Anaerobic digestion of organic matter results from the metabolic activity of many groups of microorganisms. Interactions between microorganisms during acidogenesis, acetogenesis and methanogenesis, source of inoculum, type of feedstock and operational conditions determine
metabolic pathways in bioreactors and consequently the efficiency of fermentation processes.
In innovative installations it is desirable to separate acidogenesis from acetogenesis and methanogenesis to favour respectively the production of biohydrogen or biomethane under controlled conditions