Isolation and Screening of Cellulolytic Fungi from Cocoa Pod Husks and Optimization Conditions for Cellulase Production

This study aimed at isolating fungi from cocoa pod husks, screen for their ability to degrade cellulose, optimize, produce and purify cellulase. Cocoa pod husks were obtained from Badeku area of Oyo State. The isolates that showed consistent zone of hydrolysis and negative for aflatoxin production were used for cellulase production. Cellulase activity was measured in terms of FPUase and CMCase. A total of 23 fungal isolates were obtained from cocoa pod husk out of which 12 showed a consistent zone of hydrolysis. The fungal isolates were: Aspergillus niger CH2, A. niger CH4, A. flavus CH5, Fusarium oxysporium CH8, A. niger CH10, A. flavus CH13, A. niger CH15, Phytophthora sp. CH16, A. niger CH18, A. niger CH20, A. flavus CH21, A. niger CH23. A. niger CH4 and F. oxysporium CH8 were the isolates used in this study. Incubation time, pH, temperature and substrate concentrations were the parameters used for the optimization of cellulase. The preferred optimized conditions determined for the production of cellulase by A. niger CH4 were 96 hrs, pH 5.5, 30°C and 5% CPH concentration while for F. oxysporium CH8 they were 72 hrs, pH 5.9, 30°C and 4% CPH concentration. Endoglucanase activity was higher in F. oxysporium CH8 while exoglucanase was higher in A. niger CH4. The purification of the ammonium sulphate purified cellulase enzyme using Sephadex G-200 gel filtration increased A. niger CH4 cellulase activity by 1.49-times while that of F. ox¬ysporium CH8 increased by 1.63-times. A. niger CH4 and F. oxysporum CH8 can be used for the production of cellulose.