Nealson K H, Saffarini D
Center for Great Lakes Studies, University of Wisconsin-Milwaukee 53204.
Annu Rev Microbiol. 1994;48:311-43. doi: 10.1146/annurev.mi.48.100194.001523.
Dissimilatory iron and/or manganese reduction is known to occur in several organisms, including anaerobic sulfur-reducing organisms such as Geobacter metallireducens or Desulfuromonas acetoxidans, and facultative aerobes such as Shewanella putrefaciens. These bacteria couple both carbon oxidation and growth to the reduction of these metals, and inhibitor and competition experiments suggest that Mn(IV) and Fe(III) are efficient electron acceptors similar to nitrate in redox abilities and capable of out-competing electron acceptors of lower potential, such as sulfate (sulfate reduction) or CO2 (methanogenesis). Field studies of iron and/or manganese reduction suggest that organisms with such metabolic abilities play important roles in coupling the oxidation of organic carbon to metal reduction under anaerobic conditions. Because both iron and manganese oxides are solids or colloids, they tend to settle downward in aquatic environments, providing a physical mechanism for the movement of oxidizing potential into anoxic zones. The resulting biogeochemical metal cycles have a strong impact on many other elements including carbon, sulfur, phosphorous, and trace metals.
异化铁和/或锰还原作用已知在多种生物体中发生，包括厌氧的硫还原生物体，如金属还原地杆菌或乙酸氧化脱硫单胞菌，以及兼性需氧菌，如腐败希瓦氏菌。这些细菌将碳氧化和生长与这些金属的还原作用相耦合，抑制剂和竞争实验表明，锰（IV）和铁（III）是有效的电子受体，在氧化还原能力方面与硝酸盐相似，并且能够胜过较低电位的电子受体，如硫酸盐（硫酸盐还原）或二氧化碳（甲烷生成）。铁和/或锰还原作用的现场研究表明，具有这种代谢能力的生物体在厌氧条件下将有机碳的氧化与金属还原相耦合的过程中发挥着重要作用。由于铁和锰的氧化物都是固体或胶体，它们往往在水生环境中向下沉降，为氧化电位进入缺氧区提供了一种物理机制。由此产生的生物地球化学金属循环对包括碳、硫、磷和痕量金属在内的许多其他元素有强烈影响。
