Feasibility of automated head-space gas chromatography in identification of anaerobic bacteria

Neutral and acidic metabolites of some anaerobic bacteria cultured in a liquid growth medium were analysed by gas chromatography. Studies on the head-space vapours above heated broth cultures, using a gas chromatograph equipped with a fused silica capillary column and a unit for automatic head-space injection, enabled volatile alcohols and fatty acids to be readily detected. By contrast, when studying ether extracts of the same cultures, using a packed column, alcohols were only rarely registered, being more or less "hidden" under the solvent peak. Head-space gas chromatography was thus found to provide more diagnostic information on anaerobes, as exemplified by the registration of volatile alcohols produced by Clostridium sporogenes. Being suited for automation, this technique should be considered as an alternative to the study of solvent extracts of broth cultures in gas chromatographic identification of anaerobic bacteria.