Superfund Research Program

Gene Enhanced Remediation of Co-Contaminated Soils

Project Leaders: Christopher G. Rensing, Ian L. Pepper
Grant Number: P42ES004940
Funding Period: 1995-2005

Project-Specific Links

Final Progress Reports

Year:   2004  1999 

The aim of this research is to create innovative technology that aids in degrading xenobiotic compounds. The soil microbial gene pool can be altered and/or enhanced through bioaugmentation, i.e., the introduction of donor organisms that contain specific degradative genes allowing horizontal gene transfer into indigenous soil recipients. Dr. Pepper’s group successfully applied this approach in the study of 2-chlorobenzoate, 3-chlorobenzoate and 4-chlorobenzoate degradation in different soils. They showed that a novel technique, real-time PCR, can be utilized to indirectly monitor non-culturable bacteria and their biodegradative genes. As a transition to studying how the soil microbial gene pool can be altered by the addition of metal contaminants, Dr. Pepper teamed with Dr. Christopher Rensing and showed that arsenic contamination of soil resulted in the “adaptation” of the gene pool to allow enhanced microbial transformations of arsenic in soil.  Recently they have shown that soil detoxification of arsenic can be achieved through the microbial oxidation of arsenite (more toxic and mobile) to arsenate (less toxic and mobile).  The researchers are currently conducting genetic analyses of selected microbial isolates.  This study may have potential to minimize the potential arsenic toxicity of residuals frequently placed in landfills.