Fermentation of natural gas with a cyclone column fermenter

A mixed flora, capable of using natural gas as a carbon substrate, was derived from a laboratory sewage sludge. Fermentations in a cyclone column fermenter, on a 1:1 natural gas/air mixture, resulted in a doubling time of 4.6 h and production of 0.065 mg dry cell mass per square centimeter interfacial area per hour. Foaming problems limited cell concentrations to 6.1 g/l.