Fig. 2

Possible modes of methane oxidation for methane-grown M. buryatense 5GB1. Upper panel a genome scale FBA was used to test three possible modes of methane oxidation: a redox-arm mode, the currently accepted model in which electrons driving methane oxidation come from NADH produced by formate or formaldehyde oxidation, while electrons produced from methanol oxidation are linked to a redox-arm and used for ATP production (adapted from Semrau et al. [30]); b direct coupling mode, in which methanol oxidation supplies electrons for methane oxidation; and c uphill electron transfer model, in which methanol oxidation partially supports methane oxidation (from [18]). Proton translocation and ATP synthesis were omitted for simplicity. P periplasm, L ICM (lumen), C cytoplasm