UNS: Priming of Organohalide-Respirers to Degrade Chlorinated Ethenes with Natural Organochlorines

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1511767KrzmarzickDespite several decades of bioremediation efforts, chlorinated ethenes (widely used solvents in the past) are still present and pose significant threats to water systems. Bioremediation of these compounds depends on the activity of bacteria capable of destroying those compounds, but their activity and presence is often low and unevenly distributed. Published studies have demonstrated that these bacteria grow while treating naturally-occurring compounds which are similar in structure. By exploiting this physiology, technologies may be developed to enhance the ability of bacteria to treat these compounds.The objective of this proposal is to determine the feasibility and effectiveness of using naturally-occurring organochlorine compounds as stimulants for effective remediation of chlorinated solvents. The central hypothesis is that organohalide respiring bacteria will be stimulated to dechlorinate chlorinated solvents faster and more completely in response to natural organochlorine amendments. The rationale is that with this knowledge, chlorinated pollutants may be more thoroughly and quickly remediated, thus removing major threats to groundwater systems and human health. By investigating the biogeochemical links between organohalide respiring bacteria, natural organochlorine compounds, and chlorinated pollutants, a significant barrier in bioremediation is likely be found. Current research and strategies for bioremediation has focused on increasing the availability of electron donor (and perhaps carbon) to organohalide respirers, and/or by bioaugmentation with cultures rich with organohalide respiring bacteria. Both of these methods have a fundamental weakness in approach, which is the assumption that the electron acceptor needed for the bacteria's growth and energy, the chlorinated pollutant, is sufficiently bioavailable and biochemically suitable for the biology of the bacteria. This proposal is innovative because it approaches the stimulation of organohalide bacteria on the respiration side (electron-accepting side) of its metabolism using naturally produced substrates. Giving organohalide respiring bacteria the electron acceptors they need to live to stimulate their broader organohalide respiring abilities represents a paradigm shift from current bioremediation practice. The high-throughput metatranscriptomic sequencing of this proposal will be used as a component of an independent research topic undertaken in a graduate level course on molecular methodologies. Findings of this proposal will also be incorporated immediately into undergraduate and graduate lecture classes that cover biogeochemistry topics, which will expose the undergraduate and graduate students to ongoing research. The proposal will fund one PhD student who will travel to conferences to present this work and who might otherwise not pursue this degree. With undergraduate funding, up to three undergraduate researchers are expected to be trained in research over the three years of the grant, and these researchers will pursue small and independent projects which will be presented at local symposia. This research has the potential to fundamentally impact society. This proposal aims to complete the fundamental knowledge needed prior to the development of engineering technologies. This work has the potential to complete the fundamental knowledge needed for future SBIR/STTR or similar grants that would then phase this research towards the development of technologies for field implementation.