Dynamic synergistic effect on Trichoderma reesei cellulases by novel β-glucosidases from Taiwanese fungi

Dynamic synergistic effects in cellulosic bioconversion have been revealed between Trichoderma reesei cellulases and β-glucosidases (BGLs) from six Taiwanese fungi. A high level of synergy (8.9-fold) was observed with the addition of Chaetomella raphigera BGL to T. reesei cellulases. In addition, the C. raphigera BGL possessed the highest activity (V(max)/K(m)=46.6 U/mg mM) and lowest glucose inhibition (Ki=4.6mM) with the substrate 4-nitrophenyl β-d-glucopyranoside. For the natural cellobiose substrate, however, the previously isolated Aspergillus niger BGL Novo-188 had the highest V(max)/K(m) (0.72 U/mg mM) and lowest Ki (59.5mM). The demonstrated dynamic synergistic effects between some BGLs and the T. reesei cellulase system suggest that BGLs not only prevent the inhibition by cellobiose, but also enhance activities of endo- and exo-cellulases in cellulosic bioconversion. Comparisons of kinetic parameters and synergism analyses between BGLs and T. reesei cellulases can be used for further optimization of the cellulosic bioconversion process.