Transcellobiosylation Reactions Catalyzed by Different Exoglucanase Components of a Trichoderma viride Cellulase in Aqueous Organic Solvent

The contribution of three exoglucanases from a commercial Trichoderma viride cellulase to transcellobiosylation, and the tolerance of these enzymes to acetonitrile co-solvent were studied. The enzymatic reactions were performed with p-nitrophenyl-β-d-cellobioside as the starting substrate. Among these enzymes, the least anionic exoglucanase (Exo I) showed the highest transcellobiosylation activity and acetonitrile tolerance. Exo I retained considerable activity even in 30% MeCN/water and produced p-nitrophenyl-β-d-cellotetraoside at about 1.5% conversion from the initial substrate in 30% MeCN/water. The residual activity of Exo I after incubation in MeCN/water mixture was almost identical to that of the crude cellulase and a considerable amount of the transcellobiosylation properties of the crude cellulase seemed to be attributable to this Exo I component.