Oxidation of Dimethyl Ether, Methyl Formate and Bromomethane by Methylococcus capsulatus (Bath)

Abstract

Suspensions of Methylococcus capsulatus strain Bath oxidized dimethyl ether, methyl formate and bromomethane. The rate of disappearance of dimethyl ether was enhanced up to 11-fold in the presence of co-substrates such as formaldehyde. Dimethyl ether was oxidized by the purified methane mono-oxygenase from M. capsulatus (Bath) to give various amounts of methanol and formaldehyde. As M. capsulatus (Bath) cannot grow on dimethyl ether it was concluded that this ether is a non-growth substrate which can be fortuitously oxidized. Possible reasons for the lack of growth on dimethyl ether are discussed. Methyl formate and bromomethane were oxidized by the purified methane mono-oxygenase to yield equal stoicheiometric amounts of formaldehyde and formic acid, and formaldehyde alone, respectively. Methylococcus capsulatus (Bath) grew on methyl formate but not on bromomethane and it was concluded that the latter is a non-growth substrate which can be fortuitously oxidized. Preliminary evidence is presented for carbon assimilation during the oxidation of bromomethane.