Leuconostoc ficulneum sp. nov., a novel lactic acid bacterium isolated from a ripe fig, and reclassification of Lactobacillus fructosus as Leuconostoc fructosum comb. nov.

An isolate, designated strain FS-1T, was recovered from a ripe fig. Phylogenetic analysis of the 16S rRNA genes and DNA-DNA reassociation values showed that the organism represented a novel species of the genus Leuconostoc closely related to Lactobacillus fructosus. The novel isolate could be distinguished from the type strain of Lactobacillus fructosus by the fatty acid composition and several phenotypic and growth characteristics. In strain FS-1T, 18:1 delta9 (18:1omega9c) was present in relatively large amounts whilst, in Lactobacillus fructosus, this fatty acid was a minor component. Strain FS-1T and Lactobacillus fructosus produced acid in API 50CHL microtubes from glucose, fructose and mannitol within 48 h, whereas only strain FS-1T also fermented trehalose, gluconate, turanose and sucrose after 48 h. Other differences in acid production from carbohydrates also distinguished strain FS-1T from Lactobacillus fructosus. Both organisms were heterofermentative with fructose as a substrate and fermented glucose only in the presence of fructose, as determined by nuclear magnetic resonance studies. Strain FS-1T was catalase-positive. On the basis of the phylogenetic analysis, DNA-DNA reassociation values, physiological and biochemical characteristics and fatty acid composition, the name Leuconostoc ficulneum is proposed for the novel species represented by strain FS-1T, and it is proposed that Lactobacillus fructosus be reclassified in the genus Leuconostoc as Leuconostoc fructosum comb. nov.