Identification of Live and Dead Bacteria: A Raman Spectroscopic Study

Raman spectroscopy has been used to identify bacterial strains, bacterial components, such as protein and DNA bases, and the ratio of live to dead bacteria before and after exposure to ultraviolet (UV) radiation. New vibrational bands and changes in their intensity as a function of UV irradiation time have been recorded by high resolution Raman spectroscopy which made it possible to determine the mechanism of the UV inactivation of Escherichia coli (E. coli) , Serratia marcescens (S. marcescens) , and Micrococcus luteus (M. luteus) bacteria in saline solutions. We have also employed a novel, new, handheld spectrometer capable of recording, in situ , within minutes, the absorption, fluorescence, synchronous fluorescence, and Raman spectra of bacteria and other biological species and large molecules.