Differentiation of mixed bacteria samples in the generic level using infrared spectroscopy and multivariate analysis

Abstract

In the present study we examined the potential of Fourier Transformed Infrared (FTIR) spectroscopy for accurate identification and differentiation of mixed bacteria samples in a time span of a few minutes. The bacterial samples used in this study are Escherichia (E.) coli, Bacillus (B.) megaterium and a mixture of E. coli and B. megaterium. The best results of differentiation were obtained within the 675-1800 cm -1 range. In this range the dimension of the feature vector is 293. Principal components analysis (PCA) followed by linear discriminant analysis (LDA) as a linear classifier were performed on the spectra of the three measured classes. When differentiating between the pure sets of E. coli and B. megaterium, 100% success was obtained for a feature vector composed of the first 12 principal components (PCs). An error rate of less than 2% was achieved taking only the first 20 PCs among the three categories of samples.

Characterization of Ralstonia solanacearum Using Fourier Transform Infrared (FTIR) Spectroscopy

“…A large absorbance band at 1080 cm -1 is mainly contributed to carbohydrate and nucleic acid vibrations found in this region. The peak at 1080 cm -1 was attributed to PO2symmetric stretching of nucleic acids and phospholipids (Salman et al, 2014). Also, the peaks at 1050 and 970 cm -1 were found and assigned as PO2 very strong stretching, representative of glycopeptides and ribose as shown in Figure 5 (Maity et al, 2013).…”