THE USE OF ACETATE AS AN ADDITIONAL COSUBSTRATE IMPROVES METHYLOTROPHIC GROWTH OF THE ACETOGENIC ANAEROBE EUBACTERIUM-LIMOSUM WHEN CO-2 FIXATION IS RATE-LIMITING

Growth of the acetogenic anaerobe Eubacterium limosum on methanol/CO2 mixtures is limited by the rate at which CO2 can be assimilated. This limitation can be offset by the consumption of acetate as an additional co-substrate. Growth on methanol/CO2/acetate mixtures improves growth rates but stimulates production of an unidentified polymer leading to cell aggregation and wall growth under chemostat conditions. Production of butyrate as major fermentation end-product leads to growth inhibition visualized by an increased maintenance requirement as demonstrated by Y(ATP) estimations.