Laccase-producing fungus (MY3) was successfully isolated from soil samples collected from Mansoura Governorate, Egypt. This fungal isolate has shown a high laccase production level over other isolated fungi. The identity of this isolate was determined by the molecular technique 18SrRNA as Curvularia lunata MY3. The enzyme purification was performed using ammonium sulfate precipitation followed by Sephacryl S-200 and DEAE-Sepharose column chromatography. The denatured enzyme using SDS-PAGE had a molar mass of 65 kDa. The purified laccase had an optimum temperature at 40 °C for enzyme activity with 57.3 kJ/mol activation energy for 2,2'-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) oxidation. The enzyme had an optimum pH of 5.0, and it has shown a high stability at the acidic range (4.5 to 5.5). Mn2+ and Mg2+ ions enhanced the enzyme activity, while most of the enzyme activity was inhibited by Hg2+. Some compounds such as 2-mercaptoethanol, L-cysteine, and sodium azide at a concentration of 10 mmol/L had shown a high suppression effect on the enzyme activity. The enzyme strongly oxidized ABTS and syringaldazine and moderately oxidized DMP and guaiacol. The antimicrobial activity of the purified enzyme towards three pathogenic strains (Escherichia coli ATCC-25922, Staphylococcus aureus NRRLB-767, and Candida albicans ATCC-10231) was evaluated for the potential use as an antimicrobial therapeutic enzyme.

• Keywords
• Characterization, Curvularia lunata, Laccase, Purification,
• MeSH
• Anti-Infective Agents * MeSH
• Azo Compounds * MeSH
• Benzothiazoles * MeSH
• Curvularia * MeSH
• Hydrogen-Ion Concentration MeSH
• Sulfonic Acids * MeSH
• Laccase * metabolism   MeSH
• Enzyme Stability MeSH
• Substrate Specificity MeSH
• Temperature MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• 2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid MeSH Browser
• Anti-Infective Agents * MeSH
• Azo Compounds * MeSH
• Benzothiazoles * MeSH
• Sulfonic Acids * MeSH
• Laccase * MeSH
• mordant yellow 3 MeSH Browser

Fungi are producers of lignolytic extracellular enzymes which are used in industries like textile, detergents, biorefineries, and paper pulping. This study assessed for the production, purification, and characterization of novel p-diphenol oxidase (PDO; laccase) enzyme from lignolytic white-rot fungal isolate. Fungi samples collected from different areas of Pakistan were initially screened using guaiacol plate method. The maximum PDO producing fungal isolate was identified on the basis of ITS (internal transcribed spacer sequence of DNA of ribosomal RNA) sequencing. To get optimum enzyme yield, various growth and fermentation conditions were optimized. Later PDO was purified using ammonium sulfate precipitation, size exclusion, and anion exchange chromatography and characterized. It was observed that the maximum PDO producing fungal isolate was Schizophyllum commune (MF-O5). Characterization results showed that the purified PDO was a monomeric protein with a molecular mass of 68 kDa and showed stability at lower temperature (30 °C) for 1 h. The Km and Vmax values of the purified PDO recorded were 2.48 mM and 6.20 U/min. Thermal stability results showed that at 30 °C PDO had 119.17 kJ/K/mol Ea value and 33.64 min half-life. The PDO activity was stimulated by Cu2+ ion at 1.0 mM showing enhanced activity up to 111.04%. Strong inhibition effect was noted for Fe2+ ions at 1 mM showing 12.04% activity. The enzyme showed stability against 10 mM concentration oxidizing reducing agents like DMSO, EDTA, H2O2, NaOCl, and urea and retained more than 75% of relative activity. The characterization of purified PDO enzyme confirmed its tolerance against salt, metal ions, organic solvents, and surfactants indicating its ability to be used in the versatile commercial applications.

• Keywords
• 2′-azino-di(3-ethylbenzthiazoline-6-sulfonate), ABTS 2, Characterization, Fungi, Guaiacol, PDO (p-diphenol oxidase/laccase), Process optimization, Schizophyllum commune,
• MeSH
• Hydrogen-Ion Concentration MeSH
• Laccase * metabolism   MeSH
• Hydrogen Peroxide MeSH
• Schizophyllum * genetics   metabolism   MeSH
• Enzyme Stability MeSH
• Temperature MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Laccase * MeSH
• Hydrogen Peroxide MeSH

Laccases (Lac) and tyrosinases (TYR) are mild oxidants with a great potential in research and industry. In this work, we review recent advances in their use in organic synthesis. We summarize recent examples of Lac-catalyzed oxidation, homocoupling and heterocoupling, and TYR-catalyzed ortho-hydroxylation of phenols. We highlight the combination of Lac and TYR with other enzymes or chemical catalysts. We also point out the biological and pharmaceutical potential of the products, such as dimers of piceid, lignols, isorhamnetin, rutin, caffeic acid, 4-hydroxychalcones, thiols, hybrid antibiotics, benzimidazoles, benzothiazoles, pyrimidine derivatives, hydroxytyrosols, alkylcatechols, halocatechols, or dihydrocaffeoyl esters, etc. These products include radical scavengers; antibacterial, antiviral, and antitumor compounds; and building blocks for bioactive compounds and drugs. We summarize the available enzyme sources and discuss the scalability of their use in organic synthesis. In conclusion, we assume that the intensive use of laccases and tyrosinases in organic synthesis will yield new bioactive compounds and, in the long-term, reduce the environmental impact of industrial organic chemistry.

• Keywords
• bioactive compound, catechol, dimer, heterocoupling, homocoupling, laccase, oligomer, organic synthesis, oxidation, tyrosinase,
• MeSH
• Phenols chemistry   MeSH
• Laccase * metabolism   MeSH
• Oxidation-Reduction MeSH
• Chemistry Techniques, Synthetic MeSH
• Monophenol Monooxygenase * metabolism   MeSH
• Publication type
• Journal Article MeSH
• Review MeSH
• Names of Substances
• Phenols MeSH
• Laccase * MeSH
• Monophenol Monooxygenase * MeSH

The JS7 strain, isolated from an old forest tree, produces extracellular enzymes that decolorize synthetic and natural melanin from human hair. Phylogenetic analysis based on the internal transcribed spacer (ITS) sequence indicated that JS7 belongs to the genus Irpex. The JS7 strain has laccase activity while it lacks manganese and lignin peroxidase activity, which suggests that the JS7 strain melanin decolorization activity originated from laccase. Laccase production from the Irpex sp. JS7 improved three-fold in the presence of veratryl alcohol, compared to without an inducer. The optimum pH and temperature for melanin decolorization were 7.5 and 40 °C, respectively. The crude enzyme half-life at 25 °C was about 100 days, and it had high storage stability. The melanin decolorization reaction rate by the crude enzyme conformed to typical enzyme kinetic principles. In the presence of syringaldehyde as a redox mediator, the melanin decolorization rate was 75% within 5 days, similar to the decolorization percentage obtained using the enzyme alone. Based on these results, the Irpex sp. JS7 enzyme is suitable for use in melanin decolorization by whitening agents in the cosmetics industry.

• MeSH
• Phylogeny MeSH
• Laccase * genetics   metabolism   MeSH
• Humans MeSH
• Melanins metabolism   MeSH
• Oxidation-Reduction MeSH
• Polyporales * metabolism   MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Laccase * MeSH
• Melanins MeSH

Humic substances (HS) in soil are widely distributed in cold environments and account for a significant fraction of soil's organic carbon. Bacterial strains (n = 281) were isolated at 15 °C using medium containing humic acids (HA), a principal component of HS, from a variety of polar soil samples: 217 from the Antarctic and 64 from the Arctic. We identified 73 potential HA-degrading bacteria based on 16S rRNA sequence similarity, and these sequences were affiliated with phyla Proteobacteria (73.9%), Actinobacteria (20.5%), and Bacteroidetes (5.5%). HA-degrading strains were further classified into the genera Pseudomonas (51 strains), Rhodococcus (10 strains), or others (12 strains). Most strains degraded HA between 10 and 25 °C, but not above 30 °C, indicating cold-adapted degradation. Thirty unique laccase-like multicopper oxidase (LMCO) gene fragments were PCR-amplified from 71% of the 73 HA-degrading bacterial strains, all of which included conserved copper-binding regions (CBR) I and II, both essential for laccase activity. Bacterial LMCO sequences differed from known fungal laccases; for example, a cysteine residue between CBR I and CBR II in fungal laccases was not detected in bacterial LMCOs. This suggests a bacterial biomarker role for LMCO to predict changes in HS-degradation rates in tundra regions as global climate changes. Computer-aided molecular modeling showed these LMCOs contain a highly-conserved copper-dependent active site formed by three histidine residues between CBR I and CBR II. Phylogenetic- and modeling-based methods confirmed the wide occurrence of LMCO genes in HA-degrading polar soil bacteria and linked their putative gene functions with initial HS-degradation processes.

• MeSH
• Bacteria * enzymology   genetics   MeSH
• Phylogeny MeSH
• Humic Substances * microbiology   MeSH
• Laccase * genetics   metabolism   MeSH
• Soil MeSH
• Soil Microbiology * MeSH
• RNA, Ribosomal, 16S genetics   MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Humic Substances * MeSH
• Laccase * MeSH
• Soil MeSH
• RNA, Ribosomal, 16S MeSH

Use of nanoparticles (NPs) in several commercial products has led to emergence of novel contaminants of air, soil and water bodies. The NPs may exhibit greater ecotoxicity due to nano-scale dependent properties over their bulk counterparts. The present investigation explores the effect of in vitro supplementation of TiO2, silica and silver NPs on radial growth and ultrastructural changes in the hyphae and spores of two mushroom genera, Ganoderma lucidum and Volvariella volvaceae. A concentration dependent decrease in radial growth on NP amended potato dextrose agar medium was recorded. However, in comparison to control, there was decrease in radial diameter on supplementation with TiO2 NPs while an increase was recorded for silica and silver NPs amendments as compared to their bulk salts at same concentrations after 48 h of incubation. Optical microscopy studies showed decrease in the number of spores while increase in spore diameter and thinning of hyphal diameter on NPs supplementation. Scanning electron microscopy analysis of fungal growth showed presence of deflated and oblong spores in two fruiting strains of Ganoderma while Volvariella exhibited decreased sporulation. Further, hyphal thinning and branching was recorded in response to NP amendments in both the test mushrooms. Enhancement of protein content was observed on NP compared to bulk supplementation for all cultures, concentrations and hours of incubation except for TiO2 NPs. Likewise, bulk and NP supplementations (at 100 mg L -1) resulted in enhanced laccase activity with occurrence of laccase specific protein bands on SDS-PAGE analysis.

• Keywords
• Laccase enzyme, nanoparticles, protein content, radial diameter,
• Publication type
• Journal Article MeSH

To obtain enzymatic preparations with higher laccase activity levels from Funalia floccosa LPSC 232, available for use in several applications, co-cultures with six filamentous microfungi were tested. A laccase non-producing soil fungus, identified as Penicillium commune GHAIE86, showed an outstanding ability to increase laccase activity (3-fold as compared to that for monoculture) when inoculated in 6-day-old F. floccosa cultures. Maximum laccase production with the F. floccosa and P. commune co-culture reached 60 U/mL, or twice that induced by chemical treatments alone. Our study demonstrated that co-culture with soil fungi might be a promising method for improving laccase production in F. floccosa. Although the enhancement of laccase activity was a function of P. commune inoculation time, two laccase isoenzymes produced by F. floccosa remained unchanged when strains were co-cultured. These data are compatible with the potential of F. floccosa in agricultural applications in soil, whose enzyme machinery could be activated by soil fungi such as P. commune.

• MeSH
• Time Factors MeSH
• Coculture Techniques MeSH
• Laccase biosynthesis   chemistry   metabolism   MeSH
• Microbial Interactions * MeSH
• Penicillium genetics   growth & development   physiology   MeSH
• Colony Count, Microbial MeSH
• Polyporaceae enzymology   growth & development   MeSH
• Polyporales MeSH
• Soil Microbiology MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Laccase MeSH

The key to obtaining an optimum performance of an enzyme is often a question of devising a suitable enzyme and optimisation of conditions for its immobilization. In this study, laccases from the native isolates of white rot fungi Fomes fomentarius and/or Trametes versicolor, obtained from Czech forests, were used. From these, cross-linked enzyme aggregates (CLEA) were prepared and characterised when the experimental conditions were optimized. Based on the optimization steps, saturated ammonium sulphate solution (75 wt.%) was used as the precipitating agent, and different concentrations of glutaraldehyde as a cross-linking agent were investigated. CLEA aggregates formed under the optimal conditions showed higher catalytic efficiency and stabilities (thermal, pH, and storage, against denaturation) as well as high reusability compared to free laccase for both fungal strains. The best concentration of glutaraldehyde seemed to be 50 mM and higher efficiency of cross-linking was observed at a low temperature 4 °C. An insignificant increase in optimum pH for CLEA laccases with respect to free laccases for both fungi was observed. The results show that the optimum temperature for both free laccase and CLEA laccase was 35 °C for T. versicolor and 30 °C for F. fomentarius. The CLEAs retained 80% of their initial activity for Trametes and 74% for Fomes after 70 days of cultivation. Prepared cross-linked enzyme aggregates were also investigated for their decolourisation activity on malachite green, bromothymol blue, and methyl red dyes. Immobilised CLEA laccase from Trametes versicolor showed 95% decolourisation potential and CLEA from Fomes fomentarius demonstrated 90% decolourisation efficiency within 10 h for all dyes used. These results suggest that these CLEAs have promising potential in dye decolourisation.

• Keywords
• CLEA, enzyme immobilization, laccase, white rot fungi,
• MeSH
• Azo Compounds chemistry   MeSH
• Color MeSH
• Coloring Agents chemistry   MeSH
• Bromthymol Blue chemistry   MeSH
• Enzymes, Immobilized chemistry   MeSH
• Glutaral chemistry   MeSH
• Catalysis MeSH
• Laccase chemistry   MeSH
• Polyporales enzymology   MeSH
• Cross-Linking Reagents chemistry   MeSH
• Rosaniline Dyes chemistry   MeSH
• Ammonium Sulfate chemistry   MeSH
• Temperature MeSH
• Trametes enzymology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Names of Substances
• Azo Compounds MeSH
• Coloring Agents MeSH
• Bromthymol Blue MeSH
• Enzymes, Immobilized MeSH
• Glutaral MeSH
• Laccase MeSH
• malachite green MeSH Browser
• methyl red MeSH Browser
• Cross-Linking Reagents MeSH
• Rosaniline Dyes MeSH
• Ammonium Sulfate MeSH

Laccases are multi-copper oxidoreductases which catalyze the oxidation of a wide range of substrates during the simultaneous reduction of oxygen to water. These enzymes, originally found in fungi, plants, and other natural sources, have many industrial and biotechnological applications. They are used in the food, textile, pulp, and paper industries, as well as for bioremediation purposes. Although natural hosts can provide relatively high levels of active laccases after production optimization, heterologous expression can bring, moreover, engineered enzymes with desired properties, such as different substrate specificity or improved stability. Hence, diverse hosts suitable for laccase production are reviewed here, while the greatest emphasis is placed on yeasts which are commonly used for industrial production of various proteins. Different approaches to optimize the laccase expression and activity are also discussed in detail here.

• Keywords
• Expression optimization, Heterologous expression, Laccase, Recombinant, Yeasts,
• MeSH
• Bacteria genetics   MeSH
• Insecta cytology   genetics   MeSH
• Fungi genetics   MeSH
• Yeasts genetics   MeSH
• Laccase genetics   metabolism   MeSH
• Protein Engineering methods   MeSH
• Recombinant Proteins genetics   metabolism   MeSH
• Substrate Specificity MeSH
• Animals MeSH
• Check Tag
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Laccase MeSH
• Recombinant Proteins MeSH

Understanding the activity of bacteria in coniferous forests is highly important, due to the role of these environments as a global carbon sink. In a study of the microbial biodiversity of montane coniferous forest soil in the Bohemian Forest National Park (Czech Republic), we succeeded in isolating bacterial strain S55(T), which belongs to one of the most abundant operational taxonomic units (OTUs) in active bacterial populations, according to the analysis of RNA-derived 16S rRNA amplicons. The 16S rRNA gene sequence analysis showed that the species most closely related to strain S55(T) include Bryocella elongata SN10(T) (95.4% identity), Acidicapsa ligni WH120(T) (95.2% identity), and Telmatobacter bradus TPB6017(T) (95.0% identity), revealing that strain S55(T) should be classified within the phylum Acidobacteria, subdivision 1. Strain S55(T) is a rod-like bacterium that grows at acidic pH (3 to 6). Its phylogenetic, genotypic, phenotypic, and chemotaxonomic characteristics indicate that strain S55(T) corresponds to a new genus within the phylum Acidobacteria; thus, we propose the name Terracidiphilus gabretensis gen. nov., sp. nov. (strain S55(T) = NBRC 111238(T) = CECT 8791(T)). This strain produces extracellular enzymes implicated in the degradation of plant-derived biopolymers. Moreover, analysis of the genome sequence of strain S55(T) also reveals the presence of enzymatic machinery required for organic matter decomposition. Soil metatranscriptomic analyses found 132 genes from strain S55(T) being expressed in the forest soil, especially during winter. Our results suggest an important contribution of T. gabretensis S55(T) in the carbon cycle in the Picea abies coniferous forest.

• MeSH
• Acidobacteria genetics   isolation & purification   metabolism   MeSH
• Biodegradation, Environmental MeSH
• Biotransformation MeSH
• Phylogeny MeSH
• Forests MeSH
• Molecular Sequence Data MeSH
• Soil Microbiology * MeSH
• Plants metabolism   microbiology   MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH