ABSTRACT
Genetic engineering of bacteria to improve their ability to degrade contaminants in the environment was the subject of the first patent for a living organism issued to Dr. Chakrabarty, who constructed an organism to degrade petroleum. In many cases, natural organisms have been isolated that can degrade manmade pollutants and these can be used with fewer tests, so that even when genetically modified organisms with higher activity have been developed, natural organisms are more likely to be used. A number of bacteria have been genetically engineered to remove a specific heavy metal from contaminated water by overexpressing a heavy metal binding protein, such as metallothionein, along with a specific metal transport system. An organism was constructed that actively degrades styrene and also contains a gene containment system to reduce lateral transfer of the styrene degrading genes to other hosts.
