Elucidation of Alkene Metabolism in Two Sulfate-Reducing Isolates Via Metabolite Profiling and Transcriptomics

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Intellectual MeritAnaerobic bacteria and archaea play key roles in biogeochemical cycling, the biotransformation of pollutants, and in both subsurface production and oxidation of methane, an important biofuel. The past 30 years of research have yielded novel mechanisms by which anaerobes activate hydrocarbons in the absence of oxygen. However, there is still a great deal to be learned regarding the enzymes catalyzing reactions in the requisite biochemical pathways. Alkenes are ubiquitous hydrocarbons derived from both natural and anthropogenic sources. Although more reactive than aromatic hydrocarbons and alkanes, little is known regarding the biochemistry of anaerobic alkene biotransformation. This project aims to elucidate the fundamental mechanisms of microbial activation and degradation of alkenes in two model strains of sulfate-reducers, Desulfatibacillum alkenivorans AK-01 and Desulfococcus oleovorans Hxd3, by coupling transcriptomics with metabolite profiling. The bacteria are not only model organisms for anaerobic hydrocarbon degradation, they are also two of only three sulfate-reducing, hydrocarbon-utilizing microbes (the other is the archaeon Archaeoglobus fulgidus) for which complete (i.e. closed) genome sequences are available. The project will shed light on the novel biochemistry of anaerobic alkene activation and degradation by a class of microorganisms that is both environmentally and economically important.Broader ImpactsAlkenes are widely present in the environment, and are generated from both natural and industrial processes. These chemicals are economically and environmentally important. This project aims to increase understanding of the activation and biotransformation of alkene substrates and environmental contaminants with similar structures, as well as the biochemistry and physiology of the relevant organisms involved in biogeochemical cycling, bioremediation, and biofuel production. As part of this project, research activities will be integrated into the education of high-school, undergraduate, and graduate students by providing laboratory research experience and mentoring. Students will be trained in aspects of molecular biology, anaerobic cultivation and monitoring of microorganisms, metabolite profiling, microbial ecology, and "omics". Research will be incorporated into existing department courses, and future efforts are aimed toward developing a "Nucleotide Sequence Analysis" class that integrates the project's omics datasets into classroom learning, with the long-term goal of implementing a Biotechnology program at the University of Oklahoma. Educational outreach to the community will be coordinated through the K-20 Center for Education and Community Renewal, which partners faculty and graduate students with K-12 teachers and students and collaborates with over 800 Oklahoma schools and industrial partners to enhance learning across all educational levels. Goals to integrate diversity into NSF programs, projects and activities will be achieved through the McNair Scholars program, which prepares undergraduate students from underrepresented ethnicities for doctoral studies through research opportunities and activities. Efforts to disseminate project results and enhance scientific and technological understanding will be achieved via participation in the OU Annual Student Research and Performance Day, Science Café of Norman, and BioBlitz! Oklahoma.