Alsobacter ponti sp. nov., a novel denitrification and sulfate reduction bacterium isolated from Pearl River sediment.

A Gram-staining negative, aerobic, motile, and short rods strain, designated SYSU M60028T, was isolated from a Pearl River sediment sample in Guangzhou, Guangdong, China. The isolate could be able to grow at pH 6.0-8.0 (optimum, pH 7.0), 25-37 °C (optimum, 28 °C) and in the presence of 0-2% (w/v) NaCl (optimum, 0% NaCl). The cellular polar lipids of this strain were phosphatidylethanolamine, diphosphatidylglycerol, phosphatidylglycerol, phosphatidylcholine, one unidentified aminolipid and three unidentified lipids. The respiratory quinone of SYSU M60028T was found to be Q-10. The major fatty acids (> 5% of total) were summed feature 8, C16:0, and C18:1 ω7c 11-methy1. The genomic DNA G + C content was 69.9%. Phylogenetic analyses based on 16S rRNA gene sequences and core genes indicated that strain SYSU M60028T belonged to the genus Alsobacter and had the highest sequences similarities to Alsobacter metallidurans SK200a-9T (96.87%) and Alsobacter soli SH9T (96.87%). Based on the phenotypic, genotypic, and phylogenetic data, strain SYSU M0028T should be considered to represent a novel species of the genus Alsobacter, for which the name Alsobacter ponti sp. nov. is proposed. The type strain is SYSU M60028T (= CGMCC 1.19341T = KCTC 92046T).

Alsobacter soli sp. nov., a novel bacterium isolated from paddy soil, emended description of the genus Alsobacter and description of the family Alsobacteraceae fam. nov.

Strain SH9T, an aerobic bacterium isolated from a paddy soil sample collected in Shanghai, China, was characterized using a polyphasic approach. It grew optimally at pH 7.0, temperatures of 30-35 °C and in the presence of 1 % (w/v) NaCl. Comparative analysis of 16S rRNA gene sequences showed that strain SH9T fell within the genus Alsobacter, forming a clear cluster with the type strain of Alsobacter metallidurans, with which it exhibited a 16S rRNA gene sequence similarity value of 98.5 %. Cells of strain SH9T were Gram-stain-negative, motile, non-spore-forming, rod-shaped, positive for catalase and oxidase activity, and negative for atmospheric nitrogen fixation and nitrate reduction. The strain was a chemo-organotrophic bacterium, incapable of growth on C1 substrates. The chemotaxonomic properties of strain SH9T were consistent with those of the genus Alsobacter: the predominant ubiquinone was Q-10, and the major fatty acid was summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c). The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, phosphatidylcholine and phosphatidylmonomethylethanolamine. The DNA G+C content was 68.5 mol%. Strain SH9T exhibited a DNA-DNA relatedness level of 20±2 % with A. metallidurans NBRC 107718T. Based on the data obtained, strain SH9T represents a novel species of the genus Alsobacter, for which the name Alsobactersoli sp. nov. is proposed. The type strain is SH9T (=JCM 32501T=CCTCC AB 2017284T). A new family, Alsobacteraceae fam. nov., is also proposed encompassing strain SH9T and Alsobacter metallidurans NBRC 107718T.