COMPARISON OF THE ENERGETIC EFFICIENCIES OF HYDROGEN AND OXYCHEMICALSFORMATION IN KLEBSIELLA-PNEUMONIAE AND CLOSTRIDIUM-BUTYRICUM DURING ANAEROBIC GROWTH ON GLYCEROL

Data for the anaerobic growth of Klebsiella pneumoniae DSM 2026 and Cl ostridium butyricum DSM 5431 on glycerol have been analyzed using the concept of material and available electron balances with consideration for hydrogen production. Models for the kinetics of energetic efficie ncies of product formation under low residual glycerol are presented. For Klebsiella pneumoniae, the specific rates of electron transfer to the products were mainly significantly dependent on specific growth ra te with the exception of ethanol and hydrogen which were also signific antly non-growth associated. In the case of Clostridium butyricum, the rates were only growth rate dependent, except for hydrogen formation. The analysis also indicated that the production of 1,3-propanediol by Klebsiella pneumoniae was favoured by limitations other than glycerol limitation, while hydrogen generation was best under low residual gly cerol and particularly in the presence of external 1,3-propanediol. Kl ebsiella pneumoniae appeared to be able to incorporate more of the ava ilable electrons of glycerol into hydrogen as compared with the Clostr idium butyricum. The study demonstrates the need for properly consider ing H-2 in models describing anaerobic processes.