Identifying additives for cellulase enhancement-A systematic approach

- Additives influenced the functionality of endoglucanase, exoglucanase and β-glucosidase.
- The different cellulases exhibited distinct affinity towards different additives.
- CaCl2 and Tween 20 improved the synergism of the cellulase cocktail.
- Pretreatment of empty palm fruit bunch (substrate) was necessary for high sugar yields.

The use of cellulases to obtain useful biochemicals from cellulosic feedstocks has been a research of high interest. The enzymes hydrolyze the glycosidic linkages within the cellulose matrix to yield useful intermediate products for diverse biotechnological use. Recent practices in cellulose depolymerization have witnessed the use of biological and chemical additives to improve the performance of these cellulases. However, there is a scanty information on this development which systematically assess the enzyme-additive effect on model substrate vis-à-vis lignocellulosic biomass. Such information is relevant in the selection of additives to target certain cellulases, especially in an enzyme concoction. Herein, we report the effects of additives, such as MgCl2, ZnSO4, KCl, CaCl2, Triton X-100, Tween 20 and EDTA on the functionalities of endoglucanase, exoglucanase and β-glucosidase from Trichoderma reesei, using model substrates, pure cellulose and pretreated empty palm fruit bunch (EFB). The distinct cellulases displayed diverse selectivity towards certain additives. However, CaCl2 and Tween 20 exceptionally improved the enzyme synergism on cellulosic feedstock. The results demonstrate the need to consider enzyme synergism in selecting additives for an enzyme cocktail.

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