Compiled By Jill Jusko Researchers from Purdue University and the University of British Columbia believe they are one step closer to a solution for PCB contamination. The team of scientists has identified what it calls a "key stumbling block" that prevents microorganisms from decomposing PCBs (polychlorinated biphenyls), a hazardous industrial chemical once widely used. Identification of the stumbling block could one day help researchers teach bacteria how to break down PCBs into ecologically safe molecules, the researchers say. "PCB molecules actually look very similar to many organic molecules that certain bacteria eat," explains Jeffrey T. Bolin, professor of biological sciences at Purdue, West Lafayette, Ind. "Bu there are enough little differences that bacteria can't quite digest them. "What we have done is isolate one of the steps that causes problems for the bacteria, a clog in the biochemical pipeline, if you will," Bolin says. Challenges remain before a natural solution is achieved, but Lindsay Eltis says the new perspective on the problem will help improve bacteria for the fight against PCBs. The associate professor of microbiology and biochemistry at the University of British Columbia, Vancouver, predicts bacteria can be bred to consume PCBs. "A species will fit itself to a new environment, given many generations to adapt," Eltis says. "We hope to use certain species of bacteria with a slight taste for PCBs and improve this trait through breeding until it's strong enough to make them consume PCBs as a food source."