Metabolism of model substrates by syntrophic microbial communities
In collaboration with the Atomic Structure and Enabling Capabilities team we will utilize next-gen omics methods to elucidate the molecular patterns, pathways and enzymes underlying community-driven syntrophic substrate bioconversions.
The essential anaerobic recycling of carbon in natural and manmade environments requires the actions of many fermentative and syntrophic groups of microbes. This cooperative process requires cell-cell interactions with back-and-forth adjustments of upstream fermentation reactions with downstream syntrophic community reactions that control optimal recycling rates. Many processes of syntrophic metabolism are not well understood, and this impacts the ability to predict and model their metabolism and roles in carbon recycling in nature. To address this, we use an integrated set of omics tools coupled with new informatics approaches to identify and characterize core metabolic pathways in model syntrophic communities when growing on unstudied or poorly studied classes of substrates (i.e., amino acids, carboxylates, and long chain fatty acids). Also targeted for study are their associated oxidation reduction reactions, electron transfer pathways, modes of energy conservation and other essential cell functions. Biochemical and structural approaches further complement these studies. Limited genomic sequencing is planned for other poorly characterized syntrophic strains to further dissect and predict their metabolic potential along with associated cell-cell interactions within the anaerobic communities. With the Atomic Structure and Enabling Capabilities team we further elucidate their shared versus unique features to fill gaps in our bioinformatic and structural understanding of these processes. Resulting information enables future prediction and modeling efforts of syntrophic and other anaerobic carbon recycling of plant materials by the larger BER DOE community.
The anaerobic decomposition of plant and animal polymers including polysaccharides, proteins, nucleic acids and lipids to CO2, H2O and methane requires syntrophic metabolism as an essential step. In this multi-stage process, fermentative bacteria hydrolyze the polymeric substrates present in all anaerobic habitats and then ferment the hydrolysis products to acetate and longer chain fatty acids, alcohols, aromatic compounds, CO2, formate, and H2. Then, propionate and longer chain fatty acids, aromatic compounds, amino acids, carboxylates, and alcohols are syntrophically metabolized to acetate, H2, and formate. Lastly, two different groups, the hydrogen/formate-using and acetate-using methanogens, complete the process by converting the acetate, formate and hydrogen to CO2 and CH4.