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1.
D. Bianchi A. Bosetti D. Cidaria A. Bernardi I. Gagliardi P. D'Amico 《Applied microbiology and biotechnology》1997,47(5):596-599
The mutant strain Pseudomonas fluorescens TTC1 (NCIMB 40605), derived from the naphthalene-degrading P. fluorescens N3 (NCIMB 40530), was used for the biotransformation of polycyclic aromatic heterocycles such as dibenzothiophene, dibenzofuran,
thianthrene xanthen and acridine. The cis-1,2- and cis-3,4-dihydrodiols produced were isolated and identified from the culture filtrate. Both the regioselectivity and the productivity
of the transformations, catalysed by the naphthalene dioxygenase enzymatic system, were dramatically influenced by the presence
of the heteroatom. The high substrate tolerance displayed by the enzyme might be useful in the biotransformation of other
related compounds.
Received: 10 October 1996 / Received revision: 17 December 1996 / Accepted: 20 December 1996 相似文献
2.
Lipase from Pseudomonas aeruginosa LP602, a bacterial strain isolated from a domestic wastewater sample, was preliminarily characterized. The enzyme exhibited
maximum lipolytic activity at pH 8.0 where it was also stably maintained. At 55°C, the lipase had the highest activity but
not stability. The enzyme was insensitive to EDTA and to many ions tested except Zn2+. It was sensitive to SDS but not to Tween-20, Tween-80 or Triton X-100. The enzyme was active towards a number of commercial
food grade fats and oils. A suitable medium formula for lipase production was MMP containing 6.25% whey as a carbon source,
1% soybean oil as inducer and 0.5% yeast extract supplement. The culture was fed with glucose to a final concentration of
0.1% at the 15th hour of incubation. Lipase production under this condition was 3.5 U ml−1. Both P. aeruginosa LP602 cells and the lipase were shown to be usable for lipid-rich wastewater treatment.
Received 21 April 1998/ Accepted in revised form 6 August 1998 相似文献
3.
The biodegradation of an oily sludge is facilitated by a microbial tensio-active agent isolated from Pseudomonas aeruginosa USB-CS1. The optimal oil-in-water dispersion conditions are as follows: pH 6.5, temperature 30 °C, agitation 150 rev/min.
The total hydrocarbon content shows that the biodegradation of the oily substrate mediated by the biosurfactant or by the
biosurfactant–P. aeruginosa USB-CS1 complex is significantly higher after 30 days of incubation than that in other experimental conditions, by a mean
of 70%. Substrate fractionation by column chromatography reveals that, if biosurfactant is present, saturated and aromatic
compounds are more susceptible to microbial degradation than they are in other biodegradation systems by an average of 55%
and 40% respectively. These results suggest that the stimulatory effects of the biosurfactant on the biodegradation of the
oily substrate are limited over time by the loss of surface activity of the biosurfactant after 30 days of incubation.
Received : 7 August 1996 / Received revision : 6 December 1996 / Accepted : 4 January 1997 相似文献
4.
J. Rabenhorst 《Applied microbiology and biotechnology》1996,46(5-6):470-474
In our screening program for microorganisms that are able to metabolize eugenol, the main component of the essential oil
of the clove tree Syzigium aromaticum (sy. Eugenia cariophyllus), we found a new Pseudomonas sp. that produces several substituted methoxyphenols when eugenol is fed to the culture. A taxonomic characterization of this
new organism has been performed. Examples of the biotransformation products, produced in high amounts, were vanillic acid
with 3.25 g/l within 99 h, ferulic acid with 5.8 g/l within 75 h and coniferyl alcohol with 3.22 g/l within 47.5 h. By changing
the culture conditions the ratio of the different metabolites could be varied. Based on these results a scheme for the degradation
of eugenol by this strain has been established.
Received: 1 April 1996 / Received revision: 24 June 1996 / Accepted: 1 July 1996 相似文献
5.
Cometabolic biodegradation of methyl t-butyl ether by Pseudomonas aeruginosa grown on pentane 总被引:1,自引:0,他引:1
A bacterial strain identified as Pseudomonas aeruginosa was isolated from a soil consortium able to mineralize pentane. P. aeruginosa could metabolize methyl t-butyl ether (MTBE) in the presence of pentane as the sole carbon and energy source. The carbon balance for this strain, grown
on pentane, was established in order to determine the fate of pentane and the growth yield (0.9 g biomass/g pentane). An inhibition
model for P. aeruginosa grown on pentane was proposed. Pentane had an inhibitory effect on growth of P. aeruginosa, even at a concentration as low as 85 μg/l. This resulted in the calculation of the following kinetic parameters (μmax = 0.19 h−1, K
s = 2.9 μg/l, K
i = 3.5 mg/l). Finally a simple model of MTBE degradation was derived in order to predict the quantity of MTBE able to be degraded
in batch culture in the presence of pentane. This model depends only on two parameters: the concentrations of pentane and
MTBE.
Received: 16 July 1998 / Received revision: 11 November 1998 / Accepted 31 November 1998 相似文献
6.
Chen TY Shang HF Chen TL Lin CP Hui CF Hwang J 《Applied microbiology and biotechnology》1999,52(4):524-533
We have constructed a chimeric protein composed of the receptor binding and membrane translocation domains of Pseudomonas exotoxin A (PE) with the outer membrane proteins I and F, together designated as PEIF. The potential of PEIF as a vaccine
against Pseudomonas infection was evaluated in BALB/c mice and New Zealand white rabbits. We examined titers of anti-PE and anti-OprF antibodies,
and the ability both to neutralize PE cytotoxicity and to increase opsonophagocytic uptake of Pseudomonas aeruginosa strain PAO1, serogroups 2 and 6. The results showed that PEIF can induce antibodies not only to neutralize the PE cytotoxicity
but also to promote the uptake of various strains of P. aeruginosa by murine peritoneal macrophages. In a burned mouse model, PEIF afforded significant protection against infection by the
homologous P. aeruginosa strain PAO1, heterologous serogroup 2, and the PE hyperproducing strain PA103. These observations thus indicate that PEIF
may be used as a novel vaccine against P. aeruginosa infection.
Received: 10 March 1999 / Received revision: 21 April 1999 / Accepted: 16 May 1999 相似文献
7.
L. Lesage-Meessen M. Haon M. Delattre J.-F. Thibault B. Colonna Ceccaldi M. Asther 《Applied microbiology and biotechnology》1997,47(4):393-397
The effects of adding cellobiose on the transformation of vanillic acid to vanillin by two strains of Pycnoporus cinnabarinus MUCL39532 and MUCL38467 were studied. When maltose was used as the carbon source in the culture medium, very high levels
of methoxyhydroquinone were formed from vanillic acid. When cellobiose was used as the carbon source and/or added to the culture
medium of P. cinnabarinus strains on day 3 just before vanillic acid was added, it channelled the vanillic acid metabolism via the reductive route
leading to vanillin. Adding 3.5 g l−1 cellobiose to 3-day-old maltose cultures of P. cinnabarinus MUCL39532 and 2.5 g l−1 cellobiose to 3-day-old cellobiose cultures of P. cinnabarinus MUCL38467, yielded 510 mg l−1 and 560 mg l−1 vanillin with a molar yield of 50.2 % and 51.7 % respectively. Cellobiose may either have acted as an easily metabolizable
carbon source, required for the reductive pathway to occur, or as an inducer of cellobiose:quinone oxidoreductase, which is
known to inhibit vanillic acid decarboxylation.
Received: 24 July 1996 / Received revision: 29 November 1996 / Accepted: 29 November 1996 相似文献
8.
The lipA gene, a structural gene encoding for protein of molecular mass 48 kDa, and lipB gene, encoding for a lipase-specific chaperone with molecular mass of 35 kDa, of Pseudomonas aeruginosa B2264 were co-expressed in heterologous host Escherichia coli BL21 (DE3) to obtain in vivo expression of functional lipase. The recombinant lipase was expressed with histidine tag at
its N terminus and was purified to homogeneity using nickel affinity chromatography. The amino acid sequence of LipA and LipB
of P. aeruginosa B2264 was 99–100% identical with the corresponding sequence of LipA and LipB of P. aeruginosa LST-03 and P. aeruginosa PA01, but it has less identity with Pseudomonas cepacia (Burkholderia cepacia) as it showed only 37.6% and 23.3% identity with the B. cepacia LipA and LipB sequence, respectively. The molecular mass of the recombinant lipase was found to be 48 kDa. The recombinant
lipase exhibited optimal activity at pH 8.0 and 37°C, though it was active between pH 5.0 and pH 9.0 and up to 45°C. K
m and V
max values for recombinant P. aeruginosa lipase were found to be 151.5 ± 29 μM and 217 ± 22.5 μmol min−1 mg−1 protein, respectively. 相似文献
9.
The esterification reaction between stearic acid and lactic acid using Rhizomucor miehei lipase and porcine pancreas lipase was optimized for maximum esterification using response surface methodology. The formation
of the ester was found to depend on three parameters namely enzyme/substrate ratio, lactic acid (stearic acid) concentration
and incubation period. The maximum esterification predicted by theoretical equations for both lipases matched well with the
observed experimental values. In the case of R. miehei lipase, stearoyl lactic acid ester formation was found to increase with incubation period and lactic acid (stearic acid)
concentrations with maximum esterification of 26.9% at an enzyme/substrate (E/S) ratio of 125 g mol−1. In the case of porcine pancreas lipase, esterification showed a steady increase with increase in incubation period and lactic
acid (stearic acid) concentration independent of the E/S ratios employed. In the case of PPL, a maximum esterification of
18.9% was observed at an E/S ratio of 25 g mol−1 at a lactic acid (stearic acid) concentration of 0.09 M after an incubation period of 72 h.
Received: 12 February 1999 / Received revision: 31 May 1999 / Accepted: 4 June 1999 相似文献
10.
A. Brunella M. Graf M. Kittelmann K. Laumen O. Ghisalba 《Applied microbiology and biotechnology》1997,47(5):515-520
Rhodococcus equi Ac6 was found to express an inducible (S )-specific N-acetyl-1-phenylethylamine amidohydrolase. Optimal bacterial growth and amidohydrolase expression were both observed around
pH 6.5. Purification of the enzyme to a single band in a Coomassie-blue-stained sodium dodecyl sulfate/polyacrylamide gel
(SDS-PAGE) was achieved by ammonium sulfate precipitation of R. equi Ac6 crude extract and column chromatographies on Fractogel TSK Butyl-650(S) and Superose 12HR. At pH 7.0 and 30 °C the amidohydrolase
had a half-life of around 350 days; at 44 °C it was only 10 min. Except for Ni2+ and, to some extent, Zn2+ and Co2+, the enzyme was neither strongly influenced by metal cations nor by chelating agents, but was inhibited by 95% at 0.1 mM
phenylmethylsulfonyl fluoride. The molecular mass of the native enzyme was estimated to be 94 kDa by gel filtration and 50 kDa
by SDS-PAGE, suggesting a dimeric structure. Specificity experiments revealed a spectrum of related N-acetylated compounds being hydrolyzed with variable enantiomeric selectivities.
Received: 20 September 1996 / Received revision: 23 December 1996 / Accepted: 30 December 1996 相似文献
11.
M. Graf A. Brunella M. Kittelmann K. Laumen O. Ghisalba 《Applied microbiology and biotechnology》1997,47(6):650-657
A new amidohydrolase deacetylating several N-acetyl-1-phenylethylamine derivatives (R)-specifically was found in Arthrobacter aurescens AcR5b. The strain was isolated from a wet haystack by enrichment culture with (R)-N-acetyl-1-phenylethylamine as the sole carbon source. (R) and (S )-N-acetyl-1-phenylethylamine do not serve as inducers for acylase formation. By improving the growth conditions the enzyme production
was increased 47-fold. The amidohydrolase was purified to homogeneity leading to a 5.2-fold increase of the specific activity
with a recovery of 67%. A molecular mass of 220 kDa was estimated by gel filtration. Sodium dodecyl sulfate/polyacrylamide
gel electrophorosis shows two subunits with molecular masses of 16 kDa and 89 kDa. The optimum pH and temperature were pH 8
and 50 °C, respectively. The enzyme was stable in the range of pH 7–9 and at temperatures up to 30 °C. The enzyme activity
was inhibited by Cu2+, Co2+, Ni2+, and Zn2+, and this inhibition was reversed by EDTA.M
Received: 20 September 1996 / Received version: 23 December 1996 / Accepted: 30 December 1996 相似文献
12.
Jeffke T Jende D Mätje C Ehlers RU Berthe-Corti L 《Applied microbiology and biotechnology》2000,54(3):326-330
Photorhabdus luminescens, a bacterial symbiont of entomopathogenic biocontrol nematodes, was grown in batch and glucose fed-batch culture. The cell
density, bioluminescence, production of antibiotic substances, number of cells with inclusion bodies, glucose concentration
and oxygen uptake rate were recorded. The addition of 12.4 g l−1 glucose prolonged the growth, and the yield almost doubled, from 6.85 g l−1 to 12.45 g l−1 dry mass. The production of antibiotic substances increased by 140%. Bioluminescence was higher in the batch culture. A shift
of P. luminescens to phase II variants was not detected.
Received: 21 January 2000 / Received revision: 3 April 2000 / Accepted: 7 April 2000 相似文献
13.
P. Becker I. Abu-Reesh S. Markossian G. Antranikian H. Märkl 《Applied microbiology and biotechnology》1997,48(2):184-190
A thermostable lipase was produced in continuous cultivation of a newly isolated thermophilic Bacillus sp. strain IHI-91 growing optimally at 65 °C. Lipase activity decreased with increasing dilution rate while lipase productivity
showed a maximum of 340 U l−1 h−1 at a dilution rate of 0.4 h−1. Lipase productivity was increased by 50% compared to data from batch fermentations. Up to 70% of the total lipase activity
measured was associated to cells and by-products or residual substrate. Kinetic and stoichiometric parameters for the utilisation
of olive oil were determined. The maximal biomass output method led to a saturation constant K
S of 0.88 g/l. Both batch growth data and a washout experiment yielded a maximal specific growth rate, μmax, of 1.0 h−1. Oxygen uptake rates of up to 2.9 g l−1h−1 were calculated and the yield coefficient, Y
X/O, was determined to be 0.29 g dry cell weight/g O2. From an overall material balance the yield coefficient, Y
X/S, was estimated to be 0.60 g dry cell weight/g olive oil.
Received: 8 January 1997 / Received revision: 30 April 1997 / Accepted: 4 May 1997 相似文献
14.
A. M. Fauzi David J. Hardman Alan T. Bull 《Applied microbiology and biotechnology》1996,46(5-6):660-666
The degradation of low concentrations of 1,3-dichloro-2-propanol (1,3-DCP) and related halohydrins by whole cells and cell-free
extracts of soil bacteria has been investigated. Three bacteria (strains A1, A2, A4), isolated from the same soil sample,
were distinguished on the basis of cell morphology, growth kinetics and haloalcohol dehalogenase profiles. Strain A1, probably
an Agrobacterium sp., dehalogenated 1,3-DCP with the highest specific activity (0.33 U mg protein−1) and also had the highest affinity for 1,3-DCP (K
m, 0.1 mM). Non-growing cells of this bacterium dehalogenated low concentrations of 1,3-DCP with a first-order rate constant
(k
1) of 1.13 h−1 . The presence of a non-dehalogenating bacterium, strain G1 (tentatively identified as Pseudomonas mesophilius), did not enhance the dehalogenation rate of low 1,3-DCP concentrations. However, the mixed-species consortium of strains
A1 and G1 had greater stability than the mono-species culture at DCP concentrations above 1.0 gl−1.
Received: 30 April 1996 / Received revision: 30 July 1996 / Accepted: 5 August 1996 相似文献
15.
Six goats were injected transthoracically with live Pasteurella multocida A:3 to examine if an extracellular enzyme, neuraminidase, was produced in vivo during infection with this organism. The principal
group of goats (n = 6) each received 1 ml of live 7.5 × 104 cfu of P. multocida mixed with polyacrylate beads transthoracically in the left lung on day 0 and 1 ml of live P. multocida (2.2 × 108 cfu) mixed with polyacrylate beads transthoracically in the left lung on day 22. Six goats were used as negative controls
and received 0.3 g of polyacrylate beads subcutaneously in the right flank on days 0 and 22. Serum was obtained from all animals
on days 0, 7, 14, 22, 29, and 36. Preimmune sera from all animals showed no detectable antibody to P. multocida A:3 neuraminidase in an enzyme neutralization assay. None of the sera from the negative control animals demonstrated a significant
antibody titer against the P. multocida A:3 neuraminidase. On day 36, serum samples from the six infected animals possessed complete enzyme-neutralizing activity.
Anti-neuraminidase antibody could be detected as early as day 14 in the infected animals. These data show that neuraminidase
is produced in vivo during an active P. multocida A:3 lobar infection.
Received: 16 March 1996 / Accepted: 19 April 1996 相似文献
16.
δ1-Pyrroline-5-carboxylate (P5C) dehydrogenase (EC 1.5.1.12) activity was measured in extracts from cultured tobacco (Nicotiana plumbaginifolia Viviani) cells. Two putative isozymes were resolved by anion-exchange fast protein liquid chromatography. These enzyme forms
showed different patterns of expression during the culture growth cycle: activity-I increased in exponentially growing cells
and declined rapidly in late logarithmic phase, while activity-II was found at substantial level only in cells which were
entering the stationary phase. Both P5C dehydrogenases were partially purified and characterized with respect to kinetic and
biochemical properties. They showed similar molecular masses as judged from retention patterns upon gel-filtration chromatography.
The in vitro activity of both enzymes had a broad maximum around pH 7.4, and was progressively inhibited by Cl− at concentrations ranging from 0.1 to 1 M. A pronounced difference was found between their apparent K
m values for the two substrates, P5C and NAD+, the higher affinities being shown by activity-I. Regulation of P5C dehydrogenase during salt-stress-induced proline accumulation
was investigated. Following the addition of 175 mM NaCl to the culture medium the level of activity-I was substantially unaffected,
while the specific activity of the other isozyme failed to increase even after the onset of the stationary phase of growth.
Possible roles for P5C dehydrogenase isozymes in proline and arginine metabolism are discussed.
Received: 23 May 1996 / Accepted: 18 December 1996 相似文献
17.
L. Mojovic Z. Knezevic R. Popadic S. Jovanovic 《Applied microbiology and biotechnology》1998,50(6):676-681
Lipase from Candida rugosa was immobilized by adsorption onto a macroporous copolymer support. Under optimum conditions the maximum amount of protein
bound was 15.4 mg/g and the immobilization efficiency was 62%. The kinetics of lipase binding to the selected polymer carrier
was assessed by using a general model of topochemical reactions. The effect of temperature on adsorption was thoroughly investigated,
as was the adsorption mechanism itself. Analysis of the proposed kinetic model and the specific kinetic parameters measured
suggest that surface kinetics control the adsorption process. According to the activation energy (E
a) and the rate constant, k, the enzyme has rather a high affinity for the support's active sites. The immobilized enzyme was used to catalyse the hydrolysis
of palm oil in a lecithin/isooctane reaction system, in which the enzyme's activity was 70% that of the free enzyme. Kinetic
parameters such as maximum velocity (V
max) and the Michaelis constant (K
m) were determined for the free and the immobilized lipase. Following repeated use, the immobilized lipase retained 56% of
its initial activity after the fifth hydrolysis cycle.
Received: 3 April 1998 / Received revision: 28 July 1998 / Accepted: 29 July 1998 相似文献
18.
P. J. M. Teunissen H. J. Swarts J. A. Field 《Applied microbiology and biotechnology》1997,47(6):695-700
Ligninolytic basidiomycetes were screened for their ability to produce the tetrachlorinated hydroquinone metabolites drosophilin
A (DA, tetrachloro-4-methoxyphenol) and drosophilin A methyl ether (DAME, tetrachloro-1,4-dimethoxybenzene). Five fungal strains
produced these metabolites in detectable amounts, including strains from Bjerkandera and Peniophora, which are genera not previously known for DA or DAME production. Phellinus fastuosus ATCC26.125 had the highest and most reliable production of DA and DAME in peptone medium, respectively 15–60 μM and 4–40 μM.
This fungus was used to study culture conditions that could increase DAME production. A fourfold increase in DAME production
was found after the addition of hydroquinone to growing cultures of P. fastuosus. Therefore, hydroquinone is postulated to be a possible biosynthetic precursor of DAME in the fungus. Antagonising P. fastuosus by adding filter-sterilised culture fluid of a competing fungus, Phlebia radiata, increased DAME production significantly by tenfold. This result suggests that DAME production is elicited by compounds present
in the culture fluid of P. radiata, indicating that DAME has an antibiotic function in P. fastuosus.
Received: 17 September 1996 / Received revision: 7 February 1997 / Accepted: 15 February 1997 相似文献
19.
Degradation of styrene by white-rot fungi 总被引:2,自引:0,他引:2
A. Braun-Lüllemann A. Majcherczyk A. Hüttermann 《Applied microbiology and biotechnology》1997,47(2):150-155
Degradation of styrene in the gaseous phase was investigated for white-rot fungi Pleurotus ostreatus (two strains), Trametes versicolor, Bjerkandera adusta and Phanerochaete chrysosporium. Fungi were grown in liquid culture and the gas/mycelium contact surface was enhanced with the help of perlite. The influence
of various inducers on styrene degradation was studied. The best inducers for styrene degradation were lignosulphonate for
P. ostreatus and T. versicolor and wood meal for B. adusta and P. chrysosoporium. Under these conditions all fungi were able to degrade styrene almost completely in 48 h at a concentration of 44 μmol/250 ml
total culture volume; one strain of P. ostreatus was able to remove 88 μmol styrene under these conditions. Three transformation products of [14C]styrene in cultures of P. ostreatus were identified: phenyl-1,2-ethanediol, 2-phenylethanol and benzoic acid; 4% of the styrene was metabolised to CO2 in 24 h and no other volatile products were found.
Received: 16 July 1996 / Received revision: 23 September 1996 / Accepted: 29 September 1996 相似文献
20.
The effect of different aeration conditions during the culture of Azotobacter vinelandii on the production and molecular mass of alginate was evaluated in shake flasks. In baffled flasks, the bacteria grew faster
and produced less alginate (1.5 g/l) than in conventional (unbaffled) flasks (4.5 g/l). The viscosity of the culture broth
was also influenced by the type of flask. Higher final viscosities were attained in unbaffled flasks [520 cP (520 mPa s)]
as compared to baffled flasks (30 cP). This latter phenomenon was closely related to the changes in the molecular mass distribution.
In either cases, the mean molecular mass increased with culture age; however, at the end of the fermentation, the mean molecular
mass of the alginate obtained in unbaffled flasks was fivefold higher than that obtained in baffled flasks. As the culture
proceeded, the cells of Azotobacter grown in unbaffled flasks increased in diameter, whereas those cultured in baffled flasks decreased in size.
Received: 13 December 1996 / Received revision: 10 April 1997 / Accepted: 27 April 1997 相似文献