A number of processes for remediating contaminated soils and groundwater based on the use of microorganisms to convert contaminants to less hazardous substances. Most commercial bioremediation processes are intended to convert organic substances to carbon dioxide and water, although processes for addressing metals are under development. Many bacteria ubiquitously found in soils and groundwater are able to biodegrade a range of organic compounds. Compounds found in nature, and ones similar to those, such as petroleum hydrocarbons, are most readily biodegraded by these bacteria. Bioremediation of chlorinated solvents, polychlorinated biphenyl (PCB)s, pesticides, and many munitions compounds, while of great interest, is more difficult and has thus been much slower to reach commercialization.

In most bioremediation processes the bacteria use the contaminant as a food and energy source and thus survive and grow in numbers at the expense of the contaminant. In order to grow new cells, bacteria, like...