The rod-shaped bacterium C. metallidurans primarily lives in soils that are enriched with numerous heavy metals. Over time some minerals break down in the soil and release toxic heavy metals and hydrogen into their environment. “Apart from the toxic heavy metals, living conditions in these soils are not bad. There is enough hydrogen to conserve energy and nearly no competition. If an organism chooses to survive here, it has to find a way to protect itself from these toxic substances,” explains Professor Dietrich H. Nies, a microbiologist at MLU. Together with his Australian counterpart, Professor Frank Reith from the University of Adelaide, he was able to prove in 2009 that C. metallidurans is able to deposit gold biologically. Why it does this and the exact processes that take place remained unknown. Now the researchers have finally been able to solve the mystery.