Partition of enzymes between the solvent and insoluble substrate during the hydrolysis of lignocellulose by cellulases

The interfacial and interphasic behavior of enzyme plays an important role in heterologous biocatalysis, such as the enzymatic hydrolysis of lignocellulose. The solid-solution partition of the major cellulases from a highly effective Trichoderma reesei cellulolytic system was evaluated during the enzymatic cellulolysis of a pretreated corn-stover substrate. Upon mixing with the insoluble substrate, almost all of the enzymes (including CBH-I, CBH-II, EG-I, EG-II, and BG) were adsorbed, as shown by the protein and activity assay of the solution fraction. No significant desorption was detected during as well as after the cellulolysis, indicating the enzymes’ ability to function at the lignocellulose surface. The adsorption was attributed to the specific binding to and activating of cellulose during the cellulolysis, and to the non-specific binding to lignin, particularly after the cellulolysis. The presence of several representative cellulolysis enhancers, substances capable of enhancing the cellulase action on lignocellulosic substrate, led to a significant desorption of the adsorbed cellulases. The effect might be related to the enhancing effect of these substances on the cellulases.