Synergism of Endo and Exo-α-1,3-Glucanases in α-1,3-Glucan Degradation: A Kinetic Study

Biobased materials are promising alternatives to traditional fossil-derived synthetic polymers to mitigate greenhouse gas emissions and to provide end-of-life benefits addressing increasing environmental concerns. Biobased polymers with advantaged degradation and reuse characteristics have attracted increasing attention. In this work, a dual-enzyme system (combining endo α-1,3-glucanase Agl-ST from Streptomyces thermodiastaticus HF 3–3 and exo α-1,3-glucanase YgjK from Escherichia coli K12) was identified for the targeted degradation of α-1,3-glucan. The effects of pH, metal ions, enzyme concentration, temperature, and reaction time were investigated to assess the degradation characteristics of α-1,3-glucan using the synergistic enzyme system. After degradation under model conditions for 10 h, the dual-enzyme system achieved a weight loss rate of 29%, releasing 4.0 mM reducing sugar from 1% α-1,3-glucan. Binding behavior and degradation kinetics of α-1,3-glucanase on α-1,3-glucan were studied by a quartz crystal microbalance with dissipation monitoring. This dual-α-1,3-glucanase enzyme cocktail is a promising example for efficient biobased α-1,3-glucan polymer degradation, thereby contributing toward the concept of a circular economy.