Shewanella oneidensis
Shewanella oneidensis is a bacterium notable for its ability to reduce metal ions and live in environments with or without oxygen. This proteobacterium was first isolated from Lake Oneida, NY in 1988, hence its name. Shewanella oneidensis is a facultative bacterium, capable of surviving and proliferating in both aerobic and anaerobic conditions. The special interest in S. oneidensis MR-1 revolves around its behavior in an anaerobic environment contaminated by heavy metals such as iron, lead and uranium. Experiments suggest it may reduce ionic mercury to elemental mercury and ionic silver to elemental silver. Cellular respiration for these bacteria is not restricted to heavy metals though; the bacteria can also target sulfates, nitrates and chromates when grown anaerobically. Name This species is referred to as S. oneidensis MR-1, indicating "manganese reducing", a special feature of this organism. It is a common misconception to think that MR-1 refers to "metal-reducing" instead of the original intended "manganese-reducing" as observed by Kenneth H. Nealson, who first isolated the organism. Qualities Metal reduction Shewanella oneidensis MR-1 belongs to a class of bacteria known as "Dissimilatory Metal-Reducing Bacteria (DMRB)" because of their ability to couple metal reduction with their metabolism. The means of reducing the metals