The Journal of Applied Bacteriology

Abstract

The effects of the partial pressure of carbon dioxide (pCO,) on the growth rate of Clostridium sporogenes NCIB 8053 in batch culture were investigated in defined minimal media.Depending upon the growth medium, C O , was stimulatory or inhibitory to growth.The absolute C O , requirement for growth displayed by Cl. sporogenes in certain media was shown to be due to the involvement of C O , in the synthesis of branched-chain amino acids.High concentrations of C O , were growth inhibitory except in complex media.In media where an optimal pCO, was observed it was approximately 0.45 atm.The pattern of fermentation end-products displayed by this organism was also modified by the pCO,.The equilibria of the different species of 'CO,' present in microbiological media are described.Finally, the metabolic control theory of Kacser, Burns, Heinrich and Rapoport has been applied to the results obtained, to provide a quantitative description of the effects of pCO, on the growth rate of Cl. sporogenes.Carbon dioxide has been shown to inhibit the growth of numerous micro-organisms (e.g.