MOLECULAR CHARACTERIZATION OF ARSENIC RESISTANT BACTERIA ISOLATED FROM SEMI ARID COAL MINE TAILINGS OF ASSAM, INDIAALKA SINGH1, SURYA PRAKASH DWIVEDI, ALKA SRIVASTAVA AND PRAVEEN C. VERMA
North Eastern Coal mines soil and rhizospheric soils of Assam, India were sampled for arsenic resistant bacteria which could transform in different arsenic forms. Identification of Bacillus subtilis spp. was done by 16S rDNA ribotyping, capable of growing at 4500 mg/L, Rhodanobacter thiooxydans spp. at 7500 mg/L, Bacillus cereus spp. at 5000mg/L and Bacillus sp. at 7500 mg/L for arsenate As (V) and 1500 mg/L, 2000 mg/L, 1500 mg/L and 2500mg/L for arsenite as (III) respectively. Characterization of arsenic resistance genes of all the four bacterial strains was accomplished, probably associated with the high level of resistance in the ecosystem of arsenic contaminated areas. All the four potent strains were treated with 7500 mg/L As (V) to monitor changes in their protein expression profiles followed by comparison in their protein profiles. A sodium dodecyl sulphate gel of arsenic treated and untreated all the three bacterial cultures, entailed a significant difference in their proteome analysis. Assessment was also done on the change in the pH of the cultivating growth medium, growth pattern (kinetics) of the bacterial cultures and absorption of arsenic. After 3-4 days of incubation, the strains were capable of removing arsenic from the culture medium amended with arsenate and arsenite. Bacterial strains were isolated from semi arid coal mine tailings of Assam followed by identification and characterization based on the presence of ars genotype features. Data obtained from the present study reflect their ability to survive in growth medium containing excessively high arsenic concentrations, which would be considered a good evidence for their As-resistant characteristic and thus suggest a potential application for bioremediation of As contaminated abandoned mines in Assam.
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