Phenylobacterium lituiforme sp. nov., a moderately thermophilic bacterium from a subsurface aquifer, and emended description of the genus Phenylobacterium.

A facultative anaerobic bacterium, strain FaiI3(T), was isolated from samples collected from the free-flowing waters of a bore well (Fairlea Bore, registration number 3768) which taps into the Australian Great Artesian Basin subsurface thermal aquifer. Strain FaiI3(T) developed yellow to pale-yellow colonies (0.5-1.5 mm) after 48 h. The non-spore forming rods (0.5x1-3 microm) were slightly curved, occurred singly and as pairs and were motile with a single polar flagellum. Cells tended to form clumps in liquid medium and rosettes were commonly observed. The cells stained Gram-negative and electron micrographs of thin sections revealed a multi-layered complex Gram-negative cell wall structure. Strain FaiI3(T) grew optimally at 40-41 degrees C, with growth observed at 45 degrees C but not at 50 degrees C. The pH growth range was between pH 6 and 9 and optimal growth occurred between pH 6 and 6.5. Strain FaiI3(T) grew best with yeast extract as the sole carbon and energy source. Peptone, yeast extract, acetate, xylose, sucrose, glucose, glycerol, succinate, butyrate, lactate, fumarate, citrate, L-phenylalanine, cellobiose and gelatin supported growth but maltose, fructose, glycine, ethanol, benzoate and oxalate did not. Tyrosine was produced from L-phenylalanine. Strain FaiI3(T) was catalase-positive and oxidase-negative and did not hydrolyse starch. Growth was inhibited by neomycin, tetracycline, streptomycin, chloramphenicol, ampicillin, vancomycin and spectinomycin. The G+C content was determined to be 66.5+/-0.5 mol%. On the basis of the 16S rRNA gene sequence analysis, strain FaiI3(T) was assigned as a novel species of the genus Phenylobacterium, Phenylobacterium lituiforme sp. nov. in the order Caulobacterales, subclass alpha-Proteobacteria, class Proteobacteria. The type strain is FaiI3(T) (=ATCC BAA-294(T)=DSM 14363(T)).