Hydrogen-oxidizing bacteria are the members of gram-negative bacteria, metabolism involves using hydrogen as an electron source and oxygen as a terminal electron acceptor, hence forming water.
Gram-negative genera Aquifex and hydrogenobacter stand for "water-maker" to indicate hydrogen oxidation and terminal electron transfer to oxygen. They are chemoautotrophs, that share the ability to oxidize H₂ and fix CO₂ to provide energy and synthesize cellular material. Applicatated for resource recovery and pollution removal.
They are known to grow at the highest temperature and grow usually at neutral or slightly acidic pH. These microorganisms use CO₂ assimilation pathways. They are metabolically versatile chemolithoautotrophs, using reductive tricarboxylic acid (rTCA) cycle.
