Journal of Applied Bacteriology 1988,65, 1 19-133 Growth energetics of Clostridium sporogenes NCIB 8053:

The effects of the partial pressure of carbon dioxide on the growth energetics of Clostridiurn sporogenes NCIB 8053 grown in chemostat culture were investigated in defined minimal media. Both the 'maintenance ' requirements and the growth yield coefficients were dependent upon the partial pressure of carbon dioxide in otherwise glucose-limited cultures. Since growth yield coefficients decreased along with the apparent 'maintenance ' requirements in essential amino acidlfatty acid medium when the partial pressure of carbon dioxide was increased above 0.5 atm, the occurrence of some type of metabolic uncoupling seemed likely. By contrast, when the organism was grown in amino acid complete medium both the maintenance requirements and the growth yield coefficients were increased when the partial pres-sure of carbon dioxide was raised above 0.5 atm partial pressure of carbon dioxide, suggesting an increased efficiency of growth. A futile cycle involving carbon dioxide is proposed as a factor contributing to the variable extent of free energy dissipation within this organism. The clostridia are a diverse group of spore