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1.
The in vitro depolymerization of humic acids derived from German lignite (low-rank coal, brown coal) was studied using a
manganese peroxidase preparation from the white-rot fungus Nematoloma frowardii b19. The H2O2 required was continuously generated by glucose oxidase. Mn peroxidase depolymerized high-molecular-mass humic acids by forming
fulvic-acid-like compounds. The depolymerization process was accompanied by the decolorization of the dark-brown humic acid
fraction soluble in alkaline solutions (decrease in absorbance at 450 nm) and by the yellowish coloring of the fraction of
acid-soluble fulvic-acid-like compounds (increase in absorbance at 360 nm). The Mn peroxidase of N. frowardii b19 has been proved to be highly stable; even after an in vitro reaction time of 7 days in the presence of humic acids, less
than 10% loss in total oxidizing activity was detectable.
Received: 16 September 1996 / Received revision: 16 December 1996 / Accepted: 20 December 1996 相似文献
2.
Differential expression of manganese peroxidase and laccase in white-rot fungi in the presence of manganese or aromatic compounds 总被引:4,自引:0,他引:4
White-rot fungi (basidiomycetes) play an important role in the degradation of lignin which is, beside cellulose, the major
compound of wood. This process is catalyzed by ligninolytic enzymes, which are able to cleave oxidatively aromatic rings in
lignin structure. Manganese peroxidase and laccase of white-rot-fungi are the most important of these among the ligninolytic
enzymes. In addition, they are able to degrade xenobiotic aromatic polymers, persisting as environmental pollutants. Manganese
and aromatic compounds have often been discussed as being inducers, enhancers or mediators of these ligninolytic enzymes.
It is known that supplementing the growth medium with either Mn2+, veratryl alcohol or coal-derived humic acids leads to significantly enhanced extracellular ligninolytic activities. Measuring
the amount of expressed mRNA of the two enzymes by quantitative RT-PCR provided evidence that the expression of manganese
peroxidase was induced in the three tested white-rot fungi, Clitocybula dusenii b11, Nematoloma frowardii b19, and a straw-degrading strain designated i63–2. Laccase, on the other hand, was expressed in all three fungi with a significant
basic activity even without inducer added. However, since the level of laccase mRNA was higher in cultures supplemented with
any one of the tested inducers, we conclude that both manganese and the aromatic substances also increase the expression of
laccase.
Received: 4 February 2000 / Received revision: 11 May 2000 / Accepted: 12 May 2000 相似文献
3.
The majority of lignin-degrading basidiomycetes are able to depolymerize humic acids. In this presentation the relationship
and possible similarities between enzymes involved in lignin degradation and humic acid depolymerization were examined on
the genetic level. We have cloned fragments of the gene encoding the extracellular ligninolytic enzyme laccase from Clitocybula dusenii, Nematoloma frowardii and a fungal strain designated i63-2, and compared the three sequences with those of several other published laccase genes.
The sequenced fragments displayed a high homology both on the DNA (97%–77%) and amino acid (100%–85%) level. Furthermore,
the expression of this gene in the above-mentioned fungi was demonstrated by a nested polymerase chain reaction with cDNA
as template.
Received: 3 February 1998 / Received revision: 31 August 1998 / Accepted: 3 September 1998 相似文献
4.
A miniscale screening system was developed to detect depolymerizing activities of fungi toward low-rank coals. This system
was suitable for the determination of changes in molecular masses as well as for the measurement of the enzymes responsible.
A total of 486 fungal strains of different ecophysiological and taxonomic groups were tested for their ability to decolorize
agar media containing coal-derived humic acids; 38 wood- and litter-decaying basidiomycetes caused a strong bleaching effect
and 49 a weak effect. In contrast, micromycetes were proved to be unable to decolorize the coal substances. The wood-decaying
fungus Nematoloma frowardii b19 most effectively bleached the medium. It could be demonstrated by gel-permeation chromatography that the strain really
depolymerizes the high molecular-mass fractions of coal humic acids by forming fulvic-acid-like compounds. Extracellular enzyme
activities of oxidases and peroxidases towards 2,2′-azinobis(3-ethylbenzthiazolinesulphonate) were extractable from the agar
media.
Received: 5 February 1996/Received revision: 15 April 1996/Accepted: 22 April 1996 相似文献
5.
Lignite (brown coal) can be liquefied/solubilized with several fungi by different mechanisms. When applied industrially,
only catalytic mechanisms can compete with chemical methods. The well-known fungal ligninolytic peroxidases are at a disadvantage,
in that the relatively expensive hydrogen peroxide must be used as a cofactor. Comparing several fungal strains, we observed
that the fungus Trametes versicolor is able to decolorize coal-derived humic acids, producing a considerable amount of laccase in the process. During this reaction
the amount of humic acids decreases whilst that of fulvic acids increases; this was verified by optical density measurement
and GPC after the two substance classes had been separated.
Received: 27 August 1998 / Received revision: 4 November 1998 / Accepted: 7 November 1998 相似文献
6.
Detoxification of wood hydrolysates with laccase and peroxidase from the white-rot fungus Trametes versicolor 总被引:1,自引:0,他引:1
L. J. Jönsson E. Palmqvist N.-O. Nilvebrant B. Hahn-Hägerdal 《Applied microbiology and biotechnology》1998,49(6):691-697
Fermentation of wood hydrolysates to desirable products, such as fuel ethanol, is made difficult by the presence of inhibitory
compounds in the hydrolysates. Here we present a novel method to increase the fermentability of lignocellulosic hydrolysates:
enzymatic detoxification. Besides the detoxification effect, treatment with purified enzymes provides a new way to identify
inhibitors by assaying the effect of enzymatic attack on specific compounds in the hydrolysate. Laccase, a phenol oxidase,
and lignin peroxidase purified from the ligninolytic basidiomycete fungus Trametes versicolor were studied using a lignocellulosic hydrolysate from willow pretreated with steam and SO2. Saccharomyces cerevisiae was employed for ethanolic fermentation of the hydrolysates. The results show more rapid consumption of glucose and increased
ethanol productivity for samples treated with laccase. Treatment of the hydrolysate with lignin peroxidase also resulted in
improved fermentability. Analyses by GC-MS indicated that the mechanism of laccase detoxification involves removal of monoaromatic
phenolic compounds present in the hydrolysate. The results support the suggestion that phenolic compounds are important inhibitors
of the fermentation process.
Received: 3 November 1997 / Received revision: 4 February 1998 / Accepted: 6 February 1998 相似文献
7.
Novotný C Erbanová P Cajthaml T Rothschild N Dosoretz C Sasek V 《Applied microbiology and biotechnology》2000,54(6):850-853
Growth parameters, ligninolytic enzyme activities and ability to degrade polycyclic aromatic hydrocarbons by the fungus Irpex lacteus were characterized and compared with those of other white rot fungi capable of rapid decolorization of poly R-478 and Remazol
Brilliant Blue R dyes. I. lacteus was able to grow on mineral and complex media and efficiently colonized sterile and non-sterile soil by exploratory mycelium
growing from a wheat straw inoculum. In shallow stationary cultures growing on high nitrogen mineral medium containing 45 mM
ammonium as nitrogen source, the fungus produced lignin peroxidase (LIP), Mn-dependent peroxidase (MnP) and laccase simultaneously,
the respective maximal activities of 70, 970 and 36 U/l being attained around day 18. Growing in nitrogen-limited medium (2.4 mM
ammonium), no LIP was formed and levels of MnP and laccase decreased significantly. During growth in sterile soil, the fungus
synthesized LIP and laccase but not MnP. I. lacteus efficiently removed three- and four-ringed PAHs from liquid media and artificially spiked soil. The variety of ligninolytic
enzymes, robust growth, capability of soil colonization and resistance to inhibitory action of soil bacteria make I. lacteus a suitable fungal organism for use in bioremediation.
Received: 30 March 2000 / Accepted: 19 May 2000 相似文献
8.
A. Rodríguez M. A. Falcón A. Carnicero F. Perestelo G. De la Fuente J. Trojanowski 《Applied microbiology and biotechnology》1996,45(3):399-403
An extracellular laccase capable of oxidizing ABTS (the diammonium salt of 2,2′-azinobis-3-ethylbenzothiazoline-6-sulfonic
acid) was detected in ligninolytic cultures of Penicillium chrysogenum. By contrast, no lignin peroxidase, manganese-dependent peroxidase or aryl-alcohol oxidase was detected at any time during
culturing. Both ABTS laccase activity and mineralization of dehydrogenative polymerizate of coniferyl alcohol were regulated
by the C/N ratio in the medium and partially inhibited in the presence of thioglycolic acid, suggesting that both events are
associated. In the presence of several known laccase inducers neither ABTS laccase activity nor mineralization rates were
enhanced. However, a new laccase was detected in P. chrysogenum, able to oxidize 2,6-dimethoxyphenol but not involved in lignin mineralization. Studies with the known ligninolytic basidiomycete
Trametes villosa suggest that lignin degradation by this fungus also involves the action of laccase.
Received: 6 July 1995/Received revision: 28 October 1995/Accepted: 6 November 1995 相似文献
9.
Production of ligninolytic enzymes and synthetic lignin mineralization by the bird's nest fungus Cyathus stercoreus 总被引:3,自引:0,他引:3
Production of ligninolytic enzymes and degradation of 14C-ring labeled synthetic lignin by the white-rot fungus Cyathus stercoreus ATCC 36910 were determined under a variety of conditions. The highest mineralization rate for 14C dehydrogenative polymerizates (DHP; 38% 14CO2 after 30 days) occurred with 1 mM ammonium tartrate as nitrogen source and 1% glucose as additional carbon source, but levels
of extracellular laccase and manganese peroxidase (MnP) were low. In contrast, 10 mM ammonium tartrate with 1% glucose gave
low mineralization rates (10% 14CO2 after 30 days) but higher levels of laccase and manganese peroxidase. Lignin peroxidase was not produced by C. stercoreus under any of the studied conditions. Mn(II) at 11 ppm gave a higher rate of 14C DHP mineralization than 0.3 or 40 ppm, but the highest manganese peroxidase level was obtained with Mn(II) at 40 ppm. Cultivation
in aerated static flasks gave rise to higher levels of both laccase and manganese peroxidase compared to the levels in shake
cultures. 3,4-Dimethoxycinnamic acid at 500 μM concentration was the most effective inducer of laccase of those tested. The
purified laccase was a monomeric glycoprotein having an apparent molecular mass of 70 kDa, as determined by calibrated gel
filtration chromatography. The pH optimum and isoelectric point of the purified laccase were 4.8 and 3.5, respectively. The
N-terminal amino acid sequence of C. stercoreus laccase showed close homology to the N-terminal sequences determined from other basidiomycete laccases. Information on C. stercoreus, whose habitat and physiological requirements for lignin degradation differ from many other white-rot fungi, expands the
possibilities for industrial application of biological systems for lignin degradation and removal in biopulping and biobleaching
processes.
Received: 29 January 1999 / Received revision: 5 July 1999 / Accepted: 9 July 1999 相似文献
10.
There is need for new effective technologies to convert coal into environmentally acceptable liquid fuels. Thermochemical
coal-conversion processes occur under extreme conditions. Thus there is a potential to use the biotransformation of coal as
a cheap alternative method. A basidiomycete strain, which decomposes coal macromolecules, was isolated from humic-acid-rich
soil of a lignite surface-mining region. The isolate showed the ability to decolorize liquid dark-brown media containing water-soluble
coal-derived substances (humic acids). The presence of an easily available substrate is necessary for the biodegradation.
The influence of different culture conditions on the bleaching effect was studied. Evidence for decomposition of water-soluble
coal substances was provided by measuring the decrease of absorbance and the modification in the distribution of molecular
masses. The degradation process resulted in a complete decolorization of the coal-derived humic acids and was also combined
with massive alterations in their molecular structure. Solid-state #13C-NMR spectroscopy showed an increase of carboxylic
groups as well as hydroxylated and methoxylated aliphatic groups, which indicates an oxidative attack. Enzymatic analysis
showed the presence of a Mn peroxidase in the culture supernatant. Extracellular lignin peroxidase and laccase activities
were not detectable. The production of the peroxidase was induced by addition of humic acids. But, in vitro, this enzyme did
not cause a decolorization or reduction in molecular mass of the coal-derived humic acids.
Received: 30 May 1996 / Received revision: 11 September 1996 / Accepted: 13 September 1996 相似文献
11.
Sivakumar U. Kalaichelvan G. Ramasamy K. 《World journal of microbiology & biotechnology》2004,20(6):563-568
Biodegradation of lignin by Streptomyces spp. results in the production of value-added chemicals such as Acid Precipitable Polymeric Lignins (APPLs), low molecular
weight phenols, etc. To hasten the conversion metabolism through genetic manipulation, a preliminary attempt was made to standardize
the methodology for isolation and regeneration of protoplasts. Protoplast fusion recombinants were developed and assayed for
their ligninolytic activity, production of ligninolytic enzymes viz., peroxidase, laccase, polyphenol oxidase and crude protein. In comparison with the mutants and wild strain, fusion recombinant
F4 showed higher laccase activity and lower peroxidase activity. This attribute can be positively used for polymerization of
free phenolics to polycondensates related to humic acids in soil or composting environments.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
12.
Trametes versicolor was shown to produce extracellular laccase during surface cultivation on glucose, wheat straw and beech wood. Growth on both
wheat straw and beech wood led to an increase as high as 3.5-fold in extracellular laccase activity, in comparison with growth
on glucose. The corresponding yields in fungal biomass reached only about 20% of the value obtained on glucose. Manganese
peroxidase activity␣appeared during growth on wheat straw and beech wood. Mycelia grown on glucose, wheat straw and beech
wood also showed intracellular laccase activities, monitored with 2,6-dimethoxyphenol, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic
acid), 4-hydroxy-3,5-dimethoxybenzaldehyde azine (syringaldazine) and 3,4-dihydroxyphenylalanine (l-DOPA). Assaying intracellular laccase with 2,6-dimethoxyphenol, syringaldazine and l-DOPA showed the maximum oxidation rates to be at pH values different from those producing maximum oxidation rates with extracellular
laccase. In each case most of the total laccase activity was recovered from the culture filtrates. Growth on wheat straw and
beech wood led to increased values for both extra- and intracellular laccase activities, based on fungal dry weight, in comparison
with growth on glucose.
Received: 18 July 1996 / Received revision: 19 November 1996 / Accepted: 23 November 1996 相似文献
13.
Mineralization of synthetic humic substances by manganese peroxidase from the white-rot fungus Nematoloma frowardii 总被引:3,自引:0,他引:3
M. Hofrichter K. Scheibner I. Schneegaß D. Ziegenhagen W. Fritsche 《Applied microbiology and biotechnology》1998,49(5):584-588
A manganese peroxidase preparation from the white-rot fungus Nematoloma frowardii was found to be capable of releasing up to 17% 14CO2 from 14C-labelled synthetic humic substances. The latter were prepared from [U-14C]catechol by spontaneous oxidative polymerization or laccase-catalysed polymerization. The ex-tent of humic substance mineralization
was considerably enhanced in the presence of the thiol mediator glutathione (up to 50%). Besides the evolution of 14CO2, the treatment of humic substances with Mn peroxidase resulted in the formation of lower-molecular-mass products. Analysis
of residual radioactivity by gel-permeation chromatography demonstrated that the predominant molecular masses of the initial
humic substances ranged between 2 kDa and 6 kDa; after treatment with Mn peroxidase, they were reduced to 0.5–2 kDa. The extracellular
depolymerization and mineralization of humic substances by the Mn peroxidase system may play an important role in humus turnover
of habitats that are rich in basidiomycetous fungi.
Received: 25 September 1997 / Received revision: 12 January 1998 / Accepted: 13 January 1998 相似文献
14.
I. Schneegaß M. Hofrichter K. Scheibner W. Fritsche 《Applied microbiology and biotechnology》1997,48(5):602-605
The main manganese peroxidase isoenzyme MnP2 of the South American white-rot fungus Nematoloma frowardii b19 was purified to homogeneity using anion-exchange chromatography (Mono Q) and preparative isoelectric focusing. The purified
enzyme has a molecular mass of 44 kDa and a pI of 3.2.
Received: 23 May 1997 / Received revision: 1 July 1997 / Accepted: 4 July 1997 相似文献
15.
Mineralisation of 14C-labelled synthetic lignin and ligninolytic enzyme activities of litter-decomposing basidiomycetous fungi 总被引:4,自引:0,他引:4
Within a screening program, 27 soil litter-decomposing basidiomycetes were tested for ligninolytic enzyme activities using
agar-media containing 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonate), a humic acid or Mn2+ ions as indicator substrates. Most active species were found within the family Strophariaceae (Agrocybe praecox, Stropharia coronilla, S. rugosoannulata) and used for mineralisation experiments with a 14C-ring-labelled synthetic lignin (14C-DHP). The fungi mineralised around 25% of the lignin to 14CO2 within 12 weeks of incubation in a straw environment; about 20% of the lignin was converted to water-soluble fragments. Mn-peroxidase
was found to be the predominant ligninolytic enzyme of all three fungi in liquid culture and its production was strongly enhanced
in the presence of Mn2+ ions. The results of this study demonstrate that certain ubiquitous litter-decomposing basidiomycetes possess ligninolytic
activities similar to the wood-decaying white-rot fungi, the most efficient lignin degraders in nature.
Received: 20 April 2000 / Received revision: 12 July 2000 / Accepted: 16 July 2000 相似文献
16.
Wunderwald U Kreisel G Braun M Schulz M Jäger C Hofrichter M 《Applied microbiology and biotechnology》2000,53(4):441-446
A synthetic fluorinated humic acid (FHA) was prepared by the spontaneous oxidative polymerization of 3-fluorocatechol. The
13C-solid-state NMR spectrum showed signals in the region for aromatic carbons with different substituents (aryl-H, aryl-C,
aryl-O carbons) and for carboxyl-carbon. The latter indicated the formation of carboxylic groups, probably caused by ring
cleavages during the polymerization process. An indication of the formation of carboxylic groups was also found in the infrared
spectrum (band at 1715 cm−1). The dissolved FHA was degraded with active mycelium of the agaric white-rot fungus Nematoloma frowardii as well as with its isolated manganese peroxidase. In both cases, decolorization of the brownish FHA solution and partial
defluorination (45–60%) took place. Degradation proceeded via formation of lower-molecular-mass fulvic acid-like substances.
The results demonstrate that halogenated humic substances, e.g., resulting from the humification of xenobiotic compounds (bound
residues), can in principle be eliminated by ligninolytic fungi (e.g., soil colonizing litter decomposers) and their manganese
peroxidase system.
Received: 28 June 1999 / Received revision: 14 October 1999 / Accepted: 16 October 1999 相似文献
17.
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
18.
Extracellular lignin peroxidase (LiP) was not detected during decoloration of the azo dye, Amaranth, by Trametes versicolor. Approximately twice as much laccase and manganese peroxidase (MnP) was produced by decolorizing cultures compared to when
no dye was added. At a low Mn2+ concentration (3 M), N-limited (1.2 mM NH4
+) cultures decolorized eight successive additions of Amaranth with no visible sorption to the mycelial biomass. At higher
Mn2+ concentrations (200 M), production of MnP increased and that of laccase decreased, but the rate or number of successive Amaranth
decolorations was unaffected. There was always a 6-h to 8-h lag prior to decoloration of the first aliquot of Amaranth, regardless
of MnP and laccase concentrations. Although nitrogen-rich (12 mM NH4
+) cultures at an initial concentration of 200 M Mn2+ produced high laccase and MnP levels, only three additions of Amaranth were decolorized, and substantial mycelial sorption
of the dye occurred. While the results did not preclude roles for MnP and laccase, extracellular MnP and laccase alone were
insufficient for decoloration. The cell-free supernatant did not decolorize Amaranth, but the mycelial biomass separated from
the whole broth and resuspended in fresh medium did. This indicates the involvement of a mycelial-bound, lignolytic enzyme
or a H2O2-generating mechanism in the cell wall. Nitrogen limitation was required for the expression of this activity.
Received: 19 May 1998 / Received revision: 22 October 1998 / Accepted: 7 November 1998 相似文献
19.
Won Ryul Ryu Seong Hoon Shim Moon Yup Jang Yeong Joong Jeon Kwang Keun Oh Moo Hwan Cho 《Biotechnology and Bioprocess Engineering》2000,5(3):211-214
The roles of lignin peroxidase, manganese peroxidase, and laccase were investigated in the biodegradation of pentachlorophenol
(PCP) by several white rot fungi. The disappearance of pentachlorophenol from cultures of wild type strains,P. chrysosporium, Trametes sp. andPleurotus sp., was observed. The activities of manganese peroxidase and laccase were detected inTiametes sp. andPleurotus sp. cultures. However, the activities of ligninolytic enzymes were not detected inP. chrysosporium cultures. Therefore, our results showed that PCP was degraded under ligninolytic as well as nonligninolytic conditions. Indicating
that lignin peroxidase, manganese peroxidase, and laccase are not essential in the biodegradation of PCP by white rot fungi. 相似文献
20.
The white-rot fungus Phanerochaete chrysosporium can degrade macromolecules in low-rank coal, offering the potential for converting coal to specific products. We investigated
the influence of temperature, veratryl alcohol and oxygen on transformation of a solubilised fraction of Morwell brown coal
(SWC6 coal) and on the activity of lignin peroxidase and manganese (Mn) peroxidase in N-limited cultures of P. chrysosporium. After 20 days, the mass and A
400 of SWC6 coal recovered from cultures containing 0.03% SWC6 coal, incubated at 28 °C under hyperbaric oxygen, were reduced
by over 95%. The modal apparent molecular mass of the residuum was reduced by 50%. Addition of 2 mM veratryl alcohol had little
effect on the transformation of SWC6 coal. The extent of transformation was reduced in cultures incubated at 37 °C or under
air. In cultures under air, coal molecules were transiently polymerised. Decolourisation of SWC6 coal reflects conversion
to products that cannot be recovered from the medium, not the destruction of chromophores within recoverable material. The
activity of lignin peroxidase, measured in cultures free of SWC6 coal to avoid interference with the assay, correlates directly
with the degradation of SWC6 coal as measured by the decline in A
400. The data suggest that lignin peroxidase is more important than Mn peroxidase in converting SWC6 coal to products that are
assimilated by cells.
Received: 16 July 1997 / Received revision: 14 November 1997 / Accepted: 18 November 1997 相似文献