Enzymatic hydrolysis of pre-treated lignocellulose with Penicillium verruculosum cellulases

摘要

Pre-treatment of lignocellulosic materials is one of the essential keys for an economical process for bioethanol production. In this study natural pulping, a treatment method with performic acid, and pre-treatment with sodium hydroxide were compared. The aim of this study is to characterise and optimise the enzymatic hydrolysis of feedstock pre-treated in the named manner. For these investigations an alternative enzyme complex from Penicillium verruculosum was used. Both investigated pre-treatment methods increased the initial rate of enzymatic hydrolysis. In case of pre-treatment with sodium hydroxide, complete conversion of the substrate was observed after 5 h. The investigated cellulase complex exhibits significant advantages in comparison to the typically used Trichoderma reesei cellulase complex. This is demonstrated in a higher resistance towards ethanol for instance. Ethanol concentrations of up to 20g L~(-1) were shown to not affect enzymatic hydrolysis. Furthermore the β-glucosidase content of the investigated cellulase complex from P. verruculosum is twice as high as in the T. reesei complex. Hence it could be established that there is no accumulation of cellobiose. Thus there is no product inhibition of the enzyme complex while in the same course a higher hydrolysis rate was achieved.