁺, the bacteria performed different cellulase productivity. The results showed that the optimum concentration for Ca²⁺ and Mn²⁺were 0.007 mmol/L and 0.013mmol/L respectively, while Mg²⁺ promoted the cellulase productivity of strain F within the concentration of 6.275 mmol/L.The study made great significance to the employment of the strain to agricultural and industrial production.