Environmental News Illuminating the future for bioremediation
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he first EPA-approved field release of a genetically engineered microorganism (GEM) provided new information about bioremediation, according to the experiment's collaborators from the University of Tennessee and the Department of Energy's Oak Ridge National Laboratory (ORNL). From a commercial standpoint, however, the release of the GEM, burdened with hot-button issues such as gene transfer goes beyond the science for companies working on biotechnologies The required risk assessment provides a model for companies planning to seek EPA's approval for new GEM uses In a paper published in the March issue of ES&T, a team of scientists led by Gary Sayler, director of the Center for Environmental Biotechnology at the University of Tennessee, describes the first government-approved release of the microorganism Pseudomonas fluorescens HK44 into the field [Environ. Sci. Technol. 2000, 34 (5), 846853). Over a two-year period, the researchers applied the HK44 into a semicontained lysimeter facility at ORNL to remediate soil contaminated with polyaromatic hydrocarbons (PAHs) The facility was lavered with PAH-laden soil clean soil coarse sand and an uncontaminated soil can
The HK44, infused with a lux gene that produces light much like a firefly as a byproduct, biodegraded the PAH mixture. As it worked, the HK44 generated light in response to soil hydrocarbon bioavailability. The risk assessment conducted prior to the release resulted in the first-ever consent order—known as a premanufacturing notification (PMN)—for a GEM. The quick approval process, which took nine months, provides a model for companies faced with addressing the many hot-button issues related to biotechnology, especially related to
The field release of a bioengineered microorganism in semicontained lysimeters at the Oak Ridge National Laboratory provides clues for companies struggling to assure regulators that their new uses for bioengineered organisms are safe.
GEMs, said John Davis, research leader for Dow Chemical Co.'s environmental chemistry laboratory in Midland, MI. Dow, for example, is pursuing bioengineered feedstocks as alternatives to hydrocarbons and oil for chemical production, Davis said. "Let's put it this way: No one likes to be the first person," said Davis, referring to Sayler's PMN application. "The regulatory process is not really worked out [for GEMs], and that is one regulatory hurdle [companies] just don't need. It is a very controversial topic, and there are a lot of issues surrounding this." The issues, including gene transfer, are of obvious concern to EPA, said Davis. Before a GEM is released into the field or even used in a production process, a company must apply for a PMN and EPA approval, said David Giamporcaro, in EPA's Office of Pollution Prevention and Toxics. Sayler's PMN application highlights the issues EPA is most concerned with related to GEMs including those that would be "show stoppers" as well as the data the agency will accept to address these concerns said Davis Sayler's application allows other PMN applicants to "proactively
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try to answer the questions EPA asked," said Davis. From a scientific perspective, the experiment demonstrated that the biodegradative organisms could be maintained for long periods—in this case, for two years—a necessity when using natural processes to degrade contaminants, said Sayler. "This approach helps us to understand that the added organisms are actually responding to the contaminant under field conditions and that they are inducing the expected enzyme systems" added Craig Criddle associate professor in civil and environmental engineering at Stanford University. The work has spawned corporate and government interest in using reporter genes, Sayler said. The bioluminescence-based HK44 microorganism that illuminated the degradative process at the ORNL site was later put into a microchip using radio frequency picked up by a receiving station. "Using this, we would have essentially real-time monitoring of the remediation of organisms in the environment" Sayler said. Officials from DOE and companies saddled with cleaning up their hazarddebris velop this technology he added CATHERINE M. COONEY © 2000 American Chemical Society
