ABSTRACT
Arsenic (As), a carcinogenic element is abundant in earth’s crust, is increasingly contaminating different ecosystems due to various natural and anthropogenic reasons. The presence of this toxic element has been known to influence the bacterial community composition of natural ecosystems. This study, therefore, reviews the major bacterial populations found to be associated with As contaminated aquifers, agricultural fields, mines and mine tailings, and marine environments. Bacterial genera belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Deltaproteobacteria, Epsilonproteobacteria, Bacteroidetes, Firmicutes, Nitrospira, Aquificeae, Acidobacterium, Verrucomicrobium, Ignavibacterium, etc., were found to be associated with different As-impacted ecosystems globally, among which Proteobacteria were found to be the most abundant. Metabolic capabilities of these dominant bacterial genera with respect to various electron-donor oxidation and electron-acceptor 116reduction are reviewed. An unweighted paired group mean analysis suggests that bacterial genera of the different phylogenetic lineage may act in consortia. Besides, As (V) reduction is found to be better associated with potential chemoautolithotrophs, nitrate reduction, and ammonia oxidation. This review shall provide essential information regarding As contamination of various environments and the usual consortia associated with that particular ecosystem. Therefore, this study would act as a useful resource for designing of strategies pertaining to as bioremediation of impacted sites without disturbing the natural bacterial flora.
