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1.
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
2.
Laccase can be used for enzymatic detoxification of lignocellulosic hydrolysates. A Saccharomyces cerevisiae strain with enhanced resistance to phenolic inhibitors and thereby improved ability to ferment lignocellulosic hydrolysates
would presumably be obtained by heterologous expression of laccase. Sequencing of the cDNA for the novel laccase gene lcc2 from the lignin-degrading basidiomycete Trametes versicolor showed that it encodes an isoenzyme of 499 amino-acid residues preceded by a 21-residue signal peptide. By comparison with
Edman degradation data, it was concluded that lcc2 encodes an isoenzyme corresponding to laccase A. The gene product of lcc2 displays 71% identity with the previously characterized T. versicolor lcc1 gene product. An alignment of laccase sequences revealed that the T. versicolor isoenzymes in general are more closely related to corresponding isoenzymes from other white-rot fungi than to the other T. versicolor isoenzymes. The multiplicity of laccase is thus a conserved feature of T. versicolor and related species of white-rot fungi. When the T. versicolor lcc2 cDNA was expressed in S. cerevisiae, the production of active enzyme was strongly dependent on the temperature. After 3 days of incubation, a 16-fold higher laccase
activity was found when a positive transformant was kept at 19 °C instead of 28 °C. Similar experiments with Pichia pastoris expressing the T. versicolor laccase gene lcc1 also showed that the expression level was favoured considerably by lower cultivation temperature, indicating that the observation
made for the S. cerevisiae expression system is of general significance.
Received: 8 December 1998 / Received revision: 9 April 1999 / Accepted: 16 April 1999 相似文献
3.
Dias Albino A. Bezerra Rui M. Lemos Paula M. Nazaré Pereira A. 《World journal of microbiology & biotechnology》2003,19(9):969-975
Bioremediation is considered a promising eco-efficient alternative for industrial wastewater treatment. Particular attention is currently being given to biological degradation of synthetic dyes and more specifically to colour removal by fungi. This work looks at the extracellular enzymatic system of strain Euc-1. Its ability to decolourize 14 xenobiotic azo dyes was evaluated and compared with the well-known species Phanerochaete chrysosporium. Strain Euc-1 is a mesophilic white-rot basidiomycete, the main secreted ligninolytic enzyme being laccase (0.38 U ml–1). Although low manganese-dependent peroxidase activity (0.05 U ml–1) was also detected, neither lignin peroxidase nor aryl alcohol oxidase could be found in batch culture. Optimum pH values of 4.0 and 5.0 were obtained in the laccase-catalysed oxidation of guaiacol and syringaldazine, respectively. Laccase activity increased with the temperature rise up to 50–60 °C and remarkable thermal stability was observed at 50 °C with a half-life of 12 h and no deactivation within the first 2 h. Solid-plate decolourization studies showed that basidiomycete Euc-1 decolourized 11 azo dyes whereas P. chrysosporium only two. Moreover, it is shown that purified laccase from basidiomycete Euc-1 efficiently decolourizes the azo dye acid red 88. 相似文献
4.
5.
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
6.
Industrial Dye Decolorization by Laccases from Ligninolytic Fungi 总被引:14,自引:0,他引:14
White-rot fungi were studied for the decolorization of 23 industrial dyes. Laccase, manganese peroxidase, lignin peroxidase,
and aryl alcohol oxidase activities were determined in crude extracts from solid-state cultures of 16 different fungal strains
grown on whole oats. All Pleurotus ostreatus strains exhibited high laccase and manganese peroxidase activity, but highest laccase volumetric activity was found in Trametes hispida. Solid-state culture on whole oats showed higher laccase and manganese peroxidase activities compared with growth in a complex
liquid medium. Only laccase activity correlated with the decolorization activity of the crude extracts. Two laccase isoenzymes
from Trametes hispida were purified, and their decolorization activity was characterized.
Received: 26 May 1998 / Accepted: 7 August 1998 相似文献
7.
Expression of laccase gene lcc1 in Coprinopsis cinerea under control of various basidiomycetous promoters 总被引:1,自引:0,他引:1
Kilaru S Hoegger PJ Majcherczyk A Burns C Shishido K Bailey A Foster GD Kües U 《Applied microbiology and biotechnology》2006,71(2):200-210
Coprinopsis cinerea laccase gene lcc1 was expressed in this basidiomycete under naturally non-inductive conditions using various homologous and heterologous promoters. Laccase expression was achieved in solid and liquid media with promoter sequences from the C. cinerea tub1 gene, the Agaricus bisporus gpdII gene, the Lentinus edodes priA gene and the Schizophyllum commune Sc3 gene. As measured by enzyme activity in liquid cultures, a 277-bp gpdII promoter fragment, followed by a 423-bp priA fragment, was most efficient. A shorter priA sequence of 372 bp was inactive. tub1 promoter fragments were reasonably active, whereas the S. commune Sc3 promoter sequence was less active, in comparison. Irrespective of the promoter used, addition of copper to the medium increased enzymatic activities for highly active transformants by 10- to 50-fold and for less active transformants for 2- to 7-fold. The highest enzymatic activities (3 U/ml) were reached with the gpdII promoter in the presence of 0.1 mM CuSO4. 相似文献
8.
The laccase gene lacD, cloned from a novel laccase-producing basidiomycete Trametes sp. 420, contained 2,052 base pairs (bp) interrupted by 8 introns. lacD displayed a relatively high homology with laccase genes from other white rot fungi, whereas the homology between lacD and laccase genes from plants, insects, or bacteria was less than 25%. A 498–amino acid peptide encoded by the lacD cDNA was heterologously expressed in the Pichia pastoris strain GS115, resulting in the highest yield of laccase (8.3 × 104 U/l) as determined with ABTS (2,2′-azinobis [3-ethylbenzothia-zoline-6-sulfonic acid]) as the substrate. Additionally, the
enzyme activity of recombinant laccase on decolorization of some industrial dyes was assessed. 相似文献
9.
Vandertol-Vanier HA Vazquez-Duhalt R Tinoco R Pickard MA 《Journal of industrial microbiology & biotechnology》2002,29(5):214-220
We are studying the enzymatic modification of polycyclic aromatic hydrocarbons (PAHs) by the laccase from Coriolopsis gallica UAMH 8260. The enzyme was produced during growth in a stirred tank reactor to 15 units ml−1, among the highest levels described for a wild-type fungus; the enzyme was the major protein produced under these conditions.
After purification, it exhibited characteristics typical of a white rot fungal laccase. Fifteen azo and phenolic compounds
at 1 mM concentration were tested as mediators in the laccase oxidation of anthracene. Higher anthracene oxidation was obtained
with the mediator combination of ABTS and HBT, showing a correlation between the oxidation rate and the mediator concentration.
Reactions with substituted phenols and anilines, conventional laccase substrates, and PAHs were compared using the native
laccase and enzyme preparations chemically modified with 5000 MW-poly(ethylene glycol). Chemically modified laccase oxidized
a similar range of substituted phenols as the native enzyme but with a higher catalytic efficiency. The k
cat increase by the chemical modification may be as great as 1300 times for syringaldazine oxidation. No effect was found of
chemical modification on mediated PAH oxidation. Both unmodified and PEG-modified laccases increased PAH oxidation up to 1000
times in the presence of radical mediators. Thus, a change of the protein surface improves the mediator oxidation efficiency,
but does not affect non-enzymatic PAH oxidation by oxidized mediators.
Received 10 December 2001/ Accepted in revised form 20 July 2002 相似文献
10.
Stepanova E. V. Koroleva O. V. Gavrilova V. P. Landesman E. O. Makower A. Papkovsky D. B. 《Applied Biochemistry and Microbiology》2003,39(5):482-487
Stability characteristics of the laccases of the basidiomycetes Coriolus hirsutus and Coriolus zonatus were measured comparatively at temperatures of 25 and 40°C in the presence of various effectors (proteins, salts, polyalcohols, polyacids, and polyelectrolytes). Stabilization effects of cations on the laccases from C. hirsutus and C. zonatus decreased in the descending series Cu2+ > Mg2+ > Ca2+ and Ca2+ > Mg2+ > Mn2+, respectively. Tween 20 caused insignificant stabilization of the two enzymes. The C. zonatus laccase was also insignificantly stabilized as a result of treatment with bovine serum albumin. The enzymatic activity of the laccase preparations from C. hirsutus and C. zonatus was conserved virtually completely after vacuum drying (84 and 93%, respectively). The most effective stabilizer of the C. hirsutus laccase was found to be dextran (17 kDa). Dry preparations treated with this agent conserved up to 95% of the enzymatic activity. The most effective stabilizer of the C. zonatus laccase was polyacrylic acid (102% of the initial activity). 相似文献
11.
A. Chernykh N. Myasoedova M. Kolomytseva M. Ferraroni F. Briganti A. Scozzafava L. Golovleva 《Journal of applied microbiology》2008,105(6):2065-2075
Aims: To isolate and characterize the laccase isoforms from S. ochraceum 1833 – a new active producer of high extracellular laccase activity. Methods and Results: Three laccase isoforms (laccases I, II and III) with 57·5, 59·5 and 63 kDa molecular masses respectively were purified from S. ochraceum 1833 and in contrast to the known laccases had strongly pronounced absorption at 611 nm with molar extinction coefficients ranging from 7170 to 7830 mol?1 l cm?1. All isoforms showed maximal activity with ABTS at low pH (≤2) and temperatures in the range 70–80°C, were stable for long time of incubation at high temperature (60–80°C) and at pH values ranging from 2 to 6. Laccase II showed a higher activity and wider substrate specificity. N‐terminal amino acid sequence analysis of the purified laccase II (VQIGPVTDLH) showed 80% identity with the N‐terminal amino acid sequence of laccase from Lentinula edodes [Appl Microbiol Biotechnol 60 (2002) 327]. Conclusions: Elevated temperature optima, high thermo‐ and pH‐stabilities, the broad substrate specificity of the isoforms make the laccases from S. ochraceum 1833 a suitable model for biotechnological processes proceeding at high temperatures. Significance and Impact of the Study: For the first time, new basidiomycete strain S. ochraceum was reported as a producer of novel thermostable, pH stable, acidophilic laccases with unusual spectral properties. 相似文献
12.
Rosario Díaz Mario C. N. Saparrat Miguel Jurado Inmaculada García-Romera Juan Antonio Ocampo María Jesús Martínez 《Applied microbiology and biotechnology》2010,88(1):133-142
Two laccase isoenzymes were purified and characterized from the basidiomycete Coriolopsis rigida during transformation of the water-soluble fraction of “alpeorujo” (WSFA), a solid residue derived from the olive oil production
containing high levels of toxic compounds. Zymogram assays of laccases secreted by the fungus growing on WSFA and WSFA supplemented
with glucose showed two bands with isoelectric points of 3.3 and 3.4. The kinetic studies of the two purified isoenzymes showed
similar affinity on 2,6-dimethoxyphenol and 2,2′-azinobis-(3-ethylbenzthiazoline-6-sulfonic acid), used as phenolic and non-phenolic
model substrate, respectively. The molecular mass of both proteins was 66 kDa with 9% N-linked carbohydrate. Physico-chemical
properties of the purified laccases from media containing WSFA were similar to those obtained from medium with glucose as
the main carbon source. In-vitro studies performed with the purified laccases revealed a 42% phenol reduction of WSFA, as
well as changes in the molecular mass distribution. These findings indicate that these laccases are involved in the process
of transformation, via polymerization by the oxidation of phenolic compounds present in WSFA. A single laccase gene, containing
an open reading frame of 1,488 bp, was obtained in PCR amplifications performed with cDNA extracted from mycelia grown on
WSFA. The product of the gene shares 90% identity (95% similarity) with a laccase from Trametes trogii and 89% identity (95% similarity) with a laccase from Coriolopsis gallica. This is the first report on purification and molecular characterization of laccases directly involved in the transformation
of olive oil residues. 相似文献
13.
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
14.
Stability and kinetic behavior of immobilized laccase from Myceliophthora thermophila in the presence of the ionic liquid 1‐ethyl‐3‐methylimidazolium ethylsulfate 下载免费PDF全文
María Fernández‐Fernández Diego Moldes Alberto Domínguez M. Ángeles Sanromán Ana Paula M. Tavares Oscar Rodríguez Eugénia A. Macedo 《Biotechnology progress》2014,30(4):790-796
The use of ionic liquids (ILs) as reaction media for enzymatic reactions has increased their potential because they can improve enzyme activity and stability. Kinetic and stability properties of immobilized commercial laccase from Myceliophthora thermophila in the water‐soluble IL 1‐ethyl‐3‐methylimidazolium ethylsulfate ([emim][EtSO4]) have been studied and compared with free laccase. Laccase immobilization was carried out by covalent binding on glyoxyl–agarose beads. The immobilization yield was 100%, and the activity was totally recovered. The Michaelis‐Menten model fitted well to the kinetic data of enzymatic oxidation of a model substrate in the presence of the IL [emim][EtSO4]. When concentration of the IL was augmented, the values of Vmax for free and immobilized laccases showed an increase and slight decrease, respectively. The laccase–glyoxyl–agarose derivative improved the laccase stability in comparison with the free laccase regarding the enzymatic inactivation in [emim][EtSO4]. The stability of both free and immobilized laccase was slightly affected by small amounts of IL (<50%). A high concentration of the IL (75%) produced a large inactivation of free laccase. However, immobilization prevented deactivation beyond 50%. Free and immobilized laccase showed a first‐order thermal inactivation profile between 55 and 70°C in the presence of the IL [emim][EtSO4]. Finally, thermal stability was scarcely affected by the presence of the IL. © 2014 American Institute of Chemical Engineers Biotechnol. Prog., 30:790–796, 2014 相似文献
15.
16.
Sarita W. Nazareth Judith D. Sampy 《International biodeterioration & biodegradation》2003,52(4):207-214
This study on the lignocellulases in broth cultures of the basidiomycete Panus tigrinus indicates that laccase and xylanase enzymes are constitutive and cellulase is inducible. In stationary culture at 28°C, the greatest laccase and xylanase activity was observed after growth for approximately nine days. Laccase production was dependent on the presence, and the particular brand, of malt extract in the growth medium. While production of laccase was enhanced by growth at 37°C and 42°C, xylanase was not. Raising the pH of the growth medium from pH 5.6 to pH 7.0 did not affect xylanase production, but laccase production was reduced at the higher pH. In shake culture, growth was pelleted and biomass lower than in stationary culture, and synthesis of both enzymes was strongly inhibited. Cultures of P. tigrinus decolourised Poly R-478 and the toxic triphenyl methane dye, crystal violet. It was also shown to degrade a natural lignocellulosic waste, sawdust. 相似文献
17.
A homogenous enzyme with both bilirubin oxidase and laccase activities was isolated from a submerged culture of the basidiomycete
Pleurotus ostreatus mycelium and characterized. The yield of the enzyme was 127 μg/g dry biomass of the mycelium. The specific activity of the
enzyme was 21 and 261 U/mg to bilirubin and to a laccase substrate ABTS, respectively. The intracellular phenol oxidase from
the P. ostreatus mycelium was identified as bilirubin oxidase with the amino acid sequence highly homologous to that of the pox2 gene-encoded product. The enzyme displayed the maximal laccase activity at 50–55°C to all substrates examined, whereas the
pH optimum was substrate-dependent and changed from 3.0 for ABTS to 7.0 for syringaldazine and guaiacol. The enzyme maintained
catalytic activity within a broad pH range but was inactivated at pH 4.0. The enzyme was thermostable but very sensitive to
metal chelating inhibitors. Trypan Blue (5 mg/liter) was completely decolorizated upon 3 h of incubation with the bilirubin
oxidase (20 mU/ml) at room temperature. 相似文献
18.
Pedro H. Mainardi Valker A. Feitosa Livia B. Brenelli de Paiva Rafaella C. Bonugli-Santos Fabio M. Squina Adalberto Pessoa Lara D. Sette 《Fungal biology》2018,122(5):302-309
Laccase production in saline conditions is still poorly studied. The aim of the present study was to investigate the production of laccase in two different types of bioreactors by the marine-derived basidiomycete Peniophora sp. CBMAI 1063. The highest laccase activity and productivity were obtained in the Stirred Tank (ST) bioreactor, while the highest biomass concentration in Air-lift (AL) bioreactor. The main laccase produced was purified by ion exchange and size exclusion chromatography and appeared to be monomeric with molecular weight of approximately 55 kDa. The optimum oxidation activity was obtained at pH 5.0. The thermal stability of the enzyme ranged from 30 to 50 °C (120 min). The Far-UV Circular Dichroism revealed the presence of high β-sheet and low α-helical conformation in the protein structure. Additional experiments carried out in flask scale showed that the marine-derived fungus was able to produce laccase only in the presence of artificial seawater and copper sulfate. Results from the present study confirmed the fungal adaptation to marine conditions and its potential for being used in saline environments and/or processes. 相似文献
19.
Anthropogenic release of biologically available N has increased atmospheric N deposition in forest ecosystems, which may slow
decomposition by reducing the lignolytic activity of white-rot fungi. We investigated the potential for atmospheric N deposition
to reduce the abundance and alter the composition of lignolytic basidiomycetes in a regional network of four northern hardwood
forest stands receiving experimental NO3
− deposition (30 kg NO3
−−N ha−1 year−1) for a decade. To estimate the abundance of basidiomycetes with lignolytic potential, we used PCR primers targeting laccase
(polyphenol oxidase) and quantitative fluorescence PCR to estimate gene copy number. Natural variation in laccase gene size
permitted use of length heterogeneity PCR to profile basidiomycete community composition across two sampling dates in forest
floor and mineral soil. Although past work has identified significant and consistent negative effects of NO3
− deposition on lignolytic enzyme activity, microbial biomass, soil respiration, and decomposition rate, we found no consistent
effect of NO3
− deposition on basidiomycete laccase gene abundance or community profile. Rather, laccase abundance under NO3
− deposition was lower (−52%), higher (+223%), or unchanged, depending on stand. Only a single stand exhibited a significant
change in basidiomycete laccase gene profile. Basidiomycete laccase genes occurring in mineral soil were a subset of the genes
observed in the forest floor. Moreover, significant effects on laccase abundance were confined to the forest floor, suggesting
that species composition plays some role in determining how lignolytic basidiomycetes are affected by N deposition. Community
profiles differed between July and October sampling dates, and basidiomycete communities sampled in October had lower laccase
gene abundance in the forest floor, but higher laccase abundance in mineral soil. Although experimental N deposition significantly
suppresses lignolytic activity in these forests, this change is not related to the abundance or community composition of basidiomycete
fungi with laccase genes. Understanding the expression of laccases and other lignolytic enzymes by basidiomycete fungi and
other lignin-decaying organisms appears to hold promise for explaining the consistent decline in lignolytic activity elicited
by experimental N deposition.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
20.
Although field studies have demonstrated an ecosystem-specific effect of experimental atmospheric nitrogen (N) deposition
on litter decomposition, a mechanistic understanding of how ligninolytic microbial communities respond to atmospheric deposition
is lacking. Because high levels of inorganic N suppress lignin decomposition by some basidiomycetes, it is plausible that
the abundance and activity of these key microorganisms underlies differential ecosystem responses of decomposition to atmospheric
N deposition. We hypothesize that: (a) atmospheric N deposition will cause an ecosystem-specific reduction in basidiomycete
activity and abundance with greatest decreases in ecosystems with lignin-rich forest litter and (b) the abundance of lignin
degrading basidiomycetes will be positively correlated with ligninolytic enzyme activity. To test these hypotheses, we measured
the effects of experimental N deposition on the potential activity of phenol oxidase enzymes, and the abundance of basidiomycete
genes encoding laccase, a primary phenol oxidase enzyme, in three hardwood forests spanning a range of leaf litter lignin
content. The black oak-white oak (BOWO) contains high lignin litter, the sugar maple-basswood (SMBW) has low lignin litter,
and the sugar maple-red oak (SMRO) is intermediate. An ecosystem by N deposition interaction significantly influenced phenol
oxidase activity in the surface soil (P = 0.05), where phenol oxidase activity decreased with increasing experimental N deposition in the BOWO ecosystem. No consistent
response to N deposition was evident for surface soil phenol oxidase activity within either the SMRO or SMBW ecosystem. This
interaction did not influence laccase gene abundance. Instead, basidiomycete laccase gene abundance was reduced by experimental
N deposition (main effect) in surface soil. There was only a weak correlation between basidiomycete laccase gene abundance
and potential phenol oxidase enzyme activity, suggesting that the abundance of organisms possessing laccase genes may not
control phenol oxidase activity in soil. Our results suggest that the regulation of laccase gene expression may mediate the
decomposition response to atmospheric N deposition. 相似文献