TSR&TP Student Receives National Inventor's Award
by Mika Pringle Tolson
Eric Gilbert, a doctoral student in the Environmental Toxicology Graduate Program at UC Riverside, has just received one of three awards in the all-collegiate category in the national competition of the BF Goodrich Collegiate Inventors Program. His discovery is an inexpensive, non-toxic method of degrading PCBs. Each winner received a cash award of $5,000, and their advisors received $2,500. Gilbert was flown to Akron, Ohio to participate in the award ceremony on September 20, 1996 and to attend the induction ceremonies for the National Inventors Hall of Fame. Gilbert, along with his faculty advisor Dr. David Crowley, has been investigating PCB biodegradation with a grant from the TSR&TP through Associate Director Dr. Arthur Winer. Dr. Crowley had an interest in the influence of plants on bacteria and their ability to potentially improve biodegradation of chemicals in soils through cometabolism with bacteria. Because bacteria cannot directly metabolize PCBs, they need a structurally similar substrate mixed in with a PCB-contaminated medium to break down the toxic compounds into nontoxic components, or to cometabolize them. One of the only substances known to induce cometabolism is biphenyl, the nonchlorinated backbone of PCBs, but biphenyl is also toxic. So Gilbert and Crowley searched for an alternative substrate. Gilbert developed a simple assay that would indicate if a plant contained a chemical that could be used to stimulate PCB degradation. At first, they were randomly testing different kinds of agricultural plants, but after a while, says Gilbert, "I got to thinking, spearmint is aromatic in the flavored sense, but it is also aromatic in the chemical sense. Maybe because PCBs are also aromatic in the chemical sense, the enzymes involved in breaking down the plant compounds might also be able to degrade PCBs." Thus began his discovery that carvone, the aromatic chemical compound in spearmint, serves as a cosubstrate for bacteria to break down PCBs. This is an important discovery because it could lead to a low cost field scale technology for remediating sites with PCB contamination. Through collaborations with EcoSoils Systems, Inc., a company in San Diego that manufactures a field scale fermentor and holds a patent on application of bacteria to soil through irrigation lines, Gilbert and Crowley hope to see their invention put to use soon. Gilbert is well on his way to achieving his future goal of finding work that "actually reduces the amount of toxic waste in the environment." As he says, "I think it's important to clean up the environment. It's only going to get worse unless we put some energy into making it better, and we have to do it with technology that keeps the cost down."
| <-Fall Issue 1996 |