Enzymatic Properties of Cel5B and Cel7 A-2 from Penicillium oxalicum and Their Role in the Enzymatic Saccharification of Lignocellulose.

Abstract

Cellulase cocktails play a crucial role in enzymatic saccharification of lignocellulosic biomass, a critical step in sustainable biofuel production. However, the efficiency of cellulase cocktails remains suboptimal due to incomplete understanding of enzyme synergy. In this study, we aimed to enhance biomass hydrolysis by optimizing the synergistic action of recombinant Cel5B, an endoglucanase and Cel7A-2, cellobiohydrolase from Penicillium oxalicum within a reconstituted cellulase system. Both enzymes were successfully expressed, purified, and characterized to optimize their synergistic action. The enzymatic properties of both enzymes were assessed, revealing optimal activities at 55-65°C and pH 4.2-4.8. Their combined action significantly enhanced the hydrolysis of filter paper and corncob residues. Using a central composite design, enzyme ratios were optimized to 11.6% rCel7A-2, 23.7% rCel5B, and 31.7% β-glucosidase. This formulation achieved the predicted glucan conversion of 58.1% for corncob residue hydrolysis, with experimental validation yielding 57.2%, demonstrating a 98.5% agreement with the model. Compared to the that of the commercial cellulase produced from P. oxalicum (38.1%), the optimized process improved glucan conversion by 50.1%. These findings demonstrate the effectiveness of rational enzyme synergy optimization and provide valuable insights into the strategy for improving the lignocellulosic biomass saccharification efficiency of the cellulase system.