EFFECTS OF SUBSTRATE LIMITATION ON PRODUCT DISTRIBUTION AND H-2 CO2 RATIO IN KLEBSIELLA-PNEUMONIAE DURING ANAEROBIC FERMENTATION OF GLYCEROL/

Product formation during anaerobic degradation of glycerol by Klebsiel la pneumoniae DSM 2026, under glycerol limitation and glycerol excess in continuous cultures, has been investigated. Major and minor product s and by-products as well as gaseous products were measured. The resul ts indicated a positive correlation between specific glycerol uptake a nd most product formation rates under glycerol limitation. The product ion of 1,3-propanediol, lactate, formate, acetate, succinate and the b y-products of anaerobic glycerol degradation by K. pneumoniae, acetoin and 2,3-butanediol, was favoured by glycerol excess, while hydrogen g eneration and ethanol formation were best under glycerol limitation. I t was also found that under glycerol limitation the rate of hydrogen e volution was generally higher than the CO2 production rate while under excess glycerol the reverse was true. Hence, on the basis of the rati o of the specific rates of evolution of H-2 and CO2 (q(H2)/q(CO2)), it is possible to infer the existence of glycerol limitation. On the bas is of the carbon and available electron balances, which are independen t of metabolic pathways, the data are consistent. The NADH, balance, w hich took into consideration the pathways of product formation, was al so tested to check the validity of the assumed pathways and to check c ritically the consistency of the data. Good balances were also obtaine d.