The use of the natural properties of living things to remove hazards that threaten human and animal health. When a pollutant ﬁrst appears in a local environment, existing microorganisms such as bacteria attempt to make use of the potential source of energy and as a side-eﬀect detoxify the polluting substance. This is an evolutionary process that normally would take years.
Scientists have engineered appropriate genes from other organisms into BACTERIA, or sometimes plants, to accelerate this natural evolutionary process. For eﬀective ‘digestion of waste’, a micro-organism must quickly and completely digest organic waste without producing unpleasant smells or noxious gases, be non-pathogenic and be able to reproduce in hostile conditions. For example, American researchers have discovered an anaerobic bacterium that neutralises dangerous chlorinated chemical compounds such as trichlorethane, which can pollute soil, into a harmless molecule called ethens. But the bacteria do not thrive in soil. So the dechlorinating genes in this bacterium are transferred to bacteria that are acclimatised to living in toxic areas and can more eﬃciently carry out the required detoxiﬁcation. Other research has been aimed at detoxifying the byproducts of DDT, a troublesome and resistant pollutant. Bioremediation should prove to be an environmentally friendly and cost-eﬀective alternative to waste incineration or chemically based processes for washing contaminated soils.