Resonance Raman spectra for the in-situ identification of bacteria strains and their inactivation

Abstract

The resonance Raman spectra of bacterial carotenoids have been employed to identify bacterial strains and their intensity changes as a function of ultraviolet(UV) radiation dose have been used to differentiate between live and dead bacteria. The enhanced resonance Raman spectra of color-pigmented bacteria were recorded after excitation with visible light diode lasers. In addition, the resonance enhanced Raman spectra enabled us to detect bacteria in water at much lower concentrations (~108 cells/mL) than normally detected spectroscopically. A handheld spectrometer capable of recording resonance Raman spectra in-situ was designed, constructed and was used to record the spectra. In addition to bacteria, the method presented in this paper may also be used to identify fungi, viruses and plants, in-situ, and detect infections within a very short period of time.