Troy, N.Y. -- Researchers at Rensselaer Polytechnic Institute have discovered a tiny bacterium that could one day transform the way we remove polychlorinated biphenyls (PCBs) from our environment. The organism could be the key to developing methods that help detoxify commercial PCB compounds on site without the need for dredging.
The results will appear in the April 15 issue of Applied and Environmental Microbiology.
Commercial PCBs, which were banned from production in the United States in 1977, were once commonly used by industry. The compounds are mixtures of 70-90 different molecular forms that vary in the number and positions of chlorine atoms, making them difficult to degrade. To date, the most commonly used method to remove PCBs from the environment is to dredge and then deposit the sediments in a landfill.
In order to detoxify PCBs the strong bonds between the chlorine atoms and the biphenyl compounds that make up the PCB atomic structure need to be broken, a process known as dechlorination. More than two decades ago, scientists discovered that PCBs were slowly being dechlorinated by naturally occurring microbes, but despite years of research, the exact microbes responsible have remained elusive until now.
"For the first time we have been able to cultivate in defined media naturally occurring bacteria that can extensively dechlorinate PCBs right at the site of the contamination," said Donna Bedard, professor of biology at Rensselaer and lead author of the paper. "This is a major step toward the development of cost-effective methods for on-site PCB remediation."
Bedard used sediments from the Housatonic River in Massachusetts an area known to be contaminated with PCBs to develop sediment-free cultures and to identify the bacteria that were breaking down the PCBs. Using molecular techniques, the research team determined that the microbes that are dechlorinating the PCBs belong to a group of bacteri
Contact: Gabrielle DeMarco
Rensselaer Polytechnic Institute