Screening, Identifying of Cellulose-decomposing Strain L-06 and Its Enzyme-producing Conditions

The strain of L-06 with high cellulase activity was screened from rice straw compost and classified as Penicillium decumbens by the analysis of its morphology and 18S rDNA gene sequences. Different conditions of liquid fermentation medium including nitrogen source, carbon source, surfactant, temperature, initial pH, inoculation quantity for the production of cellulase had been studied. The maximal β-1,4-glucosidase (BGL) activity was 1662 u/mL, which is 1.49 times than the initial activity, and the maximal exo-β-1,4-glucanases (CBH) activity was 2770 u/mL, which is 1.36 times of the previous, cultured in the optimal condition for three days. And the maximal endo-β-1, 4-glucanases (EG) activity was 18064 u/mL, which is 1.87 times of the previous, and the maximal filter paper enzyme (FPase) activity was 4035 u/mL, which is 1.47 times of the previous, cultured in the optimal condition for four days. In the optimization experiments, the EG and CBH in the culture condition (pH 10) maintained 70% and 43% activity. In the culture condition (50°C), EG and CBH maintained 59% and 68% activity, which showed heat and alkali resistant characteristics.