Potential of ligninolytic enzymatic complex produced by white‐rot fungi from genus Trametes isolated from Bulgarian forest soil

Because of the crucial role of ligninolytic enzymes in a variety of industrial processes, the demand for a new effective producer has been constantly increasing. Furthermore, information on enzyme synthesis by autochthonous fungal strains is very seldom found. Two fungal strains producing ligninolytic enzymes were isolated from Bulgarian forest soil. They were identified as being Trametes trogii and T. hirsuta. These two strains were assessed for their enzyme activities, laccase (Lac), lignin peroxidase (LiP) and Mn‐dependent peroxidase (MnP) in culture filtrate depending on the temperature and the type of nutrient medium. T. trogii was selected as the better producer of ligninolytic enzymes. The production process was further improved by optimizing a number of parameters such as incubation time, type of cultivation, volume ratio of medium/air, inoculum size and the addition of inducers. The maximum activities of enzymes synthesized by T. trogii was detected as 11100 U/L for Lac, 2.5 U/L for LiP and 4.5 U/L for MnP after 14 days of incubation at 25°C under static conditions, volume ratio of medium/air 1:6, and 3 plugs as inoculum. Among the supplements tested, 5% glycerol increased Lac activity to a significant extent. The addition of 1% veratryl alcohol had a positive effect on MnP.     

Irpex lacteus, a white rot fungus applicable to water and soil bioremediation

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     

Enhanced ligninolytic enzyme production and degrading capability of Phanerochaete chrysosporium and Trametes versicolor

Ligninolytic enzyme production by the white-rot fungi Phanerochaete chrysosporium and Trametes versicolor precultivated with different insoluble lignocellulosic materials (grape seeds, barley bran and wood shavings) was investigated. Cultures of Phanerochaete chrysosporium precultivated with grape seeds and barley bran showed maximum lignin peroxidase (LiP) and manganese-dependent peroxidase (MnP) activities (1000 and 1232 U/l, respectively). Trametes versicolor precultivated with the same lignocellulosic residues showed the maximum laccase activity (around 250 U/l). For both fungi, the ligninolytic activities were about two-fold higher than those attained in the control cultures. In vitro decolorization of the polymeric dye Poly R-478 by the extracellular liquid obtained in the above-mentioned cultures was monitored in order to determine the respective capabilities of laccase, LiP and MnP. It is noteworthy that the degrading capability of LiP when P. chrysosporium was precultivated with barley bran gave a percentage of Poly R-478 decolorization of about 80% in 100 s, whereas control cultures showed a lower percentage, around 20%, after 2 min of the decolorization reaction.     

Evaluation of Argentinean white rot fungi for their ability to produce lignin-modifying enzymes and decolorize industrial dyes

The decolorizing capacity of 26 white rot fungi from Argentina was investigated. Extracellular production of ligninolytic enzymes by mycelium growing on solid malt extract/glucose medium supplemented with different dyes (Malachite Green, Azure B, Poly R-478, Anthraquinone Blue, Congo Red and Xylidine), dye decolorization and the relationship between these two processes were studied. Only ten strains decolorized all the dyes, all ten strains produced laccase, lignin peroxidase and manganese peroxidase on solid medium. However, six of the strains could not decolorize any of the dyes; all six strains tested negative for lignin peroxidase, and produced less than 0.05 U/g agar of manganese peroxidase. Comparing the isolates with the well-known dye-degrader Phanerochaete chrysosporium, a new fungus was identified: Coriolus versicolor f. antarcticus, potentially a candidate for use in biodecoloration processes. Eighteen day-old cultures of this fungus were able to decolorize in an hour 28%, 30%, 43%, 88% and 98% of Xylidine (24 mg/l), Poly R-478 (75 mg/l), Remazol Brilliant Blue R (9 mg/l), Malachite Green (6 mg/l) and Indigo Carmine (23 mg/l), respectively. Laccase activity was 0.13 U/ml, but neither lignin peroxidase nor manganese peroxidase were detected in the extracellular fluids for that day of incubation.     

Optimization of a culture medium for ligninolytic enzyme production and synthetic dye decolorization using response surface methodology

A Box-Wilson central composite design was applied to optimize copper, veratryl alcohol and l-asparagine concentrations for Trametes trogii (BAFC 212) ligninolytic enzyme production in submerged fermentation. Decolorization of different dyes (xylidine, malachite green, and anthraquinone blue) by the ligninolytic fluids from the cultures was compared. The addition of copper stimulated laccase and glyoxal oxidase production, but this response was influenced by the medium N-concentration, with improvement higher at low N-levels. The medium that supported the highest ligninolytic production (22.75 U/ml laccase, 0.34 U/ml manganese peroxidase, and 0.20 U/ml glyoxal oxidase) also showed the greatest ability to decolorize the dyes. Only glyoxal oxidase activity limited biodecoloration efficiency, suggesting the involvement of peroxidases in the process. The addition of 1-hydroxybenzotriazole (a known laccase mediator) to the ligninolytic fluids increased both their range and rate of decolorization. The cell-free supernatant did not decolorize xylidine, poly R-478, azure B, and malachite green as efficiently as the whole broth, but results were similar in the case of indigo carmine and remazol brilliant blue R. This indicates that the mycelial biomass may supply other intracellular or mycelial-bound enzymes, or factors necessary for the catalytic cycle of the enzymes. It also implies that this fungus implements different strategies to degrade dyes with diverse chemical structures.     

Screening for novel laccase-producing microbes

AIMS: To discover novel laccases potential for industrial applications. METHODS AND RESULTS: Fungi were cultivated on solid media containing indicator compounds that enabled the detection of laccases as specific colour reactions. The indicators used were Remazol Brilliant Blue R (RBBR), Poly R-478, guaiacol and tannic acid. The screening work resulted in isolation of 26 positive fungal strains. Liquid cultivations of positive strains confirmed that four efficient laccase producers were found in the screening. Biochemical characteristics of the four novel laccases were typical for fungal laccases in terms of molecular weight, pH optima and pI. The laccases showed good thermal stability at 60 degrees C. CONCLUSIONS: Plate-test screening based on polymeric dye compounds, guaiacol and tannic acid is an efficient way to discover novel laccase producers. The results indicated that screening for laccase activity can be performed with guaiacol and RBBR or Poly R-478. SIGNIFICANCE AND IMPACT OF THE STUDY: Laccases have many potential industrial applications including textile dye decolourization, delignification of pulp and effluent detoxification. It is essential to find novel, efficient enzymes to further develop these applications. This study showed that relatively simple plate test screening method can be used for discovery of novel laccases.     

Characterization of a fungal strain isolated from a polyphenol polluted site

A group of fungal strains were isolated from a polyphenol polluted soil, taken from an olive oil processing plant in Attica, Greece. The fungi were tested for their ability to decolorize a polyaromatic dye Poly R-478, which was used as a model compound to test their ligninolytic activities. The strain K1.1 decolorized efficiently the dye on agar plates and was further studied. PCR amplification of the internal transcribed spacer (ITS) region of the ribosomal RNA genes from the genomic DNA isolated from mycelium grown in liquid culture resulted in amplified fragments. Via BLASTN search, the length of a 773 base pairs was identified as the basidiomycetes Coprinellus xanthothrix. The growth rates and the tolerance of the fungus were compared on solid media, containing four different concentrations of pentachlorophenol. Extracellular enzyme activities (lignin peroxidase, manganese peroxidase and laccase) were determined in defined liquid medium. The isolate expressed laccase and manganese peroxidase but not lignin peroxidase. The removal of the dye was also estimated in liquid medium. The fungus showed biosorption and biotransformation as removal mechanisms.     

Depolymerization of low-rank coal by extracellular fungal enzyme systems. II. The ligninolytic enzymes of the coal-humic-acid-depolymerizing fungus Nematoloma frowardii b19

The production of ligninolytic enzymes was studied in surface cultures of the South American white-rot fungus Nematoloma frowardii b19 and four other strains of this ecophysiological group (Clitocybula dusenii b11, Auricularia sp. m37a, wood isolates u39 and u45), which are able to depolymerize low-rank-coal-derived humic acids with the formation of fulvic-acid-like compounds. The fungi produced the three crucial enzymes of lignin degradation – lignin peroxidase, manganese peroxidase and laccase. In the case of N. frowardii b19, laccase and the two peroxidases could be stimulated by veratryl alcohol. Manganese (II) ions (Mn²⁺) caused a rapid increase of Mn peroxidase activity accompanied by the complete repression of lignin peroxidase. Under nitrogen-limited conditions the growth as well as the production of ligninolytic enzymes was partly repressed. During the depolymerization process of coal humic acids using solid agar media, gradients of ligninolytic enzyme activities toward 2,2′-azinobis(3-ethylbenzthiazoline-6-sulphonate) and syringaldazine were detectable inside the agar medium. Received: 5 August 1996 / Received revision: 13 November 1996 / Accepted: 15 November 1996     

Biodegradation of pentachlorophenol by white rot fungi under ligninolytic and nonligninolytic conditions

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.     

Role of copper in poly R-478 decolorization by the marine cyanobacterium Phormidium valderianum BDU140441

The marine cyanobacterium Phormidium valderianum BDU140441 was tested for its capability of decolorizing Poly R-478 in the presence of copper. The rate of dye decolorization was decreased when the concentration of copper was increased in the medium, whereas copper in low amount (10 μM) enhanced the decolorization. To analyse the fate of dye-decolorizing and stress-stabilizing enzymes upon copper and dye exposure, four different conditions were maintained. The conditions were (A) only the organism P. valderianum BDU140441, (B) organism + Poly R-478 (0.0075%), (C) organism + copper (10 μM) and (D) organism + Poly R-478 (0.0075%) + copper (10 μM). After 16 h of exposure to Poly R-478 and copper, an increased trend in the activity of laccase and peroxidase was observed. In contrast, polyphenol oxidase revealed only a mild increase in activity along with the induction of a new isoform. The tested cellular antioxidants carotenoid and reduced glutathione were found to be reduced in varying percentage in accordance to the degree of stress bared by the cyanobacterium. Dye and copper exposure divulged an increased pattern in the production of reactive oxygen species (ROS). Concomitant with ROS, esterase activity was also found to increase. Towards copper and dye exposure, the activity of the primary stress-stabilizing enzymes catalase and superoxide dismutase were found to be increased in varied degrees. Upon copper exposure glutathione S-transferase and glutathione peroxidase expressed new isoforms. The results suggest that copper at this juncture played a role as inducer for dye-decolorizing copper oxidases and subjugated the antioxidant system to the objective of Poly R-478 decolorization.     

The physiology of anthracene biodegradation by the white-rot fungus Bjerkandera sp. strain BOS55

A recently isolated white-rot strain, Bjerkandera sp. strain BOS55, displays high extracellular peroxidase activity, and rapidly degrades polycyclic aromatic hydrocarbons (PAH). In this study, the culture conditions for the biodegradation of the model PAH compound, anthracene, were optimized with respect to O₂, N, and C. An additional objective was to determine if the decolorization of the polymeric ligninolytic indicator dye, Poly R-478, could be correlated to anthracene biodegradation observed under a wide range of culture conditions. The supply of O₂ was found to be the most important parameter in the biodegradation of anthracene. Increasing culture aeration enhanced the biodegradation of anthracene and the accumulation of its peroxidase-mediated oxidation product anthraquinone. Decolorization of Poly R-478 was less affected by inadequate aeration. Provided that ample aeration was supplied, the degradation of anthracene under different culture conditions was strongly correlated with the ligninolytic activity as indicated by the rate of Poly R-478 decolorization. Concentrations up to 22 mM NH₄ ⁺ N did not repress anthracene biodegradation and only caused a 0%–40% repression of the Poly R-478 decolorizing activity in various experiments. A cosubstrate requirement of 100 mg glucose / mg anthracene biodegraded was observed in this study.     

Enzymatic characterization of Chilean native wood-rotting fungi for potential use in the bioremediation of polluted environments with chlorophenols

This work presents a preliminary report of a series of studies on the ability of several indigenous wood-rotting fungi from Chile to produce hydrolytic and ligninolytic enzymes and the evaluation of these native microorganism to future research on potential applications in bioremediation programs. Wood-rotting Basidiomycete fungi were collected from indigenous hardwood forest in the South of Chile. Twenty-eight strains were identified and qualitative enzymatic tests for peroxidases, laccase, tyrosinase, xylanase and cellulase production were performed in solid medium. Eleven selected strains were evaluated in liquid medium to quantify their ligninolytic enzyme production and their capacity to grow in solid medium supplemented with 2,4-dichlorophenol (2,4-DCF), 2,4,6-trichlorophenol (2,4,6-TCF) and pentachlorophenol (PCP). PCP degradation and ligninolytic enzymes production were also evaluated in liquid medium. Results showed that laccase was present in 28 of the selected strains (≈73%). Peroxidase was present in 40% and cellulase in 37% of the strains. Xilanase and tyrosinase were obtained in a smaller percentage in the strains (28% and 7%, respectively). The 11 selected strains showed high concentrations of lignin peroxidase (Lip) and manganese peroxidase (MnP). Anthracophyllum discolor (Sp4), produced LiP and MnP at 90.3 and MnP 125.5 U L⁻¹ respectively, compared to the control fungus Phanerochaete chrysosporium CECT-2798 that produced 58.1 and 118.4 U L⁻¹ of LiP and MnP. Tolerance test showed that native Chilean fungi did not present high tolerance to 2,4,6-TCF and PCP but were quite tolerant to 25 and 50 mg L⁻¹ of 2,4-DCF. However, pre-acclimatization in 2,4-DCP notably improved the growth in medium with 2,4,6-TCP and PCP. PCP in liquid medium was efficiently degraded by the fungi Anthracophyllum discolor, Lenzites betulina (Ru-30) and Galerina patagónica (Sp3), and the major MnP activity was produced by A. discolor (Sp4) (67 U L⁻¹).     

In vivo decolourization of the polymeric dye poly R‐478 by corncob cultures of Phanerochaete chrysosporium

In this paper, the in vivo decolourization of the polymeric dye Poly R‐478 by semi‐solid‐state cultures of Phanerochaete chrysosporium BKM‐F‐1767 (ATCC 24725) was investigated, employing corncob as a support. In order to stimulate the ligninolytic system of the fungus, the cultures were supplemented with veratryl alcohol (2 mM) or manganese (IV) oxide (1 g/l). Maximum manganese‐dependent peroxidase (MnP) and lignin peroxidase (LiP) activities of around 2,000 U/l and 400 U/l were attained by the former, whereas the activities reached by the latter were of about 1,500 U/l and 200 U/l, respectively. Furthermore, laccase activity (around 150 U/l) was only detected in manganese (IV) oxide supplemented cultures. The polymeric dye Poly R‐478 (0.02 w/v) was added to three‐day‐old cultures. A percentage of biological decolourization of about 85% was achieved using cultures supplemented with veratryl alcohol, whereas MnO₂ cultures showed a rather lower percentage of around 58% after nine days of dye incubation. Moreover, a correlation between MnP activity and Poly R‐478 decolourization could be observed, indicating that this enzyme is mainly responsible for dye degradation. In the present work, the in vivo decolourizing capability of the ligninolytic complex secreted by P. chrysosporium was investigated under the above‐mentioned cultivation conditions, employing a model compound, such as the polymeric dye Poly R‐478.     

Decolourisation of Remazol Brilliant Blue R via a novel Bjerkandera sp. strain

A novel strain of Bjerkandera sp. (B33/3), with particularly high decolourisation activities upon Poly R-478 and Remazol Brilliant Blue R (RBBR) dyes, was isolated. The role of the ligninolytic extracellular enzymes produced by this strain on decolourisation of RBBR was studied in some depth. The basis of decolourisation is an enzyme-mediated process, in which the main enzyme responsible is a recently described peroxidase with capacity for oxidation of manganese, as well as veratryl alcohol and 2,6-dimethoxyphenol in a manganese-independent reaction.     

Effect of soya lecithin on the enzymatic system of the white-rot fungi Anthracophyllum discolor

The present work optimized the initial pH of the medium and the incubation temperature for ligninolytic enzymes produced by the white-rot fungus Anthracophyllum discolor. Additionally, the effect of soya lecithin on mycelial growth and the production of ligninolytic enzymes in static batch cultures were evaluated. The critical micelle concentration of soya lecithin was also studied by conductivity. The effects of the initial pH (3, 4, and 5) and incubation temperature (20, 25, and 30°C) on different enzymatic activities revealed that the optimum conditions to maximize ligninolytic activity were 26°C and pH 5.5 for laccase and manganese peroxidase (MnP) and 30°C and pH 5.5 for manganese-independent peroxidase (MiP). Under these culture conditions, the maximum enzyme production was 10.16, 484.46, and 112.50 U L⁻¹ for laccase, MnP, and manganese-independent peroxidase MiP, respectively. During the study of the effect of soya lecithin on A. discolor, we found that the increase in soya lecithin concentration from 0 to 10 g L⁻¹ caused an increase in mycelial growth. On the other hand, in the presence of soya lecithin, A. discolor produced mainly MnP, which reached a maximum concentration of 30.64 ± 4.61 U L⁻¹ after 25 days of incubation with 1 g L⁻¹ of the surfactant. The other enzymes were produced but to a lesser extent. The enzymatic activity of A. discolor was decreased when Tween 80 was used as a surfactant. The critical micelle concentration of soya lecithin calculated in our study was 0.61 g L⁻¹.     

White-rot fungi capable of decolourising textile dyes under alkaline conditions

Twelve white-rot fungal strains belonging to seven different species were screened on plates under alkaline condition to study the decolourisation of the textile dyes Reactive Black 5 and Poly R-478. Three strains of Trametes versicolor (Micoteca da Universidade do Minho (MUM) 94.04, 04.100 and 04.101) and one strain of Phanerochaete chrysosporium (MUM 94.15) showed better decolourisation results. These four strains were used for decolourisation studies in liquid culture medium. All four selected strains presented more efficient decolourisation rates on Reactive Black 5 than on Poly R-478. For both dyes on solid and liquid culture media, the decolourisation capability exhibited by these strains depended on dye concentration and pH values of the media. Finally, the decolourisation of Reactive Black 5 by T. versicolor strains MUM 94.04 and 04.100 reached 100 %. In addition, the highest white-rot fungi ligninolytic enzyme activities were found for these two strains.     

Evaluation of the white-rot fungi Ganoderma australe and Ceriporiopsis subvermispora in biotechnological applications

Ganoderma australe is a white-rot fungus that causes a selective wood biodelignification in some hardwoods found in the Chilean rainforest. Ceriporiopsis subvermispora is also a lignin-degrading fungus used in several biopulping studies. The enzymatic system responsible for lignin degradation in wood can also be used to degrade recalcitrant organic pollutants in liquid effluents. In this work, two strains of G. australe and one strain of C. subvermipora were comparatively evaluated in the biodegradation of ABTS and the dye Poly R-478 in liquid medium, and in the pretreatment of Eucalyptus globulus wood chips for further kraft biopulping. Laccase was detected in liquid and wood cultures with G. australe. Ceriporiopsis subvermispora produce laccase and manganese peroxidase when grown in liquid medium and only manganese peroxidase was detected during wood decay. ABTS was totally depleted by all strains after 8 days of incubation while Poly R-478 was degraded up to 40% with G. australe strains and up to 62% by C. subvermispora after 22 days of incubation. Eucalyptus globulus wood chips decayed for 15 days presented 1–6% of lignin loss and less than 2% of glucan loss. Kraft pulps with kappa number 15 were produced from biotreated wood chips with 2% less active alkali, with up to 3% increase in pulp yield and up to 20% less hexenuronic acids than pulps from undecayed control. Results showed that G. australe strains evaluated were not as efficient as C. subvermispora for dye and wood biodegradation, but could be used as a feasible alternative in biotechnological processes such as bioremediation and biopulping.     

Screening for decolorizing basidiomycetes in Mexico

A survey to isolate native white rot basidiomycetes from Northeast Mexico was conducted in the forests of the Sierra Madre Oriental in the state of Nuevo León. A total of 92 isolates from at least 20 different genera, were screened on Bran-Flakes solid plate cultures for the production of ligninolytic oxidases and/or peroxidases with guaiacol and o-anisidine as substrates; their lignin depolymerizing potential using the polymeric dye Poly R 478; their ability to decolorize anthraquinonic (Remazol Brilliant Blue Reactive), azo (Acid Red 44) and triphenylmethane (Crystal Violet) dyes. Among all fungi tested, 15 isolates showed extensive decolorization of the three dyes within a week and gave a positive reaction in guaiacol and o-anisidine tests. Nine of them were also efficient degraders of Poly R-478. Two isolates (CS5 and CU1) showed decolorization of all dyes within 5 days, comparing favorably with reference strains of P. chrysosporium, Pleurotus ostreatus, and Bjerkandera adusta. Decolorization was associated with laccase activity in both isolates and reached 90% or more for all dyes within 24 h in 8-day-old liquid cultures. The coupling of pairs 2,4-dichlorophenol + 4-aminoantipyrine and 3-dimethylaminobenzoic acid + 3-methyl-2-benzothiazolinone hydrazone, strongly suggest that the laccases of both strains correspond to those considered of high redox potential. These strains are considered good candidates for bioremediation of dye polluted effluents due to their ligninolytic potential and decolorizing performance.     

An Evaluation of Soil Colonisation Potential of Selected Fungi and their Production of Ligninolytic Enzymes for Use in Soil Bioremediation Applications

Initially sixteen fungi were screened for potential ligninolytic activity using decolourisation of a polymeric dye Poly R-478. From this, four fungi were selected, Trametes versicolor, Pleurotus ostreatus, Collybia sp., and an isolate (identified as Rhizoctonia solani) isolated from a grassland soil. Differences in the ligninolytic enzyme profiles of each of the fungi were observed. All of the four fungi tested produced MnP and laccase while the Collybia sp. and R. solani produced LiP in addition. Enzyme activity levels also varied greatly over the 21 days of testing with T. versicolor producing levels of MnP and laccase three to four times greater than the other fungi. The four fungi were then tested for their ability to colonise sand, peat (forest) and basalt and marl mixed till (field) soils through visual measurement and biomass detection in soil microcosms. Trametes versicolor and the Collybia sp. failed to grow in any of the non-sterilised soils whereas the R. solani and P. ostreatus isolates grew satisfactorily. Primers were␣designed to detect MnP and laccase genes in P.␣ostreatus and RTPCR was used to detect that these genes are expressed in forest and field soils.     

Removal of PCBs by various white rot fungi in liquid cultures

The ability ofPhanerochœte chrysosporium, Trametes versicolor, Coriolopsis polyzona, andPleurotus ostreatus growing in a nitrogen-limited mineral medium (NMM) to degrade PCBs in a commercial, Delor 106 mixture at a concentration of 0.9 ppm was compared. The respective amounts of PCBs removed from the fungal cultures within 3 weeks were 25, 50, 41, and 0%. The capacities of the individual fungal species to remove PCBs correlated to some extent with their capabilities of decolorization of NMM agar containing both Poly R-478 or Remazol Brilliant Blue R dyes. Enzyme estimations indicated that both high and relatively stable activities of Mn-dependent peroxidase, Mn-independent peroxidase, lignin peroxidase, and laccase characterized efficient PCB degraders. The work was supported by a grant of theAcademy of Sciences of the Zech Republic no. A6301501 and a grant of theAgency of the Zech Republic no. 204/94/1190.