New bug to tackle pollution

A new, all-natural, pollutant-busting microbe has been discovered by scientists in Germany. Research published in the October 2003 issue of Microbiology, a Society for General Microbiology journal, describes a new strain of bacterium, which could be used in the near future to clean up polluted land.

Over the years, many harsh and highly toxic chemicals have built-up in the environment. Dr Rapp and his colleagues at the National Research Centre for Biotechnology in Braunschweig, Germany, have found the first bacterium that has two essential qualities that allow it to cleanse contaminated soil of some of these chemicals.

“For a microbe, two characteristics are important for de-contamination of land,” explains Dr Peter Rapp, “not only the ability to break down the polluting chemicals, but also, the ability to actually access the chemicals in the first place”. Tests carried out show that a species of Rhodococcus bacteria, called strain MS11, not only breaks down a wide selection of pollutants, but also makes its own detergent to help it access them.

Some bacteria are already known to naturally break down pollutants in order to use them as a source of food, but unfortunately the process in soil is slow. “The problem is that chemicals stick to the particles of soil or hide inside hollows, and this makes the job of cleaning land very difficult,” explained Dr Rapp. “The bugs can’t get at the pollutants, which means that they remain in the soil for decades, slowly seeping into our water supplies”.

If they are helped, these bacteria can be used to clean up polluted soil. By adding large amounts of detergent first, the bacteria can gain access to the chemicals. Unfortunately, the use of detergents to help clean soil is limited, because it costs so much to manufacture the amounts of detergent needed for large areas of land.

“The fact that strain MS11 can degrade a wide range of chemicals, as well as making its own detergent, makes this bacterium perfect for bioremediation of sites polluted for years, or even decades, with unpleasant chemicals” explained Dr Rapp. “A further benefit is that strain MS11 has not been created in a lab, but was isolated naturally from the environment, and so there will not be the issue of transfer of dangerous genes that is associated with genetically modified organisms”.

Strain MS11 has been found to be particularly good at breaking down chlorinated benzenes. These chemicals are widely used in industry in the production of herbicides and pesticides, as well as for dissolving such materials as oils and rubber. And, although some bacteria are already known to break down chlorinated benzenes, none have the added ability to make their own detergent to help them do this.

Chlorinated benzenes are known to cause many serious health problems ranging from disorders of the immune system to harmful effects on the liver, kidney, thyroid and lung.