Geomicrobium sediminis sp. nov., A Novel Bacterium Isolated from A Sediment Sample Collected from the South China Sea

A number of haloalkaliphilic taxa that belong to the order Bacillales, such as Alkalibacillus, Gracilibacillus, Halobacillus and Sinobaca, had been isolated from various saline environments. Moreover, many novel species were isolated from South China Sea during the course of investigation of bacterial diversity, such as Streptomyces glycovorans, Streptomyces xishensis and Streptomyces abyssalis, Sinomicrobium oceani, Bacillus sediminis, among others. A novel species represented by strain YIM M13075^T was also isolated from marine sediment of South China Sea, which was moderately alkaliresisting halotolerant. This discovery further revealed the bacterial diversity of South China Sea.

In this study, a novel bacterium, designated YIM M13075^T, was isolated from a sediment sample collected from the South China Sea. Growth occurred from 4°C to 45°C (optimum 28°C), pH 6.0–11.0 (optimum pH 8.0). The strain formed yellow-cream colonies after 5 days incubation on TSA modified with 5% NaCl medium at 28°C. Cells were Grampositive, short rods and motile. Phylogenetic analyses based on 16S rRNA gene sequences indicated that strain YIM M13075^T was affiliated with the genus Geomicrobium (93.5%). The strain YIM M13075^T contained meso-diaminopimelic acid in the cell wall. The major polar lipids were diphosphatidylglycerol and phosphatidylglycerol. The major fatty acids were iso-C_15:0 and anteiso-C_15:0. The predominant menaquinones were MK-7 and MK-6. The genomic DNA G+C content was 42.7 mol%.

On the basis of the morphological and chemotaxonomic characteristics as well as genotypic data, strain YIM M13075^T represents a novel species in the genus Geomicrobium, for which the name Geomicrobium sediminis sp. nov. is proposed. The type strain is YIM M13075^T (=DSM 25540^T =JCM 18144^T =CCTCC AB 2013245^T). An emended description of the genus Geomicrobium is also proposed in the light of the new data. The result was published in Antonie van Leeuwenhoek in December 2013.