Psychrobacillus soli sp. nov., capable of degrading oil, isolated from oil-contaminated soil

Isolation and genomic characterization of Psychrobacillus isolate L3 and bacteriophage Spoks: a new phage-host pair from Antarctic soil

BACKGROUND

Most habitats on Earth house unfathomable microbial diversity, yet much of it remains uncultured. The same applies to temperate phages, most of which documented to date are predicted purely in silico from the prophage-like genomic regions of the bacteria, lacking any experimental evidence of their functional integrity (e.g., the ability to undergo lytic replication). Hard-to-access parts of our planet with unique environments serve as especially promising places to collect samples for the isolation of novel microbes highly divergent from those isolated thus far. Antarctica, a continent mostly covered by a thick ice sheet, is one such area of our planet rife with novel microbiological entities. In this study, we aimed to isolate and characterize a novel culturable phage-host pair from Antarctic soils.

RESULTS

Psychrobacillus phage Spoks was retrieved alongside its host bacterial strain designated as "L3" from an ice-free soil sample collected at Waddington Bay, Graham Coast, Antarctica. Whole-genome sequencing of both the phage and the host revealed that they are divergent from, respectively, viruses and bacteria cultured and characterized thus far, and the intergenomic differences suggest that both might represent novel taxa. The genome of siphophage Spoks is a 36,472 bp long linear double-stranded DNA molecule with 11 base long 3' cohesive overhangs. Spoks can integrate into the chromosome of its isolation host strain in a site-specific fashion. Integration takes place in the genomic region of the host chromosome between the ORFs predicted to encode a DNA topoisomerase III and a BlaI/MecI/CopY family transcriptional regulator via recombination between attP and attB, which share a 19 bp "core" overlap sequence. L3 lysogens containing Spoks are not stable, with regular spontaneous induction occurring. Although the attachment site overlap sequence was found in the publicly available genomic sequences of several other Psychrobacillus spp. strains isolated from different habitats, none were found to contain a Spoks-like prophage.

CONCLUSIONS

The isolation and characterization of Psychrobacillus temperate phage Spoks and its host strain L3 from Antarctica highlight the potential for discovering novel biological entities divergent from their closest cultured relatives with relative ease, given access to such difficult-to-access undersampled environments, and are expected to encourage similar studies.

Comparative analysis of the human microbiome from four different regions of China and machine learning-based geographical inference

The human microbiome, the community of microorganisms that reside on and inside the human body, is critically important for health and disease. However, it is influenced by various factors and may vary among individuals residing in distinct geographic regions. In this study, 220 samples, consisting of sterile swabs from palmar skin and oral and nasal cavities were collected from Chinese Han individuals living in Shanghai, Chifeng, Kunming, and Urumqi, representing the geographic regions of east, northeast, southwest, and northwest China. The full-length 16S rRNA gene of the microbiota in each sample was sequenced using the PacBio single-molecule real-time sequencing platform, followed by clustering the sequences into operational taxonomic units (OTUs). The analysis revealed significant differences in microbial communities among the four regions. Cutibacterium was the most abundant bacterium in palmar samples from Shanghai and Kunming, Psychrobacter in Chifeng samples, and Psychrobacillus in Urumqi samples. Additionally, Streptococcus and Staphylococcus were the dominant bacteria in the oral and nasal cavities. Individuals from the four regions could be distinguished and predicted based on a model constructed using the random forest algorithm, with the predictive effect of palmar microbiota being better than that of oral and nasal cavities. The prediction accuracy using hypervariable regions (V3-V4 and V4-V5) was comparable with that of using the entire 16S rRNA. Overall, our study highlights the distinctiveness of the human microbiome in individuals living in these four regions. Furthermore, the microbiome can serve as a biomarker for geographic origin inference, which has immense application value in forensic science.IMPORTANCEMicrobial communities in human hosts play a significant role in health and disease, varying in species, quantity, and composition due to factors such as gender, ethnicity, health status, lifestyle, and living environment. The characteristics of microbial composition at various body sites of individuals from different regions remain largely unexplored. This study utilized single-molecule real-time sequencing technology to detect the entire 16S rRNA gene of bacteria residing in the palmar skin, oral, and nasal cavities of Han individuals from four regions in China. The composition and structure of the bacteria at these three body sites were well characterized and found to differ regionally. The results elucidate the differences in bacterial communities colonizing these body sites across different regions and reveal the influence of geographical factors on human bacteria. These findings not only contribute to a deeper understanding of the diversity and geographical distribution of human bacteria but also enrich the microbiome data of the Asian population for further studies.

Influence Mechanism of Vermicompost with Different Maturity on Atrazine Catabolism and Bacterial Community

Atrazine causes serious contamination of agricultural soils and groundwater. This study investigated the influence mechanism of sterilized soil (CKs), unsterilized soil (CKn), sterilized soil amended with 45 (SsV1), 60 (SsV2), 75 (SsV3) days of vermicompost (the maturity days of vermicompost), and unsterilized soil amended with 45 (SnV1), 60 (SnV2), 75 (SnV3) days of vermicompost on atrazine catabolism. The atrazine degradation experiment lasted for 40 days. The results showed that the atrazine degradation rates for CKs, CKn, SsV1, SsV2, SsV3, SnV1, SnV2, and SnV3 were 24%, 56.9%, 62.8%, 66.1%, 65.9%, 87.5%, 92.9%, and 92.3%, respectively. Indigenous microorganisms capable of degrading atrazine were present in unsterilized soil, and the addition of vermicompost enhanced atrazine degradation. The humic acid content of SnV2 was the highest, at 4.11 g/kg, which was 71.97% higher than that of CKn. The addition of the vermicompost enhanced the production of hydroxyatrazine, deethylatrazine, and deisopropylatrazine. Vermicompost increased the abundance of atrazine-degrading bacteria (Mycobacterium, Devosia, etc.), and introduced new atrazine-degrading bacteria (Mesorhizobium, Demequina). The above results showed that the best degradation of atrazine was achieved with 60 days of vermicompost addition. This study provides a new, efficient, economical, and environmentally friendly strategy for the remediation of atrazine-contaminated soil.

Genome and pan-genome analysis of a new exopolysaccharide-producing bacterium Pyschrobacillus sp. isolated from iron ores deposit and insights into iron uptake

Bacterial exopolysaccharides (EPS) have emerged as one of the key players in the field of heavy metal-contaminated environmental bioremediation. This study aimed to characterize and evaluate the metal biosorption potential of EPS produced by a novel Psychrobacillus strain, NEAU-3TGS, isolated from an iron ore deposit at Tamra iron mine, northern Tunisia. Genomic and pan-genomic analysis of NEAU-3TGS bacterium with nine validated published Psychrobacillus species was also performed. The results showed that the NEAU-3TGS genome (4.48 Mb) had a mean GC content of 36%, 4,243 coding sequences and 14 RNA genes. Phylogenomic analysis and calculation of nucleotide identity (ANI) values (less than 95% for new species with all strains) confirmed that NEAU-3TGS represents a potential new species. Pangenomic analysis revealed that Psychrobacillus genomic diversity represents an "open" pangenome model with 33,091 homologous genes, including 65 core, 3,738 shell, and 29,288 cloud genes. Structural EPS characterization by attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy showed uronic acid and α-1,4-glycosidic bonds as dominant components of the EPS. X-ray diffraction (XRD) analysis revealed the presence of chitin, chitosan, and calcite CaCO3 and confirmed the amorphous nature of the EPS. Heavy metal bioabsorption assessment showed that iron and lead were more adsorbed than copper and cadmium. Notably, the optimum activity was observed at 37°C, pH=7 and after 3 h contact of EPS with each metal. Genomic insights on iron acquisition and metabolism in Psychrobacillus sp. NEAU-3TGS suggested that no genes involved in siderophore biosynthesis were found, and only the gene cluster FeuABCD and trilactone hydrolase genes involved in the uptake of siderophores, iron transporter and exporter are present. Molecular modelling and docking of FeuA (protein peptidoglycan siderophore-binding protein) and siderophores ferrienterobactine [Fe+3 (ENT)]-3 and ferribacillibactine [Fe+3 (BB)]-3 ligand revealed that [Fe+3 (ENT)]-3 binds to Phe122, Lys127, Ile100, Gln314, Arg215, Arg217, and Gln252. Almost the same for [Fe+3 (ENT)]-3 in addition to Cys222 and Tyr229, but not Ile100.To the best of our knowledge, this is the first report on the characterization of EPS and the adsorption of heavy metals by Psychrobacillus species. The heavy metal removal capabilities may be advantageous for using these organisms in metal remediation.

Microbiological exploration of the Cueva del Viento lava tube system in Tenerife, Canary Islands

Cueva del Viento, located in the Canary Islands, Spain, is the Earth's sixth-longest lava tube, spanning 18,500 m, and was formed approximately 27,000 years ago. This complex volcanic cave system is characterized by a unique geomorphology, featuring an intricate network of galleries. Despite its geological significance, the geomicrobiology of Cueva del Viento remains largely unexplored. This study employed a combination of culture-dependent techniques and metabarcoding data analysis to gain a comprehensive understanding of the cave's microbial diversity. The 16S rRNA gene metabarcoding approach revealed that the coloured microbial mats (yellow, red and white) coating the cave walls are dominated by the phyla Actinomycetota, Pseudomonadota and Acidobacteriota. Of particular interest is the high relative abundance of the genus Crossiella, which is involved in urease-mediated biomineralization processes, along with the presence of genera associated with nitrogen cycling, such as Nitrospira. Culture-dependent techniques provided insights into the morphological characteristics of the isolated species and their potential metabolic activities, particularly for the strains Streptomyces spp., Paenarthrobacter sp. and Pseudomonas spp. Our findings underscore the potential of Cueva del Viento as an ideal environment for studying microbial diversity and for the isolation and characterization of novel bacterial species of biotechnological interest.

Ancient Roman bacterium against current issues: strain Aquil_B6, Paenisporosarcina quisquiliarum, or Psychrobacillus psychrodurans?

IMPORTANCE

Since 1988, through the United States government's founding, the National Center for Biotechnology Information (NCBI) has provided an invaluable service to scientific advancement. The universality and total freedom of use if on the one hand allow the use of this database on a global level by all researchers for their valuable work, on the other hand, it has the disadvantage of making it difficult to check the correctness of all the materials present. It is, therefore, of fundamental importance for the correctness and ethics of research to improve the databases at our disposal, identifying and amending the critical issues. This work aims to provide the scientific community with a new sequence for the type strain Paenisporosarcina quisquiliarum SK 55 and broaden the knowledge of the Psychrobacillus psychrodurans species, in particular, considering the ancient strain Aquil_B6 found in an ancient Roman amphora.

Psychrobacillus antarcticus sp. nov., a psychrotolerant bioemulsifier producer isolated from King George Island, Antarctica

A Gram-stain-positive rod, psychrotolerant, aerobic and bioemulsifier-producing strain, denoted as Val9T, was isolated from soil sampled at Vale Ulman, King George Island, Antarctica. The strain grew at up to 30 °C (optimum, 15 °C), at pH 6-9 (optimum, pH 8) and with up to 5 % w/v NaCl (optimum, 3 %). The strain was motile and positive for catalase, oxidase and H2S. It did not hydrolyse starch, casein or gelatin. Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain Val9T belonged to the genus Psychrobacillus and was closely related to Psychrobacillus psychrotolerans DSM 11706T (99.9 % similarity), Psychrobacillus psychrodurans DSM 11713T (99.8 %) and Psychrobacillus glaciei PB01T (99.2 %). Digital DNA-DNA hybridization and average nucleotide identity values were lower than 37.3 and 85.5 %, respectively, with the closest phylogenetic neighbours. The DNA G+C content of strain Val9T calculated from the complete genome sequence was 36.6 mol%. The predominant cellular fatty acids were anteiso-C15 : 0, iso-C15 : 0 and anteiso-C17 : 1ω11c. Menaquinone-8 was the major respiratory quinone. The peptidoglycan type was A4β l-Orn-d-glu. The novel strain contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol as predominant polar lipids. Based on 16S rRNA phylogenetic and multilocus sequence analyses (recA, rpoB and gyrB), as well as phylogenomic, chemotaxonomic and phenotypic tests, we demonstrate that strain Val9T represents a novel species of the genus Psychrobacillus, for which the name Psychrobacillus antarcticus sp. nov. is proposed. The type strain is Val9T (=DSM 115096T=CCGB 1952T=NRRL B-65674T).

Microbial isolates with Anti-Pseudogymnoascus destructans activities from Western Canadian bat wings

Pseudogymnoascus destructans (Pd) is the causative agent of white-nose syndrome, which has resulted in the death of millions of bats in North America (NA) since 2006. Based on mortalities in eastern NA, the westward spread of infections likely poses a significant threat to western NA bats. To help prevent/reduce Pd infections in bats in western NA, we isolated bacteria from the wings of wild bats and screened for inhibitory activity against Pd. In total, we obtained 1,362 bacterial isolates from 265 wild bats of 13 species in western Canada. Among the 1,362 isolates, 96 showed inhibitory activity against Pd based on a coculture assay. The inhibitory activities varied widely among these isolates, ranging from slowing fungal growth to complete inhibition. Interestingly, host bats containing isolates with anti-Pd activities were widely distributed, with no apparent geographic or species-specific pattern. However, characteristics of roosting sites and host demography showed significant associations with the isolation of anti-Pd bacteria. Specifically, anthropogenic roosts and swabs from young males had higher frequencies of anti-Pd bacteria than those from natural roosts and those from other sex and age-groups, respectively. These anti-Pd bacteria could be potentially used to help mitigate the impact of WNS. Field trials using these as well as additional microbes from future screenings are needed in order to determine their effectiveness for the prevention and treatment against WNS.

Choosing source of microorganisms and processing technology for next generation beet bioinoculant

The increase of human population and associated increasing demand for agricultural products lead to soil over-exploitation. Biofertilizers based on lyophilized plant material containing living plant growth-promoting microorganisms (PGPM) could be an alternative to conventional fertilizers that fits into sustainable agricultural technologies ideas. We aimed to: (1) assess the diversity of endophytic bacteria in sugar and sea beet roots and (2) determine the influence of osmoprotectants (trehalose and ectoine) addition during lyophilization on bacterial density, viability and salt tolerance. Microbiome diversity was assessed based on 16S rRNA amplicons sequencing, bacterial density and salt tolerance was evaluated in cultures, while bacterial viability was calculated by using fluorescence microscopy and flow cytometry. Here we show that plant genotype shapes its endophytic microbiome diversity and determines rhizosphere soil properties. Sea beet endophytic microbiome, consisting of genera characteristic for extreme environments, is more diverse and salt resistant than its crop relative. Supplementing osmoprotectants during root tissue lyophilization exerts a positive effect on bacterial community salt stress tolerance, viability and density. Trehalose improves the above-mentioned parameters more effectively than ectoine, moreover its use is economically advantageous, thus it may be used to formulate improved biofertilizers.

Bacterial Microbiota Isolated from Cysts of Globodera rostochiensis (Nematoda: Heteroderidae)

The potato cyst nematode (PCN) Globodera rostochiensis is a plant parasite of potato classified into a group of quarantine organisms causing high economic losses worldwide. Due to the long persistence of the parasite in soil, cysts harbor numerous bacteria whose presence can lead to cyst death and population decline. The cysts of G. rostochiensis found in two potato fields were used as a source of bacteria. The universal procedure was applied to extract DNA from bacteria which was then sequenced with 16S primers. The aims of the study were to identify bacterial microbiota associated with the PCN populations and to infer their phylogenetic relationships based on the maximum likelihood and Bayesian phylogeny of the 16S sequences. In addition, the impact of the most significant climate and edaphic factors on bacterial diversity were evaluated. Regarding the higher taxonomy, our results indicate that the prevalent bacterial classes were Bacilli, Actinobacteria and Alphaproteobacteria. Phylogenetic analyses clustered Brevibacterium frigoritolerans within the family Bacillaceae, confirming its recent reclassification. Long-term climate factors, such as air temperature, insolation hours, humidity and precipitation, as well as the content of soil organic matter, affected the bacterial diversity. The ability of cyst nematodes to persist in soil for a long time qualifies them as a significant natural source to explore the soil bacterial microbiota.

Co-occurrence pattern and function prediction of bacterial community in Karst cave

Background

Karst caves are considered as extreme environments with nutrition deficiency, darkness, and oxygen deprivation, and they are also the sources of biodiversity and metabolic pathways. Microorganisms are usually involved in the formation and maintenance of the cave system through various metabolic activities, and are indicators of changes environment influenced by human. Zhijin cave is a typical Karst cave and attracts tourists in China. However, the bacterial diversity and composition of the Karst cave are still unclear. The present study aims to reveal the bacterial diversity and composition in the cave and the potential impact of tourism activities, and better understand the roles and co-occurrence pattern of the bacterial community in the extreme cave habitats.

Results

The bacterial community consisted of the major Proteobacteria, Actinobacteria, and Firmicutes, with Proteobacteria being the predominant phylum in the rock, soil, and stalactite samples. Compositions and specialized bacterial phyla of the bacterial communities were different among different sample types. The highest diversity index was found in the rock samples with a Shannon index of 4.71. Overall, Zhijin cave has relatively lower diversity than that in natural caves. The prediction of function showed that various enzymes, including ribulose-bisphosphate carboxylase, 4-hydroxybutyryl-CoA dehydratase, nitrogenase NifH, and Nitrite reductase, involved in carbon and nitrogen cycles were detected in Zhijin cave. Additionally, the modularity indices of all co-occurrence network were greater than 0.40 and the species interactions were complex across different sample types. Co-occurring positive interactions in the bacteria groups in different phyla were also observed.

Conclusion

These results uncovered that the oligotrophic Zhijin cave maintains the bacterial communities with the diverse metabolic pathways, interdependent and cooperative co-existence patterns. Moreover, as a hotspot for tourism, the composition and diversity of bacterial community are influenced by tourism activities. These afford new insights for further exploring the adaptation of bacteria to extreme environments and the conservation of cave ecosystem.

Comparative Genome Analysis of Psychrobacillus Strain PB01, Isolated from an Iceberg

A novel psychrotolerant Psychrobacillus strain PB01, isolated from an Antarctic iceberg, was comparatively analyzed with five related strains. The complete genome of strain PB01 consists of a single circular chromosome (4.3 Mb) and a plasmid (19 Kb). As potential low-temperature adaptation strategies, strain PB01 has four genes encoding cold-shock proteins, two genes encoding DEAD-box RNA helicases, and eight genes encoding transporters for glycine betaine, which can serve as a cryoprotectant, on the genome. The pan-genome structure of the six Psychrobacillus strains suggests that strain PB01 might have evolved to adapt to extreme environments by changing its genome content to gain higher capacity for DNA repair, translation, and membrane transport. Notably, strain PB01 possesses a complete TCA cycle consisting of eight enzymes as well as three additional Helicobacter pylori-type enzymes: ferredoxin-dependent 2-oxoglutarate synthase, succinyl-CoA/acetoacetyl-CoA transferase, and malate/quinone oxidoreductase. The co-existence of the genes for TCA cycle enzymes has also been identified in the other five Psychrobacillus strains.

Psychrobacillus glaciei sp. nov., a psychrotolerant species isolated from an Antarctic iceberg

We performed taxonomic studies on a psychrotolerant strain, designated PB01^T, isolated from an Antarctic iceberg. The cells of strain PB01^T were Gram-stain-positive, strictly aerobic, white-yellow and rod-shaped. The results of 16S rRNA gene sequence analysis revealed that strain PB01^T was closely related to Psychrobacillus psychrodurans DSM 11713^T (99.19 % similarity), Psychrobacillus psychrotolerans DSM 11706^T (98.91 %) and Psychrobacillus insolitus DSM 5^T (98.85 %). Despite high 16S rRNA gene sequence similarity, the degrees of DNA-DNA relatedness between strain PB01^T and its three closest phylogenetic neighbours were 62.4±7.3 % for P. psychrodurans DSM 11713^T, 61.1±5.4 % for P. psychrotolerans DSM 11706^T and 56.1±6.9 % for P. insolitus DSM 5^T. The predominant cellular fatty acids were anteiso-C_15 : 0, iso-C_15 : 0 and C16 : 1ω7с-OH. Menaquinone-8 was the major respiratory quinone, and phosphatidylethanolamine was the major polar lipid. The DNA G+C content of strain PB01^T calculated from the complete genome sequence was 36.0 mol%. Based on the phenotypic, chemotaxonomic, genomic and phylogenetic data obtained in the present study, we conclude that strain PB01^T represents a novel species of the genus Psychrobacillus, for which we propose the name Psychrobacillus glaciei sp. nov. The type strain is PB01^T (=CECT 9792^T=KCTC 43041^T).

Psychrobacillus vulpis sp. nov., a new species isolated from faeces of a red fox in Spain

A facultative anaerobic, chemoheterotrophic, endospore-forming, Gram-stain-positive rod, designated as strain Z8^T, was isolated from red fox (Vulpes vulpes) faeces sampled at Tablas de Daimiel National Park, Ciudad Real, Spain. Strain Z8^T grew at 0-37 °C (optimum, 28 °C), in the presence of 0-5.5 % (w/v) NaCl (2.5 %, w/v) and at pH 6-10 (pH 7). The strain was motile and positive for catalase, oxidase, H₂S and siderophore production, acid and alkaline phosphatases, and N-acetylglucosamine, adipic acid and malate assimilation. It hydrolysed starch, DNA, l-tyrosine, Tween 20, Tween 80 and lecithovitellin. Phylogenetic analysis of the 16S rRNA gene sequence indicated that strain Z8^T is a member of the genus Psychrobacillus, showing high sequence similarity to Psychrobacillus lasiicapitis NEAU-3TGS17^T (99.2 %) and Psychrobacillus soli NHI-2T^T (99.1 %), and around 98 % to other known species of the genus Psychrobacillus. Digital DNA-DNA hybridization and average nucleotide identity values were lower than 24 and 79 %, respectively, with the most related species. In silico G+C content was 35.9 mol%. The major cellular fatty acids of strain Z8^T were iso-C_14 : 0, iso-C_15 : 0 and anteiso-C_15 : 0. The novel strain contained diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol as predominant polar lipids, and the main respiratory isoprenoid quinone was MK-8. Based on the 16S rRNA phylogenetic analysis, together with MLSA (recA, rpoB and gyrB), phylogenomic, chemotaxonomic and phenotypic results, we demonstrate that strain Z8^T represents a novel species of the genus Psychrobacillus, for which the name Psychrobacillus vulpis sp. nov., is proposed. The type strain is Z8^T (=CECT 9721^T=LMG 31001^T).

Psychrobacillus lasiicapitis sp. nov., isolated from the head of an ant (Lasius fuliginosus)

A novel Gram-stain-positive, motile, endospore-forming, rod-shaped bacterium, designated strain NEAU-3TGS17^T, was isolated from the head of an ant (Lasius fuliginosus). The isolate grew at 0-35 °C (optimum 28-30 °C), at pH 6.0-11.0 (optimum pH 7.0-8.0) and with 0-6 % (w/v) NaCl (optimum 0 %). Phylogenetic analysis based on 16S rRNA gene sequences indicated that strain NEAU-3TGS17^T belonged to the genus Psychrobacillus. Sequence similarities between strain NEAU-3TGS17^T and members of the genus Psychrobacillus with validly published names (Psychrobacillus psychrotolerans DSM 11706^T, Psychrobacillus insolitus DSM 5^T, Psychrobacillus psychrodurans DSM 11713^T and Psychrobacillus soli NBRC 110600^T) were 98.4-99.1 %. DNA-DNA relatedness values between strain NEAU-3TGS17^T and its closest relatives were below 70 %. The major cellular fatty acids (>5 %) were iso-C14 : 0, anteiso-C15 : 0, C16 : 0 and iso-C15 : 0. The major polar lipids were diphosphatidylglycerol, phosphatidylethanolamine and phosphatidylglycerol. The cell-wall peptidoglycan type was A4β with ornithine as the diamino acid and the predominant menaquinones were MK-8 and some MK-7. The DNA G+C content was 35.8 mol%. On the basis of phenotypic data and phylogenetic inference, strain NEAU-3TGS17^T was classified as representing a novel species in the genus Psychrobacillus, for which the name Psychrobacillus lasiicapitis sp. nov. is proposed. The type strain is NEAU-3TGS17^T (=DSM 100484^T=CGMCC 1.15308^T).

Sphingomonas olei sp. nov., with the ability to degrade aliphatic hydrocarbons, isolated from oil-contaminated soil

A yellow-coloured, Gram-stain-negative, non-motile, rod-shaped bacterium, designated K-1-16T, that is capable of degrading aliphatic hydrocarbons was isolated from oil-contaminated soil at Biratnagar, Morang, Nepal. It was able to grow at 15-45 °C, at pH 5.5-9.5 and with 0-5 % (w/v) NaCl. This strain was taxonomically characterized by a polyphasic approach. Based on 16S rRNA gene sequence analysis, strain K-1-16T belongs to the genus Sphingomonas and is closely related to Sphingomonas mucosissima CP173-2T (98.6 % similarity), Sphingomonas dokdonensis DS-4T (97.9 %), Sphingomonas faeni MA-olkiT (97.9 %), Sphingomonas aurantiaca MA101bT (97.8 %) and Sphingomonas xinjiangensis 10-1-84T (96.6 %). The predominant respiratory quinone was ubiquinone Q-10 and the major polyamine was homospermidine. The polar lipid profile revealed the presence of phosphatidylethanolamine, phosphatidylglycerol, diphosphatidylglycerol, phosphatidylcholine, phosphatidyldimethylethanolamine and sphingoglycolipid. The predominant fatty acids of strain K-1-16T were summed feature 8 (C18 : 1ω7c and/or C18 : 1ω6c), C16 : 0, summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c), C18 : 1ω7c 11-methyl and C14 : 0 2-OH. The genomic DNA G+C content was 64.8 mol%. Levels of DNA-DNA relatedness between strain K-1-16T and S. mucosissima DSM 17494T, S. dokdonensis KACC 17420T, S. faeni KCCM 41909T and S. aurantiaca KCCM 41908T were 49.7, 41.3, 43.7 and 36.7 %, respectively. The morphological, physiological, chemotaxonomic and phylogenetic analyses clearly distinguished this strain from its closest phylogenetic neighbours. Thus, strain K-1-16T represents a novel species of the genus Sphingomonas, for which the name Sphingomonas olei sp. nov. is proposed. The type strain is K-1-16T (=KEMB 9005-450T=KACC 19002T=JCM 31674T).

Acinetobacter halotolerans sp. nov., a novel halotolerant, alkalitolerant, and hydrocarbon degrading bacterium, isolated from soil

A novel aerobic, non-motile, halotolerant, alkalitolerant, hydrocarbon degrading, and rod shaped bacterium, designated strain R160^T, was isolated from soil in South Korea. Cells were Gram-staining-negative, catalase-positive, and oxidase-negative. This strain grew up to 7% of NaCl and in the pH range of 6-11 (optimum 7.0-10.0). The isolate degraded 51.7 ± 1.3% of hydrocarbon components (C-18, C-20, and C-22) and 45.8 ± 1.4% oil components (kerosene, diesel, and gasoline). Phylogenetic analysis based on 16 S rRNA gene sequences revealed that strain R160^T formed a lineage within the genus Acinetobacter, and was closely related to 'Acinetobacter oleivorans' DR1^T (97.47%, sequence similarity). Other closely related members have sequence similarity between 97.47 to 96.52%. The predominant respiratory lipoquinones of strain R160^T were ubiquinone 9 (Q-9) and ubiquinone 8 (Q-8). The major polar lipids were phosphatidylethanolamine (PE), diphosphatidylglycerol (DPG), phosphatidylglycerol (PG), and phosphatidylcholine (PC). The major cellular fatty acids were 9-octadecenoic acid (C_18:1 ω9c), hexadecanoic acid (C_16:0), and summed feature (comprising C_16:1 ω7c and/or C_16:1 ω6c). The DNA G + C content of strain R160^T was 44.9 mol%. On the basis of phenotypic, genotypic, chemotaxonomic, and phylogenetic characteristics, strain R160^T represents a novel species of the genus Acinetobacter, for which the name Acinetobacter halotolerans sp. nov. is proposed. The type strain is R160^T (= KEMB 9005-333^T = KACC 18453^T = JCM 31009^T).