Photoelectrochemical sterilization of microbial cells by semiconductor powders

Abstract

We report the novel concept of photochemical sterilization. Microbial cells were killed photoelectrochemically with semiconductor powder (platinum-loaded titanium oxide, TiO2/Pt). Coenzyme A, (CoA) in the whole cells was photo-electrochemically oxidized and, as a result, the respiration of cells was inhibited. Inhibition of respiratory activity caused death of the cells. Lactobacillus acidophilus, Saccharomyces cerevisiae and Escherichia coli (103 cells/ml respectively) were completely sterilized when they were incubated with TiO2/Pt particles under metal halide lamp irradiation for 60–120 min.