Iron reduction by bacteria: range of organisms involved and metals reduced

The majority of the bacteria tested were able to reduce both ferric iron and nitrate. However, ferric iron may be reduced by bacteria which do not possess a nitrate reductase and, conversely, the possession of a nitrate reductase does not confer the ability to reduce ferric iron. A glucose-fermenting Vibrio and an anaerobic lithotroph were tested for their ability to reduce a greater variety of metals. The Vibrio reduced the wider range of metals and to a greater degree. Lithotrophic bacteria not only reduce a more restricted range of metals, they also appear not to possess the capacity of fermentative bacteria to use metals as minor electron sinks.