共查询到20条相似文献,搜索用时 421 毫秒
1.
R. Beaudet M.-J. Lévesque R. Villemur M. Lanthier M. Chénier F. Lépine J.-G. Bisaillon 《Applied microbiology and biotechnology》1998,50(1):135-141
Anaerobic biodegradation of pentachlorophenol (PCP) in a contaminated soil from a wood-treating industrial site was studied
in soil slurry microcosms inoculated with a PCP-degrading methanogenic consortium. When the microcosms containing 10%–40%
(w/v) soil were inoculated with the consortium, more than 90% of the PCP was removed in less than 30 days at 29 °C. Less-chlorinated
phenols, mainly 3-chlorophenol were slowly degraded and accumulated in the cultures. Addition of glucose and sodium formate
to the microcosms was not necessary, suggesting that the organic compounds in the soil can sustain the dechlorinating activity.
Inoculation of Desulfitobacterium frappieri strain PCP-1 along with a 3-chlorophenol-degrading consortium in the microcosms also resulted in the rapid dechlorination
of PCP and the slow degradation of 3-chlorophenol. Competitive polymerase chain reaction experiments showed that PCP-1 was
present at the same level throughout the 21-day biotreatment. D. frappieri, strain PCP-1, inoculated into the soil microcosms, was able to remove PCP from soil containing up to 200 mg PCP/kg soil.
However, reinoculation of the strain was necessary to achieve more than 95% PCP removal with a concentration of 300 mg and
500 mg PCP/kg soil. These results demonstrate that D. frappieri strain PCP-1 can be used effectively to dechlorinate PCP to 3-chlorophenol in contaminated soils.
Received: 14 November 1997 / Received revision: 29 January 1998 / Accepted: 24 February 1998 相似文献
2.
M. Wenk T. Baumgartner J. Dobovšek T. Fuchs J. Kucsera J. Zopfi G. Stucki 《Applied microbiology and biotechnology》1998,49(5):624-630
The evaluation of pesticide-mineralising microorganisms to clean-up contaminated soils was studied with the widely applied
and easily detectable compound atrazine, which is rapidly mineralised by several microorganisms including the Pseudomonas sp. strain Yaya 6. The rate of atrazine removal was proportional to the water content of the soil and the amount of bacteria
added to the soil. In soil slurry, 6 mg atrazine kg soil−1 was eliminated within 1 day after application of 0.3 g dry weight inoculant biomass kg soil−1 and within 5 days when 0.003 g kg soil−1 was used. In partially saturated soil (60% of the maximal water-holding capacity) 15 mg atrazine kg soil−1 was eliminated within 2 days by 1 g biomass kg soil−1 and within 25 days when 0.01 g biomass kg soil−1 was used. In unsaturated soil, about 60% [U-ring-14C]atrazine was converted to 14CO2 within 14 days. Atrazine was very efficiently removed by the inoculant biomass, not only in soil that was freshly contaminated
but also in soil aged with atrazine for up to 260 days. The bacteria exposed to atrazine in unsaturated sterile soil were
still active after a starvation period of 240 days: 15 mg newly added atrazine kg soil−1 was eliminated within 5 days.
Received: 31 October 1997 / Received revision: 16 January 1998 / Accepted: 18 January 1998 相似文献
3.
M. Megharaj R.-M. Wittich R. Blasco D. H. Pieper K. N. Timmis 《Applied microbiology and biotechnology》1997,48(1):109-114
The dibenzo-p-dioxin(DD)- and dibenzofuran(DF)-degrading bacterium, Sphingomonas sp. strain RW1, was tagged by insertion of a mini-Tn5 lacZ transposon in order to follow its fate in complex laboratory soil systems. The tagged strain was tested for its ability to
survive in soil and degrade DF and DD applied at a concentration of 1 mg/g. Bacteria pre-adapted to soil conditions were found
to survive better in DF- and DD-amended soil and degrade the substrate more efficiently than bacteria that had not been subjected
to pre-adaptation. The concentration of soil-applied DF and DD, individually and in combination, decreased to less than 2%
of the original concentrations within 3 weeks of addition of the RW1 derivative, accompanied by a short, but significant exponential
increase in RW1 viable cells. During the same period the native bacterial population in soil was stable while viable fungi
declined.
Received: 12 November 1996 / Received revision: 21 February 1997 / Accepted: 22 February 1997 相似文献
4.
C Wittmann A-P Zeng W-D Deckwer 《Journal of industrial microbiology & biotechnology》1998,21(6):315-321
The physiological characteristics of growth and pentachlorophenol degradation of the bacteria Sphingomonas chlorophenolica RA2 and Mycobacterium chlorophenolicum PCP-1 were studied quantitatively in liquid culture under various conditions of pH, temperature, pO2, pCO2 and PCP concentration. Concerning their metabolic properties, RA2 and PCP-1 can be regarded as r-strategist and K-strategist,
respectively. RA2 showed a higher activity concerning growth and PCP degradation than PCP-1 under optimum conditions. However,
PCP-1 performed better under extreme conditions. Maximum growth rates or RA2 and PCP-1 on glucose were 0.21 h−1 and 0.024 h−1 and maximum PCP degradation rates 315 and 40 μmol (g of dry cells)−1 h−1, respectively. Optimized cultivation for RA2 on a technical scale led to the production of 40 g L−1 of cell dry mass within 55 h. The cultivation strategy including pH-controlled ammonium feeding can be used to effectively
produce sufficient biomass of both strains for both research and application as inoculants in soil clean-up.
Received 28 July 1998/ Accepted in revised form 30 November 1998 相似文献
5.
S. Fancelli M. Castaldini M. T. Ceccherini C. Di Serio R. Fani E. Gallori M. Marangolo N. Miclaus M. Bazzicalupo 《Applied microbiology and biotechnology》1998,49(2):221-225
Probes for the detection of Azospirillum strains were obtained from DNA fragments generated by random amplification of polymorphic DNA (RAPD) and tested to assess
their specificity towards DNA extracted from pure cultures. The most specific probe, referred to as α4, produced a hybridization
signal only with amplified DNA of A. lipoferum ATCC29731. This strain was inoculated, together with two other Azospirillum strains, in soil microcosms of different complexity and its presence tested with the probe α4. This probe confirmed its high
specificity with amplified DNA extracted from the soil microcosm and in the presence of other A. lipoferum strains, indicating that the strategy for bacterial detection, based on RAPD markers, is useful for monitoring the presence
of a particular strain under environment-like conditions. Other RAPD-derived probes, when tested on soil samples, did not
show the same level of specificity as that shown on DNA from pure cultures. This result suggests that some precautions are
necessary in the choice of a really specific RAPD marker. In a further development of this strategy, the α4 probe was sequenced
and two pairs of “nested” primers were designed, which enabled a diagnostic polymerase chain reaction from soil samples that
was specific for the A. lipoferum species.
Received: 7 July 1997 / Accepted: 14 October 1997 相似文献
6.
An efficient one-step transformation method for the dimorphic yeast Yarrowia lipolytica is described. Using cells grown overnight on agar plates, the whole process is carried out within 1 h. The transformant clones
could be recovered on selective plates as early as 36–48 h after plating. The efficiency was better than 105 transformants/μg replicative plasmid DNA. Effects of cell density, dithiothreitol, heat shock, poly(ethylene glycol) 4000
concentration and the wetness of selective plates were investigated.
Received: 17 February 1997 / Received revision: 4 April 1997 / Accepted: 19 April 1997 相似文献
7.
Cryptosporidium parvum is an enteric protozoan parasite of medical and veterinary importance. Dissemination of environmentally resistant oocysts
in surface water plays an important role in the epidemiology of cryptospridiosis. Although the polymerase chain reaction (PCR)
is a well-established technique and is widely used for detecting microorganisms, it is not routinely applied for monitoring
waterborne C. parvum. In order to facilitate the application of PCR to the detection of waterborne C. parvum oocysts, a comparison of published PCR protocols was undertaken and different sample-preparation methods tested. The sensitivity
of a one-step PCR method, consisting of 40 temperature cycles, was 10 purified oocysts or fewer than 100 oocysts spiked in
raw lake water. The detection limit of two primer pairs, one targeting the ribosomal small subunit and another specific for
a C. parvum sequence of unknown function, was approximately ten-fold lower than achieved with a primer pair targeting an oocyst shell
protein gene. Three cycles of freezing/thawing were sufficient to expose oocyst DNA and resulted in higher sensitivity than
proteinase K digestion, sonication or electroporation. Inhibition of PCR by surface water from different local sources was
entirely associated with the soluble fraction of lake water. Membrane filtration was evaluated in bench-scale experiments
as a means of removing lake water inhibitors and improving the detection limit of PCR. Using gel and membrane filtration,
the molecular size of inhibitory solutes from lake water was estimated to less than 27 kDa.
Received: 14 November 1996 / Received revision: 18 March 1997 / Accepted: 27 March 1997 相似文献
8.
Isolation and characterization of a marine bacterium capable of utilizing 2-methylphenanthrene 总被引:3,自引:0,他引:3
M. Gilewicz Ni'matuzahroh T. Nadalig H. Budzinski P. Doumenq V. Michotey J. C. Bertrand 《Applied microbiology and biotechnology》1997,48(4):528-533
A marine bacterium isolated from a coastal hydrocarbon-polluted sediment has been described and attributed on the basis of
its phenotypic and genotypic characteristics to the genus Sphingomonas sp. This strain was capable of using an alkylated phenanthrene 2-methylphenanthrene, as sole source of carbon and energy.
In experiments, 2-methylphenanthrene (0.2 g/l) was added as crystals to the culture medium. After 5 days of aerobic growth
at 30 °C, 70% was degraded and the complete dissipation occurred after 20 days. Furthermore, the strain could degrade various
kinds of polyaromatic compounds, but failed to grow on aliphatic hydrocarbons.
Received: 27 December 1996 / Received last revision: 10 June 1997 / Accepted: 14 June 1997 相似文献
9.
Optimization of compactin fermentation 总被引:3,自引:0,他引:3
A Kónya A Jekkel J Sütő J Salát 《Journal of industrial microbiology & biotechnology》1998,20(3-4):150-152
A compactin producer Penicillium sp strain was isolated from soil in our screening program. The compactin-biosynthesising capacity of the strain was improved
from 5 μg ml−1 to 250 μg ml−1 by mutation-selection method. We investigated the effect of the medium composition on compactin productivity. A central,
orthogonal three-factor experimental design by Box and Wilson was used in the investigation. The results were analysed by
non-linear regression analysis. The composition of the production medium was optimized according to the calculated mathematical
model using the steepest ascent method. The compactin productivity was increased to 400 μg ml−1 by applying this method.
Received 08 October 1997/ Accepted in revised form 04 December 1997 相似文献
10.
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
11.
Poly(hydroxybutyric acid) (PHB) was produced by a selectant of Azotobacter beijerinckii in media containing only organic nitrogen sources such as N substrates. The chosen compounds were casein peptone, yeast extract,
casamino acids and urea, each combined with carbon substrates glucose or sucrose. The PHB was synthesized under growth-associated
conditions. The concentrations amounted to more than 50% of cell dry mass on casein peptone/glucose as well as urea/glucose
medium within 45 h fermentation time. Corresponding to these yields, productivities of about 0.8 g PHB l−1 h−1 were discovered. The highest values increased to 1.06 g PHB l−1 h−1 on casein peptone/glucose medium and 1.1 g PHB l−1 h−1 on yeast extract/glucose medium after a period of 20 h. It was found that oxygen limitation was essential for successful
product formation, as demonstrated earlier. These data from basic research may support further investigations into the use
of technical proteins from renewable sources as substrates for PHB production by a strain of A. beijerinckii.
Received: 3 June 1997 / Received revision: 29 August 1997 / Accepted: 15 September 1997 相似文献
12.
5-Hydroxypyrazine-2-carboxylic acid, a versatile building block for the synthesis of new antituberculous agents, was prepared
by whole-cell biotransformation from 2-cyanopyrazine via pyrazinecarboxylic acid using Agrobacterium sp. DSM 6336. By developing a fermentation process for this two-enzyme-step bioconversion, a product concentration of 286 mM
(40 g/l) was obtained. After the isolation method had been optimized the total yield was 80%.
Received: 28 February 1997 / Received revision: 28 April 1997 / Accepted: 4 May 1997 相似文献
13.
R. Webster M. Pacey T. Winchester P. Johnson S. Jezequel 《Applied microbiology and biotechnology》1998,49(4):371-376
The 4′-hydroxylated metabolite of diclofenac was produced by biocatalysis for probing specific human drug-metabolising enzymes
(CYP2C9). An initial screen of 11 microorganisms was carried out (50 ml scale) to identify the organism best suited to the
regioselective conversion of diclofenac to its 4′-hydroxylated metabolite. From this screen, the fungus Epicoccum nigrum IMI354292 was selected as the most suitable microorganism. Scale-up was carried out in a 30-l fermenter to which 2 g diclofenac
was added. After 48 h, 50% of the diclofenac had been converted to it 4′-hydroxylated metabolite. The broth was then extracted
with ethyl acetate and purified by chromatography and crystallisation. This yielded 0.3 g 4′-hydroxydiclofenac with a purity
of at least 99%. The 4′-hydroxydiclofenac produced by E. nigrum was characterised by HPLC, mass spectrometry and NMR.
Received: 28 July 1997 / Received revision: 8 December 1997 / Accepted: 14 December 1997 相似文献
14.
In order to improve the production rate of l-lysine, a mutant of Corynebacterium glutamicum ATCC 21513 was cultivated in complex medium with gluconate and glucose as mixed carbon sources. In a batch culture, this
strain was found to consume gluconate and glucose simultaneously. In continuous culture at dilution rates ranging from 0.2
h−1 to 0.25 h−1, the specific l-lysine production rate increased to 0.12 g g−1 h−1 from 0.1 g g−1 h−1, the rate obtained with glucose as the sole carbon source [Lee et al. (1995) Appl Microbiol Biotechnol 43:1019–1027]. It
is notable that l-lysine production was observed at higher dilution rates than 0.4 h−1, which was not observed when glucose was the sole carbon source. The positive effect of gluconate was confirmed in the shift
of the carbon source from glucose to gluconate. The metabolic transition, which has been characterized by decreased l-lysine production at the higher glucose uptake rates, was not observed when gluconate was added. These results demonstrate
that the utilization of gluconate as a secondary carbon source improves the maximum l-lysine production rate in the threonine-limited continuous culture, probably by relieving the limiting factors in the lysine
synthesis rate such as NADPH supply and/or phosphoenolpyruvate availability.
Received: 16 May 1997 / Received revision: 28 August 1997 / Accepted: 29 August 1997 相似文献
15.
D. Segura C. Santana R. Gosh L. Escalante S. Sanchez 《Applied microbiology and biotechnology》1997,48(5):615-620
In Streptomyces peucetius var. caesius, the production of anthracyclines was suppressed either by 330 mM d-glucose or 25 mM phosphate. In addition, the anthracycline doxorubicin and the glucose analogue 2-deoxyglucose inhibited
the growth of this microorganism at concentrations of 0.025 mM and 10 mM respectively. Spontaneous and induced mutants, resistant
to the action of these compounds, were isolated, tested and chosen by their ability to overproduce anthracyclines. Genetic
recombination between representative mutants was carried out by the protoplast fusion technique. Some recombinants carrying
resistance to doxorubicin, phosphate and 2-deoxyglucose produced more than 40-fold greater levels of anthracyclines than those
obtained with the parental strain. This improvement resulted in total antibiotic titres of more than 2 g/l culture medium
at 6 days of fermentation.
Received: 14 April 1997 / Received revision: 19 June 1997 / Accepted: 4 July 1997 相似文献
16.
Rapid and sensitive method for the detection of Mycobacterium chlorophenolicum PCP-1 in soil based on 16S rRNA gene-targeted PCR. 总被引:1,自引:1,他引:0
下载免费PDF全文
![点击此处可从《Applied microbiology》网站下载免费的PDF全文](/ch/ext_images/free.gif)
A method based on 16S rRNA gene-targeted PCR and oligonucleotide probing was developed for detecting Mycobacterium chlorophenolicum PCP-1 in soil. The primers and probe were specific for PCP-1 in DNA extracts of three soils. The method allowed for PCP-1 detection in soil with a detection limit of 3 x 10(2) cells per g. 相似文献
17.
S. Nakotte S. Schaffer M. Böhringer P. Dürre 《Applied microbiology and biotechnology》1998,50(5):564-567
Procedures have been developed allowing recombinant DNA work with Clostridium acetobutylicum DSM 792. Electroporation was used to introduce plasmid DNA into exponentially growing clostridial cells and 6 × 102 transformants/μg DNA could be obtained at a time constant of 5.5 ms, 1.8 kV, 50 μF, and 600 Ω. The method also allowed the
taxonomic group IV strain NI-4082 to be transformed (101 transformants/μg DNA). Plasmid preparation from recombinant clostridia was optimal when a modification of the alkaline lysis
method was employed. It was also important to use cells from the mid-logarithmic growth phase. Recombinant strains could be
easily preserved as spore suspensions; under all conditions tested plasmids were maintained.
Received: 17 March 1998 / Received revision: 17 August 1998 / Accepted: 26 August 1998 相似文献
18.
Bioremediation of pentachlorophenol-contaminated soil by bioaugmentation using activated soil 总被引:11,自引:0,他引:11
C. Barbeau L. Deschênes D. Karamanev Y. Comeau R. Samson 《Applied microbiology and biotechnology》1997,48(6):745-752
The use of an indigenous microbial consortium, pollutant-acclimated and attached to soil particles (activated soil), was
studied as a bioaugmentation method for the aerobic biodegradation of pentachlorophenol (PCP) in a contaminated soil. A 125-l
completely mixed soil slurry (10% soil) bioreactor was used to produce the activated soil biomass. Results showed that the
bioreactor was very effective in producing a PCP-acclimated biomass. Within 30 days, PCP-degrading bacteria increased from
105 cfu/g to 108 cfu/g soil. Mineralization of the PCP added to the reactor was demonstrated by chloride accumulation in solution. The soil-attached
consortium produced in the reactor was inhibited by PCP concentrations exceeding 250 mg/l. This high level of tolerance was
attributed to the beneficial effect of the soil particles. Once produced, the activated soil biomass remained active for 5
weeks at 20 °C and for up to 3 months when kept at 4 °C. The activated attached soil biomass produced in the completely mixed
soil slurry bioreactor, as well as a PCP-acclimated flocculent biomass obtained from an air-lift immobilized-soil bioreactor,
were used to stimulate the bioremediation of a PCP-impacted sandy soil, which had no indigenous PCP-degrading microorganisms.
Bioaugmentation of this soil by the acclimated biomass resulted in a 99% reduction (from 400 mg/kg to 5 mg/kg in 130 days)
in PCP concentration. The PCP degradation rates obtained with the activated soil biomass, produced either as a biomass attached
to soil particles or as a flocculent biomass, were similar.
Received: 31 March 1997 / Received revision: 22 July 1997 / Accepted: 25 August 1997 相似文献
19.
Effects of ethanol concentration and stripping temperature on continuous fermentation rate 总被引:1,自引:0,他引:1
F. Taylor M. J. Kurantz N. Goldberg J. C. Craig Jr. 《Applied microbiology and biotechnology》1997,48(3):311-316
The operation of a pilot plant consisting of a 14-l fermentor, 10-cm packed column and condenser for continuous fermentation
and stripping of ethanol was stable for more than 100 days. The feed consisted of a non-sterile solution of 560 g/l glucose
with 100 g/l corn steep water. Fouling of the packing in the column with attached growth of yeast cells was controlled by
in situ washing at intervals of 3–6 days. A computer simulation of the pilot plant was developed and used to analyze the data.
The productivity of the continuous fermentor varied from 14 g ethanol to 17 g ethanol l−1 h−1. The yield was equal to the maximum theoretically possible: 0.51 g ethanol/g glucose consumed. Results are fit to linear
models for the effects of ethanol concentration on specific growth rate and cell yield, and for the effect of stripping temperature
on specific growth rate.
Received: 16 October 1996 / Received revision: 3 January 1997 / Accepted: 24 January 1997 相似文献
20.
W. Malek M. Inaba H. Ono Y. Kaneko Y. Murooka 《Applied microbiology and biotechnology》1998,50(2):261-265
Rhizobium huakuii bv. renge B3, a native symbiont of Astragalus sinicus, outcompeted Rhizobium sp. strain ACMP18, which was isolated from Astragalus cicer nodules, in the formation of root nodules on A.␣sinicus when plants were co-inoculated with these strains. The strains occupying the nodules were identified by antibiotic resistance
and phage sensitivity markers and also by polymerase chain reaction (PCR) genomic fingerprintings, which were performed by
using enterobacterial repetitive intergenic consensus sequences. In PCR genomic fingerprintings, the total genomic DNA isolated
from pure bacterial culture and from squashed root nodules showed identical profiles, indicating that this technique can be
a useful tool for identification of rhizobia in ecological studies. When Rhizobium sp. strain ACMP18 outnumbered R. huakuii bv. renge strain B3 by a factor of ten, and even when strain ACMP18 was added to plants 1 week before bacterization with
strain B3, the strain B3 occupied most nodules. Dually infected nodules were not observed, although Rhizobium sp. ACMP18 formed active nodules on A. sinicus when the bacterial strain was inoculated alone.
Received: 5 February 1998 / Received revision: 23 March 1998 / Accepted: 27 April 1998 相似文献