two microorganisms that break down benzene without the aid of oxygen have been isolated by scientists at Southern Illinois University ( siuc ), Carbondale, usa. This could be an important breakthrough that could help remove the highly toxic chemical from the environment. Benzene, used as an additive in petrol and other petroleum-based fuels, is one of the most common contaminants found in groundwater supplies. Benzene is a known human carcinogen. Although benzene is readily biodegraded when exposed to the atmosphere, removing the compound from airless environments is much more difficult.

Researchers at siuc , led by John D Coates, assistant professor of microbiology, identified the organisms as Dechloromonas strain rcb and Dechloromonas strain jj. "Fuel spills and leaking underground storage tanks are the main culprits. One of the big problems in contaminated environments is a lack of oxygen,' says Coates. Without oxygen, the biodegradation of benzene essentially slows to a crawl. These organisms are able to speed up the process. What once took 70 days now takes place in seven days.

And the organisms can be found, as Coates tells, just about anywhere. "They've been found in a broad range of environments,' Coates notes. "We've found them in soil samples taken from around the university and in samples taken from the Antarctic.'

While Coates' discovery could have major implications for environmental remediation, there are a host of other applications. This study provides the first example of an organism of any type that can oxidise benzene anaerobically,' says Coates. "For many years, the ability of microorganisms to degrade benzene in the absence of oxygen has been pursued by researchers because of the chemical stability of this compound. "With these organisms in hand, we can now get a better understanding of how microorganisms can be used to tackle this problem,' says Coates ( www.newswise.com , June 28).