Pathway of Glucose Fermentation in Relation to the Taxonomy of Bifidobacteria

Abstract

Cell-free extracts of 17 strains of Bifidobacterium bifidum ( Lactobacillus bifidus ) were examined for the presence of aldolase, glucose-6-phosphate dehydrogenase, and fructose-6-phosphate phosphoketolase. All strains turned out to lack aldolase, an enzyme unique to glycolysis, and glucose-6-phosphate dehydrogenase, characteristic of the hexosemonophosphate pathway. In all strains, fructose-6-phosphate phosphoketolase could be demonstrated. It can be concluded that bifidobacteria ferment glucose via a pathway which is different from those found in members of the genus Lactobacillus . The results strengthen the previous suggestions that classification of the bifidobacteria in the genus Lactobacillus is not justified.