Green immobilization of CdS-Pt nanoparticles on recombinant Escherichia coli boosted by overexpressing cysteine desulfurase for photocatalysis application

Herein, we propose a facile synthetic strategy for biogenic photocatalyst by sequentially immobilizing CdS and Pt nanoparticles (NPs) on engineered recombinant Escherichia coli (e-E. coli) strains. In particular, we transferred the cysteine desulfurase gene to the heterologous host to overexpress cysteine desulfurase and the resulting e-E. coli strain could serve as a biofactory for the extracellular growth of CdS NPs involving catalyzing L-cysteine (Cys) to form a reactive sulfur source, followed by the precipitation of CdS via the reaction between Cd2+ ions and the locally concentrated active sulfur source around the strain. The subsequent modification of e-E. coli/CdS composites with noble metal Pt NPs further enhanced the catalytic degradation performance towards organic dyes, due to suppressing the recombination of the photogenerated electron-hole pairs. Accordingly, the ternary e-E. coli/CdS/Pt composites emerged as robust photocatalysts for pollutant degradation in waste-water treatment, which is promising for environmental remediation in ambient conditions.