Semicontinuous methanol biosynthesis by Methylosinus trichosporium OB3b

Abstract

Methylosinus trichosporium OB3b is a methanotrophic bacterium containing methane monooxygenase, catalyzing hydroxylation of methane to methanol. When methane is oxidized, the product is subsequently oxidized by methanol dehydrogenase contained in the same bacterium. To prevent further oxidation of methanol, the cell suspension was treated by cyclopropanol, an irreversible inhibitor for methanol dehydrogenase, leading to extracellular methanol accumulation. However, the batch type of methanol synthesis by M. trichosporium OB3b was terminated at ca. 6 mM of methanol, for MMO is inhibited by increasing methanol concentration. For prolonged methanol accumulation, a semicontinuous process was carried out. In this process, the reaction was repeated several times and the produced methanol was 36.1 μmol for 6 h.