Culture-dependent study of arsenic-reducing bacteria in deep aquatic sediments of Bengal Delta
2021
Bandopadhyay, Chinmay | Manna, Sanjib Kumar | Samanta, Srikanta | Chowdhury, Atalanta Narayan | Maitra, Nilanjan | Mohanty, Bimal Prasanna | Sarkar, Keka | Mukherjee, Samir Kumar
Biogeochemical release of soil-bound arsenic (As) governs mobilization of the toxic metalloid into the groundwater. The present study has examined Asⱽ-reduction ability of bacteria from anoxic aquatic sediments that might contribute to arsenic mobilization in the Bengal Delta. Arsenic-reducing bacteria from deep layers of pond sediment were enriched and isolated in anaerobic environments and Asⱽ reduction was assessed in culture medium. The pond sediment enrichments harboured Asⱽ-reducing bacteria belonging to the phyla Firmicutes and Proteobacteria with dominance of Paraclostridium benzoelyticum and P. bifermentans. Among total 17 isolates, the respiratory reductase genes were not detected by the most common primers and only 3 strains had arsenic reductase ArsC gene suggesting involvement of resistance and some unknown mechanisms in Asⱽ reduction. Presence of high levels of organic matter, As, and As-reducing bacteria might make deep aquatic sediments a hot spot of As mobilization and aquifer contamination.
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