Pseudomonas oceani sp. nov., isolated from deep seawater

Taxonomic identification, phenol biodegradation and soil remediation of the strain Rhodococcus sacchari sp. nov. Z13T

Phenols are highly toxic chemicals that are extensively used in industry and produce large amounts of emissions. Notably, phenols released into the soil are highly persistent, causing long-term harm to human health and the environment. In this study, a gram-positive, aerobic, and rod-shaped bacterial strain, Z13T, with efficient phenol degradation ability, was isolated from the soil of sugarcane fields. Based on the physiological properties and genomic features, strain Z13T is considered as a novel species of the genus Rhodococcus, for which the name Rhodococcus sacchari sp. nov. is proposed. The type strain is Z13T (= CCTCC AB 2022327T = JCM 35797T). This strain can use phenol as its sole carbon source. Z13T was able to completely degrade 1200 mg/L phenol within 20 h; the maximum specific growth rate was μmax = 0.93174 h-1, and the maximum specific degradation rate was qmax = 0.47405 h-1. Based on whole-genome sequencing and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis, strain Z13T contains a series of phenol degradation genes, including dmpP, CatA, dmpB, pcaG, and pcaH, and can metabolize aromatic compounds. Moreover, the potential of strain Z13T for soil remediation was investigated by introducing Z13T into simulated phenol-contaminated soil, and the soil microbial diversity was analyzed. The results showed that 100% of the phenol in the soil was removed within 7.5 d. Furthermore, microbial diversity analysis revealed an increase in the relative species richness of Oceanobacillus, Chungangia, and Bacillus.

Halopseudomonas species: Cultivation and molecular genetic tools

The Halopseudomonas species, formerly classified as Pseudomonas pertucinogena lineage, form a unique phylogenetic branch within the Pseudomonads. Most strains have recently been isolated from challenging habitats including oil- or metal-polluted sites, deep sea, and intertidal zones, suggesting innate resilience to physical and chemical stresses. Despite their comparably small genomes, these bacteria synthesise several biomolecules with biotechnological potential and a role in the degradation of anthropogenic pollutants has been suggested for some Halopseudomonads. Until now, these bacteria are not readily amenable to existing cultivation and cloning methods. We addressed these limitations by selecting four Halopseudomonas strains of particular interest, namely H. aestusnigri, H. bauzanensis, H. litoralis, and H. oceani to establish microbiological and molecular genetic methods. We found that C4 -C10 dicarboxylic acids serve as viable carbon sources in both complex and mineral salt cultivation media. We also developed plasmid DNA transfer protocols and assessed vectors with different origins of replication and promoters inducible with isopropyl-β-d-thiogalactopyranoside, l-arabinose, and salicylate. Furthermore, we have demonstrated the simultaneous genomic integration of expression cassettes into one and two attTn7 integration sites. Our results provide a valuable toolbox for constructing robust chassis strains and highlight the biotechnological potential of Halopseudomonas strains.

Revealing the Host-Dependent Nature of an Engineered Genetic Inverter in Concordance with Physiology

Broad-host-range synthetic biology is an emerging frontier that aims to expand our current engineerable domain of microbial hosts for biodesign applications. As more novel species are brought to "model status," synthetic biologists are discovering that identically engineered genetic circuits can exhibit different performances depending on the organism it operates within, an observation referred to as the "chassis effect." It remains a major challenge to uncover which genome-encoded and biological determinants will underpin chassis effects that govern the performance of engineered genetic devices. In this study, we compared model and novel bacterial hosts to ask whether phylogenomic relatedness or similarity in host physiology is a better predictor of genetic circuit performance. This was accomplished using a comparative framework based on multivariate statistical approaches to systematically demonstrate the chassis effect and characterize the performance dynamics of a genetic inverter circuit operating within 6 Gammaproteobacteria. Our results solidify the notion that genetic devices are strongly impacted by the host context. Furthermore, we formally determined that hosts exhibiting more similar metrics of growth and molecular physiology also exhibit more similar performance of the genetic inverter, indicating that specific bacterial physiology underpins measurable chassis effects. The result of this study contributes to the field of broad-host-range synthetic biology by lending increased predictive power to the implementation of genetic devices in less-established microbial hosts.

Pseudomonas citri sp. nov., a potential novel plant growth promoting bacterium isolated from rhizosphere soil of citrus

A novel potential plant growth promoting bacterium, designated OPS13-3^T, was isolated from rhizosphere soil of citrus in Aotou Town of Guangzhou, Guangdong Province, PR China. It showed high ability to dissolve insoluble inorganic phosphate and organic phosphorus and to produce 3-indoleacetic acid (IAA) and siderophore. Cells of the novel strain were Gram-stain-negative, rod-shaped, aerobic and motile with polar flagellum. It shared the highest 16S rRNA gene similarity with Pseudomonas mucoides CCUG 74874^T (98.7%) and P. bijieensis LMG 31948^T (98.7%). Phylogenetic analyses based the 16S rRNA gene and genome sequences revealed that strain OPS13-3^T belonged to the genus Pseudomonas, and was most closely related to P. mediterranea ICMP 14184^T and P. corrugate ICMP 5819^T. The average nucleotide identity (ANI) and DNA-DNA hybridization (dDDH) values between the novel strain and closely relatives with high 16S rRNA gene similarities were 80.8‒87.5% and 24.7‒34.6%, respectively, which were much below the threshold values for species delimitation. The major fatty acids included C_16:0, C_10:0 3-OH and summed feature 3 (C_16:1ω7c and/or C_16:1ω6c). It took ubiquinone 9 as the predominant respiratory quinone and the polar lipids contained phosphatidylglycerol (PG), diphosphatidylglycerol (DPG), phosphatidylethanolamine (PE), three unidentified phospholipids, an unidentified aminophospholipid and an unidentified lipid. Based on the phylogenetic, phenotypic and chemotaxonomic analyses and genome comparison, strain OPS13-3^T should be considered as a novel species of the genus Pseudomonas, for which the name Pseudomonas citri sp. nov. is proposed (type strain OPS13-3^T = GDMCC 1.3118^T = JCM 35385^T).

Study on potential microbial community to the waste water treatment from bauxite desilication process

Discharging waste water from the bauxite desilication process will bring potential environmental risk from the residual ions and organic compounds, especially hydrolyzed polyacrylamide. Characterization of the microbial community diversity in waste water plays an important role in the biological treatment of waste water. In this study, eight waste water samples from five flotation plants in China were investigated. The microbial community and functional profiles within the waste water were analyzed by a metagenomic sequencing method and associated with geochemical properties. The results revealed that Proteobacteria and Firmicutes were the dominant bacterial phyla. Both phylogenetical and clusters of orthologous groups' analyses indicated that Tepidicella, Paracoccus, Pseudomonas, and Exiguobacterium could be the dominant bacterial genera in the waste water from bauxite desilication process for their abilities to biodegrade complex organic compounds. The results of the microbial community diversity and functional gene compositions analyses provided a beneficial orientation for the biotreatment of waste water, as well as regenerative using of water resources. Besides, this study revealed that waste water from bauxite desilication process was an ideal ecosystem to find novel microorganisms, such as efficient strains for bio-desilication and bio-desulfurization of bauxite.

Pseudomonas marianensis sp. nov., a marine bacterium isolated from deep-sea sediments of the Mariana Trench

A novel marine Gram-stain-negative, aerobic, rod-shaped bacterium, designated as strain PS1^T, was isolated from the deep-sea sediments of the Mariana Trench and characterized phylogenetically and phenotypically. Bacterial optimal growth occurred at 35 °C (ranging 10-45 °C), pH 6 (ranging pH 5-10) and with 11% (w/v) NaCl (ranging 0-17%). The 16S rRNA gene sequence similarity results revealed that strain PS1^T was most closely related to Pseudomonas stutzeri ATCC 17588^T, Pseudomonas nitrititolerans GL14^T, Pseudomonas zhaodongensis NEAU-ST5-21^T, Pseudomonas xanthomarina DSM 18231^T and Pseudomonas kunmingensis HL22-2^T with 98.3-98.7%. The digital DNA-DNA hybridization values and the average nucleotide identity between strain PS1^T and the reference strains were 20.4-40.1% and 78.7-79.4%, respectively. The major respiratory quinone is ubiquinone Q-9. The major polar lipids were phosphatidylethanolamine, diphosphatidyglycerol, phosphatidylglycerol, phosphatidylcholine, aminoglycolipid, two unidentified glycolipids and one unidentified lipid. The predominant cellular fatty acids of strain PS1^T were summed feature 8 (C_18:1ω7c and/or C_18:1ω6c), summed feature 3 (C_16:1ω7c and/or C_16:1ω6c), C_16:0 and cyclo-C_19:0 ω8c. The G + C content of the genomic DNA was 63.0%. The combined genotypic and phenotypic data indicated that strain PS1^T represents a novel species of the genus Pseudomonas, for which the name Pseudomonas marianensis sp. nov. is proposed, with the type strain PS1^T (= DSM 112238^T = MCCC 1K05112^T).

Phylogenomic and comparative genomic analyses of species of the family Pseudomonadaceae: Proposals for the genera Halopseudomonas gen. nov. and Atopomonas gen. nov., merger of the genus Oblitimonas with the genus Thiopseudomonas, and transfer of some misclassified species of the genus Pseudomonas into other genera

The evolutionary relationships among species of the family Pseudomonadaceae were examined based on 255 available genomes representing >85 % of the species from this family. In a phylogenetic tree based on concatenated sequences of 118 core proteins, most species of the genus Pseudomonas grouped within one large cluster which also included members of the genera Azotobacter and Azomonas. Within this large cluster 18-30 clades/subclades of species of the genus Pseudomonas consisting of between 1 and 36 species, were observed. However, a number of species of the genus Pseudomonas branched outside of this main cluster and were interspersed among other genera of the family Pseudomonadaceae. This included a strongly supported clade (Pertucinogena clade) consisting of 19 mainly halotolerant species. The distinctness of this clade from all other members of the family Pseudomonadaceae is strongly supported by 24 conserved signature indels (CSIs) in diverse proteins that are exclusively found in all members of this clade. Nine uncharacterized members of the genus Pseudomonas also shared these CSIs and they branched within the Pertucinogena clade, indicating their affiliation to this clade. On the basis of the strong evidence supporting the distinctness of the Pertucinogena clade, we are proposing transfer of species from this clade into a novel genus Halopseudomonas gen. nov. Pseudomonas caeni also branches outside of the main cluster and groups reliably with Oblitimonas alkaliphila and Thiopseudomonas denitrificans. Six identified CSIs are uniquely shared by these three species and we are proposing their integration into the emended genus Thiopseudomonas, which has priority over the name Oblitimonas. We are also proposing transfer of the deep-branching Pseudomonas hussainii, for which 22 exclusive CSIs have been identified, into the genus Atopomonas gen. nov. Lastly, we present strong evidence that the species Pseudomonas cissicola and Pseudomonas geniculata are misclassified into the genus Pseudomonas and that they are specifically related to the genera Xanthomonas and Stenotrophomonas, respectively. In addition, we are also reclassifying 'Pseudomonas acidophila' as Paraburkholderia acidicola sp. nov. (Type strain: G-6302=ATCC 31363=BCRC 13035).

Phylogenomic Analyses of the Genus Pseudomonas Lead to the Rearrangement of Several Species and the Definition of New Genera

Pseudomonas is a large and diverse genus broadly distributed in nature. Its species play relevant roles in the biology of earth and living beings. Because of its ubiquity, the number of new species is continuously increasing although its taxonomic organization remains quite difficult to unravel. Nowadays the use of genomics is routinely employed for the analysis of bacterial systematics. In this work, we aimed to investigate the classification of species of the genus Pseudomonas on the basis of the analyses of the type strains whose genomes are currently available. Based on these analyses, we propose the creation of three new genera (Denitrificimonas gen nov. comb. nov., Neopseudomonas gen nov. comb. nov. and Parapseudomonas gen nov. comb. nov) to encompass several species currently included within the genus Pseudomonas and the reclassification of several species of this genus in already described taxa.

Pseudomonas laoshanensis sp. nov., isolated from peanut field soil

A novel Gram-stain-negative, aerobic strain, designated Y22^T, was isolated from peanut field soil in Laoshan Mountain in China. Cells of strain Y22^T were rod-shaped and motile by a single flagellum. The strain was found to be oxidase- and catalase-positive. 16S rRNA gene sequence based on phylogenetic analysis indicated that strain Y22^T belonged to the genus Pseudomonas, and showed the highest 16S rRNA gene sequence similarity of 99.0% to Pseudomonas pelagia JCM 15562^T, followed by Pseudomonas salina JCM 19469^T (98.4%), Pseudomonas sabulinigri JCM 14963^T (97.9%), Pseudomonas bauzanensis CGMCC 1.9095^T (97.6%) and Pseudomonas litoralis KCTC23093^T (97.5%). The phylogenetic analysis based on multilocus sequence analyses with concatenated 16S rRNA, gyrB, rpoD and rpoB genes indicated that strain Y22^T belonged to Pseudomonas pertucinogena lineage. The average nucleotide identity scores between strain Y22^T and closely related species were 74.6-82.8%, and the Genome-to-Genome Distance Calculator scores were 16.4-44.9%. The predominant cellular fatty acids of strain Y22^T were C_18:1ω7c (29.6%), C_17:0 cyclo (17.5%) and summed feature 3 (C_16:1ω7c and/or C_16:1ω6c) (17.4%). The genomic DNA G+C content was 57.9 mol%. On the basis of phenotypic characteristics, phylogenetic analyses and in silico DNA-DNA relatedness, a novel species, Pseudomonas laoshanensis sp. nov. is proposed. The type strain is Y22^T (= JCM 32580^T = KCTC 62385^T = CGMCC 1.16552^T).

Agar plate-based screening methods for the identification of polyester hydrolysis by Pseudomonas species

Hydrolases acting on polyesters like cutin, polycaprolactone or polyethylene terephthalate (PET) are of interest for several biotechnological applications like waste treatment, biocatalysis and sustainable polymer modifications. Recent studies suggest that a large variety of such enzymes are still to be identified and explored in a variety of microorganisms, including bacteria of the genus Pseudomonas. For activity-based screening, methods have been established using agar plates which contain nanoparticles of polycaprolactone or PET prepared by solvent precipitation and evaporation. In this protocol article, we describe a straightforward agar plate-based method using emulsifiable artificial polyesters as substrates, namely Impranil® DLN and liquid polycaprolactone diol (PLD). Thereby, the currently quite narrow set of screening substrates is expanded. We also suggest optional pre-screening with short-chain and middle-chain-length triglycerides as substrates to identify enzymes with lipolytic activity to be further tested for polyesterase activity. We applied these assays to experimentally demonstrate polyesterase activity in bacteria from the P. pertucinogena lineage originating from contaminated soils and diverse marine habitats.

The biotechnological potential of marine bacteria in the novel lineage of Pseudomonas pertucinogena

Marine habitats represent a prolific source for molecules of biotechnological interest. In particular, marine bacteria have attracted attention and were successfully exploited for industrial applications. Recently, a group of Pseudomonas species isolated from extreme habitats or living in association with algae or sponges were clustered in the newly established Pseudomonas pertucinogena lineage. Remarkably for the predominantly terrestrial genus Pseudomonas, more than half (9) of currently 16 species within this lineage were isolated from marine or saline habitats. Unlike other Pseudomonas species, they seem to have in common a highly specialized metabolism. Furthermore, the marine members apparently possess the capacity to produce biomolecules of biotechnological interest (e.g. dehalogenases, polyester hydrolases, transaminases). Here, we summarize the knowledge regarding the enzymatic endowment of the marine Pseudomonas pertucinogena bacteria and report on a genomic analysis focusing on the presence of genes encoding esterases, dehalogenases, transaminases and secondary metabolites including carbon storage compounds.

Pseudomonas pharmafabricae sp. nov., Isolated From Pharmaceutical Wastewater

A Gram-stain-negative, aerobic, rod-shaped bacterial strain, designated ZYSR67-Z^T, was isolated from a pharmaceutical wastewater sample collected from a chemical factory in Zhejiang, China. The strain was motile by a single polar flagellum and grew at 4-42 °C (optimum, 35 °C), pH 5.0-9.0 (optimum, 6.0) and 0-5.0% (w/v) NaCl (optimum, 2.0%). Based on multilocus sequence analysis using 16S rRNA, gyrB, rpoB and rpoD, the strain ZYSR67-Z^T formed a distinct phylogenetic group in the genus Pseudomonas. The average nucleotide identity values between strain ZYSR67-Z^T and the closely related 10 type strains of the Pseudomonas species were 75.8-78.6%. The in silico DNA-DNA hybridization values indicated that strain ZYSR67-Z^T and the type strains of the Pseudomonas shared 21.4-23.1% DNA relatedness. The predominant isoprenoid quinone system was ubiquinone-9 while ubiquinone-8 was present in trace amounts. The major fatty acids (> 10%) identified were C_12:0, C_16:0, C_18:1 ω7c and summed features 3 (C_16:1 ω7c and/or iso-C_15:0 2OH). The major polar lipids consisted of phosphatidylethanolamine, phosphatidylglycerol and diphosphatidylglycerol. The genomic DNA G+C content was 62.6 mol%. On the basis of morphological, physiological and chemotaxonomic characteristics, together with the results of phylogenetic analysis, strain ZYSR67-Z^T was proposed to represent a novel species of the genus Pseudomonas, named Pseudomonas pharmafabricae sp. nov.. The type strain is ZYSR67-Z^T (= CGMCC 1.15498^T = JCM 31306^T).

Draft Genome Sequence of Pseudomonas oceani DSM 100277T, a Deep-Sea Bacterium

Pseudomonas oceani DSM 100277^T was isolated from deep seawater in the Okinawa Trough at 1390 m. P. oceani belongs to the Pseudomonas pertucinogena group. Here, we report the draft genome sequence of P. oceani, which has an estimated size of 4.1 Mb and exhibits 3,790 coding sequences, with a G+C content of 59.94 mol%.

The current status on the taxonomy of Pseudomonas revisited: An update

The genus Pseudomonas described in 1894 is one of the most diverse and ubiquitous bacterial genera which encompass species isolated worldwide. In the last years more than 70 new species have been described, which were isolated from different environments, including soil, water, sediments, air, animals, plants, fungi, algae, compost, human and animal related sources. Some of these species have been isolated in extreme environments, such as Antarctica or Atacama desert, and from contaminated water or soil. Also, some species recently described are plant or animal pathogens. In this review, we revised the current status of the taxonomy of genus Pseudomonas and the methodologies currently used for the description of novel species which includes, in addition to the classic ones, new methodologies such as MALDI-TOF MS, MLSA and genome analyses. The novel Pseudomonas species described in the last years are listed, together with the available genome sequences of the type strains of Pseudomonas species present in different databases.

Draft Genome Sequence of Pseudomonas pachastrellae Strain CCUG 46540T, a Deep-Sea Bacterium

Pseudomonas pachastrellae strain CCUG 46540^T (KMM 330^T) was isolated from a deep-sea sponge specimen collected in the Philippine Sea at a depth of 750 m. The draft genome has an estimated size of 4.0 Mb, exhibits a G+C content of 61.2 mol%, and is predicted to encode 3,592 proteins, including pathways for the degradation of aromatic compounds.