Process optimization of β-glucosidase production by a mutant strain, Aspergillus niger C112

Abstract

Enzymatic saccharification is a key step in the green conversion of lignocellulose to biofuels and other products. A key deficiency in common biocatalytic systems, such as Trichoderma reesei, is the insufficient presence of β-glucosidase (BGL). This study intended to develop an efficient process of BGL production as an enhancement to the T. reesei system. The authors investigated the process optimization of BGL by the mutant strain Aspergillus niger C112, which was previously developed in the authors’ laboratory. The culture medium and process (carbon, nitrogen, temperature, and pH) were optimized for cost-effective BGL production, which led to a maximum BGL activity of 8.91 ± 0.35 U/mL. In addition, the dynamics of the physio-chemical parameters (zeta potential and dissolved organic matter) of the process were studied and showed good correlations to the yield of BGL. Furthermore, a three-dimensional excitation-emission matrix fluorescence spectroscopy was successfully applied for analyzing the component, origin, and dynamics of dissolved organic matter, which contributed to a further understanding and optimization of BGL production.

A novel sucrose-inducible expression system and its application for production of biomass-degrading enzymes in Aspergillus niger

“…In this study, the sucrose-inducible expression system was successfully utilized for the production of a BGL from A. niger C112, which is the rate and cost-limiting enzyme for efficient utilization of cellulose. The BGL activity of FBL9 could reach 17.84 U/mL, which is higher than the previous report, in which the BGL yield ranged from 5.87 to 8.91 U/mL in different expression systems [ 63 , 64 ]. Notably, the enzyme samples could be obtained directly from the supernatant after 72 h of cultivation without any purification procedure, and the purity of the secreted aBGLA was estimated to be over 86% (Fig.…”

Optimization of mixed enzymolysis of acid-exploded poplar wood residues for directional bioconversion

“…Cellulase is a multi-enzyme that consists of at least three different enzyme families, namely, cellobiohydrolase (CBH), endoglucanase (EG), and β-glucosidase (βG). These enzymes synergistically hydrolyze cellulose into reducing sugars, which are then fermented into targeted products (Zhan et al 2017). Most commercial cellulases, including CBHs and EGs, have been produced by Trichoderma reesei (Xia et al 2018).…”