TAXONOMIC DIVERSITY OF ANAEROBIC GLYCEROL DISSIMILATION IN THE ENTEROBACTERIACEAE

A total of 1,123 strains representing 128 taxa in the Enterobacteriace ae (named species or subspecies and genomic species) were screened for the presence of glycerol dehydrogenases and 1,3-propanediol dehydroge nase. Only eight taxa, Citrobacter freundii sensu stricto, C. youngae, C. braakii, C. werkmanii, Citrobacter genomospecies 10 and 11, Entero bacter gergoviae and Klebsiella pneumoniae subsp. pneumoniae could gro w fermentatively on glycerol and possessed both glycerol dehydrogenase type I (induced by glycerol and dihydroxyacetone) and 1,3-propanediol dehydrogenase which are typical enzymes of the anaerobic glycerol dis similation pathway. Six other species. C. koseri, E. aerogenes, E. int ermedium, K. oxytoca, K. planticola and K. terrigena could not grow fe rmentatively on glycerol and possessed a glycerol dehydrogenase type I but no 1,3-propanediol dehydrogenase. Other glycerol dehydrogenases t ypes were found: type II (induced by glycerol and hydroxyacetone), typ e III (induced by glycerol only) and type IV (induced by hydroxyaceton e only). They were widely distributed among the Enterobacteriaceae. Cl assification and identification may take advantage of tests exploring the dissimilation of glycerol.