Hydrogenophilalia Boden et al. 2017
General information
Description and emendation
This class has been circumscribed on the basis of 16S rRNA gene sequences, ribosomal protein gene concatamers and a phylogenetic distance from the Betaproteobacteria greater than the Yarza median for class. It shows no affinity to other classes. This class comprises one order - the Hydrogenophilales (type order) - containing thermophilic, heterotrophic organisms (using fatty acids, amino acids, aromatic acids and complex media) and autotrophic organisms that use molecular hydrogen as an energy source. Carboxysomes are not observed in electron micrographs of autotrophic members. Contains UQ-8 as the dominant respiratory quinone and menaquinones and rhodoquinones are not observed. Contains ω-cyclohexyl saturated fatty acids as major components of the lipid fraction, probably as an adaptation to high temperature.