Polaromonas vacuolata

Polaromonas vacuolata is a psychrophilic bacterium with gas vesicles from the genus Polaromonas, which was isolated from Antarctica. The optimum temperature for growth is  4°C, and the growth temperature range is 0 to 12°C. Colonies are snowy white, circular,  and convex with  smooth  surfaces and entire edges. The more gas vesicles within the cells, the whiter the colony. Good growth occurs in media containing NaCl at concentrations ranging from 0 to 6.0%, but no growth occurs in the presence of 7.0% NaC1.

Tests for catalase, oxidase, urease, deaminase, and lipase are positive. Amylase, protease (gelatin), tryptophanase (indole), nitrate reductase, cysteine desulfurase, and  agarase tests are negative.

The following carbon sources are utilized: acetate, lactate, malate, fumarate, pyruvate, propionate, citrate, succinate, oxaloacetate, butyrate, 2-oxoglutarate7 glucose, glycerol, sorbitol, DL-alanine, DL-glutamate, DL-proline, DL-aspartate, and DL-asparagine.

The following carbon  sources are not utilized: maltose, D- fructose, sucrose, lactose, D-xylose, D-ribose, formate, cellobiose, D-mannose, L-fucose, melibiose, melezitose, L-rhamnose, sorbose,  trehalose, methanol,  ethanol, erythritol, propanol, benzoate, malonate, DL-arginine, glycine, DL-serine, DL-isoleucine, DL-lysine, DL-histidine, DL-ornithine, DL-methionhe, DL- valine, DL-threonine, and DL-tryptophan.

The fatty acid composition is 75% 16:l o7c, 17% 16:0, and 8% 18:l 07c, 18:l o9t, or 18:l o12t. Susceptible to novobiocin, tetracycline, neomycin, and kanamycin. Resistant  to bacitracin, streptomycin, and gentamicin.

The G+C content is 52.0 mol% (as determined by the thermal denaturation method).