Bioremediation of arsenic contamination from the environment: New approach to sustainable resource management

Abstract

Present acceleration of Arsenic [As] exposure leads to severe health problems. Modern scientific approaches look towards potent bio-agents for the removal of such types of contaminations in sustainable ways. Microbes can potentially change the redox potential, solubility, pH by different complex reactions during bioremediation. There are many enzymes present in the microbial system which are involved in methylation such as As (V) reductase, monomethyl arsonic acid reductase, As (III) methyltransferase, and MMA (III) methyltransferase. On the other hand, microbes have As transformation ability and changed into different extractable forms with sulfide minerals such as arsenopyrite (FeAsS), enargite (Cu₃AsS₄) and realgar (As₄S₄). In some bacteria, the As-operon machinery thiol group bind with As, itdetoxifies its toxicity. Ars R gene and arsenic reductase enzyme (Ars C) play the key role in the reduction of As (V) to As (III) and detoxify by being transported outside of the cell by Ars AB As chemiosmotic efflux system. In fungi, As (V) is reduced to As (III) by the arsenate reductase and GSH glutathione converted into GSSH glutathione disulfide. In plants, As (III) conjugates with phytochelatin (PC) or GSH glutathione and accumulates in the vacuole or is converted into less toxic forms in the presence of arsenic reductase enzyme. This review focused on the potentiality and mechanisms of different microbes for As-detoxification in a sustainable manner.