Sphingosinicella humi

Sphingosinicella humi is a Gram-negative, rod-shaped bacterium that is a member of the genus "Sphingosinicella". It is strictly aerobic, flagellated, and motile. Colonies are white, convex, circular, and slightly transparent. "S. humi" grows in the presence of arsenic and sodium chloride. The optimum temperature for growth is 28˚C, but "S. humi" can grow within the temperature range of 16-42 ˚C. The organism can grow in a pH range of 6.5-9. Culture growth occurs on Reasoner’s 2A agar (R2A agar) medium and in 1/10 tryptic soy broth.
Metabolism.
"S. humi" reduces nitrogen. It is capable of hydrolyzing tween 20, arginine, and urea. It is oxidase positive, meaning that it produces cytochrome c oxidases. It is catalase negative, suggesting that it is incapable of forming catalase, and is therefore incapable of neutralizing hydrogen peroxide. "S. humi" can also produce acid from D-galactose and assimilate propionate, L-proline, acetate, D-galactose, and valerianate.
Genomic Sequencing.
The genome of "S. humi" was sequenced using 16S rRNA. The chromosome of "S. humi" is 3.0Mb long, contains 4 contigs, and is predicted to be composed of 2981 genes. The DNA G-C content range of "S. humi" is 65.9 mol%. "S. humi" was significantly similar to four strains of "Sphingosinicella", specifically 97% similar to "Sphingosinicella vermicomposti" YC7378, 96.1% similar to "Sphingosinicella xenopeptidilytica" 3-2W4, 96% similar to "Sphingosinicella microcystineivorans" Y2, and 95.9% similar to "Sphingosinicella soli" KSL-125. The genomic similarities aid in the determination of "S. humi" as part of the genus "Sphingosinicella".
Ecology.
"S. humi" was isolated from arsenic contaminated farmland red soil from the village, Jiaotain, in the city of Daye, Hubei Province, People’s Republic of China. The soil sample had an arsenic concentration of 35.8 mg/kg and a pH of 6.95.