Metabolic Reconstruction and Analysis of Methane Producing Methanosarcina Barkeri

Methane is a clean-burning renewable resource that is often overlooked as a potential bioenergy source. Methane already has a well established infrastructure and many uses ranging from fuel for certain forms of transportation to heating homes. Methanosarcina barkeri has the ability to produce methane through the process of methanogenesis. Methanogenic Archaea grow on a limited substrate profile including methanol, hydrogen with carbon dioxide and acetic acid. The methanosarcina species can be manipulated to consume a wider variety of substrates including byproducts and inhibitors of current fermentation processes. Starting from a metabolic reconstruction of Methanosarcina barkeri, we have updated the model under the guidance of experienced methanogenic archea researchers. The current reconstruction links the previous draft annotation with the current gene annotation as well as incorporates new thermodynamic estimations utilizing published algorithms (Group Contribution Method). The reconstruction consists of 470 enzymatic genes that govern 764 reactions. Constraint-based analysis of the metabolic model offers guidance when incorporating new substrate pathways as well as a method to align natural objectives (growth) with engineering objectives (methane production). We can perform simulated gene insertions and deletions in the model and make predictions of experimental outcomes. The model serves as a guide for current experimentation in M. barkeri to increase production of methane.