Lactobacillus florum sp. nov., a fructophilic species isolated from flowers

Abstract

Three strains of fructophilic lactic acid bacteria were isolated from flowers in South Africa. The isolates formed a subcluster in the Lactobacillus buchneri phylogenetic group, closely related to Lactobacillus fructivorans, Lactobacillus homohiochii, Lactobacillus lindneri and Lactobacillus sanfranciscensis according to phylogenetic analysis based on the 16S rRNA gene sequences. Levels of DNA-DNA relatedness indicated that the three strains belonged to the same taxon and formed a genetically distinct group, well separated from their phylogenetic relatives. The three strains produced acids from only two of the 49 carbohydrates tested, i.e. D-glucose and D-fructose. D-Fructose was more rapidly fermented than D-glucose. Good growth was recorded on d-fructose or D-glucose in the presence of external electron acceptors. However, delayed growth was recorded on d-glucose without electron acceptors. The novel strains produced lactic acid, ethanol and acetic acid from D-glucose at a ratio of 1 : 0.8 : 0.2. These characteristics were distinct from other species of the genus Lactobacillus. Based on the data provided, the three isolates represent a fructophilic and novel species of the genus Lactobacillus, for which the name Lactobacillus florum sp. nov. is proposed. The type strain is F9-1(T) (=JCM 16035(T)=DSM 22689(T)=NRIC 0771(T)).