PHENOTYPIC DIVERSITY OF ANAEROBIC GLYCEROL DISSIMILATION SHOWN BY 7 ENTEROBACTERIAL SPECIES

The anaerobic glycerol pathway was studied in seven enterobacterial sp ecies selected as representative of different behaviours in terms of a naerobic glycerol dissimilation. The presence of oxidative and reducti ve pathways of the dha regulon in Klebsiella pneumoniae enabled the ce lls to grow fermentatively on glycerol. The first two enzymes of the d ha regulon (glycerol dehydrogenase type I and dihydroxyacetone kinase) represent the oxidative branch, while the latter two (glycerol dehydr atase and 1,3-propanediol dehydrogenase) represent the reductive branc h of glycerol fermentation. The slower utilization of glycerol by K. o xytoca was attributed to low production of 1,3-propanediol. K. oxytoca lacked glycerol dehydratase and demonstrated low 1,3-propanediol dehy drogenase activity. K. planticola and K. ozaenae differed from K. pneu moniae and K. oxytoca in lacking the ability to grow on glycerol. K. p lanticola lacked both enzymes of the reductive branch of glycerol ferm entation, and K. ozaenae possessed glycerol dehydrogenase only. K. rhi noscleromatis and Hafnia alvei, like Escherichia coil, did not possess a dha regulon. The glycerol dehydrogenase type II of H. alvei was dis tinct from that of E. coli. The phenotypic diversity of anaerobic glyc erol dissimilation may have taxonomic applications.