Lactobacillus thermotolerans sp. nov., a novel thermotolerant species isolated from chicken faeces

1 Laboratory of Microbial Resources and Ecology, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo 060-8589, Japan 2 Laboratory of Applied Microbiology, Graduate School of Agriculture, Hokkaido University, Kita-9 Nishi-9, Kita-ku, Sapporo 060-8589, Japan 3 Research Institute of Biological Resources, National Institute of Advanced Industrial Science and Technology (AIST), Tsukuba Central 6, Higashi 1-1-1, Tsukuba, Ibaraki 305-8566, Japan 4 Department of Biology, Faculty of Science, Chiang Mai University, Huay Kaew Road, Muang District, Chiang Mai 50200, Thailand 5 Department of Biotechnology, Faculty of Science, Mahidol University, Rama 6 Road, Bangkok 10400, Thailand Correspondence Atsushi Yokota yokota{at}chem.agr.hokudai.ac.jp Five strains of thermotolerant lactic acid bacteria (G 12, G 22, G 35 T , G 43 and G 44) isolated from chicken faeces were characterized taxonomically. The strains were facultatively anaerobic, Gram-positive, catalase-negative, non-motile, non-spore-forming rods. They were heterofermentative lactobacilli that produced DL -lactic acid. Growth of the strains occurred at 45 °C but not at 15 °C. The optimum temperature for growth was 42 °C, as determined from the specific growth rate. The highest permissive temperatures for growth were 50 °C for strain G 35 T and 48 °C for the other four strains. DNA G+C content of the strains was between 49 and 51 mol%. Complex fatty acid patterns of the strains showed the presence of C 14 : 0 , C 16 : 0 , sometimes C 18 : 0 , C 18 : 1 and C 19 : 0 cyclo in the cell walls. Phylogenetic analysis of the 16S rRNA gene sequences of the five strains placed them in the Lactobacillus casei / Pediococcus group, with Lactobacillus fermentum as their closest relative (about 95 % sequence similarity). DNA–DNA hybridization data indicated that the thermotolerant strains were not L. fermentum . Taken together, the findings of this study show that the five strains isolated from chicken faeces represent a novel species within the genus Lactobacillus , for which the name Lactobacillus thermotolerans is proposed (G 35 T =DSM 14792 T =JCM 11425 T ). Abbreviations: LAB, lactic acid bacteria; TLAB, thermotolerant lactic acid bacteria Published online ahead of print on 19 July 2002 as DOI 10.1099/ijs.0.02347-0. The GenBank accession numbers for the 16S rDNA sequences of strains G 12, G 22, G 35 T , G 43 and G 44 are AF308146 , AF308147 , AF317702 , AF317703 and AF317704 , respectively.