Deciphering heterogeneous enzymatic surface reactions on xylan using surface plasmon resonance spectroscopy

Journal article, 2024

Xylans' unique properties make it attractive for a variety of industries, including paper, food, and biochemical
production. While for some applications the preservation of its natural structure is crucial, for others the
degradation into monosaccharides is essential. For the complete breakdown, the use of several enzymes is
required, due to its structural complexity. In fact, the specificity of enzymatically-catalyzed reactions is guided by
the surface, limiting or regulating accessibility and serving structurally encoded input guiding the actions of the
enzymes. Here, we investigate enzymes at surfaces rich in xylan using surface plasmon resonance spectroscopy.
The influence of diffusion and changes in substrate morphology is studied via enzyme surface kinetics simulations, yielding reaction rates and constants. We propose kinetic models, which can be applied to the degradation
of multilayer biopolymer films. The most advanced model was verified by its successful application to the
degradation of a thin film of polyhydroxybutyrate treated with a polyhydroxybutyrate-depolymerase. The herein
derived models can be employed to quantify the degradation kinetics of various enzymes on biopolymers in
heterogeneous environments, often prevalent in industrial processes. The identification of key factors influencing
reaction rates such as inhibition will contribute to the quantification of intricate dynamics in complex systems.