Decolorization and biodegradation of melanoidin contained in beet molasses by an anamorphic strain of Bjerkandera adusta CCBAS930 and its mutants.

We used a ligninolytic strain of the white-rot fungus B. adusta CCBAS 930 and its mutants with modified ligninolytic activity to assess their potential to remove of molasses. The analyzed strains have been shown to be able to decolorize 1% or 2% molasses solutions containing brown-colored toxic melanoidins. It was found that the decolorization process was determined by the transition to the stage of production of sporulating aerial mycelium (liquid and agar cultures) coupled with an increase in peroxidase activity, which was accompanied by a decrease in the level of melanoidin, free radicals, and phenolic compounds. Four different peroxidase activities were detected in post-culture liquids, i.e. horseradish-like (HRP-like), manganese-dependent (MnP), lignin (LiP), and versatile (VP) peroxidase activities. The HRP-like peroxidase was characterized by the highest activity. The efficiency of removal of melanoidins from a 1% molasses solution by the parental strain and the mutants was dependent on the culture method. The highest efficiency was noted in immobilized cultures (threefold higher than in the mycelium-free cultures), which was accompanied by stimulation of HRP-like peroxidase activity. Mutant 930-5 was found to be the most effective in the decolorization and decomposition of melanoidin. The HRP-like activity in the immobilized cultures of B. adusta 930-5 was 640-fold higher than in the mycelium-free cultures of the fungus. Moreover, decolorization and biodegradation of melanoidin by B. adusta CCBAS 930 and 930-5 was coupled with detoxification.

Formation of Decatrienones with a Pineapple-like Aroma from 1-13C-Acetate by Cell Cultures of the Birch Polypore, Fomitopsis betulina.

During submerged cultivation, the edible basidiomycete Fomitopsis betulina (previously Piptoporus betulinus) developed a fruity odor, strongly reminding of pineapple. Olfactometric analysis showed that this impression was mainly caused by the two (5E/Z,7E,9)-decatrien-2-ones. At the time of maximum concentration on the 5th day, the (5E/5Z)-ratio was 94:6. Three hypotheses were experimentally examined to shed light onto the genesis of the uncommon volatiles: first, an indirect effect of agro-industrial side-streams, such as cabbage cuttings, supporting good growth; second, an unsaturated odd-numbered fatty acid precursor; and third, a polyketide-like pathway. In the presence of 1-13C- or 2-13C-acetate up to five acetates were incorporated into the molecular ions of the C10-body. Addition of 1-13C-pyruvate or 1-13C-lactate did not confirm an odd-numbered starter of the polyketide chain. None of the methylketones was found in pineapple or any other food before.

Growth conditions, physiological properties, and selection of optimal parameters of biodegradation of anticancer drug daunomycin in industrial effluents by Bjerkandera adusta CCBAS930.

The study characterizes the anamorphic Bjerkandera adusta strain CCBAS 930, including growth conditions, physiological properties, and enzymatic activities related to basic metabolism and specific properties coupled with the fungal secondary metabolism. It was established that the fungus grows in a wide pH range (3.5-7.5), up to 3% of salt concentration and a temperature of 5-30 °C. Media rich in natural organic components (potato, maize extracts, whey) are optimal for biomass propagation. Minimal media, containing mineral salts and glucose as well as static growth conditions, are required to obtain idiophasic mycelium, equivalent to the secondary metabolism of the fungus. Of the 7 complex C, N, and energy sources tested, the strain did not utilize only fibrous cellulose. Lipolytic activity reached the highest values of the enzymatic activities corresponding to those capabilities. The specific properties of strain B. adusta CCBAS 930 determined by the production of HRP-like peroxidase were related to the decolorization and biodegradation of anthraquinone derivative daunomycin. The decolorization of 30% of daunomycin effluents occurred most rapidly in iso-osmotic medium and non-enriched with nitrogen, containing 0.25% glucose, pH = 5.0-6.0, and 25-30 °C. In agitated cultures, the strain decolorized solutions of daunomycin by biosorption, which coincided with the inhibition of aerial mycelium production and HRP-like biosynthesis. Based on knowledge, potential and real possibilities of using the strain in bioremediation of colored industrial sewage were discussed.

Cultivation and Medicinal Value of the Red Belt Conk Mushroom Fomitopsis pinicola (Agaricomycetes).

This study examined biological characteristics, liquid fermentation, and cultivation of Fomitopsis pinicola. A single-factor test concluded that the optimal carbon and nitrogen sources for mycelial growth were soluble starch and yeast paste; the optimal culture temperature was 31°C, and the optimal pH was 6.0. The orthogonal experiment indicated that the optimal formula for mycelial culture was 25 g soluble starch, 2 g yeast extract, 1 g KH2PO4, and 1.5 g MgSO4 added to 1 L water. The optimal conditions for liquid fermentation culture consisted of the following: a loading volume 90 mL, inoculation volume 30 mL, and rotation speed 160 rpm. The optimal substrate formula for domestic culture was 20% corn cob, 30% sawdust, 20% wheat bran, 25% cotton seed shell, 3% corn meal, 1% gypsum, and 1% lime, which produced the highest yield of fruiting bodies. The results provided basic data for deep liquid fermentation culture and recommendations for the further development and utilization of F. pinicola.

Fomitopsis mounceae and F. schrenkii-two new species from North America in the F. pinicola complex.

Two new species, Fomitopsis mounceae and F. schrenkii (Polyporales, Basidiomycota) in the F. pinicola species complex in North America, are described and illustrated. Previous molecular phylogenetic analyses identified three well-delimited lineages that represent F. mounceae and F. ochracea from Canada, the Appalachian Mountains, and the northern United States and F. schrenkii from western and southwestern regions of the United States. Fomitopsis pinicola sensu stricto is restricted to Eurasia and does not occur in North America. Morphological descriptions of basidiocarps and cultures for F. mounceae, F. schrenkii, and F. ochracea are presented. The three species are readily differentiated by nuc rDNA internal transcribed spacer (ITS1-5.8S-ITS2 = ITS) sequence, geographic distribution, and basidiospore size. Polyporus ponderosus H. Schrenk is an earlier illegitimate synonym of F. schrenkii. Both F. mounceae and F. schrenkii have a heterothallic multiallelic incompatibility system.

Extracts of Polypore Mushroom Mycelia Reduce Viruses in Honey Bees.

Waves of highly infectious viruses sweeping through global honey bee populations have contributed to recent declines in honey bee health. Bees have been observed foraging on mushroom mycelium, suggesting that they may be deriving medicinal or nutritional value from fungi. Fungi are known to produce a wide array of chemicals with antimicrobial activity, including compounds active against bacteria, other fungi, or viruses. We tested extracts from the mycelium of multiple polypore fungal species known to have antiviral properties. Extracts from amadou (Fomes) and reishi (Ganoderma) fungi reduced the levels of honey bee deformed wing virus (DWV) and Lake Sinai virus (LSV) in a dose-dependent manner. In field trials, colonies fed Ganoderma resinaceum extract exhibited a 79-fold reduction in DWV and a 45,000-fold reduction in LSV compared to control colonies. These findings indicate honey bees may gain health benefits from fungi and their antimicrobial compounds.

Profiles of Little-Known Medicinal Polypores: Funalia trogii (Agaricomycetes).

The purpose of this study was to comprehensively characterize little-known polypores that have recently been found to possess anticancer activity and thus can be used in targeted cancer therapy. Funalia trogii is a polypore with bipolar distribution and has been found by harvesters working in taiga forests, broadleaf forests, and forest-steppes of the Holarctic, and in semiarid temperate forests of the Southern Hemisphere. Substances such as gibberellic acid, abscisic acid, indole-3-acetic acid, and natural cytokinin were determined in culture media of F. trogii. Also, laccases and peroxidases of spare action have been reported in F. trogii culture media. All of the aforementioned substances can be used in targeted cancer therapy, but further investigation of F. trogii is recommended; more details of its health benefits could expand its use in mycotherapy.

Decolorization of textile dyes in an air-lift bioreactor inoculated with Bjerkandera adusta OBR105.

A new decolorizing white-rot fungus, OBR105, was isolated from Mount Odae in South Korea and identified by the morphological characterization of its fruit body and spores and partial 18s rDNA sequences. The ligninolytic enzyme activity of OBR105 was studied to characterize their decolorizing mechanism using a spectrophotometric enzyme assay. For the evaluation of the decolorization capacity of OBR105, the isolate was incubated in an erlenmeyer flask and in an airlifte bioreator with potato dextrose broth (PDB) medium supplemented with each dye. In addition, the decolorization efficiency of real textile wastewater was evaluated in an airlift bioreactor inoculated with the isolate. The isolate was identified as Bjerkandera adusta and had ligninolytic enzymes such as laccase, lignin peroxidase (LiP), and Mn-dependent peroxidase (MnP). Its LiP activity was higher than its MnP and laccase activities. B. adusta OBR105 successfully decolorized reactive dyes (red 120, blue 4, orange 16, and black 5) and acid dyes (red 114, blue 62, orange 7, and black 172). B. adusta OBR105 decolorized 91-99% of 200 mg L-1 of each dye (except acid orange 7) within 3 days in a PDB medium at 28°C, pH 5, and 150 rpm. This fungus decolorized only 45% of 200 mg L-1 acid orange 7 (single azo-type dye) within 3 days, and the decolorization efficiency did not increase by prolonging the cultivation time. In the air-lift bioreactor, B. adusta OBR105 displayed a high decolorization capacity, greater than 90%, for 3 acid dyes (red 114, blue 62, and black 172) and 1 reactive dye (blue 4) within 10-15 h of treatment. B. adusta OBR105 could decolorize real textile wastewater in the air-lift bioreactor. This result suggests that an air-lift reactor employing B. adusta OBR105 is a promising bioreactor for the treatment of dye wastewater.

Role of carbon source in the shift from oxidative to hydrolytic wood decomposition by Postia placenta.

Brown rot fungi initiate wood decay using oxidative pretreatments to improve access for cellulolytic enzymes. These pretreatments are incompatible with enzymes, and we recently showed that Postia placenta overcomes this issue by delaying glycoside hydrolase (GH) gene upregulation briefly (<48h) until expression of oxidoreductases (ORs) is repressed. This implies an inducible cellulase system rather than a constitutive system, as often reported, and it remains unclear what cues this transition. To address this, we grew P. placenta along wood wafers and spatially mapped expression (via quantitative PCR) of twelve ORs and GHs targeted using functional genomics analyses. By layering expression patterns over solubilized sugar data (via HPLC) from wood, we observed solubilization of wood glucose, cellobiose, mannose, and xylose coincident with the OR-GH transition. We then tested effects of these soluble sugars, plus polymeric carbon sources (spruce powder, cellulose), on P. placenta gene expression in liquid cultures. Expression of ORs was strictly (aox1, cro5) or progressively repressed over time (qrd1, lcc1) by all soluble sugars, including cellobiose, but not by polymeric sources. Simple sugars repressed hemicellulase gene expression over time, but these sugars did not repress cellulases. Cellulase genes were upregulated, however, along with hemicellulases in the presence of soluble cellobiose and in the presence of polymeric carbon sources, relative to starvation (carbon-free). This verifies an inducible cellulase system in P. placenta that lacks carbon catabolite repression (CCR), and it suggests that brown rot fungi use soluble sugars, particularly cellobiose, to cue a critical oxidative-hydrolytic transition.

Abilities of Co-cultures of Brown-Rot Fungus Fomitopsis pinicola and Bacillus subtilis on Biodegradation of DDT.

DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) is one of the pesticides that are hazardous for the environment and human health. Effective environmental-friendly treatment using co-cultures of fungi and bacteria is needed. In this study, the bacteria Bacillus subtilis at various volumes of 1, 3, 5, 7, and 10 mL (1 mL ≈ 6.7 × 108 CFU) were mixed into 10 mL of the brown-rot fungus Fomitopsis pinicola culture for degrading DDT during a 7-days incubation period. DDT was degraded by approximately 42% by F. pinicola during the 7-days incubation period. The addition of 10 mL of B. subtilis into F. pinicola culture showed the highest DDT degradation of approximately 86% during the 7-days incubation period. DDD (1,1-dichloro-2,2-bis(4-chlorophenyl)ethane), DDE (1,1-dichloro-2,2-bis(4-chlorophenyl)ethylene), and DDMU (1-chloro-2,2-bis(4-chlorophenyl)ethylene) were detected as metabolic products from DDT degradation by co-cultures of F. pinicola and B. subtilis. Transformation pathway was proposed in which DDT was transformed into three pathways as follows: (1) dechlorination to DDD, (2) dehydrochlorination to DDE, and (3) formation of DDMU.

Distinct Growth and Secretome Strategies for Two Taxonomically Divergent Brown Rot Fungi.

Brown rot fungi are wood-degrading fungi that employ both oxidative and hydrolytic mechanisms to degrade wood. Hydroxyl radicals that facilitate the oxidative component are powerful nonselective oxidants and are incompatible with hydrolytic enzymes unless they are spatially segregated in wood. Differential gene expression has been implicated in the segregation of these reactions in Postia placenta, but it is unclear if this two-step mechanism varies in other brown rot fungi with different traits and life history strategies that occupy different niches in nature. We employed proteomics to analyze a progression of wood decay on thin wafers, using brown rot fungi with significant taxonomic and niche distances: Serpula lacrymans (Boletales; "dry rot" lumber decay) and Gloeophyllum trabeum (order Gloeophyllales; slash, downed wood). Both fungi produced greater oxidoreductase diversity upon wood colonization and greater glycoside hydrolase activity later, consistent with a two-step mechanism. The two fungi invested very differently, however, in terms of growth (infrastructure) versus protein secretion (resource capture), with the ergosterol/extracted protein ratio being 7-fold higher with S. lacrymans than with G. trabeum In line with the native substrate associations of these fungi, hemicellulase-specific activities were dominated by mannanase in S. lacrymans and by xylanase in G. trabeum Consistent with previous observations, S. lacrymans did not produce glycoside hydrolase 6 (GH6) cellobiohydrolases (CBHs) in this study, despite taxonomically belonging to the order Boletales, which is distinguished among brown rot fungi by having CBH genes. This work suggests that distantly related brown rot fungi employ staggered mechanisms to degrade wood, but the underlying strategies vary among taxa.IMPORTANCE Wood-degrading fungi are important in forest nutrient cycling and offer promise in biotechnological applications. Brown rot fungi are unique among these fungi in that they use a nonenzymatic oxidative pretreatment before enzymatic carbohydrate hydrolysis, enabling selective removal of carbohydrates from lignin. This capacity has independently evolved multiple times, but it is unclear if different mechanisms underpin similar outcomes. Here, we grew fungi directionally on wood wafers and we found similar two-step mechanisms in taxonomically divergent brown rot fungi. The results, however, revealed strikingly different growth strategies, with S. lacrymans investing more in biomass production than secretion of proteins and G. trabeum showing the opposite pattern, with a high diversity of uncharacterized proteins. The "simplified" S. lacrymans secretomic system could help narrow gene targets central to oxidative brown rot pretreatments, and a comparison of its distinctions with G. trabeum and other brown rot fungi (e.g., Postia placenta) might offer similar traction in noncatabolic genes.

Localizing gene regulation reveals a staggered wood decay mechanism for the brown rot fungus Postia placenta.

Wood-degrading brown rot fungi are essential recyclers of plant biomass in forest ecosystems. Their efficient cellulolytic systems, which have potential biotechnological applications, apparently depend on a combination of two mechanisms: lignocellulose oxidation (LOX) by reactive oxygen species (ROS) and polysaccharide hydrolysis by a limited set of glycoside hydrolases (GHs). Given that ROS are strongly oxidizing and nonselective, these two steps are likely segregated. A common hypothesis has been that brown rot fungi use a concentration gradient of chelated metal ions to confine ROS generation inside wood cell walls before enzymes can infiltrate. We examined an alternative: that LOX components involved in ROS production are differentially expressed by brown rot fungi ahead of GH components. We used spatial mapping to resolve a temporal sequence in Postia placenta, sectioning thin wood wafers colonized directionally. Among sections, we measured gene expression by whole-transcriptome shotgun sequencing (RNA-seq) and assayed relevant enzyme activities. We found a marked pattern of LOX up-regulation in a narrow (5-mm, 48-h) zone at the hyphal front, which included many genes likely involved in ROS generation. Up-regulation of GH5 endoglucanases and many other GHs clearly occurred later, behind the hyphal front, with the notable exceptions of two likely expansins and a GH28 pectinase. Our results support a staggered mechanism for brown rot that is controlled by differential expression rather than microenvironmental gradients. This mechanism likely results in an oxidative pretreatment of lignocellulose, possibly facilitated by expansin- and pectinase-assisted cell wall swelling, before cellulases and hemicellulases are deployed for polysaccharide depolymerization.

Morphological Characterization and Quantification of the Mycelial Growth of the Brown-Rot Fungus Postia placenta for Modeling Purposes.

Continuous observation was performed using confocal laser scanning microscopy to visualize the three-dimensional microscopic growth of the brown-rot fungus, Postia placenta, for seventeen days. The morphological characterization of Postia placenta was quantitatively determined, including the tip extension rate, branch angle and branching length, (hyphal length between two adjacent branch sites). A voxel method has been developed to measure the growth of the biomass. Additionally, the tip extension rate distribution, the branch angle distribution and the branching length distribution, which quantified the hyphal growth characteristics, were evaluated. Statistical analysis revealed that the extension rate of tips was randomly distributed in space. The branch angle distribution did not change with the development of the colony, however, the branching length distribution did vary with the development of the colony. The experimental data will be incorporated into a lattice-based model simulating the growth of Postia placenta.

Cultivation and utility of Piptoporus betulinus fruiting bodies as a source of anticancer agents.

Piptoporus betulinus is a wood-rotting basidiomycete used in medicine and biotechnology. However, to date, no indoor method for cultivation of this mushroom fruiting bodies has been developed. Here we present the first report of successful production of P. betulinus mature fruiting bodies in artificial conditions. Four P. betulinus strains were isolated from natural habitats and their mycelia were inoculated into birch sawdust substrate supplemented with organic additives. All the strains effectively colonized the medium but only one of them produced fruiting bodies. Moisture and organic supplementation of the substrate significantly determined the fruiting process. The biological efficiency of the P. betulinus PB01 strain cultivated on optimal substrate (moisture and organic substance content of 55 and 65 and 25 or 35 %, respectively) ranged from 12 to 16 %. The mature fruiting bodies reached weight in the range from 50 to 120 g. Anticancer properties of water and ethanol extracts isolated from both cultured and nature-derived fruiting bodies of P. betulinus were examined in human colon adenocarcinoma, human lung carcinoma and human breast cancer cell lines. The studies revealed antiproliferative and antimigrative properties of all the investigated extracts. Nevertheless the most pronounced effects demonstrated the ethanol extracts, obtained from fruiting bodies of cultured P. betulinus. Summarizing, our studies proved that P. betulinus can be induced to fruit in indoor artificial culture and the cultured fruiting bodies can be used as a source of potential anticancer agents. In this respect, they are at least as valuable as those sourced from nature.

Morphological and enzymatic response of the thermotolerant fungus Fomes sp. EUM1 in solid state fermentation under thermal stress.

Thermotolerance of the fungus Fomes sp. EUM1 was evaluated in solid state fermentation (SSF). This thermotolerant strain improved both hyphal invasiveness (38%) and length (17%) in adverse thermal conditions exceeding 30°C and to a maximum of 40°C. In contrast, hyphal branching decreased by 46% at 45°C. The production of cellulases over corn stover increased 1.6-fold in 30°C culture conditions, xylanases increased 2.8-fold at 40°C, while laccase production improved 2.7-fold at 35°C. Maximum production of lignocellulolytic enzymes was obtained at elevated temperatures in shorter fermentation times (8-6 days), although the proteases appeared as a thermal stress response associated with a drop in lignocellulolytic activities. Novel and multiple isoenzymes of xylanase (four bands) and cellulase (six bands) were secreted in the range of 20-150 kDa during growth in adverse temperature conditions. However, only a single laccase isoenzyme (46 kDa) was detected. This is the first report describing the advantages of a thermotolerant white-rot fungus in SSF. These results have important implications for large-scale SSF, where effects of metabolic heat are detrimental to growth and enzyme production, which are severely affected by the formation of high temperature gradients.

High yield production in seven days of Coriolopsis gallica 1184 laccase at 50 L scale; enzyme purification and molecular characterization.

The optimization of culture conditions for high yield laccase production by white rot fungi has been extensively studied. However, to achieve short time laccase production remains a major challenge in several cases. The present study investigated an optimal process for production of Coriolopsis gallica 1184 laccase in a high yield of 200 900 Ul(-1) in 7 d by 50 L scale submerged fermentation. Coriolopsis gallica 1184 laccase appeared as a robust enzyme against downstream process; only 13.5 % of laccase activity was lost at the end of downstream procedure. The pure enzyme appeared as a one-species laccase, with a molecular mass of 66 kDa as determined by SDS-PAGE. The pH optimum for 2,2'-azino-bis-[3-ethyltiazoline-6-sulfonate] oxidation ranged between 2.5 and 3.0 in 100 mM tartrate buffer. Optimum temperature for laccase activity was determined to be around 70 °C. The kinetic of laccase was investigated with four phenolic substrates. The lowest Km values (17 and 20 µM) were found for ABTS and guaiacol, respectively. Coriolopsis gallica 1184 laccase was characterized by mass spectrometry and shows that C. gallica 1184_LacI is very likely a new member of the AA1_1 subfamily. Our results clearly show high competitive potential of the robust extracellular C. gallica 1184 laccase to use it in different industrial processes.

De novo transcriptomic assembly and profiling of Rigidoporus microporus during saprotrophic growth on rubber wood.

BACKGROUND: The basidiomycete Rigidoporus microporus is a fungus that causes the white rot disease of the tropical rubber tree, Hevea brasiliensis, the major source of commercial natural rubber. Besides its lifestyle as a pathogen, the fungus is known to switch to saprotrophic growth on wood with the ability to degrade both lignin and cellulose. There is almost no genomic or transcriptomic information on the saprotrophic abilities of this fungus. In this study, we present the fungal transcriptomic profiles during saprotrophic growth on rubber wood. RESULTS: A total of 266.6 million RNA-Seq reads were generated from six libraries of the fungus growing either on rubber wood or without wood. De novo assembly produced 34, 518 unigenes with an average length of 2179 bp. Annotation of unigenes using public databases; GenBank, Swiss-Prot, Kyoto Encyclopedia of Genes and Genomes (KEGG), Cluster of Orthologous Groups (COG) and Gene Ontology (GO) produced 25, 880 annotated unigenes. Transcriptomic profiling analysis revealed that the fungus expressed over 300 genes encoding lignocellulolytic enzymes. Among these, 175 genes were up-regulated in rubber wood. These include three members of the glycoside hydrolase family 43, as well as various glycosyl transferases, carbohydrate esterases and polysaccharide lyases. A large number of oxidoreductases which includes nine manganese peroxidases were also significantly up-regulated in rubber wood. Several genes involved in fatty acid metabolism and degradation as well as natural rubber degradation were expressed in the transcriptome. Four genes (acyl-CoA synthetase, enoyl-CoA hydratase, 3-hydroxyacyl-CoA dehydrogenase and acyl-CoA acetyltransferase) potentially involved in rubber latex degradation pathway were also induced. A number of ATP binding cassette (ABC) transporters and hydrophobin genes were significantly expressed in the transcriptome during saprotrophic growth. Some genes related to energy metabolism were also induced. CONCLUSIONS: The analysed data gives an insight into the activation of lignocellulose breakdown machinery of R. microporus. This study also revealed genes with relevance in antibiotic metabolism (e.g. cephalosporin esterase) as well as those with potential applications in fatty acid degradation. This is the first study on the transcriptomic analysis of R. microporus on rubber wood and should serve as a pioneering resource for future studies of the fungus at the genomic or transcriptomic level.

Effects of saline-alkaline stress on benzo[a]pyrene biotransformation and ligninolytic enzyme expression by Bjerkandera adusta SM46.

Benzo[a]pyrene (BaP) accumulates in marine organisms and contaminated coastal areas. The biotreatment of waste water using saline-alkaline-tolerant white rot fungi (WRF) represents a promising method for removing BaP under saline-alkaline conditions based on WRF's ability to produce ligninolytic enzymes. In a pre-screening for degradation of polycyclic aromatic hydrocarbons of 82 fungal strains using Remazol brilliant blue R, Bjerkandera adusta SM46 exhibited the highest tolerance to saline-alkaline stress. Moreover, a B. adusta culture grown in BaP-containing liquid medium exhibited resistance to salinities up to 20 g l(-1). These conditions did not inhibit fungal growth or the expression of manganese peroxidase (MnP) or lignin peroxidase (LiP). The degradation rate also became higher as salinity increased to 20 g l(-1). Fungal growth and enzyme expression were inhibited at a salinity of 35 g l(-1). These inhibitory effects directly decreased the degradation rate (>24%). The presence of MnSO4 as an inducer improved the degradation rate and enzyme expression. MnP and LiP activity also increased by seven- and fivefold, respectively. SM46 degraded BaP (38-89% over 30 days) in an acidic environment (pH 4.5) and under saline-alkaline stress conditions (pH 8.2). Investigating the metabolites produced revealed BaP-1,6-dione as the main product, indicating the important role of ligninolytic enzymes in initializing BaP cleavage. The other metabolites detected, naphthalene acetic acid, hydroxybenzoic acid, benzoic acid, and catechol, may have been ring fission products. The wide range of activities observed suggests that B. adusta SM46 is a potential agent for biodegrading BaP under saline conditions.

Stimulation of the activity of a novel tannase produced in white-rot fungi Phellinus pini, Fomes fomentarius, and Tyromyces pubescens by medium supplementation.

In recent years, tannase has gained increasing interest mainly because of its potential applications. One of the most important functions of tannic acid (TA) hydrolase is the release of gallic acid (GA) from complex tannins. The aim of the study was to determine the dynamic changes in tannase activity depending on the carbon source in the culture medium. An extracellular and intracellular tannase activity analysis was carried out with the use of spectrophotometric analysis and confirmed by capillary electrophoresis in cultures of white-rot fungi: Phellinus pini, Fomes fomentarius, and Tyromyces pubescens. The inducible potential of TA and rapeseed meal on the activity of tannin acyl hydrolase was confirmed during 14 days of culturing. Different effects of the tested compounds on stimulation of tannase activity in selected fungal strains have been demonstrated. We concluded that rapeseed meal was the best inducer of tannase activity in the case of P. pini. However, the highest concentrations of GA were observed after stimulation by the TA in the cultures of F. fomentarius and T. pubescens.

Transcriptional profiles of laccase genes in the brown rot fungus Postia placenta MAD-R-698.

One of the laccase isoforms in the brown rot fungus Postia placenta is thought to contribute to the production of hydroxyl radicals, which play an important role in lignocellulose degradation. However, the presence of at least two laccase isoforms in this fungus makes it difficult to understand the details of this mechanism. In this study, we systematically investigated the transcriptional patterns of two laccase genes, Pplcc1 and Pplcc2, by quantitative PCR (qPCR) to better understand the mechanism. The qPCR results showed that neither of the two genes was expressed constitutively throughout growth in liquid culture or during the degradation of a woody substrate. Transcription of Pplcc1 was upregulated under nitrogen depletion and in response to a high concentration of copper in liquid culture, and during the initial colonization of intact aspen wafer. However, it was subject to catabolite repression by a high concentration of glucose. Transcription of Pplcc2 was upregulated by stresses caused by ferulic acid, 2, 6-dimethylbenzoic acid, and ethanol, and under osmotic stress in liquid culture. However, the transcription of Pplcc2 was downregulated upon contact with the woody substrate in solid culture. These results indicate that Pplcc1 and Pplcc2 are differentially regulated in liquid and solid cultures. Pplcc1 seems to play the major role in producing hydroxyl radicals and Pplcc2 in the stress response during the degradation of a woody substrate.