Characterization of cellulases and hemicellulases produced by Trichodermareesei on various carbon sources

Abstract

Cellulase and hemicellulase enzymes were produced by Trichoderma reesei RUT C30 on steam pretreated spruce, willow, corn stover and delignified lignocellulose (Solka Floc), as a reference. The enzymes produced were characterized by protein and various enzyme activity measurements. On steam pretreated corn stover higher cellulolytic enzyme activities were reached than on Solka Floc, while the activities obtained on steam pretreated spruce and willow were considerably lower. The produced and two commercial cellulases (Celluclast 1.5 L and Econase CE) were compared by determining specific activities. There were minor differences among the enzymes corresponding to their specific cellulase activities. In contrast, within hemicellulase and β-glucosidase activities, the differences were found to be more significant. It should be also noted that commercial cellulases had considerably higher specific acetyl xylan esterase activities than the produced enzymes. According to subsequent hydrolysis experiments, performed to characterize the produced enzyme complexes to evaluate their applicability for hydrolysis and enzyme production, it seems that the application of the enzyme that was produced on the same substrate as was used for hydrolysis can be advantageous in the case of some substrates. As a result, these experiments demonstrated that pretreated corn stover is a good substrate both for enzyme production and hydrolysis, since high cellulolytic activities could be reached using it as carbon source. Moreover, high sugar yields could be obtained in the hydrolysis by the enzyme produced on steam pretreated corn stover.