From Mike Dempsey, Manchester Metropolitan University
Manchester
Fred Pearce quotes David Lerner as stating that chlorinated solvents are not
broken down in water (“Dirty groundwater runs deep”, 21 September, p 16). This
may be the case in underground water supplies, but there are reports in the
scientific literature of bacteria oxidising such solvents. This is because
oxygenase enzymes, such as ammonia-oxygenases and methane-mono-oxygenases, can
fortuitously oxidise chlorinated solvents, including TCE.
In the biotechnology unit at Manchester Metropolitan University, we have
succeeded in immobilising high concentrations of ammonia-oxidising bacteria in a
fluidised bed fermenter. Although these are being used to nitrify an
ammonia-containing wastewater, a similar system should be able to destroy toxic
chlorinated solvents and may even be suitable for treating contaminated
groundwater.
