MINERALIZATION OF BACTERIAL-CELL MASS ON A PHOTOCATALYTIC SURFACE IN AIR

Whole cells deposited on a titanium dioxide-coated surface have been o xidized in air to carbon dioxide via photocatalysis. This paper provid es the first evidence that the organic matter in whole cells can be co mpletely oxidized. Three experimental techniques were employed to moni tor this reaction: scanning electron microscopy, C-14 radioisotope lab eling, and batch reactor measurements. The scanning electron microscop y experiments illustrate the disappearance of Escherichia coli cell ma ss. The C-14 radioisotope labeling experiments establish that the carb on content of E. coli is oxidized to form carbon dioxide with substant ial closure of the mass balance. The batch reactor experiments corrobo rate the mass balance and provide a preliminary indication of the rate of the oxidation reaction. These results provide evidence that a phot ocatalytic surface used for disinfection can also be self-cleaning in an air-solid system.