Isolation and characterization of two marine methanotrophs from coastal sediments

Methane-oxidizing bacteria (methanotrophs) were isolated from sediments of estuaries. The representative strains, GM-I and NM-11, are gram negative mo tile rods and exhibit characteristics typical of Type I methanotrophs. Both strains possessed cytomembranes arranged in stacked lamellae, and their pr edominant fatty acids were C-16:1 and C-16:0 The DNA base ratios of the str ains, GM-I and NM-11, were 51.0, 52.9% mol G+C, respectively. The strains r equire NaCl, grew well on methane or methanol, but not on any other compoun ds as a cabon source, and their growth was inhibited in natural light.