Cellulases, xylanases, β-glucosidase and ferulic acid esterase produced by Trichoderma and Aspergillus act synergistically in the hydrolysis of sugarcane bagasse

Abstract

Trichoderma reesei and Aspergillus awamori enzymes were concentrated, pooled and assessed for the hydrolysis of steam-pretreated sugarcane bagasse. The enzyme profile of T. reesei gave (IU/L): 1700 FPA, 20,000 CMCase, 340 β-glucosidase and 12,600 xylanase. FPA and CMCase activities that were 4-fold higher than those of A. awamori (420 and 4900 IU/L, respectively). However the β-glucosidase and xylanase activities were 134- and 6-fold lower than those of A. awamori (45,600 and 79,100 IU/L, respectively). Furthermore, A. awamori produced ferulic acid esterase (160 IU/L) which acts synergistically with cellulolytic–xylanolytic enzymes in the hydrolysis of lignocellulosic materials. The FPA and CMCase activities in the T. reesei– A. awamori blends were enhanced synergistically by 2-fold. Moreover, the hydrolytic effectiveness of the blends was superior to the use of unblended T. reesei or A. awamori enzymes, under corresponding conditions (10 FPU/g bagasse, 20 g bagasse/L and 50 °C). Hydrolysis experiments, presenting either 20 or 200 g/L bagasse, resulted in 3.9 or 40 g glucose/L, respectively. These values corresponded to 41% cellulose hydrolysis within 6 or 24 h, respectively. A. awamori enzymes hydrolyzed 91% (1.7 g/L xylose) of the residual xylan in the bagasse within 6 h in experiments presenting 20 g/L bagasse.