Psychroflexus aurantiacus sp. nov., isolated from soil in the Yellow River Delta wetlands

Psychroflexus curvus sp. nov., Psychroflexus longus sp. nov. and Psychroflexus montanilacus sp. nov., isolated from salt lakes on the Tibetan Plateau

Four Gram-stain-negative, catalase- and oxidase-positive, rod-shaped and non-motile strains (CAK1WT, CAK8WT, CAK57W and CCL10WT) were isolated from salt lakes in China. Comparisons based on the 16S rRNA gene sequences showed that the four strains show less than 98.9% similarity to species of the genus Psychroflexus . The phylogenetic tree reconstructed based on 16S rRNA gene sequences also showed that Psychroflexus species are the most closely related neighbours of the four strains. The sequenced draft genome sizes of strains CAK1WT, CAK8WT, CAK57W and CCL10WT were 3.01, 2.95, 3.01 and 3.04 Mbp with G+C contents of 37.3, 35.8, 37.5 and 36.6 %, respectively. The phylogenomic trees reconstructed based on the UBCG and GET_PHYLOMARKERS pipelines all demonstrated that the four strains belong to the genus Psychroflexus . The calculated pairwise orthologous average nucleotide identity based on usearch, digital DNA–DNA hybridization and average amino acid sequence identity values among strains CAK1WT, CAK8WT, CAK57W, CCL10WT and other species of the genus Psychroflexus were equal or lower than 91.1, 43.5 and 92.2%; the values between strains CAK1WT and CAK57W were 98.8, 90.2 and 99.0 %, respectively. The respiratory quinone of the four strains was MK-6. Their major fatty acids were iso-C14 : 0, C15 : 1 ω10c, iso-C15 : 0 and anteiso-C15 : 0. The major polar lipids of the four strains included phosphatidylethanolamine, an unidentified aminolipid and two kinds of unidentified lipids, and only strain CCL10WT contained diphosphatidylglycerol. Based on the above descriptions, strains CAK1WT, CAK8WT, CAK57W and CCL10WT should belong to the genus Psychroflexus and represent three independent novel species, for which the names Psychroflexus curvus sp. nov. (type strain CAK1WT=GDMCC 1.2644T=KCTC 82857T), Psychroflexus longus sp. nov. (type strain CAK8WT=GDMCC 1.2646T=KCTC 82859T) and Psychroflexus montanilacus sp. nov. (type strain CCL10WT=GDMCC 1.2631T=KCTC 82860T) are proposed.

Halalkalibacterium roseum gen. nov., sp. nov., a new member of the family Balneolaceae isolated from soil

A Gram-stain-negative, non-motile, moderately halophilic and facultatively anaerobic bacterium, designated YR4-1T, was isolated from a saline-alkali and sorghum-planting soil sample collected in Dongying, Shandong Province, PR China. Growth occurred at 28–45 °C with the presence of 4.0–20.0 % (w/v) NaCl and pH 6.0–9.0. Phylogenetic analysis based on the 16S rRNA gene sequences revealed that YR4-1T shared the highest similarity of 92.1–92.4 % with the valid published species of Aliifodinibius . The isolate formed a separate clade at the genus level in recently described family Balneolaceae . The draft genome of strain YR4-1T is 3.83 Mbp long with 44.0 mol% G+C content. The strain possesses several genes involved in the osmotic stress response mechanism and diverse metabolic pathways, probably for the living in saline environment. This may lead to a better understanding of the underrepresented Balneolaceae lineage. The major menaquinone was MK-7. The main polar lipid profile was composed of diphosphatidylglycerol, phosphatidylglycerol, phosphoglycolipids, aminophosphoglycolipid, one glycolipid, and four unidentified lipids. The predominant cellular fatty acids were iso-C15 : 0 (35.7 %) and anteiso-C15 : 0 (33.5 %). On the basis of its phenotypic, chemotaxonomic and phylogenetic features, strain YR4-1T represents a novel species of a new genus, for which the name Halalkalibacterium roseum gen. nov., sp. nov. is proposed. The type strain is YR4-1T (=CGMCC 1.17777T=KCTC 72795T).

Pontibacillus sp. ALD_SL1 and Psychroflexus sp. ALD_RP9, two novel moderately halophilic bacteria isolated from sediment and water from the Aldabra Atoll, Seychelles

Pontibacillus sp. ALD_SL1 and Psychroflexus sp. ALD_RP9 are two novel bacterial isolates from mangrove sediment and a moderately hypersaline pool on the Aldabra Atoll, Seychelles. The isolates represent two novel species were characterised physiologically and genomically. Pontibacillus sp. ALD_SL1 is a facultatively anaerobic yellow, motile, rod-shaped Gram-positive, which grows optimally at a NaCl concentration of 11%, pH 7 and 28°C. It is the third facultatively anaerobic member of the genus Pontibacillus. The organism gains energy through the fermentation of pyruvate to acetate and ethanol under anaerobic conditions. The genome is the first among Pontibacillus that harbours a megaplasmid. Psychroflexus sp. ALD_RP9 is an aerobic heterotroph, which can generate energy by employing bacteriorhodopsins. It forms Gram-negative, orange, non-motile rods. The strain grows optimally at NaCl concentrations of 10%, pH 6.5–8 and 20°C. The Psychroflexus isolate tolerated pH conditions up to 10.5, which is the highest pH tolerance currently recorded for the genus. Psychroflexus sp. ALD_RP9 taxonomically belongs to the clade with the smallest genomes. Both isolates show extensive adaptations to their saline environments yet utilise different mechanisms to ensure survival.