Three bacterial strains belonging to the genus Lactobacillus were isolated from the digestive tracts of laboratory-reared bumblebee queens (Bombus terrestris) using MRS agar under anaerobic conditions. The isolates were identified according to 16S rRNA gene sequence analysis as undescribed members of the genus Lactobacillus, with the highest 16s rRNA gene sequence similarity (96.9%) to the uncharacterized bacterial strain Lactobacianus sp Mboho2r2 isolated from the stomach of a European honeybee (Apis mellifera). Lactobacilius tucceti was found to be the closest related species with a validly published name, with 92.9 16S rRNA sequence gene similarity to the type strain. However phylogenetic analyses based on different markers revealed that this species is phylogenetically very distant from the novel The D G +C content of the proposed t strain BTLCH M112T is 37.8 mo19%. The fatty acids 18:106c and/or C1 o cyclo c/19eo6, C 9c and C were predominant in all strains. 18:10 16:o Diphosphatidylglycerol, phosphatidylglycerol, a phospholipid, seven glycolipids and two phosphoglycolipids were detected in the novel strains. Growth was observed at 47 "C. The peptidoglycan type A43 L-Lys-D-Asp was determined for strain BTLCH M112'. Genotypic characteristics and phylogenetic analyses based on the phylogenetic markers hsp60, phes, rpoA and tuff as well as phenotypic characteristics and the results of chemotaxonomic analyses confirmed that the new isolates belong to a novel species of the genus Lactobacillus, for which the name Lactobacillus bomb sp. nov. is proposed. The type strain is BTLCH M1/2T DsM 26517 CCM 8440