Facultative methanotrophs can utilize methane as well as multi-carbon compounds，including organic acids and carbohydrates.Facultative methanotrophs from aged-refuse were enhanced in situ to overcome the limitations of methane oxidation by existing landfill covers.Methanotrophs from oligotrophic aged-refuse had a better environmental tolerance by analysis of scanning electron microscope(SEM).These bacteria could enrich quickly in the presence of carbon source.However

the methane-oxidation capability could not be improved if only adding carbohydrates or nitrate mineral salts(NMS) medium alone.Compound acclimation of facultative methanotrophs were carried out by NMS medium and glucose/starch.After a delay period of 7—9 d

methane consumption came into a logarithmic growth period

which indicated that facultative methanotrophs had strong biological activity and high substrate competitive advantage.Metabolic pathways of facultative methanotrophs were modified by adding NMS medium

and methane could be utilized despite the presence of other carbon sources.The activity of facultative methanotrophs was enhanced by low concentration of chloroform.Oxidation rate of methane reached 0.114 ml·d-1·g-1 as the concentration of chloroform was 50 mg·L-1.The problems about the engineering application of obligate methanotrophs were overcome due to the discovery of the new method

and the results would have important implication for understanding the methane-oxidizing bacteria and the factors controlling methane fluxes in the environment.