Aliidiomarina quisquiliarum sp. nov., isolated from landfill leachate

Bacterial strain Y-6^T, isolated from a landfill site in Yiwu, PR China, was characterized using a polyphasic taxonomy approach. Cells were Gram-stain-negative, aerobic, rod-shaped, motile by means of a single polar flagellum and formed pale beige colonies. Strain Y-6^T grew at 4-40 °C (optimal at 30-37 °C), pH 6.5-9.5 (optimal at pH 7.2-8.5) and in the presence of 0.5-10.0 % (w/v) NaCl (optimal at 1.0-3.0 %). Phylogenetic analysis revealed that strain Y-6^T was a member of the genus Aliidiomarina and closely related to Aliidiomarina taiwanensis MCCC 1A06493^T with a 16S rRNA sequence similarity of 98.2 %. The major cellular fatty acids of the isolate were iso-C_15 : 0, C_16 : 0, iso-C_17 : 0 and summed feature 9 (iso-C_17 : 1  ω9c and/or 10-methyl-C_16 : 0). Q-8 was the predominant ubiquinone. The major polar lipids comprised diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, aminoglycophospholipid, aminophospholipid, phospholipid, three glycolipids and two unknown lipids. The genomic DNA G+C content was 46.6 mol%. The digital DNA-DNA hybridization value between Y-6^T and A. taiwanensis MCCC 1A06493^T was 18.3 %. Strain Y-6^T had an average nucleotide identity value of 74.09 % with A. taiwanensis MCCC 1A06493^T. Results from the polyphasic taxonomy study support the conclusion that strain Y-6^T represents a novel Aliidiomarina species, for which the name Aliidiomarina quisquiliarum sp.nov. is proposed. The type strain is Y-6^T (=MCCC 1K06228^T=KCTC 82676^T).

Aliidiomarina halalkaliphila sp. nov., a haloalkaliphilic bacterium isolated from a soda lake in Inner Mongolia Autonomous Region, China

A haloalkaliphilic strain (IM 1326^T) was isolated from brine sampled at a soda lake in the Inner Mongolia Autonomous Region, China. Cells of the strain were rod-shaped and motile. Strain IM 1326^T was able to grow at 4–42 °C (optimum, 37 °C) with 0–13.0 % (w/v) NaCl concentrations (optimum at 4.0–6.0 %) and at pH 7.5–11.0 (optimum at 9.0–10.0). The 16S rRNA gene phylogenetic analysis revealed that the isolate belongs to the genus Aliidiomarina and is closely related to the type strains of Aliidiomarina sanyensis (95.8 % sequence similarity), Aliidiomarina shirensis (95.7 %), Aliidiomarina iranensis (95.4 %) and Aliidiomarina haloalkalitolerans (95.3 %). The whole genome of strain IM 1326^T was sequenced, and the genomic DNA G+C content was 49.7 mol%. Average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between the isolate and the related Aliidiomarina species were 68.1–84.9 %, 76–78 % and 18.4–20.4 %, respectively. The respiratory quinone was ubiquinone-8. The polar lipid profile included diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine and one unidentified aminophospholipid. The predominant cellular fatty acids were summed feature 9 (10-methyl-C_16 : 0/iso-C_17 : 1 ω9c, 22.2 %), iso-C_15 : 0 (16.1 %) and iso-C_17 : 0 (13.1 %). Based on the results of phylogenetic analysis, genome relatedness, and the physiological and chemotaxonomic properties of the isolate, strain IM 1326^T is considered to represent a novel species of the genus Aliidiomarina, for which the name Aliidiomarina halalkaliphila sp. nov. is proposed (type strain IM 1326^T=CGMCC 1.17056^T=JCM 34227^T).

Aliidiomarina indica sp. nov., isolated from deep seawater

A Gram-stain-negative, rod-shaped bacterial strain, designated SW123^T, was isolated from a deep-sea water sample collected from the Indian Ocean. Strain SW123^T was strictly aerobic, catalase- and oxidase-positive. The predominant cellular fatty acids were iso-C_{15 : 0}, iso-C_{17 : 0} and summed feature 9 (comprising C_{16 : 0}-methyl or iso-C_{17 : 1} ω9c). Ubiquinone-8 was the sole respiratory quinone. The major polar lipids consisted of diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The genomic DNA G+C content was 49.4 mol%. 16S rRNA gene sequence analysis showed that strain SW123^T was closely related to Aliidiomarina shirensis AIS^T (96.7 % sequence similarity), Aliidiomarina iranensis GBPy7^T (96.3%), Aliidiomarina haloalkalitolerans AK5^T (96.0%) and Aliidiomarina celeris F3105^T (95.9%). Phylogenetic trees based on 16S rRNA gene sequences showed that strain SW123^T represented a novel member of the genus Aliidiomarina, forming a distinct cluster with A. celeris F3105^T. On the basis of phylogenetic inference and phenotypic characteristics, we propose that strain SW123^T represents a novel species of the genus Aliidiomarina, with the name Aliidiomarina indica sp. nov. The type strain is SW123^T (=CGMCC1.16169^T=KCTC 82234^T).

Aliidiomarina sedimenti sp. nov., a haloalkaliphilic bacterium in the family Idiomarinaceae

A novel Gram-staining-negative straight or curved rod-shaped, moderately halophilic and alkaliphilic bacterium, designated strain GBSy1T, was isolated from a sediment sample from the coastal-marine wetland Gomishan in Iran. GBSy1T was motile, and formed non-pigmented, mucoid colonies. Growth occurred with between 1 and 15 % (w/v) NaCl and the isolate grew optimally with 5 % (w/v) NaCl. The optimum pH and temperature for growth were 8.5 and 34 °C, while the strain was able to grow at pH 7.0-10 and 4-40 °C. On the basis of the results of 16S rRNA gene sequence analysis, GBSy1T was shown to represent a member of the genus Aliidiomarina within the class Gammaproteobacteria, family Idiomarinaceae and showed closest phylogenetic similarity to Aliidiomarina marisCF12-14T (97.7 %). The DNA G+C content of GBSy1T was 51.2 mol%. The cells of GBSy1T contained the isoprenoid ubiquinones Q-8, Q-9 and Q-10 (92, 2 and 2 %, respectively). The major cellular fatty acids of the isolate were iso-C11 : 0 3-OH, iso-C15 : 0, iso-C17 : 0 and iso-C17 : 1ω9c and its polar lipid profile comprised phosphatidylglycerol, diphosphatidylglycerol, phosphatidylethanolamine and three unknown phospholipids. The level of DNA-DNA relatedness between GBSy1T and Aliidiomarina marisDSM 22154T was 31 %. All these features confirmed the placement of GBSy1T within the genus Aliidiomarina. On the basis of evidence from this study, a novel species of the genus Aliidiomarina, Aliidiomarina sedimenti sp. nov., is proposed, with GBSy1T (=IBRC-M 10764T=CECT 8340T) as the type strain.

Aliidiomarina soli sp. nov., isolated from saline-alkaline soil

A Gram-stain-negative, motile, non-spore-forming bacterium, designated strain Y4G10-17T, was isolated from the saline-alkali farmland top soil, Inner Mongolia, northern China. Strain Y4G10-17T could grow at 4-45 °C (with 30 °C as the optimal temperature), pH 6.0-12.0 (optimal at pH 9.0) and in the presence of 1.0-12.0 % (w/v) NaCl (optimal at 4.0-6.0 %). Phylogenetic analysis based on the eight different copies of the 16S rRNA gene sequences revealed that strain Y4G10-17T shared the highest sequence similarity with Aliidiomarina maris CF12-14T, 97.93-98.66 %, and lower than 97.0 % sequence similarity with all other type strains. Its major cellular fatty acids contained iso-C15 : 0, iso-C17 : 0, summed feature 9 (iso-C17 : 1ω9c and/or C16 : 0 10-methyl), iso-C15 : 1 F, iso-C11 : 0 3-OH and summed feature 3 (iso-C15 : 0 2-OH and/or C16 : 1ω7c). Q-8 was the predominantubiquinone. The major polar lipids of strain Y4G10-17T were diphosphatidylglycerol, phosphatidylglycerol, phosphatidylethanolamine, two unknown lipids and one unknown aminolipid. The genomic DNA G+C content was 49.3 mol%. DNA-DNA hybridization revealed that strain Y4G10-17T showed 20.2±5 % genomic DNA relatedness with its close relative A. maris CF12-14T. Based on the phenotypic, phylogenetic and genotypic characteristics, strain Y4G10-17T represents a novel species within the genus Aliidiomarina, for which the name Aliidiomarina soli sp. nov. is proposed. The type strain is Y4G10-17T (=CGMCC 1.15759T=KCTC 52381T).

Halophiles: biology, adaptation, and their role in decontamination of hypersaline environments

The unique cellular enzymatic machinery of halophilic microbes allows them to thrive in extreme saline environments. That these microorganisms can prosper in hypersaline environments has been correlated with the elevated acidic amino acid content in their proteins, which increase the negative protein surface potential. Because these microorganisms effectively use hydrocarbons as their sole carbon and energy sources, they may prove to be valuable bioremediation agents for the treatment of saline effluents and hypersaline waters contaminated with toxic compounds that are resistant to degradation. This review highlights the various strategies adopted by halophiles to compensate for their saline surroundings and includes descriptions of recent studies that have used these microorganisms for bioremediation of environments contaminated by petroleum hydrocarbons. The known halotolerant dehalogenase-producing microbes, their dehalogenation mechanisms, and how their proteins are stabilized is also reviewed. In view of their robustness in saline environments, efforts to document their full potential regarding remediation of contaminated hypersaline ecosystems merits further exploration.