Direct chemical editing of Gram‐positive bacterial cell walls via an enzyme‐catalyzed oxidative coupling reaction

Chemically manipulating bacterial surface structures, a cutting‐edge research direction in the biomedical field, predominantly relies on metabolic labeling by now. However, this method may involve daunting precursor synthesis and only labels nascent surface structures. Here, we report a facile and rapid modification strategy based on a tyrosinase‐catalyzed oxidative coupling reaction (TyOCR) for bacterial surface engineering. This strategy employs phenol‐tagged small molecules and tyrosinase to initiate direct chemical modification of Gram‐positive bacterial cell walls with high labeling efficiency, while Gram‐negative bacteria are inert to this modification due to the hindrance of an outer membrane. By using the biotin‒avidin system, we further present the selective deposition of various materials, including photosensitizer, magnetic nanoparticle, and horseradish peroxidase, on Gram‐positive bacterial surfaces, and realize the purification/isolation/enrichment and naked‐eye detection of bacterial strains. This work demonstrates that TyOCR is a promising strategy for engineering live bacterial cells.