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1.
2.
Non-toluene-associated respiration (NTAR) within a Pseudomonas putida 54G biofilm growing on toluene as sole external carbon source was evaluated using oxygen microelectrodes in a flat-plate
vapor-phase biological reactor. Two fluorescent probes, 2,4-diamidino-2-phenylindole and 5-cyano-2,3-ditolyltetrazolium chloride,
were used to evaluate the number of total and respiring cells respectively within the biofilm. Biofilm samples were also analyzed
for viable and toluene-culturable cells by spread-plating on non-selective and selective media respectively. Fractions of
viable stressed, respiring and non-respiring cells within the biofilm were evaluated. The NTAR rate was positively correlated
with the fraction of viable stressed and non-respiring cells within the biofilm, which suggested the capability of some cells
to grow at the expense of leakage and lysis products coming from injured and dead cells. This effect was more pronounced at
higher toluene concentration. Results suggest that NTAR should be incorporated into mathematical models of biofilm reactors
degrading volatile organic carbon compounds.
Received: 4 January 1997 / Received revision: 20 March 1997 / Accepted: 27 March 1997 相似文献
3.
Physiological stress in batch cultures of Pseudomonas putida 54G during toluene degradation 总被引:1,自引:0,他引:1
R G Mirpuri W L Jones G A McFeters H F Ridgway 《Journal of industrial microbiology & biotechnology》1997,18(6):406-413
Physiological stress associated with toluene exposure in batch cultures of Pseudomonas putida 54G was investigated. P. putida 54G cells were grown using a continuous vapor phase feed stream containing 150 ppmv or 750 ppmv toluene as the sole carbon
and energy source. Cells were enumerated on non-selective (R2A agar plates) and a selective minimal medium incubated in the
presence of vapor phase toluene (HCMM2). Differential recovery on the two media was used to evaluate bacterial stress, culturability
and loss of toluene-degrading capability. A majority of the bacteria were reversibly stressed and could resume active colony
formation on selective medium after passage on non-selective medium. A small fraction of the bacterial cells suffered an
irreversible loss of toluene degradation capability and were designated as Tol− variants. Numbers of stressed organisms increased with duration of toluene exposure and toluene concentration and coincided
with accumulation of metabolic intermediates from incomplete toluene degradation. Respiring cell numbers in the batch cultures
decreased as injury increased, indicating a possible relationship between respiring and injured cells. Rate expressions for
injury, for formation of Tol− variants and for growth of Tol− variants were determined by calibrating a theoretical model to the results obtained. These rate expressions can be used
to calibrate bioreactor models, and provide a basis for better design and control of bioremediation systems.
Received 01 July 1996/ Accepted in revised form 25 March 1997 相似文献
4.
S. Isken P. M. A. C. Santos J. A. M. de Bont 《Applied microbiology and biotechnology》1997,48(5):642-647
The effect of the adaptation to toluene on the␣resistance to different antibiotics was investigated in the␣solvent-resistant
strain Pseudomonas putida S12. We␣followed the process of the solvent adaptation of P.␣putida S12 by cultivating the strain in the presence␣of␣increasing concentrations of toluene and studied␣the correlation of this
gradual adaptation to the resistance towards antibiotics. It was shown that the tolerance to various chemically and structurally
unrelated antibiotics, with different targets in the cell, increased during this gradual adaptation. The survival of P. putida S12 in the presence of antibiotics like tetracycline, nigericin, polymyxin B, piperacillin or chloramphenicol increased 30-
to and 1000-fold after adaptation to 600 mg/l toluene. However, cells grown in the absence of any solvents lost their adaptation
to toluene even when grown in the presence of antibiotics. Results are discussed in terms of the physico-chemical properties
of membranes as affected by the observed cis/trans isomerization of unsaturated fatty acids, as well as in terms of the active efflux of molecules from the cytoplasmic membrane.
Received: 9 May 1997 / Received revision: 4 July 1997 / Accepted: 4 July 1997 相似文献
5.
Raúl Muñoz María Hernández Ana Segura Joao Gouveia Antonia Rojas Juan Luis Ramos Santiago Villaverde 《Applied microbiology and biotechnology》2009,83(1):189-198
The long-term performance and stability of Pseudomonas putida mt-2 cultures, a toluene-sensitive strain harboring the genes responsible for toluene biodegradation in the archetypal plasmid
pWW0, was investigated in a chemostat bioreactor functioning under real case operating conditions. The process was operated
at a dilution rate of 0.1 h−1 under toluene loading rates of 259 ± 23 and 801 ± 78 g m−3 h−1 (inlet toluene concentrations of 3.5 and 10.9 g m−3, respectively). Despite the deleterious effects of toluene and its degradation intermediates, the phenotype of this sensitive
P. putida culture rapidly recovered from a 95% Tol− population at day 4 to approx. 100% Tol+ cells from day 13 onward, sustaining elimination capacities of 232 ± 10 g m−3 h−1 at 3.5 g Tol m−3 and 377 ± 13 g m−3 h−1 at 10.9 g Tol m−3, which were comparable to those achieved by highly tolerant strains such as P. putida DOT T1E and P. putida F1 under identical experimental conditions. Only one type of Tol− variant, harboring a TOL-like plasmid with a 38.5 kb deletion (containing the upper and meta operons for toluene biodegradation), was identified. 相似文献
6.
A two-phase aqueous/organic partitioning bioreactor scheme was used to degrade mixtures of toluene and benzene, and toluene
and p-xylene, using simultaneous and sequential feeding strategies. The aqueous phase of the partitioning bioreactor contained
Pseudomonas sp. ATCC 55595, an organism able to degrade benzene, toluene and p-xylene simultaneously. An industrial grade of oleyl alcohol served as the organic phase. In each experiment, the organic
phase of the bioreactor was loaded with 10.15 g toluene, and either 2.0 g benzene or 2.1 g p-xylene. The resulting aqueous phase concentrations were 50 mg/l, 25 mg/l and 8 mg/l toluene, benzene and p-xylene respectively. The simultaneous fermentation of benzene and toluene consumed these compounds at volumetric rates of
0.024 g l−1 h−1 and 0.067 g l−1 h−1, respectively. The simultaneous fermentation of toluene and p-xylene consumed these xenobiotics at volumetric rates of 0.066 g l−1 h−1 and 0.018 g l−1 h−1, respectively. A sequential feeding strategy was employed in which toluene was added initially, but the benzene or p-xylene aliquot was added only after the cells had consumed half of the initial toluene concentration. This strategy was shown
to improve overall degradation rates, and to reduce the stress on the microorganisms. In the sequential fermentation of benzene
and toluene, the volumetric degradation rates were 0.056 g l−1 h−1 and 0.079 g l−1 h−1, respectively. In the toluene/p-xylene sequential fermentation, the initial toluene load was consumed before the p-xylene aliquot was consumed. After 12 h in which no p-xylene degradation was observed, a 4.0-g toluene aliquot was added, and p-xylene degradation resumed. Excluding that 12-h period, the microbes consumed toluene and p-xylene at volumetric rates of 0.074 g l−1 h−1 and 0.025 g l−1 h−1, respectively. Oxygen limitation occurred in all fermentations during the rapid growth phase.
Received: 16 November 1998 / Received revision: 29 March 1999 / Accepted: 9 April 1999 相似文献
7.
The aim of the study was to investigate whether toxic fine chemical production can be improved using the solvent-tolerant
Pseudomonas putida S12 in a two-liquid-phase system consisting of aqueous media and a water-immiscible octanol phase with production of 3-methylcatechol
from toluene as the model conversion. For this purpose the genes involved in this conversion, todC1C2BAD from P. putida F1, were introduced into P. putida S12 with high stable expression. Production of 3-methylcatechol was monitored in batch incubations with different media using
a single medium and a two-liquid medium–octanol system. The maximum concentration of 3-methylcatechol increased two-fold using
the two-liquid medium–octanol system, irrespective of the selected medium.
Received: 29 December 1999 / Received revision: 29 February 2000 / Accepted: 6 March 2000 相似文献
8.
A. E. Filonov W. A. Duetz A. V. Karpov R. R. Gaiazov I. A. Kosheleva A. M. Breure I. F. Filonova J. G. van Andel A. M. Boronin 《Applied microbiology and biotechnology》1997,48(4):493-498
Plasmid-carrying Pseudomonas putida strains degrade naphthalene through different biochemical pathways. The influence of various combinations of host bacteria
and plasmids on growth characteristics and competitiveness of P. putida strains was studied in chemostat culture at a low dilution rate (D=0.05 h−1) with naphthalene as the sole source of carbon and energy. Under naphthalene limitation, the plasmid-bearing strains degrading
naphthalene that use catechol 1,2-dioxygenase for catechol oxidation (ortho pathway), were the most competitive. The strains bearing plasmids that control naphthalene catabolism via catechol 2,3-dioxygenase
(meta pathway), were less competitive. Under these conditions the strain carrying plasmid pBS4, which encodes for naphthalene catabolism
via gentisic acid, was the least competitive.
Received: 24 February 1997 / Received revision: 22 May 1997 / Accepted: 25 May 1997 相似文献
9.
Bacterial physiological responses to toluene exposure were investigated in five reference pseudomonad strains that express
different toluene degradation pathways: Pseudomonas putida mt-2, Pseudomonas putida F1, Burkholderia cepacia G4, Burkholderia pickettii PKO1, and Pseudomonas mendocina KR1. The intact phospholipids of these archetypes, grown with and without toluene, were characterized using liquid chromatography/electrospray
ionization/mass spectrometry. All strains showed significant changes in phospholipid content and composition as an adaptive
response to toluene exposure, as well as considerable diversity in response mechanisms. For example, the phospholipid content
of toluene-grown PKO1, F1, and KR1 were 10.9–34.7% of that found in succinate-grown strains, while the phospholipid content
of mt-2 and G4 increased by 56% and 94%, respectively, when grown on toluene. In addition, PKO1, F1, and mt-2 responded to
the presence of toluene by synthesizing more phosphatidylglycerol, whereas G4 and KR1 synthesized phospholipids with polyunsaturated
fatty acids (C18:2) on one or both of the sn-2 positions. These changes in phospholipid composition and concentration probably reflect the sensitivity and degree of tolerance
of these strains to toluene, and suggest that different mechanisms are utilized by dissimilar bacteria to maintain optimal
lipid ordering in the presence of such environmental pollutants.
Received: 13 October 1999 / Received revision: 16 February 2000 / Accepted: 25 February 2000 相似文献
10.
A two-phase organic/aqueous reactor configuration was developed for use in the biodegradation of benzene, toluene and p-xylene, and tested with toluene. An immiscible organic phase was systematically selected on the basis of predicted and experimentally
determined properties, such as high boiling points, low solubilities in the aqueous phase, good phase stability, biocompatibility,
and good predicted partition coefficients for benzene, toluene and p-xylene. An industrial grade of oleyl alcohol was ultimately selected for use in the two-phase partitioning bioreactor. In
order to examine the behavior of the system, a single-component fermentation of toluene was conducted with Pseudomonas sp. ATCC 55595. A 0.5-l sample of Adol 85 NF was loaded with 10.4 g toluene, which partitioned into the cell containing 1 l
aqueous medium at a concentration of approximately 50 mg/l. In consuming the toluene to completion, the organisms were able
to achieve a volumetric degradation rate of 0.115 g l−1 h−1. This system is self-regulating with respect to toluene delivery to the aqueous phase, and requires only feedback control
of temperature and pH.
Received: 16 November 1998 / Received revision: 28 March 1999 / Accepted: 9 April 1999 相似文献
11.
The influence of toluene concentration on the specific growth rate, cellular yield, specific CO2, and metabolite production by Pseudomonas putida F1 (PpF1) was investigated. Both cellular yield and specific CO2 production remained constant at 1.0 ± 0.1 g biomass dry weight (DW) g−1 toluene and 1.91 ± 0.31 g CO2 g−1 biomass, respectively, under the tested range of concentrations (2–250 mg toluene l−1). The specific growth rate increased up to 70 mg toluene l−1. Further increases in toluene concentration inhibited PpF1 growth, although inhibitory concentrations were far from the application range of biological treatment processes. The specific
ATP content increased with toluene concentration up to toluene concentrations of 170 mg l−1. 3-Methyl catechol (3-MC) was never detected in the cultivation medium despite being an intermediary in the TOD pathway.
This suggested that the transformation from toluene to 3-MC was the limiting step in the biodegradation process. On the other
hand, benzyl alcohol (BA) was produced from toluene in a side chain reaction. This is, to the best of our knowledge, the first
reported case of methyl monoxygenation of toluene by PpF1 not harboring the pWW0 TOL plasmid. In addition, the influence of 3-MC, BA, and o-cresol on toluene degradation was investigated respirometrically, showing that toluene-associated respiration was not significantly
inhibited in the presence of 10–100 mg l−1 of the above-mentioned compounds. 相似文献
12.
D. Bianchi A. Bernardi A. Bosetti R. Bortolo D. Cidaria E. Crespi I. Gagliardi 《Applied microbiology and biotechnology》1997,48(3):363-366
The mutant strain Pseudomonas fluorescens TTC1 (NCIMB 40605), derived from the naphthalene-degrading Pseudomonas fluorescens N3 (NCIMB 40530), was used for the oxidation of 1- and 2-naphthols to give different isomers of dihydroxynaphthalene. The
oxidation reactions proceed through the formation of dihydrodiol intermediates, which are too unstable to be isolated, since
they spontaneously eliminate water to give the fully aromatic dihydroxynaphthalenes. The high regioselectivity of the dehydration
reaction was confirmed by the study of the acid-catalysed aromatization of a series of stable monosubstituted naphthalene
cis-1,2-dihydrodiols.
Received: 24 March 1997 / Received revision: 6 June 1997 / Accepted: 7 June 1997 相似文献
13.
Michael G. Williams Patricia E. Olson Kestutis J. Tautvydas Rex M. Bitner Roger A. Mader Lawrence P. Wackett 《Applied microbiology and biotechnology》1990,34(3):316-321
Summary A biotransformation procedure has been developed to prepare intermediates for the synthesis of 3-hydroxyphenylacetylene (3-HPA), a high-value specialty chemical used in the manufacture of acetylene-terminated resins. Pseudomonas putida F39/D containing toluene dioxygenase was used to oxidize a series of substituted benzenes to their respective cis-2,3-dihydroxydihydrobenzene(cis-dihydrodiol) derivatives which in turn could be converted to 3-HPA via a meta-phenol intermediate obtained by acid-catalyzed dehydration. The cis-dihydrodiols derived from the oxidation of phenylacetylene, styrene, acetophenone, and bromobenzene dehydrated to yield predominantly ortho-phenols. Three different phenyl-1,3-dioxolanes were oxidized by P. putida F39/D to three previously undescribed cis-dihydrodiols. Unlike mono-substituted cis-dihydrodiols, phenyl-1,3-dioxolane cis-dihydrodiols were dehydrated to form meta-phenols exclusively. The dehydration products, 3-hydroxyacetophenone and 3-hydroxybenzaldehyde, are suitable precursors for the chemical synthesis of 3-HPA.
Offprint requests to: L. P. Wackett 相似文献
14.
The response of Pseudomonas putida F1 to process fluctuations and operational failures during toluene biodegradation was evaluated in a chemostat suspended
growth bioreactor. The ability of P. putida F1 to rapidly increase its specific toluene degradation capacity resulted in no significant variation in process removal
efficiency when toluene load was increased from 188 to 341 g m−3 h−1. Likewise, bacterial activity rapidly reached steady state performance (in less than 1.5 h after the restoration of steady
state operational conditions) following an 8 h process shutdown, or after episodes of toluene or mineral nutrients deprivation.
Process performance was however highly sensitive to pH, as pH levels below 4.5 dramatically inhibited bacterial activity,
decreasing severely process robustness and inducing a cycle of periodic process collapses and recoveries. This pH mediated
deterioration of bacterial activity was confirmed by further respirometric tests, which revealed a 50–60% reduction in the
O2 consumption rate during the degradation of both toluene and 3-methyl catechol when pH decreased from 5.05 to 4.55. Finally,
process robustness was quantified according to methods previously described in literature. 相似文献
15.
M. Megharaj S. Hartmans K.-H. Engesser J. H. Thiele 《Applied microbiology and biotechnology》1998,49(3):337-342
1,1-Dichloro-2,2-bis(p-chlorophenyl)ethylene (DDE) is the peri-chlorinated derivative of 1,1-diphenylethylene (DPE). Biodegradation of DDE and DPE
by bacteria has so far not been shown. Pure cultures of aerobic bacteria involved in biodegradation of styrene and polychlorinated
biphenyls (PCB) were therefore screened for their ability to degrade or cometabolize DPE and DDE. Styrene-metabolizing bacteria
(Rhodococcus strains S5 and VLB150) grew with DPE as their sole source of carbon and energy. Polychlorinated-biphenyl-degrading bacteria
(Pseudomonas fluorescens and Rhodococcus globerulus) were unable to degrade DPE even in the presence of an easily utilizable cosubstrate, biphenyl. This is the first report
of the utilization of DPE as sole carbon and energy source by bacteria. All the tested bacteria failed to degrade DDE when
it was provided as the sole carbon source or in the presence of the respective degradable cosubstrates. DPE transformation
could also be detected in cell-free extracts of Rhodococcus S5 and VLB150, but DDE was not transformed, indicating that cell wall and membrane diffusion barriers were not limiting biodegradation.
The results of the present study show that, at least for some bacteria, the chlorination of DDE is the main reason for its
resistance to biodegradation by styrene and DPE-degrading bacteria.
Received: 28 May 1997 / Received revision: 28 October 1997 / Accepted: 31 October 1997 相似文献
16.
P. Arvidsson K. Nilsson H. Håkanson B. Mattiasson 《Applied microbiology and biotechnology》1998,49(6):677-681
A chemiluminescence detector was used to measure the production of nitric oxide, NO, from the denitrifying bacteria Pseudomonas stutzeri. NO is an intermediate when P. stutzeri converts nitrate into nitrogen gas. The reaction between NO and ozone is selective and sensitive in generating chemiluminescence.
Calibrations were made down to 1 nM, with a signal-to-noise ratio of 3. Bacteria were immobilised in alginate beads. Denitrification
experiments were made in an anaerobic non-growth medium by adding nitrate to a certain concentration in the reactor. The bacteria
were exposed to nitrate in the concentration range 1 pM–5 mM. The lowest concentration to give a measurable NO response was
100 nM.
Received: 16 October 1997 / Received revision: 20 January 1998 / Accepted: 24 January 1998 相似文献
17.
Pierre Cornelis 《Applied microbiology and biotechnology》2010,86(6):1637-1645
Pseudomonads are ubiquitous Gram-negative γ proteobacteria known for their extreme versatility and adaptability. Some are
plant pathogens (Pseudomonas syringae) which have to survive on the surface of leaves while others can colonize the rhizosphere or survive in soil (Pseudomonas fluorescens, Pseudomonas putida), and one species, Pseudomonas entomophila, is an insect pathogen. The most investigated species, Pseudomonas aeruginosa, is known to be an opportunistic pathogen able to infect plants, nematodes, insects, and mammals, including humans. Like
for other bacteria, iron is a key nutrient for pseudomonads. The fluorescent pseudomonads produce siderophores, the best known
being the fluorescent high-affinity peptidic pyoverdines. Often diverse secondary siderophores of lower affinity are produced
as well (pyochelin, pseudomonin, corrugatins and ornicorrugatins, yersiniabactin, and thioquinolobactin). Reflecting their
large capacity of adaptation to changing environment and niche colonization, pseudomonads are able to obtain their iron from
heme or from siderophores produced by other microorganisms (xenosiderophores) via the expression of outer membrane TonB-dependent
receptors. As expected, iron uptake is exquisitely and hierarchically regulated in these bacteria. In this short review, the
diversity of siderophores produced, receptors, and finally the way iron homeostasis is regulated in P. aeruginosa, P. syringae, P. putida, and P. fluorescens, will be presented and, when possible, put in relation with the lifestyle and the ecological niche. 相似文献
18.
P. Barghini F. Montebove M. Ruzzi A. Schiesser 《Applied microbiology and biotechnology》1998,49(3):309-314
Pseudomonas fluorescens BF13 is especially capable of promoting the formation of vanillic acid during ferulic acid degradation. We studied the possibility
of enhancing the formation of this intermediary metabolite by using suspensions of cells at high density. The bioconversion
of ferulic into vanillic acid was affected by several parameters, such as the concentration of the biomass, the amount of
ferulic acid that was treated, the carbon source on which the biomass was grown. The optimal yield of vanillic acid was obtained
with 6 mg/ml cells pre-grown on p-coumaric acid and 2 mg/ml ferulic acid. Under these conditions the bioconversion rate was 95% in 5 h. Therefore BF13 strain
represents a valid biocatalyst for the preparative synthesis of vanillic acid.
Received: 1 July 1997 / Received revision: 28 October 1997 / Accepted: 16 November 1997 相似文献
19.
The Pseudomonas putida strain SP1 was isolated from marine environment and was found to be resistant to 280 μM HgCl2. SP1 was also highly resistant to other metals, including CdCl2, CoCl2, CrCl3, CuCl2, PbCl2, and ZnSO4, and the antibiotics ampicillin (Ap), kanamycin (Kn), chloramphenicol (Cm), and tetracycline (Tc). mer operon, possessed by most mercury-resistant bacteria, and other diverse types of resistant determinants were all located
on the bacterial chromosome. Cold vapor atomic absorption spectrometry and a volatilization test indicated that the isolated
P. putida SP1 was able to volatilize almost 100% of the total mercury it was exposed to and could potentially be used for bioremediation
in marine environments. The optimal pH for the growth of P. putida SP1 in the presence of HgCl2 and the removal of HgCl2 by P. putida SP1 was between 8.0 and 9.0, whereas the optimal pH for the expression of merA, the mercuric reductase enzyme in mer operon that reduces reactive Hg2+ to volatile and relatively inert monoatomic Hg0 vapor, was around 5.0. LD50 of P. putida SP1 to flounder and turbot was 1.5 × 109 CFU. Biofilm developed by P. putida SP1 was 1- to 3-fold lower than biofilm developed by an aquatic pathogen Pseudomonas fluorescens TSS. The results of this study indicate that P. putida SP1 is a low virulence strain that can potentially be applied in the bioremediation of HgCl2 contamination over a broad range of pH. 相似文献
20.
The stability of Pseudomonas putida F1, a strain harbouring the genes responsible for toluene degradation in the chromosome was evaluated in a bioscrubber under
high toluene loadings and nitrogen limiting conditions at two dilution rates (0.11 and 0.27 h−1). Each experiment was run for 30 days, period long enough for microbial instability to occur considering previously reported
studies carried out with bacterial strains encoding the catabolic genes in the TOL plasmid. At all tested conditions, P. putida F1 exhibited stable performance as shown by the constant values of the specific toluene degradation yield, CO2 produced versus toluene degraded yield, and biomass concentration within each steady state. Benzyl alcohol, a curing agent
causing TOL plasmid deletion in Pseudomonas strains, was present in the cultivation medium as a result of the monooxygenation of toluene by the diooxygenase system of
P. putida F1. However, no mutant population growing at the expense of the extracellular excreted carbon or lysis products was established
in the chemostat as confirmed by the constant dissolved total organic carbon (TOC) concentration and fraction of toluene degrading
cells (approx. 100%). In addition, batch experiments conducted with both lysis substrate and toluene simultaneously confirmed
that P. putida F1 preferentially consumed toluene rather than extracellular excreted carbon. 相似文献