771ISOLATION AND CHARACTERISATION OF EXOPOLYSACCHARIDES FROM A FEW SELECTED RHIZOBIUM SPECIESExopolysaccharides of the species Rhizobium leguminosarum, R. meliloti, and R. trifolii were isolated by culturing them in their respective specific growth media. R. leguminosarum was grown on Yeast Mannitol salt agar, R. meliloti on Yeast Extract Mannitol medium and R. trifolii on Tryptone Yeast extract medium. The broth culture was centrifuged after three days at 7500rpm at 4⁰C for 10 minutes. The cells were separated from the supernatant and the exopolysaccharides in the supernatant was precipitated by adding twice the volume of chilled ethanol. The assay was kept for overnight incubation and centrifuged at 10,000rpm for 10minutes at 4 ⁰C. The dried pellet was the extracted Exopolysaccharide. The FTIR analysis of EPS was characterized by using a Fourier Transform Infrared Spectrophotometer (Nicolet-380 FTIR Thermo scientific Omnic 7 software). The dried Exopolysaccharide was passed into FTIR Spectroscopy between the frequency ranges 500 to 4000 cm -1 with 32 scans. Different peaks were obtained from the vibrational spectra. The maximum peaks were obtained in the range of 1500 and 600 cm -1 . Peaks were also found in the range of 3500 and 2500 cm -1 . The C-H (Alkane) vibrational stretching was calculated to be in the region 2850 and 3000 cm -1 , then the =C-H (Alkene) vibrational bending was calculated between 675 and 1000 cm -1 . A combination band of –C-Cl and –C-Br (Alkyl Halide) vibrational stretching was calculated between 500 and 800 cm -1 , and were found to be common in the exopolysaccharides of the three Rhizobium speciesjoymarjorie@rediffmail.comResearch812017 Exopolysaccharides (EPS),Rhizobium,Vibrational spectra,FTIRJoy Marjorie Annal D,Rachel Regi DanielDepartment of Botany and Microbiology, Lady Doak College, Madurai - 2, Tamil Nadu, India,Department of Botany and Microbiology, Lady Doak College, Madurai - 2, Tamil Nadu, India