Cupriavidus metallidurans is a non-spore-forming, Gram-negative bacterium which is adapted to survive several forms of heavy metal stress. It is an ideal subject to study heavy metal disturbance of cellular processes. Cupriavidus metallidurans CH34 is a model metal-resistant strain whose can degrade benzene aerobically. Cupriavidus metallidurans CH34 is the result of Au-regulated gene expression leading to the energy-dependent reductive precipitation of toxic Au(III)-complexes.