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Pseudomonas frederiksbergensis ERDD5:01 is a psychrotrophic bacteria isolated from the glacial stream flowing from East Rathong glacier in Sikkim Himalaya. The strain showed survivability at high altitude stress conditions like freezing, frequent freeze-thaw cycles, and UV-C radiations. The complete genome of 5,746,824 bp circular chromosome and a plasmid of 371,027 bp was sequenced to understand the genetic basis of its survival strategy. Multiple copies of cold-associated genes encoding cold active chaperons, general stress response, osmotic stress, oxidative stress, membrane/cell wall alteration, carbon storage/starvation and, DNA repair mechanisms supported its survivability at extreme cold and radiations corroborating with the bacterial physiological findings. The molecular cold adaptation analysis in comparison with the genome of 15 mesophilic Pseudomonas species revealed functional insight into the strategies of cold adaptation. The genomic data also revealed the presence of industrially important enzymes.

A biosurfactant was harvested from anaerobically digested swine wastewater (ADSW) and employed to enhance ammonia removal in a comparative study using two multiple soil layer bioreactors (MSLs). Results showed that toxicity of the biosurfactant to microorganisms was negligible within the experimental concentration range. Optimal dose of the biosurfactant in MSLs to remove ammonia from ADSW was 0.1 CMC (Critical Micelle Concentration) under different hydraulic loading rate (HLR). For instance, when the HLR was adjusted as 80, 120, 160, and 200 L/(m

Solitary inoculation of bacteria has been studied widely for plant growth development and amelioration of salinity stress but co-inoculation of bacteria for salt stress amelioration in red pepper plants has been less studied till date. Here, we investigated the co-inoculation effect of Pseudomonas frederiksbergensis OB139 and Pseudomonas vancouverensis OB155 in red pepper plant growth characteristics, plant photosynthesis pigments, ethylene emission, and antioxidant properties under 0, 50, 100 and 150 mM salt stress and compared them with non-inoculated control and single inoculation of each isolate. Results showed increasing concentrations of salinity stress arrested the normal plant growth, increased the stress ethylene levels, disrupted the photosynthetic parameters and also influenced the antioxidant enzymatic activities in non-inoculated control plants. Co-inoculation of 1-aminocyclopropane-1-carboxylate (ACC) deaminase producing Pseudomonas spp. significantly reduced the stress ethylene emission and contributed to a significant increase in plant growth compared to single inoculation and non-inoculated control. Catalase activity which was significantly increased in co-inoculated red pepper plants compared to other treatments imply its ability to efficiently neutralize the hydrogen peroxide ions formed as a result of oxidative stress in plants under salinity stress. Besides, significant reduction in malondialdehyde (MDA) content can be correlated to the increased salt tolerance in co-inoculated red pepper plants. Lastly, the increased content of photosynthetic pigments suggest the importance of co-inoculation in improving photosynthesis of red pepper plants. Together, the data demonstrated the functional compatibility of the ACC deaminase producing bacterial isolates and their role in improving the plant physical and biochemical characteristics under salinity stress.

In recent years, the low Zn content of wheat has become critical. Consequently, solutions that can improve the Zn nutrition of wheat are highly researched. In the present investigation, we aimed to evaluate the potential benefits of phosphate-solubilizing bacteria isolated from Ziziphus lotus on wheat seedling growth. Based on the phosphate-solubilizing criteria, four isolated strains, J16, J143, J146, and J158, were identified by 16SrRNA gene sequencing as Pseudomonas moraviensis, Bacillus halotolerans, Enterobacter hormaechei, and Pseudomonas frederiksbergensis, respectively. Studies of the conventional properties of plant growth-promoting rhizobacteria (PGPR) showed that E. hormaechei J146 produced up to 550 mg·L−1 of indole-3-acetic acid (IAA). Siderophores and ammonia were produced by all strains but cellulase was restricted to B. halotolerans J143, whereas proteases were missing in E. hormaechei J146 and P. frederiksbergensis J158. E. hormaechei J146 tolerate up to 1.5 mg·L−1 of copper and cadmium, while B. halotolerans J143 withstood 1.5 mg·L−1 of nickel. Strains B. halotolerant J143, E. hormaechei J146, and P. frederiksbergensis J158 remarkably improved wheat seed germination, plant growth, and Zn absorption. Lastly, nutrient measurement revealed that a wheat plant inoculated with E. hormaechei J146 and P. frederiksbergensis J158 increased its nitrogen and potassium uptake by up to 17%.

The ability of the psychrotrophic bacterium Pseudomonas frederiksbergensis SI8 to grow and degrade aromatic hydrocarbons efficiently at low temperature is shown in this study. The robust growth of P. frederiksbergensis SI8 was demonstrated in jet fuel and an aromatic blend. The bacterium showed 2.5 to 3-fold faster growth in the aromatic blend than in jet fuel. The hydrocarbons degradation profile of P. frederiksbergensis SI8 at ambient temperature (i.e., 28 °C) and low temperature (i.e., 4 °C) was characterized by Gas Chromatography-Mass Spectrometry (GC–MS) analysis. GC–MS data demonstrated that P. frederiksbergensis SI8 is a novel psychrotrophic bacterium with the ability to degrade aromatic hydrocarbons at temperatures as low as 4 °C. Specifically, P. frederiksbergensis SI8 consumed toluene, ethylbenzene, n-propylbenzene and methyl ethyl benzene efficiently. The data presented here serves to characterize the hydrocarbon degradation profile of P. frederiksbergensis SI8 and corroborates the capacity of this bacterium to degrade aromatic hydrocarbons at low temperatures. The raw GC–MS data for the degradation of hydrocarbons by P. frederiksbergensis SI8 grown at 4 °C and 28 °C for 14 days have been deposited in Mendeley Data and can be retrieved from https://dx.doi.org/10.17632/z9292bvdmh.1 and https://dx.doi.org/10.17632/dp3sgwpj23.1 . The datasets and raw data presented here were associated with the main research work “Metagenomic characterization reveals complex association of soil hydrocarbon-degrading bacteria” [1].

Polycyclic aromatic hydrocarbons (PAHs), including naphthalene, are widely distributed in nature. Naphthalene has been regarded as a model PAH compound for investigating the mechanisms of bacterial PAH biodegradation. Pseudomonas sp. AS1 isolated from an arsenic-contaminated site is capable of growing on various aromatic compounds such as naphthalene, salicylate, and catechol, but not on gentisate. The genome of strain AS1 consists of a 6,126,864 bp circular chromosome and the 81,841 bp circular plasmid pAS1. Pseudomonas sp. AS1 has multiple dioxygenases and related enzymes involved in the degradation of aromatic compounds, which might contribute to the metabolic versatility of this isolate. The pAS1 plasmid exhibits extremely high similarity in size and sequences to the well-known naphthalene-degrading plasmid pDTG1 in Pseudomonas putida strain NCIB 9816-4. Two gene clusters involved in the naphthalene degradation pathway were identified on pAS1. The expression of several nah genes on the plasmid was upregulated by more than 2-fold when naphthalene was used as a sole carbon source. Strains have been isolated at different times and places with different characteristics, but similar genes involved in the degradation of aromatic compounds have been identified on their plasmids, which suggests that the transmissibility of the plasmids might play an important role in the adaptation of the microorganisms to mineralize the compounds.

Mercury tolerant bacteria Pseudarthrobacter oxydans strain MM20 and Pseudomonas frederiksbergensis strain SS18 were isolated from the tundra ecosystem of Ny-Ålesund, Svalbard, where commercial exploitation of the coal existed till 1960s. Minimum inhibitory concentration (MIC), mercury removal, mercury biosorption, and antibiotic resistance of these strains were analyzed. P. frederiksbergensis strain SS18 showed high tolerance (2.0 ppm) to mercury than P. oxydans strain MM20 (1.5 ppm). Mercury removal and biosorption studies were carried out in liquid media containing 1.0 ppm mercury. More than 90% of mercury was removed from the culture media by the selected strains. The mercury biosorption assay revealed that a part of mercury was accumulated in cell pellets and was 22 and 25% respectively for P. oxydans strain MM20 and P. frederiksbergensis strain SS18. Fourier transform infrared study revealed that alkyl halide, alkynes, alcoholic, aliphatic and aromatic amines, alkanes, nitro compound, primary amines, carboxylic acid, alkenes, and amide groups play a major role in the development of tolerance towards mercury. Out of eleven antibiotics tested, P. oxydans strain MM20 was found to be resistant to lincomycin and novobiocin while P. frederiksbergensis strain SS18 was found to be resistant to seven antibiotics. Our study demonstrates that under experimental conditions, bacterial isolates undergo detailed structural and functional changes to tolerate as well as immobilize toxic elements like mercury.

This study attempts to evaluate the capacity of wetland plants' ability to dissipate phenanthrene (PHE) under waterlogged conditions. The results indicate that Typha latifolia and Vetiveria zizanioides may efficiently degrade PHE, and were much more effective when under combined plant cultivation with the inoculation of Pseudomonas frederiksbergensis (ATCC BAA-257) . Concentrations of PHE declined from 200 to less than 52 mg kg−1 in all treatments with plant cultivation. At the end of the experimental period, PHE was undetectable in combined plant cultivation in the presence of bacteria inoculation. Microbial biomass C(carbon), N(nitrogen), and P(phosphate) were significantly different (p < 0.05) in the presence and absence of bacteria inoculation with bacteria inoculation significantly (p < 0.05) increased microbial biomass P. The presence of bacteria inoculation and different plant species significantly (p < 0.05) decreased the PHE concentrations in the microcosms. The inoculation of bacteria an...

Although endophytic bacteria are known to colonize Panax ginseng, little is known about their diversity and roles. We addressed in the present study by comparing endophytic bacterial populations in P. ginseng plants of different ages (2–6 years) and in various tissue types (root, stem, leaf, and flower stalk). A total of 116 strains assigned to 42 species were identified by 16S rDNA sequencing. The predominant phylum was Firmicutes. Two-year-old ginseng plants and root tissues showed the greatest diversity of endophytic bacteria, with Bacillales being the predominant order. The antifungal activity of isolates against two pathogens, Cylindrocarpon destructans and/or Botrytis cinerea, was evaluated in dual-culture assays. In total, 28 strains showed antifungal activity with PgBE14 (Bacillus amyloliquefaciens), PgBE40 (B. megaterium), PgBE39, PgBE45 (Pseudomonas frederiksbergensis), and PgBE42 (Staphylococcus saprophyticus) inhibiting both pathogens. These results improve our understanding of the structure and diversity of endophytic bacterial communities of P. ginseng and identify strains with antifungal activity that have potential applications as biocontrol agents.

Aims: Epiphytic bacteria, isolated from Deschampsia antarctica, were screened for their potential to inhibit the plant pathogen Botrytis cinerea, the causal agent of gray mold disease of strawberry pseudofruits. This phytopathogenic fungus is more active and the disease is more serious in temperate climate where the temperatures are lower. Methodology: The approach involved the isolation and characterization of bacteria from the phyllosphere of D. antarctica and the evaluation of their antifungal activity. Results: A total of 56 bacterial strains were isolated and only one of them, identified by the sequencing of 16S rDNA gene, as Pseudomonas frederiksbergensis CMAA 1323, inhibited the mycelial growth and the conidial germination of the fungus. Its ethyl acetate extract also inhibited Original Research Article Melo et al.; BMRJ, 14(3): 1-11, 2016; Article no.BMRJ.25314 2 the mycelial growth. Analysis of the bioactive fraction by using liquid chromatography coupled to a mass spectrometry (LC-MS) revealed the presence of cyclo(Pro-Val), a compound belonging to the class of diketopiperazines (DKPs). Conclusion: These findings support the potential use of the psychrophilic bacterium P. frederiksbergensis as promising antifungal agent, and highlight the need for more studies with this bacterium in the biological control of plant pathogenic fungi.

The role of stress induced ethylene under low temperature stress has been controversial and hitherto remains unclear. In the present study, 1-aminocyclopropane-1-carboxylate deaminase (ACCD) gene, acdS expressing mutant strains were generated from ACCD negative psychrotolerant bacterial strains Flavobacterium sp. OR306 and Pseudomonas frederiksbergensis OS211, isolated from agricultural soil during late winter. After transformation with plasmid pRKACC which contained the acdS gene, both the strains were able to exhibit ACCD activity in vitro. The effect of this ACCD under chilling stress with regards to ethylene was studied in tomato plants inoculated with both acdS expressing and wild type bacteria. On exposing the plants to one week of chilling treatment at 12/10 °C, it was found that stress ethylene, ACC accumulation and ACO activity which are markers of ethylene stress, were significantly reduced in plants inoculated with the acdS gene transformed mutants. In case of plants inoculated with strain OS211-acdS, ethylene emission, ACC accumulation and ACO activity was significantly reduced by 52%, 75.9% and 23.2% respectively compared to uninoculated control plants. Moreover, expression of cold induced LeCBF1 and LeCBF3 genes showed that these genes were significantly induced by the acdS transformed mutants in addition to reduced expression of ethylene-responsive transcription factor 13 (ETF-13) and ACO genes. Induced expression of LeCBF1 and LeCBF3 in plants inoculated with acdS expressing mutants compared to wild type strains show that physiologically evolved stress ethylene and its transcription factors play a role in regulation of cold induced genes as reported earlier in the literature.

Soil salinity, being a part of natural ecosystems, is an increasing problem in agricultural soils throughout the world. Pseudomonas frederiksbergensis OS261 has already been proved to be an effective bio-inoculant for enhancing cold stress tolerance in plants, however, its effect on salt stress tolerance is unknown. The main aim of the present study was to elucidate P. frederiksbergensis OS261 mediated salt stress tolerance in red pepper. The plants were exposed to a salt stress using NaCl at the concentrations of 50, 100, and 150 mM after 12 days of transplantation, while plant growth and enzyme activity were estimated 50 days after sowing. The height in P. frederiksbergensis OS261 inoculated plants was significantly increased by 19.05, 34.35, 57.25, and 61.07% compared to un-inoculated controls at 0, 50, 100, and 150 mM of NaCl concentrations, respectively, under greenhouse conditions. The dry biomass of the plants increased by 31.97, 37.47, 62.67, and 67.84% under 0, 50, 100, and 150 mM of NaCl concentrations, respectively. A high emission of ethylene was observed in un-inoculated red pepper plants under salinity stress. P. frederiksbergensis OS261 inoculation significantly reduced ethylene emission by 20.03, 18.01, and 20.07% at 50, 100, and 150 mM of NaCl concentrations, respectively. Furthermore, the activity of antioxidant enzymes (ascorbate peroxidase, superoxide dismutase, and catalase) also varied in the inoculated red pepper plants. Salt stress resistance in the bacterized plants was evident from the improved antioxidant activity in leaf tissues and the decreased hydrogen ion concentration. Thus, we conclude that P. frederiksbergensis OS261 possesses stress mitigating property which can enhance plant growth under high soil salinity by reducing the emission of ethylene and regulating antioxidant enzymes.

The use of synthetic organic pesticides has serious economic, social and environmental ramifications. Thus, this study describes the experiments using botanical and bacterial extracts to control the samsum ant (Pachycondyla sennaarensis). This ant is widely distributed in many parts of southern Saudi Arabia, and has been established as a household pest ant. Three Saudi plants, harmal (Rhaza stricta), boxthorn (Lycium shawii) and artemisia (Artemisia inculta) and two bacterial extracts, Pseudomonas frederiksbergensis and Streptomyces sp. were tested in a minced meat bait against the workers of samsum ant. Among the plant extracts tested, at a concentration of 0.3 mg of the plant extract of boxthorn per gram of food exhibited the highest toxicity to samsum ants, causing 20.30 % mortality per day and 100 % average death rate of all the ants in 4.9 days. Furthermore, the results demonstrate that the bacterial extract of Streptomyces sp. was the most effective agent to control these ants, with the average death rate at 30 ants per day at a concentration of 0.3 mg/g food.

Our study found that except Novosphingobium resinovorum (B5) Salvia miltiorrhiza root endophytic bacteria Pseudomonas brassicacearum sub sp. neoaurantiaca (B1), Rhizobium radiobacter (B2), Pseudomonas thivervalensis (B3), Pseudomonas frederiksbergensis (B4) significantly improved the activity of key enzymes 3-hydroxy-3-methyglutary1-CoA reductase and 1-deoxy-d-xylulose-5-phosphate synthase in the biosynthetic pathway of tanshinones. Specifically, HMGR activity with B1 treatment increased 2.1-fold that of control, 1-deoxy-d-xylulose-5-phosphate synthase activity with B2 treatment increased 5.0-fold that of control, which caused a significant increase in tanshinone content in the hairy roots. The dihydrotanshinone I and cryptotanshinone content under B1 treatment increased 19.2-fold and 11.3-fold, respectively, and total tanshinone content increased 3.7-fold that of control. The five endophytic bacteria B1, B2, B3, B4 and B5 all significantly decreased phenylalanine ammonia-lyase and tyrosine aminotransferase activity in hairy roots, of which, B3 treatment decreased phenylalanine ammonia-lyase activity by 46.2 %, and B2 treatment decreased tyrosine aminotransferase activity by 44.7 % compared with the control. Each of the five endophytic bacteria decomposed rosmarinic acid and salvianolic acid B, which caused a significant decrease in rosmarinic acid and salvianolic acid B content in hairy roots, with B2 treatment decreasing rosmarinic acid and salvianolic acid B content by 94.5 and 89.0 %, respectively, compared with the control. The five endophytic bacteria also inhibited the growth of S. miltiorrhiza hairy roots, of which, B2 and B4 treatment decreased hairy root biomass by 55.2 and 51.3 %, respectively, compared with the control, while hairy roots promoted the growth of B4 and B5 and inhibited the growth of B1 and B3.

Soil salinity, being a part of natural ecosystems, is an increasing problem in agricultural soils throughout the world. Pseudomonas frederiksbergensis OS261 has already been proved to be an effective bio-inoculant for enhancing cold stress tolerance in plants, however, its effect on salt stress tolerance is unknown. The main aim of the present study was to elucidate P. frederiksbergensis OS261 mediated salt stress tolerance in red pepper. The plants were exposed to a salt stress using NaCl at the concentrations of 50, 100, and 150 mM after 12 days of transplantation, while plant growth and enzyme activity were estimated 50 days after sowing. The height in P. frederiksbergensis OS261 inoculated plants was significantly increased by 19.05, 34.35, 57.25, and 61.07% compared to un-inoculated controls at 0, 50, 100, and 150 mM of NaCl concentrations, respectively, under greenhouse conditions. The dry biomass of the plants increased by 31.97, 37.47, 62.67, and 67.84% under 0, 50, 100, and 150 mM of NaCl concentrations, respectively. A high emission of ethylene was observed in un-inoculated red pepper plants under salinity stress. P. frederiksbergensis OS261 inoculation significantly reduced ethylene emission by 20.03, 18.01, and 20.07% at 50, 100, and 150 mM of NaCl concentrations, respectively. Furthermore, the activity of antioxidant enzymes (ascorbate peroxidase, superoxide dismutase, and catalase) also varied in the inoculated red pepper plants. Salt stress resistance in the bacterized plants was evident from the improved antioxidant activity in leaf tissues and the decreased hydrogen ion concentration. Thus, we conclude that P. frederiksbergensis OS261 possesses stress mitigating property which can enhance plant growth under high soil salinity by reducing the emission of ethylene and regulating antioxidant enzymes.

Pseudomonas community structures were investigated by analyzing 16S rRNA clone libraries derived from fertilized and unfertilized soil plots under corn–alfalfa rotation in a long-term experiment. Amplified 16S rRNA fragments derived by polymerase chain reaction (PCR) were cloned and sequenced. A total of 729 clone sequences were analyzed, of which 51 were possible chimeras and discarded. The remaining clone sequences (678) belonged to γ-proteobacteria with 61.8 % (419) classified to the genus Pseudomonas. Unclassified Gammaproteobacteria accounted for 23.4 % of total clones sequences. Rarefaction analyses showed a more diverse community structure of both Gammaproteobacteria and Pseudomonas in unfertilized than fertilized field soils irrespective of plant types under cultivation. Bacterial or Pseudomonas community structures differed significantly between fertilized and unfertilized soil plots. Clone sequences that are affiliated to Pseudomonas putida and P. oryzihabitans were more prominent in libraries from fertilized plots, while those that clustered with Pseudomonas frederiksbergensis were more often retrieved from unfertilized soil plots. A strong influence of fertilizer applications on community structure was supported by principal component analysis. We conclude that long-term use of mineral fertilizers could influence Pseudomonas community structure.

We report the production and degradation of quorum sensing N-acyl-homoserine lactones by bacteria isolated from Malaysian montane forest soil. Phylogenetic analysis indicated that these isolates clustered closely to the genera of Arthrobacter, Bacillus and Pseudomonas. Quorum quenching activity was detected in six isolates of these three genera by using a series of bioassays and rapid resolution liquid chromatography analysis. Biosensor screening and high resolution liquid chromatography-mass spectrometry analysis revealed the production of N-dodecanoyl-L-homoserine lactone (C12-HSL) by Pseudomonas frederiksbergensis (isolate BT9). In addition to degradation of a wide range of N-acyl-homoserine lactones, Arthrobacter and Pseudomonas spp. also degraded p-coumaroyl-homoserine lactone. To the best of our knowledge, this is the first documentation of Arthrobacter and Pseudomonas spp. capable of degrading p-coumaroyl-homoserine lactone and the production of C12-HSL by P. frederiksbergensis.

Fusarium culmorum causes Fusarium head blight (FHB) disease of cereals, resulting in yield loss and contamination of grain with the trichothecene mycotoxin, deoxynivalenol (DON). In a test for potential disease control organisms, Pseudomonas fluorescens strains MKB 158 and MKB 249 and Pseudomonas frederiksbergensis strain 202 significantly reduced both the severity of FHB disease symptoms caused by F. culmorum on wheat and barley (⩾23%; P ⩽ 0.050) and the disease-associated loss in 1000-grain weight (⩾16%; P ⩽ 0.050) under both glasshouse and field conditions when applied 24 h pre-pathogen inoculation. Glasshouse studies showed that these bacteria were more effective in controlling disease when applied 24 h pre- as opposed to 24 h post-pathogen inoculation. The most striking finding was that, in the F. culmorum-inoculated field trials, treatment with either of the two P. fluorescens strains (MKB 158 or MKB 249) also significantly reduced the DON levels in wheat and barley grain (74–78%; P ⩽ 0.050). This is the first report detailing the ability of fluorescent pseudomonad bacteria to control FHB disease and simultaneously reduce mycotoxin contamination of wheat and barley under field conditions.

Pseudomonas frederiksbergensis strain SI8 is a psychrotrophic bacterium capable of efficient aerobic degradation of aromatic hydrocarbons. The draft genome of P. frederiksbergensis SI8 is 6.57 Mb in size, with 5,904 coding sequences and 60.5% G+C content. The isopropylbenzene (cumene) degradation pathway is predicted to be present in P. frederiksbergensis SI8.

Phosphate-solubilizing bacteria have the ability of solubilizing mineral phosphate in soil and promoting growth of plants, but the activity of phosphate solubilization is influenced by exogenous soluble phosphate. In the present study, the effects of soluble phosphate on the activity of phosphate solubilization, acidification of media, growth, and organic acid secretion of phosphate-solubilizing bacterium Pseudomonas frederiksbergensis JW-SD2 were investigated under six levels of soluble phosphate conditions. The activity of phosphate solubilization decreased with the increase of soluble phosphate concentration, accompanying with the increase of media pH. However, the growth was promoted by adding soluble phosphate. Production of gluconic, tartaric, and oxalic acids by the strain was reduced with the increase of concentration of soluble phosphate, while acetic and pyruvic acids showed a remarkable increase. Gluconic acid predominantly produced by the strain at low levels of soluble phosphate showed that this acid was the most efficient organic acid in phosphate solubilization. Pyrroloquinoline quinone-glucose dehydrogenase gene gcd (pg5SD2) was cloned from the strain, and the expressions of pg5SD2 gene were repressed gradually with the increase of concentration of soluble phosphate. The soluble phosphate regulating the transcription of the gcd gene is speculated to underlie the regulation of the secretion of gluconic acid and subsequently the regulation of the activity of phosphate solubilization. Future research needs to consider a molecular engineering strategy to reduce the sensitivity of PSB strain to soluble phosphate via modification of the regulatory mechanism of gcd gene, which could improve the scope of PSB strains' application.

The rhizospheric bacterium JW-SD2 was identified as Pseudomonas frederiksbergensis based on phenotypic features, the Biolog Identification System and 16S rRNA sequence analysis. The phosphate-solubilizing activity, acidification in culture media, growth rate and organic acid secretion of JW-SD2 were investigated during 192 h of cultivation. The phosphate solubilized by JW-SD2 reached 7.75 mM. The decrease of pH and increase of titratable acidity were closely correlated (Pearson’s r = −0.953 and 0.969, respectively) with the phosphate-solubilizing activity. High concentrations of gluconic, 2-ketogluconic, pyruvic, maleic and malic acids were detected before 96 h of culture, when the strain displayed a high level of phosphate-solubilizing activity, indicating that these organic acids were efficient components in phosphate solubilization. However, acetic acid did not affect phosphate solubilization as shown by a remarkable increase at 144 h of culture when the phosphate-solubilizing activity decreased. The phosphate-solubilizing ability of JW-SD2 was significantly (P

Phenotypic and genotypic characterization indicated that a group of 29 closely related phenanthrene-degrading bacteria from a coal gasification site in Frederiksberg, Copenhagen, Denmark, belonged to the genus Pseudomonas. The strains were isolated at two sampling occasions 2 years apart. The isolates were phenotypically different from any known species of the genus Pseudomonas and were therefore subject to further identification. Colonies were smooth and pale yellowish and did not produce pigments fluorescent in UV light when grown on King's B agar. Cells were rod-shaped, approximately 0.5-0.8 x 1.5-3.0 microm, and grew at 4 and 30 degrees C, but not 37 degrees C. The bacteria were oxidase- and catalase-positive, accumulated poly-beta-hydroxybutyrate and denitrified, but did not utilize D-xylose. The mean G+C content was 59.6 mol%. Phenotypic data and 16S rDNA sequence data information for Pseudomonas amygdali and Pseudomonas corrugata, and 16S rDNA sequence data for Pseudomonas chlororaphis and Pseudomonas syringae showed close relationships to these strains. However, DNA-DNA hybridization data showed that the isolates belong to a new species, for which the name Pseudomonas frederiksbergensis sp. nov. is proposed. The type strain is JAJ28T (DSM 13022T).

Soil samples were screened to select microorganisms with the capability to oxidize organic sulfides into the corresponding sulfoxides with differential enantioselectivities. Several bacterial strains that preferentially produced the S- configured sulfoxide enantiomer were isolated. Surprisingly, one bacterial strain, genotypically and phenotypically characterized as Pseudomonas frederiksbergensis , selectively gave the R enantiomer. The finding that two apparently identical organisms displayed opposite enantioselectivities is novel for non-genetically modified organisms.

A gram-negative psychrophilic bacterium, with potential for biodegradation of long-chain n-alkanes was isolated from ice samples collected in Spitzbergen, Denmark. On the basis of results of biochemical and morphological tests and sequence analysis of 16S rRNA, the strain was identified as Pseudomonas frederiksbergensis. In this work, a short-chain NAD+-dependent alcohol dehydrogenase (alcDH) (Accession number: AAR13804) from the P. frederiksbergensis was cloned and transformed in E. coli BL21 (3DE) competent cells. The alcDH activity was highest in the crude extract of cells induced with 1.0 mM IPTG. The recombinant alcDH enzyme was purified to 93.4% homogeneity using three consecutive purification steps including ammonium sulphate, Q-Sepharose Fast Flow column and gel filtration chromatography employing Superdex 200 10/30 HR column. Enzyme enrichment and yield levels of 31.4 folds and 25.5%, respectively, were achieved. While the subunit molecular mass of the enzyme was determined on SDS-PAGE to be ~38 kDa, the aggregated native form of the enzyme had a molecular mass of ~238 kDa by gel filtration analysis. Reaction conditions optima for the recombinant alcDH were determined with propan-1-ol as the substrate. While the optimum pH was 9, the optimum temperature was 35 °C. The alcDH enzyme exhibited moderate thermal stability with half-lives of 150 min at 55 °C, 27 min at 65 °C and 8 min at 75 °C. Results for kinetic parameters indicated that the apparent K m value for alcDH with propan-1-ol as the substrate was found to be 1.42 mM and the V max value was 0.63 mmol mg−1 min−1. Experimental evidence revealed that the recombinant alcDH exhibited a wide range of substrate specificity, with higher levels of specific activity for aliphatic alcohols as compared to secondary alcohols. Taken together, the present study highlights the potential of alcDH as a member of cold-adapted enzymes in several key biotechnological applications including environmental bioremediation and biotransformations. It is envisaged that, with the ongoing screening of microorganisms and metagenomes, directed evolution approaches and the subsequent overexpression of recombinant proteins, more enzymes will be found that are suitable for bioremediation purposes.