Methanoplanus limicola, a plate-shaped methanogen representing a novel family, the methanoplanaceae

An angular plate-shaped weakly motile mesophilic methanogen was isolated from a swamp of drilling waste in Italy. Growth occurs on H2/CO2 or on formate. Acetate is required in addition. The optimal doubling time is 7 h at 40° C. The cell envelope is composed most likely of glycoprotein subunits in hexagonal arrangement. The GC-content of its DNA is 47.5 mol%. On the basis of DNA-RNA hybridization it was found to represent a new family, the Methanoplanaceae within the order Methanomicrobiales.