Mechanisms of heavy metal uptake in a mixed microbial system, 1989

The potential use of mixed microbial systems for the removal of heavy metals (Cr, Pb, and Se) from contaminated water was investigated. The study included the development of metal-tolerant mixed microbial strains for increased metal recovery and the investigation of the uptake mechanisms. The results showed that the growth dynamics during mat formation resulted in a typical two microbial phase pattern: (1) a mixed bacterial bloom, during which the metal ions were mobilized for uptake, and (2) a cyanobacterial phase, a period marked by the stabilization of the existing metal species in the floating mixed microbial mat. Investigations on the uptake mechanisms suggested that reduction by microbial sulfate reactions, precipitation of metal ions, adsorption at membrane sites, reduction by change of oxidation states, and chelation played major roles in describing the strategies of bacterial response to the heavy metals investigated