Massilia brevitalea sp. nov., a novel betaproteobacterium isolated from lysimeter soil.

A Gram-negative, strictly aerobic bacterium, designated strain byr23-80T, was isolated from lysimeter soil by using a high-throughput cultivation technique. Cells of strain byr23-80T were found to be short rods that multiplied by binary fission and were motile by means of a single polar flagellum. Occasionally, two to three polar or lateral flagella were observed. The optimum growth temperature was 15 degrees C and the pH optimum was 7.0-7.5. The predominant cellular fatty acids were C16 : 1omega7c (54.7 %) and C16 : 0 (21.4 %). In addition, the diagnostic fatty acids C10 : 0 3-OH and C12 : 0 2-OH were detected. Q-8 was the predominant respiratory quinone. The isolate was physiologically very versatile, using a wide range of sugars, organic acids and amino acids as single carbon and energy sources for growth. The G+C content of the genomic DNA was 65.3 mol%. Phylogenetic analyses supported the assignment of strain byr23-80T to the genus Massilia within the family Oxalobacteraceae of the class Betaproteobacteria. Within the genus, strain byr23-80T was most closely related to Massilia aurea DSM 18055T, with a 16S rRNA gene sequence similarity of 98.3 %. However, DNA-DNA hybridization revealed a pairwise similarity for the genomic DNA of only 20.1 % between strain byr23-80T and strain DSM 18055T. The novel isolate could be distinguished from the existing species Massilia timonae, Massilia dura, Massilia albidiflava, Massilia plicata, Massilia lutea and M. aurea by its significantly lower temperature optimum for growth and by the absence of gelatinase, alpha-galactosidase and beta-galactosidase activities. On the basis of these characteristics, strain byr23-80T constitutes a novel species of the genus Massilia, for which the name Massilia brevitalea sp. nov. is proposed. The type strain is byr23-80T (=DSM 18925T=ATCC BAA-1465T).