Layer-by-layer assembled cellulase-based bioreactor with dual functions: Targeted biotransformation performances and enhanced photothermal antibacterial capabilities

• A core–shell cellulase-based bioreactor with dual functions was constructed. • The bioreactor increases the yield of phloretin by 122 times. • There was no reduction in conversion efficiency of the bioreactor after ten cycles. • The photothermal antibacterial rate of the bioreactor exceeded 85%. In this work, a core–shell cellulase-based bioreactor with dual functions was constructed, which can not only fully utilize their transformation characteristics but also can be used as photothermal antibacterial material. First, cellulose microspheres with porous nano-structure were used to immobilize enzymes. Subsequently, a molecularly imprinted layer was coated around the immobilized enzyme using dopamine as functional monomer and crosslinker. Therefore, the bioreactor achieved recognition and enrichment of phlorizin through targeted recognition sites on the surface of the shell structure. The bioreactor can convert phlorizin into phloretin , which can increase the yield of phloretin in lithocarpus litseifolius leaves extract by 122 times, and its conversion efficiency still maintained more than 95 % after 10 times of reuse. The molecular imprinting layer on the surface prepared with dopamine also showed excellent photothermal conversion characteristics. It was found that the bioreactor possessed good photothermal antibacterial abilities on both P. aeruginosa (antibacterial rate was 96.19 %) and B. subtilis (antibacterial rate was 85.98 %) via near-infrared light irradiation (808 nm). Moreover, the bioreactor with photothermal antibacterial property can effectively protect C. elegans from bacterial infections, and reduce the colonization of P. aeruginosa and B. subtilis in the C. elegans , thereby enhancing their survival rate. Our study offers a promising strategy to design a dual-functional bioreactor for the biotransformation of phytochemicals and expands the application of photothermal conversion technology in antibacterial fields.