The genus Leuconostoc was divided into three subclusters by multilocus sequence
analysis based on the 16S rRNA, 16S23S rRNA intergenic spacer region, rpoC and
recA gene sequences. The subclusters were the Leuconostoc mesenteroides subcluster (L.
carnosum, L. citreum, L. gasicomitatum, L. gelidum, L. inhae, L. kimchii, L. lactis, L.
mesenteroides and L. pseudomesenteroides), the L. fructosum subcluster (L. durionis, L.
ficulneum, L. fructosum and L. pseudoficulneum) and the L. fallax subcluster (L. fallax).
Species in the L. fructosum subcluster produced rod-shaped cells, and thus
morphologically distinguished from the other Leuconostoc species. These species were
also distinct from the others by their poor sugar fermentation patterns. They fermented
only two carbohydrates (Dglucose and Dfructose) of the 22 tested. The species in the L.
fructosum subcluster grew well in a Dfructose-yeast-peptone broth but poor in a
Dglucose-yeast-peptone broth. Strains of these species needed an electron acceptor for
Dglucose dissimilation. Good growth was recorded in the Dglucose-yeast-peptone
broth with pyruvate or when incubated aerobically. No growth was obserbed under
anaerobic conditions. In addition, the species did not pr oduce ethanol but produced
acetic acid from Dglucose. On the basis of evidence described above, the four species in
the L. fructosum subcluster should be transferred to a novel genus, Fructobacillus gen.
nov. The name originates from their fructose-loving property. Interestingly, they were
originally isolated from fructose-rich-environments, such as fruits, flowers or fermented
food derived from fruits. Thus, their characteristics would be caused by adaptation to
their habitats.