LIGNOCELLULOLYTIC ENZYME ACTIVITIES AND PROCESS EFFICIENCY OF DEGRADATION OF CORN COB BY SPOROTHRIX CARNIS AND FUSARIUM OXYSPORUM

Abstract

Two white rot fungal isolates (Sporothrix carnis and Fusarium oxysporum) were cultivated in a fermentation medium at 30 °C and 160 rpm for 6 days in a shaking incubator. The cellulose, hemicellulose and lignin contents of the lignocellulosic biomass (corn cob) were determined and the efficiency of degradation of corn cob by the two organisms was evaluated by determining the amount of fermentable sugars and enzymes produced under varying substrate concentrations. The result indicated that the cellulose, hemicellulose and lignin content of the corn cob were 37.8%, 42.15% and 12.7% respectively. The maximum cellulase and xylanase activity at 25 % substrate concentration were 745.47 U/ml and 1612.89 U/ml from Fusarium oxysporum; 820.37 U/ml and 1653.18 U/ml from Sporothrix carnis respectively. The most efficient substrate concentration for the production of enzymes and fermentable sugars was 10.0 %. This concentration supported an impressive increase in enzymatic activity as well as the remarkable production of sugars by both organisms. Increasing the concentration beyond 10.0 % only caused marginal increases. This study shows that Sporothrix carnis is more efficient than Fusarium oxysporum in the production of fermentable sugars and enzymes from lignocellulolytic biomass which has the potential for use as source of biofuel.