Production of ethanol from agricultural and wood wastes degraded by cellulases of Trichoderma harzianum

Abstract

The potentials of Trichoderma harzianum in the hydrolysis of agricultural and wood residues as natural lignocellulosic materials; for the production of ethanol were studied. Corn cob, groundnut shell and sawdust were used as cellulosic waste materials to induce the production of cellulases by T. harzianum. The enzyme produced was precipitated using Ammonium sulphate, characterized and used to hydrolyse alkali pre-treated cellulosic wastes. The product of hydrolysis was fermented to ethanol using the yeast Saccharomyces cerevisae. Among the three cellulosic waste materials tested, the endoglucanase and exoglucanase activity of 0.1494±0.0056 and 0.0820±0.0013 respectively, obtained in culture medium containing corn cob were significantly high (p < 0.05), when compared to those of groundnut shell (0.0532±0.0024 and 0.0229±0.0006) and sawdust (0.0235±0.0038 and 0.0117±0.0002). The optimum condition for the activity of the enzyme was 50oC and pH 5.0. Hydrolysis of corn cob with the cellulase yielded 2.83 mg ml-1 of sugar which produced 1.04% v/v ethanol on fermentation. Comparatively, the sugar yield from hydrolysis of groundnut shell and sawdust was too low for use in fermentation to ethanol. Although cellulases of T. harzianum degraded the three lignocellulosic waste materials to sugar, highest yield was obtained with corn cob. Consequently, corn cob was established as the most viable feedstock in the production of ethanol using the yeast S. cerevisae.