Methane oxidation and C1 metabolism in a propane-utilizer Gordonia sp. strain TY-5.

Gordonia sp. strain TY-5 utilizes propane, but not methane, as the sole carbon source. In this strain, propane is oxidized to 2-propanol by propane monooxygenase (Prm), and 2-propanol is further metabolized to methyl acetate, which is subsequently converted into acetate and methanol. However, methane and methanol metabolism in strain TY-5 has remained unclear. In this study, draft genome analysis revealed that strain TY-5 possesses the one-carbon (C1) dissimilation pathway, in which methanol is oxidized to CO2, but lacks a C1 assimilation pathway, suggesting that methanol is not utilized as the carbon source but is used as an energy source. Furthermore, we found that strain TY-5 can oxidize methane by Prm. Gene disruption analysis revealed that N, N-dimethyl-4-nitrosoaniline-dependent methanol dehydrogenase contributes to methanol oxidation in strain TY-5. Our findings provide new insights into the physiological significance of C1 and hydrocarbon metabolism for adapting the natural environment where methane and propane coexist.