Screening, Isolation, Identification of Botryosphaeria dothidea and Its Cellulase Production from Corn Bran

A strain, which demonstrated the capacity of cellulase production from corn bran, was isolated from rotten apple and has been identified as Botryosphaeria dothidea by 18S rDNA sequence. The effects of corn bran concentration, pH, and temperature on cellulase production were studied and the most optimal parameters were 40 g/L corn bran (dry basis), 42 °C, and pH 3.8, respectively. Elimination of MgSO₄, nitrogen sources (urea) and trace elements (Fe²⁺, Cu²⁺, Zn²⁺, Co²⁺ and Mn²⁺⁾ from the medium had no influence on the cellulase production, whereas reduced yield of cellulase was observed when phosphate or CaCl₂ was removed. Based on those results, the final medium composition was simplified with corn bran plus KH₂PO₄, CaCl₂, tween-80 and CoCl₂. Using this medium, cellulase activity reached 4.039 IU/mL of filter paper activity (FPA), and 3.407 IU/mL of CMC enzyme activity after 4-5 days incubation. Corn bran and CMC-Na were the best substrates for cellulase production from Botryosphaeria dothidea. Current results demonstrated the potential applications of Botryosphaeria dothidea in the pollution control and process of bioenergy.