Bacillus sp. strain DJ-1, potent arsenic hypertolerant bacterium isolated from the industrial effluent of India.

Arsenic hypertolerant bacterial cells were isolated from the common industrial effluent treatment plant, Vapi, India. Strain DJ-1 sustaining 400 mM, As (V) out of 16 bacterial strains was identified as Bacillus sp. strain DJ-1 through 16S rRNA ribotyping. The maximum arsenic accumulation of 9.8+/-0.5 mg g(-1) (dry weight) was observed during stationary phase of growth. Intracellular compartmentalization has shown 80% of arsenic accumulation in cytoplasm. The lack of arsC gene and arsenate reductase activity indicated that Bacillus sp. strain DJ-1 may lack classical ars operon and detoxification may be mediated through some novel mechanism. The arsenite binding protein was purified by affinity chromatography and characterized as DNA protection during starvation (DPS) protein by electrospray ionization mass spectrometry. The induction of DPS showed the adaptation of bacteria in arsenic stress condition and/or in detoxification mechanism, relies on its ability to bind with arsenic. These results indicate the hypertolerance with higher intracellular accumulation of arsenic by Bacillus sp. strain DJ-1, which could be mediated by DPS protein thus signifying this organism is a potential candidate for the removal of arsenic from industrial wastewater, which needs further study.