Pseudaquidulcibacter saccharophilus gen. nov., sp. nov., a novel member of family Caulobacteraceae, isolated from a water purification facility with supplement of starch as a carbon source

During a survey of microbial communities in the influent (ambient water) and effluent of a water purification facility with aeration and supplement of starch as carbon source, a novel bacterial strain, designated SZ9T, was isolated from the effluent sample. Colonies of strain SZ9T were small (approximately 0.5–1.0 mm in diameter), creamy-white, circular, smooth, translucent and convex. Cells were facultative anaerobic, motile by means of a single polar flagellum, rod-shaped, multiplied by binary fission, Gram-stain-negative, oxidase-positive and catalase-negative. Growth occurred at 10–40 °C (optimum, 28 °C) and pH 5.5–8.0 (optimum, pH 7.5). The range of NaCl concentration for growth was 0–1.0 % (w/v), with an optimum of 0–0.5 % (w/v). Phylogenetic analysis based on 16S rRNA gene sequences suggested that strain SZ9T formed a lineage within the family Caulobacteraceae of the class Alphaproteobacteria and showed the highest 16S rRNA gene sequence similarities to Aquidulcibacter paucihalophilus TH1-2T (92.44%), followed by Vitreimonas flagellata SYSU XM001T (89.61 %), Asprobacter aquaticus DRW22-8T (89.49 %) and Hyphobacterium vulgare WM6T (89.49%). The predominant fatty acids (>10 % of the total fatty acids) of strain SZ9T was summed feature 3 (comprising C16 : 1  ω6c and/or C16 : 1  ω7c), summed feature 8 (C18 : 1  ω6c and/or C18 : 1  ω7c) and C16 : 0. The sole respiratory quinone was ubiquinone-10, and the major polar lipids were phosphatidylcholine and two unidentified glycolipids. The whole genome of strain SZ9T was 2 842 140 bp in size, including 2769 protein-coding genes, 37 tRNA genes and two rRNA genes, and the genomic G+C content was 41.4 mol%. The orthologous average nucleotide identity, average amino acid identity and digital DNA–DNA hybridization values between strain SZ9T and other genera within the family Caulobacteraceae were 64.50–66.62 %, 46.96–54.17 % and 27.70–31.70 %, respectively. Therefore, based on the results of phenotypic, chemotaxonomic and phylogenetic analyses, the isolated strain SZ9T could be distinguished from other genera, suggesting that it represents a novel species of a novel genus in the family Caulobacteraceae , for which the name Pseudaquidulcibacter saccharophilus gen. nov., sp. nov is proposed. The type strain is SZ9T (=CCTCC AB2021029T=KCTC 82788T).

Physiological and genomic features of Henriciella with the description of Henriciella mobilis sp. nov

Strains M65^T, M69 and JN25 were isolated from seawater of the West Pacific Ocean. Cells of the three strains were Gram-stain-negative, aerobic and rod-shaped. Cells were motile by means of flagella. On the basis of the results of 16S rRNA gene sequence analysis, strains M65^T, M69 and JN25 showed the highest 16S rRNA gene sequence similarity to Henriciella algicola MCS27^T (98.8 %), followed by Henriciella marina DSM 19595^T (98.4 %), Henriciella barbarensis MCS23^T (98.4 %), Henriciella pelagia LA220^T (98.3 %), Henriciella aquimarina P38^T (98.1 %) and Henriciella litoralis SD10^T (97.8 %). The 16S rRNA gene sequence similarities among the isolates were 100 %. Phylogenetic analyses revealed that the isolates fell within a cluster comprising the Henriciella species and represented an independent lineage. The average nucleotide identity and in silico DNA-DNA hybridization values between strain M65^T and the type strains of Henriciella species were 73.9-85.8 % and 19.9-22.4 %, respectively. The sole respiratory quinone detected in the three isolates was ubiquinone 10. The principal fatty acids were summed feature 8 (C_18 : 1  ω7c and/or C_18 : 1  ω6c) and C_16 : 0. The major polar lipids were glucuronopyranosyldiglyceride, monoglycosyldiglyceride and one unidentified glycolipid. The DNA G+C content was 61.3-61.4 mol%. Phylogenetic distinctiveness, chemotaxonomic differences, together with phenotypic properties, revealed that the isolates could be differentiated from the Henriciella species with validly published names. Therefore, it is proposed that strains M65^T, M69 and JN25 represent a novel species of the genus Henriciella, for which the name Henriciella mobilis sp. nov. (type strain, M65^T=CGMCC 1.15927^T=KCTC 52576^T) is proposed.

Taxonomically Characterized and Validated Bacterial Species Based on 16S rRNA Gene Sequences from India During the Last Decade

Microbial taxonomy dealing with identification and characterization of prokaryotes like bacteria and archaea has always been a major area of research all over the world. Exploring diversity of microbes and description of novel species with different genes and secondary compounds is of utmost importance for better future and sustenance of life. India having an enormous range of ecosystems and diverse species inhabiting these niches is considered to be one of the richest biodiversity regions of the world. During the last decade, with newer methodologies and better technology, the prokaryotic taxonomy from India has extended our inventory of microbial communities in specific niches. However, there still exist some limitations in classifying the microbes from India as compared to that is done world-over. This review enlists the taxonomic description of novel taxa of prokaryotes from India in the past decade. A total of 378 new bacterial species have been classified from different habitats in India in the last ten years and no descriptions of archaeal species is documented till date.

Polycyclic aromatic hydrocarbons in deep sea sediments: Microbe-pollutant interactions in a remote environment

Recalcitrant polycyclic aromatic hydrocarbons (PAHs) released into seawater end up in the deep sea sediments (DSSs). However, their fate here is often oversimplified by theoretical models. Biodegradation of PAHs in DSSs, is assumed to be similar to biodegradation in surface habitats, despite high hydrostatic pressures and low temperatures that should significantly limit PAH biodegradation. Bacteria residing in the DSSs (related mainly to α- and γ-Proteobacteria) have been shown to or predicted to possess distinct genes, enzymes and metabolic pathways, indicating an adaptation of these bacterial communities to the psychro-peizophilic conditions of the DSSs. This work summarizes some of the most recent research on DSS hydrocarbonoclastic populations and mechanisms of PAH degradation and discusses the challenges posed by future high CO2 and UV climate scenarios on biodegradation of PAHs in DSSs.

Defluviimonas indica sp. nov., a marine bacterium isolated from a deep-sea hydrothermal vent environment

A Gram-stain-negative, strictly aerobic, chemoheterotrophic marine bacterium, designated 20V17T, was isolated from a deep-sea hydrothermal vent chimney collected from the South-west Indian Ridge. Cells of strain 20V17T were motile, short rods, 1.2–1.8 µm in length and 0.5–0.7 µm in width. Growth was observed at between 20 and 37 °C (optimum 25 °C–28 °C), pH 5.0 and 8.0 (optimum pH 7.0) and 0.5 and 8 % (w/v) NaCl (optimum 1.5–2.0 % NaCl). The major fatty acids were C18 : 1ω7c (74.4 %), C19 : 0 cyclo ω8c (11 %), C18 : 0 (5.1 %) and C18 : 0 3-OH (2.8 %), and the polar lipid profile comprised diphosphatidylglycerol, phosphatidylethanolamine, an unidentified glycolipid and four unidentified phospholipids. Ubiquinone 10 was the major quinone. The G+C content of genomic DNA was 66.3 mol%. Phylogenetic analyses based on 16S rRNA gene sequences showed that strain 20V17T belonged to the genus Defluviimonas and shared 96.5 and 96.1 % sequence similarity with Defluviimonas denitrificans D9-3T and Defluviimonas aestuarii BS14T, respectively. On the basis of the taxonomic data obtained in this study, strain 20V17T represents a novel species of the genus Defluviimonas , for which the name Defluviimonas indica sp. nov. is proposed. The type strain is 20V17T (CGMCC 1.10859T = JCM 17871T = MCCC 1A01802T).

Litorimonas taeanensis gen. nov., sp. nov., isolated from a sandy beach

A heterotrophic, Gram-negative, prosthecate bacterium, designated strain G5T, was isolated from a sandy beach of Taean in South Korea. Cells of strain G5T were aerobic, catalase- and oxidase-positive, straight to slightly curved motile rods with a single flagellum and formed yellow–orange colonies on agar. Growth occurred at 15–40 °C (optimum 25–30 °C) and pH 6–9 (optimum pH 7–8). The major cellular fatty acids were C18 : 1ω7c, C17 : 0, C16 : 0, 11-methyl C18 : 1ω7c, C17 : 1ω8c and C17 : 1ω6c. The polar lipid pattern indicated the presence of phosphatidylglycerol, monoglycosyldiglyceride, glucuronopyranosyldiglyceride and two unidentified glycolipids. The G+C content of the genomic DNA was 63.6 mol% and the major quinone was Q-10. Comparative 16S rRNA gene sequence analysis showed that strain G5T belonged to the branch containing the genera Hellea, Robiginitomaculum and Hypomonas within the family Hyphomonadaceae. Within this group, strain G5T was most closely related to Hellea balneolensis 26III/A02/215T with 95.8 % 16S rRNA gene sequence similarity. Based on its phylogenetic position and its phenotypic, chemotaxonomic and molecular properties, strain G5T represents a novel species of a novel genus of the family Hyphomonadaceae, for which the name Litorimonas taeanensis gen. nov., sp. nov. is proposed. The type strain is G5T ( = KACC 13701T  = DSM 22008T).

Henriciella litoralis sp. nov., isolated from a tidal flat, transfer of Maribaculum marinum Lai et al. 2009 to the genus Henriciella as Henriciella aquimarina nom. nov. and emended description of the genus Henriciella

A Gram-staining-negative, strictly aerobic bacterium, designated strain SD10T, was isolated from a tidal flat of the Yellow Sea, South Korea. Cells were non-spore-forming rods that showed catalase- and oxidase-positive reactions. Growth of strain SD10T was observed at 15–40 °C (optimum, 25–30 °C), at pH 6.0–9.0 (optimum, pH 6.5–8.5) and in the presence of 1–10 % (w/v) NaCl. Strain SD10T contained ubiquinone-10 (Q-10) as a major isoprenoid quinone and C18 : 1ω7c (39.3 %), C16 : 0 (20.2 %), C17 : 0 (8.9 %) and C17 : 1ω6c (8.1 %) as major fatty acids. The cellular polar lipids were identified as phosphatidylglycerol, monoglycosyldiglyceride, glucuronopyranosyldiglyceride and two unidentified glycolipids. The G+C content of the genomic DNA was 55.2 mol%. Based on 16S rRNA gene sequence similarities, the strain was most closely related to Henriciella marina Iso4T and Maribaculum marinum P38T, with similarities of 97.8 and 97.0 %, respectively. The DNA–DNA relatedness between strain SD10T and H. marina Iso4T was 12.0±3.2 %. A phylogenetic analysis based on 16S rRNA gene sequences showed that M. marinum P38T and H. marina Iso4T formed a monophyletic cluster and that their 16S rRNA gene sequence similarity was 98.1 %. DNA–DNA hybridization between H. marina Iso4T and M. marinum LMG 24711T was 22.9±2.7 %, indicating that the two strains belong to separate species. On the basis of chemotaxonomic data and molecular properties, we propose that strain SD10T represents a novel species of the genus Henriciella, for which the name Henriciella litoralis sp. nov. is proposed. The type strain is SD10T ( = KACC 13700T  = DSM 22014T). In addition, we propose to transfer Maribaculum marinum Lai et al. 2009 to the genus Henriciella as Henriciella aquimarina nom. nov. (type strain P38T  = CCTCC AB 208227T  = LMG 24711T  = MCCC 1A01086T), and we present an emended description of the genus Henriciella.