Methyloraptor flagellatus gen. nov., sp. nov., novel Ancalomicrobiaceae-affiliated facultatively methylotrophic bacteria that feed on methanotrophs of the genus Methylococcus.

A morphologically conspicuous microbial association was detected in a bioreactor running in a continuous mode with methanotrophic bacteria of the genus Methylococcus and natural gas as a growth substrate. The association consisted of spherical Methylococcus cells colonized by elongated rods, which produced rosette-like aggregates and inhibited the cultivation process. An isolate of these bacteria, strain S20, was obtained and identified as belonging to the alphaproteobacterial family Ancalomicrobiaceae but displaying only a distant relationship (93.