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International Journal of Systematic... Oct 1990Pseudomonas facilis and Pseudomonas delafieldii are inappropriately assigned to the genus Pseudomonas. They belong to the acidovorans rRNA complex in rRNA superfamily...
Acidovorax, a new genus for Pseudomonas facilis, Pseudomonas delafieldii, E. Falsen (EF) group 13, EF group 16, and several clinical isolates, with the species Acidovorax facilis comb. nov., Acidovorax delafieldii comb. nov., and Acidovorax temperans sp. nov.
Pseudomonas facilis and Pseudomonas delafieldii are inappropriately assigned to the genus Pseudomonas. They belong to the acidovorans rRNA complex in rRNA superfamily III (i.e., the beta subclass of the Proteobacteria). The taxonomic relationships of both of these species, two groups of clinical isolates (E. Falsen [EF] group 13 and EF group 16), and several unidentified or presently misnamed strains were examined by using DNA:rRNA hybridization, numerical analyses of biochemical and auxanographic features and of fatty acid patterns, polyacrylamide gel electrophoresis of cellular proteins, and DNA:DNA hybridization. These organisms form a separate group within the acidovorans rRNA complex, and we propose to transfer them to a new genus, Acidovorax. We describe the following three species in this genus: the type species, Acidovorax facilis (formerly Pseudomonas facilis), with type strain LMG 2193 (= CCUG 2113 = ATCC 11228); Acidovorax delafieldii (for the former Pseudomonas delafieldii and most of the EF group 13 strains), with type strain LMG 5943 (= CCUG 1779 = ATCC 17505); and Acidovorax temperans (for several former Pseudomonas and Alcaligenes strains and most of the EF group 16 strains), with type strain CCUG 11779 (= LMG 7169).
Topics: Base Composition; Base Sequence; Chromatography, Gas; Cluster Analysis; DNA, Bacterial; Electrophoresis; Fatty Acids; Nucleic Acid Hybridization; Phenotype; Pseudomonas; Terminology as Topic
PubMed: 2275854
DOI: 10.1099/00207713-40-4-384 -
Journal of Microbiology and... May 2019Nitrilase is a valuable type of hydrolase that catalyzes nitriles into carboxylic acid and ammonia. Its applications, however, are severely restricted by the harsh...
Nitrilase is a valuable type of hydrolase that catalyzes nitriles into carboxylic acid and ammonia. Its applications, however, are severely restricted by the harsh conditions of industrial reaction processes. To solve this problem, a nitrilase from 72W was inserted into an shuttle vector for spore surface display. Western blot, enzyme activity measurements and flow cytometric analysis results all indicated a successful spore surface display of the CotB-nit fusion protein. In addition, the optimal catalytic pH value and temperature of the displayed nitrilase were determined to be 7.0 and 50°C, respectively. Moreover, results of reusability tests revealed that 64% of the initial activity of the displayed nitrilase was still retained at the 10 cycle. Furthermore, hydrolysis efficiency of upscale production of cyanocarboxylic acid was significantly higher in the displayed nitrilase-treated group than in the free group expressed by (pET-28a-nit). Generally, the display of 72W nitrilase on the spore surface of may be a useful method for immobilization of enzyme and consequent biocatalytic stabilization.
Topics: Aminohydrolases; Bacillus subtilis; Bacterial Proteins; Comamonadaceae; Enzyme Stability; Enzymes, Immobilized; Escherichia coli; Genetic Vectors; Hydrogen-Ion Concentration; Immobilization; Recombinant Fusion Proteins; Spores, Bacterial; Temperature; Time Factors
PubMed: 30955259
DOI: 10.4014/jmb.1901.01030 -
Journal of Hazardous Materials Apr 2018The contamination of the environment by U may affect plant life and consequently may have an impact on animal and human health. The present work describes U(VI)...
The contamination of the environment by U may affect plant life and consequently may have an impact on animal and human health. The present work describes U(VI) sequestration by Acidovorax facilis using a multidisciplinary approach combining wet chemistry, transmission electron microscopy, and spectroscopy methods (e.g. cryo-time resolved laser-induced fluorescence spectroscopy, extended X-ray absorption fine structure spectroscopy, and in-situ attenuated total reflection Fourier transform infrared spectroscopy). This bacterial strain is widely distributed in nature including U-contaminated sites. In kinetic batch experiments cells of A. facilis were contacted for 5 min to 48 h with 0.1 mM U(VI). The results show that the local coordination of U species associated with the cells depends upon time contact. U is bound mainly to phosphate groups of lipopolysaccharide (LPS) at the outer membrane within the first hour. And, that both, phosphoryl and carboxyl functionality groups of LPS and peptidoglycan of A. facilis cells may effectuate the removal of high U amounts from solution at 24-48 h of incubation. It is clearly demonstrated that A. facilis may play an important role in predicting the transport behaviour of U in the environment and that the results will contribute to the improvement of bioremediation methods of U-contaminated sites.
Topics: Biodegradation, Environmental; Comamonadaceae; Lipopolysaccharides; Radioactive Pollutants; Uranium; Water Purification
PubMed: 29324323
DOI: 10.1016/j.jhazmat.2017.12.030 -
Biotechnology Letters Aug 2021Catalytic promiscuity, or the ability to catalyze a secondary reaction, provides new opportunities for industrial biocatalysis by expanding the range of biocatalytic...
OBJECTIVES
Catalytic promiscuity, or the ability to catalyze a secondary reaction, provides new opportunities for industrial biocatalysis by expanding the range of biocatalytic reactions. Some nitrilases converting nitriles to amides, referred to as the secondary activity, show great potential for amides production. And our goal was exploiting the amide-forming potential of nitrilases.
RESULTS
In this study, we characterized and altered the secondary activity of nitrilase from Acidovorax facilis 72 W (Nit72W) towards different substrates. We increased the secondary activity of Nit72W towards 2-cyanopyridine by 196-fold and created activity toward benzonitrile and p-nitrophenylacetonitrile by modifying the active pocket. Surprisingly, the best mutant, W188M, completely converted 250 mM 2-cyanopyridine to more than 98% 2-picolinamide in 12 h with a specific activity of 90 U/mg and showed potential for industrial applications.
CONCLUSIONS
Nit72W was modified to increase its secondary activity for the amides production, especially 2-picolinamide.
Topics: Aminohydrolases; Bacterial Proteins; Biocatalysis; Comamonadaceae; Picolinic Acids; Protein Engineering; Substrate Specificity
PubMed: 33961157
DOI: 10.1007/s10529-021-03137-7 -
Journal of Hazardous Materials Nov 2016The former uranium mine Königstein (Saxony, Germany) is currently in the process of remediation by means of controlled underground flooding. Nevertheless, the flooding...
The former uranium mine Königstein (Saxony, Germany) is currently in the process of remediation by means of controlled underground flooding. Nevertheless, the flooding water has to be cleaned up by a conventional wastewater treatment plant. In this study, the uranium(VI) removal and tolerance mechanisms of the gram-negative betaproteobacterium Acidovorax facilis were investigated by a multidisciplinary approach combining wet chemistry, flow cytometry, and microscopy. The kinetics of uranium removal and the corresponding mechanisms were investigated. The results showed a biphasic process of uranium removal characterized by a first phase where 95% of uranium was removed within the first 8h followed by a second phase that reached equilibrium after 24h. The bacterial cells displayed a total uranium removal capacity of 130mgU/g dry biomass. The removal of uranium was also temperature-dependent, indicating that metabolic activity heavily influenced bacterial interactions with uranium. TEM analyses showed biosorption on the cell surface and intracellular accumulation of uranium. Uranium tolerance tests showed that A. facilis was able to withstand concentrations up to 0.1mM. This work demonstrates that A. facilis is a suitable candidate for in situ bioremediation of flooding water in Königstein as well as for other contaminated waste waters.
Topics: Adsorption; Biodegradation, Environmental; Biomass; Comamonadaceae; Flow Cytometry; Germany; Microbial Sensitivity Tests; Microbial Viability; Microscopy, Electron, Transmission; Microscopy, Fluorescence; Mining; Uranium Compounds; Wastewater; Water Pollutants, Radioactive
PubMed: 27262280
DOI: 10.1016/j.jhazmat.2016.05.062 -
Biotechnology and Bioengineering Jul 2007Hydroxycarboxylic acid monomers can be used to prepare industrially important polymers. Enzymatic production of such hydroxycarboxylic acids is often preferred to...
Hydroxycarboxylic acid monomers can be used to prepare industrially important polymers. Enzymatic production of such hydroxycarboxylic acids is often preferred to chemical production since the reactions are run at ambient temperature, do not require strongly acidic or basic reaction conditions, and produce the desired product with high selectivity at high conversion. However, native enzymes often do not perform desired reactions with the efficiency required for commercial applications. Protein engineering was used to significantly increase the specific activity of nitrilase from Acidovorax facilis 72W for the conversion of 3-hydroxyvaleronitrile to 3-hydroxyvaleric acid. Overexpression of engineered nitrilase enzymes in Escherichia coli, combined with immobilization of whole cells in alginate beads that can be recycled many times has facilitated the development of a commercially viable bioprocess for production of 3-hydroxyvaleric acid.
Topics: Alginates; Aminohydrolases; Bioreactors; Cells, Immobilized; Comamonadaceae; Escherichia coli; Fermentation; Industrial Microbiology; Microspheres; Mutagenesis, Site-Directed; Protein Engineering; Transformation, Genetic
PubMed: 17154311
DOI: 10.1002/bit.21289 -
Applied Microbiology and Biotechnology Apr 2003A regioselective aliphatic nitrilase from Acidovorax facilis 72W was purified and characterized, and the corresponding gene was cloned and sequenced. This nitrilase gene...
A regioselective aliphatic nitrilase from Acidovorax facilis 72W was purified and characterized, and the corresponding gene was cloned and sequenced. This nitrilase gene was over-expressed in Escherichia coli, generating a microorganism that efficiently and regioselectively catalyzes the conversion of aliphatic dinitriles to cyanocarboxylic acids. The high yields obtained, mild reaction conditions used, and robustness observed make this biocatalyst suitable for industrial applications.
Topics: Amino Acid Sequence; Aminohydrolases; Base Sequence; Betaproteobacteria; Cloning, Molecular; Escherichia coli; Molecular Sequence Data; Sequence Analysis, DNA; Stereoisomerism; Substrate Specificity
PubMed: 12655453
DOI: 10.1007/s00253-002-1192-4 -
The Science of the Total Environment Aug 2023Anthropogenic activities have increased the dispersal of emerging contaminants (ECs), particularly of parabens, causing an escalation of their presence in wastewater...
Anthropogenic activities have increased the dispersal of emerging contaminants (ECs), particularly of parabens, causing an escalation of their presence in wastewater (WW). Current WW technologies do not present satisfactory efficiency or sustainability in removing these contaminants. However, bioremediation with microalgae-based systems is proving to be a relevant technology for WW polishing, and the use of microalgae-bacteria consortia can improve the efficiency of WW treatment. This work aimed to study dual cultures of selected bacteria (Raoultella ornithinolytica, Acidovorax facilis, Acinetobacter calcoaceticus, Leucobacter sp. or Rhodococcus fascians) and the microalga Chlorella vulgaris in microbial growth and WW bioremediation - removal of methylparaben (MetP) and nutrients. The association with the bacteria was antagonistic for C. vulgaris biomass productivity as a result of the decreased growth kinetics in comparison to the axenic microalga. The presence of MetP did not disturb the growth of C. vulgaris under axenic or co-cultured conditions, except when associated with R. fascians, where growth enhancement was observed. The removal of MetP by the microalga was modest (circa 30 %, with a removal rate of 0.0343 mg/L.d), but increased remarkably when the consortia were used (> 50 %, with an average removal rate > 0.0779 mg/L.d), through biodegradation and photodegradation. For nutrient removal, the consortia were found to be less effective than the axenic microalga, except for nitrogen (N) removal by C. vulgaris w/ R. fascians. The overall results propose that C. vulgaris co-cultivation with bacteria can increase MetP removal, while negatively affecting the microalga growth and the consequent reduction of sludge production, highlighting the potential of microalgae-bacteria consortia for the effective polishing of WW contaminated with parabens.
Topics: Chlorella vulgaris; Wastewater; Coculture Techniques; Parabens; Bacteria; Microalgae
PubMed: 37121314
DOI: 10.1016/j.scitotenv.2023.163746 -
Otology & Neurotology : Official... Sep 2013To describe the microbial flora associated with cochlear implants (CIs) removed for infectious and noninfectious indications.
OBJECTIVE
To describe the microbial flora associated with cochlear implants (CIs) removed for infectious and noninfectious indications.
STUDY DESIGN
Prospective, controlled.
SETTING
Academic, tertiary medical center.
PATIENTS
All patients undergoing CI removal.
INTERVENTION
CIs were removed with aseptic technique and processed for microbial identification.
MAIN OUTCOME MEASURE
CI microbes were identified with routine culture and speciation and 16s deoxyribonucleic acid 454-pyrosequencing.
RESULTS
All CIs had evidence of microbes. Propionibacterium acnes and Acidovorax facilis were more common on noninfected CIs (p = 0.005, 0.031). Staphylococcus aureus was more common on infected CIs (p = 0.003). The microbial profiles associated with CI infection were different from, but overlapped with those of noninfected CIs. Microbial culture with selective media identified pathogens not identified on pyrosequencing.
CONCLUSION
Bacteria are present on all CIs, both with and without evidence of clinical infection, but species differ with clinical status. Empiric therapy for CI infections should include coverage for S. aureus. Gene pyrosequencing and selective culture techniques may yield complementary results that may impact the management of CI infections.
Topics: Adolescent; Adult; Aged; Aged, 80 and over; Bacterial Infections; Biofilms; Child; Child, Preschool; Cochlear Implants; DNA, Bacterial; Data Interpretation, Statistical; Device Removal; Ear, Inner; Female; Genes, Bacterial; Humans; Magnets; Male; Microscopy, Electron, Scanning; Middle Aged; Polymerase Chain Reaction; Propionibacterium acnes; Prosthesis-Related Infections; Risk Factors; Sequence Analysis, DNA; Staphylococcus aureus; Young Adult
PubMed: 23921938
DOI: 10.1097/MAO.0b013e3182941101 -
International Journal of Biological... Sep 2018Iminodiacetic acid (IDA) is widely used as an intermediate in the manufacturing of chelating agents, glyphosate herbicides and surfactants. To improve activity and...
Iminodiacetic acid (IDA) is widely used as an intermediate in the manufacturing of chelating agents, glyphosate herbicides and surfactants. To improve activity and tolerance to the substrate for IDA production, Acidovorax facilis nitrilase was selected for further modification by the gene site saturation mutagenesis method. After screened by a two-step screening method, the best mutant (Mut-F168V/T201N/S192F/M191T/F192S) was selected. Compared to the wild-type nitrilase, Mut-F168V/T201N/S192F/M191T/F192S showed 136% improvement in specific activity. Co stimulated nitrilase activity, whereas Cu, Zn and Tween 80 showed a strong inhibitory effect. The V and k of Mut-F168V/T201N/S192F/M191T/F192S were enhanced 1.23 and 1.23-fold, while the K was decreased 1.53-fold. The yield of Mut-F168V/T201N/S192F/M191T/F192S with 453.2 mM of IDA reached 71.9% in 5 h when 630 mM iminodiacetonitrile was used as substrate. This study indicated that mutant nitrilase obtained in this study is promising in applications for the upscale production of IDAN.
Topics: Amino Acid Substitution; Aminohydrolases; Bacterial Proteins; Comamonadaceae; Mutagenesis, Site-Directed; Recombinant Proteins
PubMed: 29753012
DOI: 10.1016/j.ijbiomac.2018.05.045