Kinetics of hydrogen assimilation in the methane fermentation

Growth and kinetic constants were studied during the operation of 2 identical continuous fermentation systems in which a liquid substrate and a gas mixture, consisting of hydrogen as nutrient, carbon dioxide, and nitrogen as 'filler', were fed into a vessel containing a mixed culture of Methanobacterium formicicum and Clostridrium sp., the gas feed being recirculated. During methane production, mass balances were calculated; steady-state data were used to compute the constants, and together With other data Were used for statistical evaluation of the identity and performance stability of the systems. The maximal observed rate of methane production was 1 10-150 per cent greater than that reported for species of methane bacteria grown on acetic, propionic, and butyric acid substrates.