Arsenic accumulating bacteria isolated from soil for possible application in bioremediation

Twenty six arsenic (As) resistant bacterial strains were isolated from As contaminated paddy soil of West Bengal, India. Among them, 10 isolates exhibited higher As resistance capacity and could grow in concentration of 12000 mg l(-1) of arsenate (AsV) and 2000 mg l(-1) of arsenite (AsIII) in growing medium. Maximum growth was observed at 1000 mg l(-1) and 100 mg l(-1) in case of AsV and AsIII respectively. Results of incubation study carried out in basal salt minimal media (BSMY) containing 25 mg l(-1) of AsV and AsIII separately showed that the isolates could accumulate 1.03 - 6.41 mg l(-1) of AsV and 2.0 - 7.6 mg l(-1) of AsIII from the media. The bacterial isolate AGH-21 showed highest As accumulating capacity both for AsV (25.64%) and AsIII (30.4%) under laboratory conditions. The isolates AGH-21 (NCBI accession no: HQ834295) showed highest sequence similarity (98%) with Bacillus sp. and could be used as a potential bioremediator in future to combat with arsenic toxicity.