Determination of optimal conditions for the cellulase production ability of selected soil-borne fungal isolates under submerged fermentation.

Cellulase-driven enzymatic hydrolysis of lignocellulosic biomass plays a crucial role in its bioconversion into renewable biofuels. The present study aimed to identify soil-borne microfungal isolates for their cellulase producing ability. Total of eleven species were selected based on their hydrolytic screening assay. The selected isolates were cultivated on four different substrates supplemented czapeck broth (i.e., corncob, wheat straw, black poplar wood, and CMC) under varying conditions of temperature, incubation time, and pH. The data were analyzed using two-factor analysis of variance (ANOVA) with interaction effect. The results revealed highly significant variability in enzyme activities in response to different substrates, pH levels, temperatures, and incubation periods. Among the tested isolates, Fusarium sp. (LMPP-24-S2) exhibited the highest endoglucanase (1.84 U/mL) and exoglucanase (2.17 U/mL) activities, while Penicellium oxalicum showed the highest β-glucosidase activity (9.09 U/mL) in corncob medium. These findings suggest that Fusarium sp. (LMPP-24-S2) and P. oxalicum are efficient producers of cellulolytic enzymes and that corncob serves as an effective substrate for an optimal cellulase induction. Maximum productivity was achieved at 30 °C, pH 5, and a 7-day incubation period. Especially, four isolates of this study comprising Clonostachys epichloë, Stagonosporopsis cucurbitacearum, Bipolaris cynodontis, and Pyrenochaetopsis leptospora were reported for the first time for their cellulase-producing potential.