methylococcaceae methylococcaceae the methylococcaceae are a family of bacteria that obtain their carbon and energy from methane, called methanotrophs. methylococcaceae methylococcus capsulatus scientific classification domain: bacteria phylum: pseudomonadota class: gammaproteobacteria order: methylococcalesbowman 2005 family: methylococcaceaewhittenbury and krieg 1984 genera methylicorpusculum saidi-mehrabad et al. 2020 methylobacter bowman et al. 1993 methylocaldum bodrossy et al. 1998 methylococcus foster and davis 1966 (approved lists 1980) methylocucumis pandit and rahalkar 2019 methylogaea geymonat et al. 2011 methyloglobulus deutzmann et al. 2015 "methylolobus" rahalkar et al. 2020 methylomagnum khalifa et al. 2015 methylomarinum hirayama et al. 2013 methylomicrobium bowman et al. 1995 methylomonas (ex leadbetter 1974) whittenbury and krieg 1984 methyloparacoccus hoefman et al. 2014 methyloprofundus tavormina et al. 2015 methylosarcina wise et al. 2001 methylosoma rahalkar et al. 2007 methylosphaera bowman et al. 1998 "candidatus methylospira" danilova et al. 2016 methyloterricola frindte et al. 2017 "methylotetracoccus" ghashghavi et al. 2019 "methylovarius" romanovskaya 1984 methylovulum iguchi et al. 2011 they comprise the type i methanotrophs, in contrast to the methylocystaceae or type ii methanotrophs. they belong to gammaproteobacteria, and are typically given their own order. the methylococcaceae have internal membranes in the form of flattened discs, perpendicular to the cell wall. methane is oxidized to give formaldehyde, which is fixed by a process called the ribulose monophosphate (rump) cycle. here formaldehyde is combined with sugar ribulose, producing hexulose. this, in turn, is broken down to produce glyceraldehyde, which is used to produce new ribulose and other organic compounds. catabolism does not involve a complete citric acid cycle. some species of the methylococcaceae have formed with certain marine mussels endosymbiotic relationships.