Bacterial Mineralization of Organic Carbon Under Anaerobic Conditions
Henry L. Ehrlich
Abstract
In microbiology, mineralization of organic matter generally refers to its complete conversion to inorganic matter through oxidation. Both aerobic mineralization and anaerobic mineralization by microbes are, with one exception, forms of respiration. Microbial mineralization is a form of catabolism. It releases free chemical energy, some of which is conserved by the organism through chemiosmosis in oxidative phosphorylation for use in anabolic processes. The bacteria that contribute to anaerobic mineralization are a very diverse group. Those currently recognized are mostly gram-positive and gram-negative eubacteria, but some archaebacteria are also able to mineralize organic matter anaerobically. Anaerobic mineralization of organic matter is important in the carbon cycle because it prevents relatively permanent anoxic environments in the biosphere from becoming permanent sinks for organic matter. Anaerobic iron and manganese respiration must now be added to denitrification, nitrate ammonification, and methanogenesis as processes that contribute significantly to anaerobic mineralization of organic matter in soils and sediments.