Molecular Insights into the Rhamnolipid-Promoted Enzymatic Performance on Removing Phenolic Pollutants

Horseradish peroxidase (HRP) is a metalloenzyme widely used in various biochemical applications but is susceptible to activity loss and instability under suboptimal conditions. In this study, rhamnolipid (RL) was, for the first time, employed as an additive to enhance the catalytic performance of HRP, including in a dual-enzyme cascade system with glucose oxidase (GOx). We carried out catalytic experiments on phenol degradation and showed that protecting HRP from deactivation is critical in maintaining the high catalytic effect in the dual-enzyme cascade. The computational simulation revealed that the selective binding between polyphenolic products with RL clears the side products at the active pocket of HRP, maintaining the accessibility and high catalytic activity of HRP to phenolic substrates. This work discovered the underpinned mechanism in RL-protected enzyme-catalysis, enabling advanced design and widespread application of natural enzymes in organic removal and water remediation.