GEOBACTER METALLIREDUCENS MUTANTS FOR CHROMIUM BIOREMEDIATION

Geobacter metallireducens is known to use oxidized metals such as Fe(III) and Mn(IV) as terminal extracellular electron acceptors. G. metallireducens can reduce the highly soluble and toxic Cr(VI) to its insoluble form Cr(III), thus enabling chromium removal from contaminated water and soil. This process is limited by the low toxicity resistance of G. metallireducens to Cr(VI). Genome shuffling can generate mutants with improved phenotype. In our work we are carrying out G. metallireducens genome shuffling, in order to increase its resistance to Cr(VI). In Geobacter species, metal toxicity resistance is correlated to the respiration rate, hence to the reduction rate of the metallic electron acceptor, when soluble electron acceptors are depleted. Our results show that mutants obtained are more resistant than wild type strain to Cr(VI). We characterized the metal reduction process of G. metallireducens wild type and mutants in potentiostat-controlled electrochemical cells through microbial biofilm voltammetry