In vivo nuclear magnetic resonance studies of the metabolism of methanol and pyruvate by Methanosarcina barkeri

The metabolism of methanol and pyruvate by cells of Methanosarcina barkeri was probed in vivo by NMR taking advantage of the non-invasive characteristics of this technique. Upon administration of substrates, the kinetics of substrate consumption, the product formation and the energetic state of the cells was monitored using carbon-13, phosphorus-31 or proton NMR. The effects of several inhibitors and uncouplers were investigated. Cells supplied with pyruvate developed considerable levels of nucleotide triphosphate; methane production was monitored, as well as CO2 and H2 formation. Most of the pyruvate was utilized for the synthesis of valine or intermediates of the valine pathway. The origin of the carbon atom in methane was elucidated using 13C-labelled pyruvate.