Separation, Screening, Fermentation And Enzymatic Characteristics Of Bacterium Producing Alkaline Cellulase

In this article , a actinomycete (Prauseria) strain IS-H with high enzyme activity was selected from soil samples. The fermentative conditions , enzymatic system and characteristics of strain IS-H were studied in shaking flask culture. Result shows that the optimal conditions for it were 28 ℃, pH 8 and the inoculation dose was 6% in shaking flask culture for 5 days . Its enzyme activity reached to 7.64U/mL. This strain can produce alkaline cellulase (CMC enzyme), which was mostly composed by Cx enzyme. The optimal temperature of enzymatic reaction was 40℃, its enzyme activity can maintain above 60% at a pH of 6¹1, a temperature of 10⁶0℃. These results could have promising applications in detergent. We screened a mutant strain MS-H₁₆ with high enzyme activity by heating the original strain IS-H with UV several times, at the same time, the component of culture medium and fermentation condition were optimized. Result shows that when 20g/L sucrose as carbon source, 10g/L NH₄NO₃ as nitrogen source, 0.5g/L MgSO₄ as metal ion, 26℃,pH 8 and the inoculation dose was 6% in shaking flask culture for 5 days, its enzyme activity was improved to 18.29U/mL, increased 6.29 times.In addition, we took the spore bacillus (B.macerans) which can produce alkaline cellulase as the original strain IS-B. At the same time, the component of culture medium and fermentation condition were optimized. Result shows that in shaking flask culture, when 4.0% maltose as carbon source, 1.0% peptone as nitrogen source, inoculation dose was 5%, the time of germ culture was 24h, pH 9, nutrient salt mass parts was 0.5% NaCl and 0.1% KH₂PO₄, medium capacity was 75mL/250mL, fermented for 48h, its enzyme activity reached to 85.69U/mL. In ferment pot (5L ),when the stirring speed was 400r/min, aeration was l.OL/min, the inoculation dose was 5%, the time of germ culture was 24h, pH 10, 37°C fermented for 48h, the solubility of oxygen could keep above 65%, its enzyme activity was improved to 130.10U/mL, achieved the national level basically. At the same time, the characteristics of the enzyme were studied, result shows that the optimal temperature of enzymatic reaction was 50°C, its enzyme activity can maintain above 60% at a pH of 7-10, a temperature of 30⁷0°C. It had a preferable stability of enzyme activity.