Molecular Biomarkers for Detecting, Monitoring, and Quantifying Reductive Microbial Processes
ER-1588
Objective
Overview of experimental plan to evaluate the use of molecular biomarkers for hydrogenases and dehalogenases to predict chloroethene biodegradation rates.
During natural attenuation and engineered bioremediation, groundwater contaminants are reductively transformed to less harmful or mobile compounds. Sufficient rates of biodegradation are difficult to obtain with natural attenuation. For engineered bioremediation, rates tend to be faster. However, when applied in the field, the process does not always show such results because of a variety of issues, including a lack of suitable organisms, competition for substrate, lack of appropriate nutrients, insufficient supply of electron donor (reductant), inhibitory conditions, etc. Thus, biomarkers are needed to help assess critical biological parameters at contaminated sites such as if the key microorganisms are present, if the key genes are present, and if the key genes are active (induced).
The objective of this project is to identify biomarkers for assessing the groundwater contaminant degradative potential of a microbial population in order to enhance the ability to effectively manage bioremediation of contaminated groundwater. Specific objectives include (1) develop and test quantitative molecular biomarkers for the hydrogen-producing and hydrogen-consuming microbial population present in groundwater and sediment material; (2) correlate the quantitative data obtained by molecular biomarkers with experimentally determined transformation rates and test and refine a mathematical model; and (3) test the developed molecular tools, methods of rate determinations, and mathematical model in a three-dimensional groundwater/sediment model simulating real-world conditions.
Technical Approach
This research will use advanced molecular approaches and methods to develop simple robust primers for polymerase chain reactions (PCR) that can be used in the field. In particular, through advanced phylogenetic analyses and primer design, in conjunction with quantitative PCR, researchers will comprehensively evaluate a mathematically supported model to predict in-situ reductive transformation reactions. In addition, microcosms, one-dimensional column studies, and near field-scale rate studies will be conducted. Specifically, the project will analyze the soil and aquifer DNA and cDNA samples for phylogenetic composition of the community, for distribution and abundance of hydrogenases genes, and for the distribution, abundance, and expression status of reductive dehalogenases. This complementary analysis is the equivalent to a “biological” mass balance in the sense that, based on quantitative molecular biomarker results, it is possible to synthesize and predict hydrogen flux from hydrogen producers to the various hydrogen consumers in the community. The model needs to be consistent, however, with the rate measurements of hydrogen flux as determined in microcosm experiments as well as overall electron donor and chloroethene transformation in the column and three-dimensional aquifer model.
Benefits
Simple inexpensive molecular biomarkers will be identified for assessing the reductive transformation potential of contaminated sites. This set of tools, supported by molecular bench-scale experimentation and mathematical modeling, can be used by practitioners to evaluate a site and recommend cost-effective remediation strategies. (Anticipated Project Completion – 2011)
Points of Contact
Principal Investigator
Dr. Alfred Spormann
Stanford University
Phone: 650-723-3668
Fax: 650-725-3164
Document Types
- Fact Sheet - Brief project summary with links to related documents and points of contact.
- Final Report - Comprehensive report for every completed SERDP and ESTCP project that contains all technical results.
- Cost & Performance Report - Overview of ESTCP demonstration activities, results, and conclusions, standardized to facilitate implementation decisions.
- Technical Report - Additional interim reports, laboratory reports, demonstration reports, and technology survey reports.
- Guidance - Instructional information on technical topics such as protocols and user’s guides.
- Workshop Report - Summary of workshop discussion and findings.
- Multimedia - On demand videos, animations, and webcasts highlighting featured initiatives or technologies.
- Model/Software - Computer programs and applications available for download.
- Database - Digitally organized collection of data available to search and access.