Bacterial surface display of metal binding peptides as whole-cell biocatalysts for 4-nitroaniline reduction

This study employed cells that express metal binding peptides on the surface for "green" synthesis of gold and platinum nanoparticles (NPs). We began by testing several surface display systems to investigate the expression of heterologous protein/peptides in Escherichia coli and Ralstonia eutropha. Cells with gold-binding-peptides on their surfaces were used to perform a quantitative comparison of labeling efficiency using gold NPs. Next, cells expressing metal binding peptides were used to simultaneously synthesize and display the metal NPs on the cell surfaces. Our results demonstrated the possibility of using microorganisms as whole-cell biocatalysts in the production and displaying of gold and platinum NPs for the reduction of 4-nitroaniline.