IDENTIFICATION AND CHARACTERIZATION OF TOLUENE DEGRADING SULPHUR-OXIDIZING BACTERIA FROM ACID MINE DRAINAGE SAMPLE OF BARJORA COAL MINE, WEST BENGAL, INDIA.

Two different neutromesophilic sulphur oxidizing bacteria, strain SOB1 and N2 were isolated from acid mine drainage water sample of Barjora Coal Mine with thiosulfate as electron donor and CO2 as carbon source. Heterotrophic growth was checked in thiosulphate agar media supplied with glucose (5 mM), fructose (5 mm), acetate (20 mM), peptone (0.1 %, w/v) and yeast extract (0.1 %, w/v). Strain SOB1 and strain N2, both were facultative chemoautotroph. These two bacteria were able to degrade toluene. The organisms were strictly aerobic. Growth were observed between pH values of 5-7.5 with an optimum growth at pH 6-7. The temperature limit for growth was 25-35?C with an optimum growth between 28-30?C. Heavy metal tolerence tests were carried out where strain SOB1 and N2 were able to grow in the presence of arsenic, copper, chromium, cadmium, cobalt, lead and zinc. The bacterium showed resistance against several antibiotics such as ampicillin, tetracycline, rifampicin, kanamycin and streptomycin. Based on the almost complete sequence of the 16S rRNA gene, strain SOB1 was found to form a polygenetic cluster with Bacillus pumilus, Bacillus sufensis and Bacillus cereus. Strain N2 formed phylogenetic cluster with Enterobacter hormaechai and Enterobacter sp. which showed 99% similarities.