Porphyrobacter mercurialis (mer.cur.ia.al'is L. adj. mercurialis, temperamental in reference to difficulties in establishing consistent growth requirements during characterization).
Gram-negative, non-spore forming pleomorphic bacteria. Strictly aerobic and chemoheterotrophic. Contains carotenoids, but not bacteriochlorophyll a. The major respiratory quinone is ubiquinone 10, the dominant phospholipds are phosphatidylglycerol, sphingoglycolipid, and phophatidylthanolamine. Colonies on LB are round, glossy, and less than 1 mm in diameter. Coloration on agar and in dense liquid culture is dark yellowish orange, appears lighter yellow in liquid culture during exponential phase. Morphology is non-motile pleomorphic ovals or short rods (average 1.6 µm length), often with pointed ends. Growth in liquid culture from 4-28 °C, optimum growth at 25 °C. Requires salt for growth, optimal growth at 0.5% NaCl, cannot grow at 3% NaCl. Tolerates up to pH 8.0, optimum around neutral pH. Oxidase-negative and catalase-positive, does not hydrolyze casein or starch. Does not grow on R2A agar. The primary fatty acids are C18:1\(\omega\)7cis and C16:0, with a high percentage of the latter relative to other species in the Erythrobacteraceae family. Can oxidize the following as sole carbon sources: Glycyl-L-Glutamic Acid, L-Rhamnose, D-Mannose, D-Trehalose, a-D-Glucose, L-Fucose, D-Galactose, Citric acid, D-Glucuronic acid, D-Galactonic acid, L-Galactonic acid-\(\gamma\)-Lactone, Acetoacetic acid, Acetic acid, Pyruvic acid, and L-Malic acid.
The type strain CoronadoT (=DSMZ 29971, =LMG 28700) was isolated from a stadium seat in Coronado, California, USA. The GC content of the type strain is 67.3%, as determined by genome sequencing. The genome size is approximately 3.5 MB.