leading to shifts in band centers from known values, asof bacteria (>1010) into the KBr, in 2nd panel and upward, progressively
lesser number of cells were added to the corresponding KBr
pellet preparation. It is evident here that although the noise level
increases with progressive cell dilution the overall pattern of the
spectra remains same, especially within wavenumber 2000 and
1000 cm1. Even at lower cell number the peak at approximate
wavenumber 1068 cm1 is present and seems to be the signature
peak for all the strains of B. subtilis obtained from NBP. We conclude
that 1068 cm1 specific absorption maxima is because of
bending vibration of some characteristic carbohydrate moiety as
Naumann (2000) postulated that the 1200–900 cm1 region
belongs to carbohydrates. In our experimental condition cell number
below 103 gives a fuzzy and noisy spectra and the basic motif of
the spectra gets lost. However, sensitivity of an FTIR instrument
depends largely on the detector used. In the present study DTGS
detector was employed. A more sensitive detector e.g. MCT (mercury
cadmium tellurium) detector or a sensitive bolometer is likely
to substantially increase the sensitivity of bacterial detection.