Optimization of microbial detoxification for an aquatic mercury-contaminated environment

ABSTRACTMercury (Hg) reduction performed by microorganisms is well recognized as a biological means for remediation of contaminated environment. Recently, studies demonstrated that Hg-resistant microorganisms of Tagus Estuary are involved in metal reduction processes. In the present study, aerobic microbial community isolated from a highly Hg-contaminated area of Tagus Estuary was used to determine the optimization of the reduction process in conditions such as the contaminated ecosystem. Factorial design methodology was employed to examine the influence of glucose, sulfate, iron, and chloride on Hg reduction. In the presence of several concentrations of these elements, microbial community reduced Hg in a range of 37–61% of the initial 0.1 mg/ml Hg2+ levels. The response prediction through central composite design showed that the increase of sulfate concentration led to an optimal response in Hg reduction by microbial community, while the rise in chloride levels markedly decreased metal reduction. Iron ma...