Effect of glucose concentration in the growth medium upon neutral and acidic fermentation end-products of Clostridium bifermentans, Clostridium sporogenes and peptostreptococcus anaerobius.

Clostridium bifermentans, C. sporogenes and Peptostreptococcus anaerobius were grown in Fastidious Anaerobe Broth with glucose concentrations from 0-1.5% (w/v). Gas chromatographic (GLC) analysis of fermentation end-products revealed that a change in glucose concentration markedly affected fermentation patterns of each microorganism. Increased glucose concentration resulted in stimulation of ethanol production by all strains, and of butanol and butyric acid by C. sporogenes. With C. bifermentans, there was a parallel increase in ethanol and acetic acid production and decreased formation of propanol and propionic, iso-butyric and iso-valeric acids. Increased ethanol formation by P. anaerobius was accompanied by an increase in acetic acid and a decrease in butan-1-ol production. The greatest incremental change in GLC profiles occurred when glucose concentration was raised from zero to 0.1% (w/v). These data suggest that glucose concentration in a medium for GLC analysis must be rigorously controlled if reproducible results are to be obtained.