Acetonema is a genus of bacteria in the family Sporomusaceae. It is H<sub>2</sub>-oxidizing CO<sub>2</sub>-reducing acetogenic strictly anaerobic endospore-forming Gram-negative motile rod-shaped, isolated from gut contents of the wood-feeding termite Pterotermes occidentis. Cells are catalase positive, oxidase negative, and have 51.5 mol percent G + C in their DNA. Optimum conditions for growth on H<sub>2</sub> + CO<sub>2</sub> are at 30âÂÂ33 degrees C and pH (initial) 7.8. Acetonema longum is the sole species within the genus.