Characterization of Microbes Capable of Using Vinyl Chloride as a Sole Carbon and Energy Source by Anaerobic Oxidation
ER-1556
Objective
Biooxidation of vinyl chloride (VC) has been suspected at numerous sites based on attenuation of VC in anaerobic zones. However, the lack of readily detectable daughter products (i.e., CO2 and Cl-) above background levels makes it almost impossible to document this process without a microcosm study (e.g., using [14C]VC). In order to develop more efficient methods that detect anaerobic oxidation in situ and possibly enhance this process, a better understanding of the microbes that mediate this process is needed. Researchers previously documented the occurrence of anaerobic VC oxidation at a contaminated site using laboratory microcosms. They then were able to develop low-sediment enrichment cultures that repeatedly consumed VC at increasing rates under anaerobic conditions without accumulation of ethene or other nonchlorinated volatile products, including methane, and demonstrated that approximately 70% of [14C]VC could be accounted for as 14CO2.
The overall objective of this project is to culture and ultimately isolate and characterize a microbe that is capable of using VC as a sole source of carbon and energy by anaerobic oxidation.
Technical Approach
Initially, this project will reestablish microcosms that are capable of anaerobically oxidizing VC. Fresh samples of sediment and groundwater will be obtained from the same southern California hazardous waste site in the vicinity of the source area where the VC plume terminates. On the basis of previous success in achieving transfer of oxidizing activity from microcosms to groundwater, researchers then will develop and characterize sediment-free enrichment cultures. Once obtained, isolation procedures that anaerobically mineralize VC will be initiated. The isolation strategy will depend on the nature of the culture and the electron acceptor utilized. Finally, one or more isolates will be subjected to microbiological characterization, including documenting morphology, cultural characteristics, 16S ribosomal ribonucleic acid (rRNA) gene sequence, and through survey of electron donors and acceptors utilized for growth.
Benefits
At anaerobic sites where there is field evidence for attenuation of VC but without accompanying evidence of biodegradation by accumulation of ethene or ethane, there is currently no efficient method to document the occurrence of anaerobic oxidation. Once an organism has been identified that can anaerobically oxidize VC as a sole carbon and energy source, it will become possible to develop a biomarker that can be used to detect the presence of these microbes in situ. Knowing the nutrient requirements of a microbe that anaerobically oxidizes VC will open the door to enhancing in-situ activity through nutrient supplementation. If the kinetics for a VC oxidizer looks favorable, consideration should be given to testing its use in bioaugmentation. (Anticipated Project Completion – 2010)
Points of Contact
Principal Investigator
Dr. David Freedman
Clemson University
Phone: 864-656-5566
Fax: 864-656-0672
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.