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1.
Repeated application of carvone-induced bacteria to enhance biodegradation of polychlorinated biphenyls in soil 总被引:4,自引:0,他引:4
Carvone, the principal component of spearmint oil, induces biodegradation of polychlorinated biphenyls (PCB) by Arthrobacter sp. strain B1B. This study investigated the effectiveness of the repeated application of carvone-induced bacteria for bioremediation
of Aroclor-1242-contaminated soil. Control treatments compared a single inoculation of carvone-induced cells, repeated applications
of noninduced cells, and repeated applications of cell-free carvone/fructose medium. The results showed that repeated application
of carvone-induced bacteria was the most effective treatment for mineralizing PCB, resulting in 27 ± 6% degradation of Aroclor
1242 after 9 weeks; whereas a single application of cells resulted in no significant degradation. Addition of cell-free, carvone/fructose
medium resulted in 10% degradation of PCB, which suggests that this treatment stimulated biodegradation of PCB by the indigenous
microflora. The di- and trichlorobiphenyls were the most readily degraded congeners. More highly chlorinated congeners, which
had been previously shown to be degraded in liquid culture, were not substantially degraded in soil, indicating that low bioavailability
may have limited their degradation. With the development of new technology, which permits automated in situ fermentation and
delivery of degrader microorganisms, the repeated application of carvone-induced bacteria may facilitate bioremediation of
PCB-contaminated soils.
Received: 7 January 1998 / Received revision: 18 June 1998 / Accepted: 27 June 1998 相似文献
2.
Bioaugmentation of activated sludge systems with specialised bacterial strains could be a powerful tool to improve several
aspects in wastewater treatment processes, such as improved flocculation and degradation of recalcitrant compounds. This review
focuses on the addition of strains to activated sludge to enhance the biodegradation of recalcitrant compounds, either through
the activity of the inoculated strain or after transfer of degradative plasmids to activated sludge bacteria. Different factors
that improve the aggregation of the sludge flocs and their influence on biodegradation are described. This review further
deals with the role of bacterial plasmids in natural genetic exchange between inoculated and indigenous sludge bacteria, and
in the construction of new genetically modified organisms. The few successful cases of bioaugmentation described in this review,
together with future research, must lead to a better understanding of sludge bioaugmentation.
Received: 5 January 1998 / Received revision: 20 April 1998 / Accepted: 20 April 1998 相似文献
3.
M. R. Natarajan W.-M. Wu J. Nye H. Wang L. Bhatnagar M. K. Jain 《Applied microbiology and biotechnology》1996,46(5-6):673-677
An anaerobic methanogenic microbial consortium, developed in a granular form, exhibited extensive dechlorination of defined
polychlorinated biphenyl (PCB) congeners. A 2,3,4,5,6-pentachlorobiphenyl was dechlorinated to biphenyl via 2,3,4,6-tetrachlorobiphenyl,
2,4,6-trichlorobiphenyl, 2,4-dichlorobi-phenyl and 2-chlorobiphenyl (CB). Removal of chlorine atoms from all three positions
of the biphenyl ring, i.e., ortho, meta and para, was observed during this reductive dechlorination process. Biphenyl was identified as one of the end-products of the reductive
dechlorination by GC-MS. After 20 weeks, the concentrations of the dechlorination products 2,4,6-CB, 2,4-CB, 2-CB and biphenyl
were 8.1, 41.2, 3.0 and 47.8 μM respectively, from an initial 105 μM 2,3,4,5,6-CB. The extent and pattern of the dechlorination
were further confirmed by the dechlorination of lightly chlorinated congeners including 2-CB, 3-CB, 4-CB, 2,4-CB and 2,6-CB
individually. This study indicates that the dechlorination of 2,3,4,5,6-CB to biphenyl is due to ortho, meta and para dechlorination by this anaerobic microbial consortium.
Received: 30 April 1996 / Received revision: 26 July 1996 / Accepted: 5 August 1996 相似文献
4.
K. A. Billingsley S. M. Backus O. P. Ward 《Applied microbiology and biotechnology》1999,52(2):255-260
A variety of commercial surfactants were tested to determine their effect on polychlorinated biphenyl (PCB) transformation
by Pseudomonas LB400. Initial tests determined that most surfactants were fully or partially able to solubilize the PCB congeners 2,5,2′-chlorobiphenyl
(CBP), 2,4,2′,4′-CBP, 2,3,5,2′,5′-CBP and 2,4,5,2′,4′,5′-CBP, at concentrations above the surfactants' critical micelle concentration
(CMC). Surfactants were also found to have no negative effect on bacterial survival, as cell numbers were the same or higher
after incubation in the presence of surfactants than after incubation without surfactants. A comparison of the extent of biotransformation
of single PCB congeners by the bacterium revealed that, at surfactant concentrations above the CMC, the presence of an anionic
surfactant promoted while nonionic surfactants inhibited PCB transformation, compared to a control with no surfactant. The
rates of transformation of PCB congeners were also higher in the presence of the anionic surfactant compared to the control.
The inhibitory effects of a nonionic surfactant, Igepal CO-630 at a concentration above its CMC, on transformation of 2,4,5,2′,5′-CBP
could be eliminated by diluting the surfactant/PCB solution to a concentration close to the surfactant CMC.
Received: 26 October 1998 / Received revision: 5 March 1999 / Accepted: 14 March 1999 相似文献
5.
A. B. Więckowski G. P. Słowik J. A. Gąsiorek P. Gąsiorek F. Domka A. Perkowska 《Applied microbiology and biotechnology》1999,52(1):96-98
A comparison of iron-sulfur proteins obtained from Thiobacillus ferrooxidans was carried out. The microorganisms were grown on iron(II)- or sulfur-containing nutrients. In both cases different, broad
elctron paramagnetic resonance (EPR) lines, originating from an iron(III) compound, were detected. Additional EPR lines of
tetrahedral iron(III) and free radicals were observed. The UV spectra of these compounds also differ.
Received: 15 July 1998 / Received revision: 8 October 1998 / Accepted: 16 October 1998 相似文献
6.
P. Rosenbrock R. Martens F. Buscot F. Zadrazil J. C. Munch 《Applied microbiology and biotechnology》1997,48(5):665-670
The potential for aerobic mineralization of [U-14C]dibenzo-p-dioxin (DD) was investigated in samples of three different agricultural soils already contaminated with polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/F) by industrial activities. The influence of amendments, i.e. wheat straw and compost, and
of soil treatment by inoculation with lignolytic fungi, grown on wheat straw substrate, was tested. All the soils tested contained
an indigenous DD-mineralizing microflora. The soil characterized by the highest organic matter content and the highest content
of soil microbial biomass displayed the best DD mineralization of 36.6% within 70 days, compared with the two organic-matter-poor
soils with an endogenous DD mineralization of 19.5% and 23.3% respectively. Amendments with compost increased DD mineralization
up to 28% in both soils with low organic matter and microbial biomass content, but did not affect mineralization in the organic-matter-rich
soil. Addition of wheat straw had no constant influence on DD mineralization in the soils tested. The best DD mineralization
resulted from inoculation with lignolytic white-rot fungi (Phanerochaete chrysosporium, Pleurotus sp. Florida, Dichomitus squalens) and with an unidentified lignolytic fungus, which was isolated originally from a long-term PCDD/F-contaminated soil. A mineralization
of up to 50% within 70 days was reached by this treatment. The influence of inoculated fungi on mineralization differed between
the soils investigated.
Received: 14 April 1997 / Received revision: 24 June 1997 / Accepted: 29 June 1997 相似文献
7.
C. Löser H. Seidel A. Zehnsdorf U. Stottmeister 《Applied microbiology and biotechnology》1998,49(5):631-636
Microbial hydrocarbon degradation in soil was studied during periodical aerobic/anaerobic switching and under purely aerobic
conditions by using a pilot-scale plant with diesel-fuel-contaminated sand. The system worked according to the percolation
principle with controlled circulation of process water and aeration. Periodical switching between 4 h of aerobic and 2 h of
anaerobic conditions was achieved by repeated saturation of the soil with water. Whatever the cultivation mode, less than
50% of the diesel was degraded after 650 h because the hydrocarbons were adsorbed. Contrary to expectations, aerobic/anaerobic
changes neither accelerated the rate of degradation nor reduced the residual hydrocarbon content of the soil. Obviously the
pollutant degradation rate was determined mainly by transport phenomena and less by the efficiency of microbial metabolism.
The total mass of oxygen consumed and carbon dioxide produced was greater under aerobic/anaerobic changing than under aerobic
conditions, although the mass of hydrocarbons degraded was nearly the same. As shown by an overall balance of microbial growth
and by a carbon balance, the growth yield coefficient was smaller during aerobic/anaerobic changes than under aerobic conditions.
Received: 25 November 1997 / Received revision: 15 January 1998 / Accepted: 18 January 1998 相似文献
8.
K. Hofvendahl E. W. J. van Niel B. Hahn-Hägerdal 《Applied microbiology and biotechnology》1999,51(5):669-672
Lactococcus lactis ssp. lactis ATCC 19435 is known to produce mixed acids when grown on maltose. A change in fermentation conditions only, elevated temperatures
(up to 37 °C) and reduced pH values (down to 5.0) resulted in a shift towards homolactic product formation. This was accompanied
by decreased growth rate and cell yield. The results are discussed in terms of redox balance and maintenance, and the regulation
of lactate dehydrogenase and pyruvate formate-lyase.
Received: 14 December 1998 / Received revision: 12 January 1999 / Accepted: 22 January 1999 相似文献
9.
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
10.
N. Kitamoto S. Yoshino M. Ito T. Kimura K. Ohmiya N. Tsukagoshi 《Applied microbiology and biotechnology》1998,50(5):558-563
A xylanase gene, xynF1, was cloned and characterized from a shoyu koji mould Aspergillus oryzae KBN616. The xynF1 gene was found to be comprised of 1484 bp with ten introns. The deduced amino acid sequence encodes a protein consisting
of 327 amino acids (35,402 Da) which is very similar to the fungal family F xylanases such as Aspergillus nidulans XlnC, Aspergillus kawachii XynA and Penicillium chrysogenum XylP. The intron/exon organization of xynF1 is very similar to that of the fungal family F xylanase genes. Plasmid pXPR64, which contains 64 copies of the xynF1 promoter region (PxynF1) in the same direction, was constructed and introduced into A. oryzae. This led to reduced expression of both xylanase and β-xylosidase genes in the transformants.
Received: 18 May 1998 / Received revision: 7 July 1998 / Accepted: 9 July 1998 相似文献
11.
Zn biosorption by Rhizopus arrhizus and other fungi 总被引:1,自引:0,他引:1
J. L. Zhou 《Applied microbiology and biotechnology》1999,51(5):686-693
Biosorption of zinc ions by inactivated fungal mycelia was studied. Of the six fungal species, Rhizopus arrhizus, Mucor racemosus, Mycotypha africana, Aspergillus nidulans, Aspergillus niger and Schizosaccharomyces pombe, R. arrhizus exhibited the highest capacity (Q
max = 213 μmol g−1 dry weight). Further experiments with different cellular fractions of R. arrhizus showed that Zn was predominantly bound to cell-wall chitin and chitosan (Q
max = 312 μmol g−1 dry weight). Adsorption data were best modelled by the Langmuir isotherm, although they can be modelled by the Freundlich
equation as well at relatively low aqueous concentrations. Biosorption generally decreased with increase in biosorbent particle
size and its concentration. Low pH reduced Zn sorption, because of the strong competition from hydrogen ions for binding sites
on fungi. The presence of ligands reduced metal uptake, chiefly by forming metal complexes of a less biosorbable nature.
Received: 2 November 1998 / Received revision: 12 January 1999 / Accepted: 17 January 1999 相似文献
12.
B. Bogovič-Matijašić I. Rogelj I. F. Nes H. Holo 《Applied microbiology and biotechnology》1998,49(5):606-612
Lactobacillus acidophilus LF221 produced bacteriocin-like activity against different bacteria including some pathogenic and food-spoilage species.
Besides some lactic acid bacteria, the following species were inhibited: Bacillus cereus, Clostridium sp., Listeria innocua, Staphylococcus aureus, Streptococcus D. L. acidophilus LF221 produced at least two bacteriocins, acidocin LF221 A and acidocin LF221 B, which were purified by ammonium sulphate
precipitation, ion-exchange chromatography, hydrophobic interaction and reverse-phase FPLC. The antibacterial substances were
heat-stable, sensitive to proteolytic enzymes (trypsin, pepsin, pronase, proteinase K) and migrated as 3500- to 5000-Da proteins
on sodium dodecyl sulphate/polyacrylamide gel electrophoresis. The sequences of 46 amino-terminal amino acid residues of peptide
A and 35 of peptide B were determined. Among the residues identified, no modified amino acids were found. No significant homology
was found between the amino acid sequences of acidocin LF221 A and other bacteriocins of lactic acid bacteria and 26% homology
was found between acidocin LF221 B and brevicin 27. L. acidophilus LF221 may be of interest as a probiotic strain because of its human origin and inhibition of pathogenic bacteria, especially
Clostridium difficile.
Received: 2 October 1997 / Received revision: 12 January 1998 / Accepted: 13 January 1998 相似文献
13.
C. Suresh A. K. Dubey S. Srikanta S. Umesh Kumar N. G. Karanth 《Applied microbiology and biotechnology》1999,51(5):673-675
A UV-induced mutant strain of Aspergillus niger (CFTRI-1105-U9) overproduced a starch-hydrolysing enzyme with properties characteristically different from the known amylases
of the fungus. The purified enzyme of 4.0 pI had an apparent molecular mass of 125 kDa and it dextrinised starch and then
saccharified the dextrins. Patterns of the enzyme activity on starch, resulting in glucose at 60 °C and glucose, maltose and
maltodextrins at 70 °C as primary products, suggested significant applications for the enzyme in starch-processing industries.
Received: 29 October 1998 / Received revision: 11 January 1999 / Accepted: 19 January 1999 相似文献
14.
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
15.
Production of ketocarotenoids by microalgae 总被引:22,自引:0,他引:22
P. Z. Margalith 《Applied microbiology and biotechnology》1999,51(4):431-438
Among the highly valued ketocarotenoids employed for food coloration, astaxanthin is probably the most important. This carotenoid
may be produced biotechnologically by a number of microorganisms, and the most promising seems to be the freshwater flagellate
Haematococcus pluvialis (Chlorophyceae), which accumulate astaxanthin in their aplanospores. Many physiological aspects of the transition of the
flagellate into aplanospores have been described. Mixotrophic cultivation and suitable irradiance may result in fairly good
yields (up to 40 mg/l; 43 mg/g cell dry weight) within a reasonable time, under laboratory conditions. In order to compete
with synthetic astaxanthin, suitable scaling-up is required. However, large-scale production in open ponds has proved unsatisfactory
because of severe contamination problems. A selective medium might overcome this difficulty. Further research for the development
of suitable strains is thus warranted.
Received: 8 July 1998 / Received revision: 12 November 1998 / Accepted: 14 November 1998 相似文献
16.
More than 70% of n-hexadecane-grown cells of Cladosporium resinae ATCC 22711 were converted to spheroplasts when they were treated with chitinase and lytic enzyme from Trichoderma harziamum. The light mitochondrial fraction, containing microbodies, mitochondria and vacuoles, was isolated from spheroplasts. Vacuoles
in cells were demonstrated by the inability of acridine orange to stain organelles previously treated with 2.5 μM Bafilomycin
A1, a vacuolar ATPase inhibitor. Microbodies, mitochondria and vacuoles were separated from the light mitochondrial fraction
by self-generated density-gradient ultracentrifugation using iodixanol as gradient medium. NADH-dependent n-alkane monooxygenase activity and fatty alcohol oxidase activity were located in the cytoplasm and mitochondrial fractions
respectively.
Received: 21 September 1998 / Received revision: 21 January 1999 / Accepted: 31 January 1999 相似文献
17.
J. Ruff T. Hitzler U. Rein A. Ritter A. M. Cook 《Applied microbiology and biotechnology》1999,52(3):446-450
Highly substituted arenesulfonates are chemically stable compounds with a range of industrial applications, and they are
widely regarded as being poorly degradable. We did enrichment cultures for bacteria able to utilise the sulfonate moiety of
14 compounds, and we obtained mixed cultures that were able to desulfonate each compound. The products formed were usually
identified as the corresponding phenol, but because we could not obtain pure cultures, we followed up these findings with
quantitative work in pure cultures of, e.g., Pseudomonas putida S-313, which generated the same phenols from the compounds studied. Many of these phenols are known to be biodegradable,
or to be subject to binding to soil components. We thus presume that the capacity to degrade aromatic sulfonates extensively
is widespread in the environment, even though the degradative capacity is spread over several organisms and conditions.
Received: 9 February 1999 / Revision received: 7 April 1999 / Accepted: 9 April 1999 相似文献
18.
Biotechnology of succinic acid production and markets for derived industrial products 总被引:29,自引:4,他引:25
Succinic acid, derived from fermentation of agricultural carbohydrates, has a specialty chemical market in industries producing
food and pharmaceutical products, surfactants and detergents, green solvents and biodegradable plastics, and ingredients to
stimulate animal and plant growth. As a carbon-intermediate chemical, fermentation-derived succinate has the potential to
supply over 2.7 × 108 kg industrial products/year including: 1,4-butanediol, tetrahydrofuran, γ-butyrolactone, adipic acid, n-methylpyrrolidone and linear aliphatic esters. Succinate yields as high as 110 g/l have been achieved from glucose by the
newly discovered rumen organism Actinobacillus succinogenes. Succinate fermentation is a novel process because the greenhouse gas CO2 is fixed into succinate during glucose fermentation. New developments in end-product recovery technology, including water-splitting
electrodialysis and liquid/liquid extraction have lowered the cost of succinic acid production to U.S. $ 0.55/kg at the 75 000
tonne/year level and to $ 2.20/kg at the 5000 tonne/year level. Research directions aimed at further improving the succinate
fermentation economics are discussed.
Received: 27 October 1998 / Received revision: 22 January 1999 / Accepted: 22 January 1999 相似文献
19.
Lentinula edodes (Berk.) Pegler was cultivated in liquid media containing malt and yeast extract. Extracellular laccase activity, measured
in the culture fluids, was 5–18 times higher in cultures incubated for 29 days than in cultures incubated for 24 days. The
addition of water-soluble lignin derivatives or Trichoderma sp. in cultures of L. edodes incubated for 11 days increased laccase activity 3- to 20 fold. The higher response was obtained with live mycelium of Trichoderma sp., but cell-free culture fluids of Trichoderma sp. in pure cultures were also effective. Trichoderma sp. induced changes in the laccase isoenzyme pattern as a result of the alteration of laccases secreted by L. edodes and not the induction of new isoforms.
Received: 3 November 1997 / Received revision: 19 January 1998 / Accepted: 24 January 1998 相似文献
20.
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