Fungal Laccase Research Articles

Evaluation of Lignin Degrading Ability and In-silico Analysis and Molecular Docking of Laccase of Schizophyllum commune with Lignin

White-rot fungi have a unique and strong ability to degrade lignin, the most abundant and the strongest natural polymer on earth. The ligninolytic enzymes of these fungi comprise of three groups of oxidative extracellular enzymes mainly, lignin peroxidase (LiP), manganese dependent peroxidase (MnP) and laccase. Fungal laccases are considered to be directly involved with the degradation of lignin. Due to the broad substrate specificity and unique ability of biodegradation, fungal laccases have a great value in industrial and biotechnological applications like bioremediation, detoxification of industrial dyes and treatment of other pollutants. The objectives of this study was to evaluate the lignin degradation ability and laccase producing ability of selected fungal isolates originated from decaying hardwoods of Dimbulagala forest reserve, Sri Lanka and to predict the three-dimensional (3D) structure of laccase from Schizophyllum commune and its binding to lignin using in silicohomology modeling and molecular docking. Ten fungal isolates originated from decaying hardwoods were screened for the lignin degradation ability by using lignin amended malt extract plate assay and laccase producing ability by using guaiacol amended PDA plates. Seven isolates showed lignin degradation ability and five of them were laccase producers. Since S. commune could produce laccase, degrade lignin and laccase protein sequence is available, it was subjected to homology modeling. Homologous templates were identified using BLASTP across Protein Data Bank from NCBI. Laccase from Cerrena sp. was selected as the template for 3D model building of laccase from S. commune using Modeller 10.1. The quality of resulted 3D model of the protein was verified by its energy and stereochemical properties. The unstable regions were selected and remodeled by loop modelling using ModLoop web server. The results of evaluation of the remodeled structure by stereochemical quality and energy was found to be improved and showed that predicted model was of good quality due to the presence of maximum residues in the favored region. Later CB-Dock server was used to perform molecular docking studies using lignin model compounds. The amino acid residues of modeled laccase of S. commune in contact with the lignin based model compounds were identified. These findings help uncovering the lignin degradation mechanisms by S. communelaccases and are useful in biofuel production and bioremediation.
 Keywords: Laccase, Homology modeling, Molecular docking, LigninAcknowledgement: Authors acknowledge the TWAS research grant (18-020 RG/BIO/AS_I), ICGEB research grant (CRP/LKA18-03) and NSF Sri Lanka (RG/2019/BT/03)

Comparison of Laccases and Hemeproteins Systems in Bioremediation of Organic Pollutants

Laccases and peroxidases have attracted great interest for industrial and environmental applications. These enzymes have a broad substrate range and a robust oxidizing ability. Moreover, using mediators or co-oxidants makes it possible to increase their catalytic activity and extend their substrate scope to more resistant chemical structures. Fungal laccases and ligninolytic peroxidases, mainly lignin and manganese peroxidases, are the privileged oxidoreductases for bioremediation processes. Nonetheless, an increasing diversity of laccases and peroxidase-type enzymes has been proposed for environmental technologies. This article aims to provide an overview of these enzymes and compare their applicability in the degradation of organic pollutants. Fundamental properties of the proteins are covered and applications towards polycyclic aromatic hydrocarbons (PAHs) and pesticides are specially focused. Laccases are multicopper oxidases initially studied for applications in the pulp and paper industry but able to oxidize a variety of environmentally concerning compounds. Relying on O2, laccases do not require peroxides nor auxiliary agents, like Mn2+, although suitable redox mediators are needed to attack the more recalcitrant pollutants (e.g., PAHs). True and pseudo-peroxidases use a stronger oxidant (H2O2) and the redox chemistry at the heme site generates high potential species that allow the oxidation of dyes and some pesticides. Lately, research efforts have been directed to enzyme discovery, testing with micropollutants, and improving biocatalysts' stability by immobilization and protein engineering. Further understanding of the effects of natural media components and solvents on the enzymes might lead to competitive enzymatic treatments of highly toxic media.

Isolation and characterization of a novel laccase from an Antarctic thermophilic Geobacillus

AbstractLaccases are enzymes from the multi-copper oxidase family that have gathered a lot of attention due to their wide range of substrates, their interspecies variability and their still elusive mechanism of action. The presence of four copper atoms in their active site makes them an interesting model for the study of the relationship between the structure and function of proteins. It is possible to find them in fungi, plants and prokaryotes. Bacterial laccases display many advantages over fungal laccases in terms of their application. They have, in general, a greater thermal stability and a different pH profile, which contributes to widening their field of possible application. In the present work, a novel laccase from an Antarctic microorganism, Geobacillus sp. ID17, is purified and characterized. This is the first Antarctic bacterial laccase to be functionally described. It was found to be active at neutral pH and to have greater activity at 55°C. Its catalytic constants are in the order of other bacterial laccases. Screening for different potential substrates was also performed, showing that this novel laccase is more selective than commercial laccases. This enzyme could find potential application in the generation of gallic acid polymers or in organic synthesis in contexts where meticulous substrate discrimination is needed.

Enzymatic bioprospecting of endophytic Aspergillus niger isolated from Albizia lebbeck (L.) Benth

Endophytic fungi reside inside plants in a mutualistic relationship with the host and produce numerous bioactive compounds, including extracellular enzymes. A rich diversity of endophytic fungi associated with the medicinal plant Albizia lebbeck (L.) Benth was bio-prospected in the present study. Thirty-three isolates obtained from the plant were assessed for secretion of six different extracellular hydrolytic enzymes. The results showed that 38%, 9%, 69%, 16%, 38%, and 13% of the endophytic isolates could produce amylase, protease, lipase, laccase, cellulase, and gelatinase enzymes, respectively. Overall, 78% of the isolates showed positive results for one or the other enzyme. Aspergillus niger (Isolate 8) isolated from the bark proved to be most efficient in producing all the enzymes and was further exploited for various applications. The crude fungal amylase of the isolate helped in 39.08% reduction in biochemical oxidation demand (BOD) of municipal wastewater. Effective blood stain removal from the white cotton cloth was achieved when crude protease was used in combination with detergent. 13.29% biodegradation of vegetable oil was observed using fungal lipase. Dye decolorization of methylene blue (71.65%) and methyl orange (56.53%) was observed by fungal laccase. Saccharification of bagasse (83.94%) and paper (64.93%) was achieved by using fungal cellulase. Complete extraction of silver from waste X-ray films was achieved by crude gelatinase. The results obtained in the present study can further be strengthened using purified enzymes.

Relevance of Surface-Exposed Lysine Residues Designed for Functionalization of Laccase

Fungal laccases are oxidoreductases with low-specificity for substrates. The characterization of laccase's surface is a prerequisite used to obtain hybrid catalysts with new properties. Surface-exposed lysine residues are targets in immobilization reactions. In this work, LAC3-K0, an enzyme devoid of lysine, was used as a platform to detect potential surface-exposed sites suitable for replacement with a lysine residue. Seven sites were selected from a LAC3-K0 3-D model, and single lysine mutants (UNIKn, n = residue number) were obtained by site-directed mutagenesis. All mutants were expressed in Saccharomyces cerevisiae W303-1A and detected as functional secreted proteins by their ability to oxidize guaiacol or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) on agar plates. All variants were active at acidic pH but presented no activity at neutral pH, as expected. Likewise, variants were stable a temperature between 15-55°C, and were completely inactivated at 70°C. Oxidation assays revealed that the replacement of one or two surface residues with lysine greatly affected enzyme activity and substrate specificity. The catalytic; parameters (KM^(app) and kcat^(app)) determined with ABTS were found to be different among the variants; Vmax^(app) was 1.5-2 fold higher in UNIK269 and triple mutant, with a KM^(app) of 0.27 and 0.30, respectively; kcat^(app )was 30.25 in UNIK238 and 32.34 in the triple mutant. The role of hydrophobic patches detected on the surface of LAC3-K0 was determined to be a favorable factor to be considered in the interaction of hybrid materials. All variants with uniquely surface located lysine created in this work can be in demand for obtaining laccases with a certain substrate specificity in the design of hybrid materials.

Transcriptome Profiling Reveals Differential Gene Expression of Laccase Genes in Aspergillus terreus KC462061 during Biodegradation of Crude Oil.

Simple SummaryThe Kingdom of Fungi is one of the most significant microorganism kingdoms, especially for soil fungi, which are still unexplored. Soil fungi play an extremely crucial role in the biodegradation of pollutants, mainly hydrocarbons. In this paper, molecular analysis delivers insights into laccase production by Aspergillus terreus KC462061 in the existence of crude oil, which is supported by the presence of five inducers, including aromatic compounds and metal ions. This paper established that the laccase of A. terreus KC462061 plays an essential function in the biodegradation of crude oil, and the synergistic effect of the Cu-ABTS compound caused an increase in laccase yields up to 22-fold after 10 days. This study confirmed that gas chromatography–mass spectrometry was a very accurate tool to demonstrate the biodegradation efficiency of A. terreus KC462061 for crude oil. The synergistic effect of the Cu-ABTS compound has the highest induction level of the transcription profile. Lcc11 and 12 were the main Lcc genes in transcription profiles throughout the life cycle of A. terreus KC462061, and their transcript abundance was correlated with the Cu-ABTS compound. A quantitative real-time polymerase chain reaction (qPCR) was used for the analysis of the transcription profile of eight laccase genes in A. terreus KC462061. Cu-ABTS was highly effective for efficient laccase expression profiling, mainly via Lcc11 and 12 transcription induction.Fungal laccases have high catalytic efficiency and are utilized for the removal of crude oil because they oxidize various aliphatic and aromatic hydrocarbons and convert them into harmless compounds or less toxic compounds, thus accelerating the biodegradation potential of crude oil. Laccases are important gene families and the function of laccases genes varied widely based on transcription and function. Biodegradation of crude oil using Aspergillus terreus KC462061 was studied in the current study beside the transcription level of eight laccase (Lcc) genes have participated in biodegradation in the presence of aromatic compounds, and metal ions. Time-course profiles of laccase activity in the presence of crude oil indicated that the five inducers individual or combined have a very positive on laccase activity. In the status of the existence of crude oil, the synergistic effect of Cu-ABTS compound caused an increase in laccase yields up to 22-fold after 10 days than control. The biodegradation efficiencies of A. terreus KC462061 for aliphatic and aromatic hydrocarbons of crude oil were 82.1 ± 0.2% and 77.4 ± 0.6%, respectively. The crude oil biodegradation efficiency was improved by the supplemented Cu-ABTS compound in A. terreus KC462061. Gas chromatography–mass spectrometry was a very accurate tool to demonstrate the biodegradation efficiencies of A. terreus KC462061 for crude oil. Significant differences were observed in the SDS-PAGE of A. terreus KC462061 band intensities of laccase proteins after the addition of five inducers, but the Cu-ABTS compound highly affects very particular laccase electrophoresis. Quantitative real-time polymerase chain reaction (qPCR) was used for the analysis of transcription profile of eight laccase genes in A. terreus KC462061 with a verified reference gene. Cu2+ ions and Cu-ABTS were highly effective for efficient laccase expression profiling, mainly via Lcc11 and 12 transcription induction. The current study will explain the theoretical foundation for laccase transcription in A. terreus KC462061, paving the road for commercialization and usage.

Considerations regarding affinity determinants for aflatoxin B1 in binding cavity of fungal laccase based on in silico mutational and in vitro verification studies

Laccase, a multicopper oxidase, is well known for its industrial potentials to remove environmental pollutants due to its low substrate specificity to oxidize phenols and thus catalytic versatility. Many efforts focused on the metabolic mechanism, yet to decipher the structural determinants responsible for the differentiation between substrates. Aflatoxin B1 (AFB1), a new substrate for laccase, is a mycotoxin with a formidable environmental threat to public health and food safety. In the present study, we combined biochemical, in silico mutational and molecular-docking data to gain an insight to the function of key residues in the active cavity close to the T1 copper site in a characterized recombinant laccase from Cerrena unicolor (rCuL). Kinetic data for computer-assisted virtual mutants established the binding affinity of hydrogen bonds and residues (Asn336, Asp207, Val391, and Thr165) in rCuL to AFB1. The augmented binding affinity to AFB1 may be related to the conformational rearrangements of the laccase and its ability to hydrogen-bond with the substrate. Furthermore, the optimal pH and temperature for rCuL and variants mediated AFB1 degradation may depend on their pH stability and thermostability. Our findings reinforce the importance of the structure-function relationship of fungal laccases in degrading AFB1, providing mechanistic guidance for future biocatalyst and bioengineering applications.

A pilot study for enhanced transformation of a metabolite 3,5-dichloroaniline derived from dicarboximide fungicides through immobilized laccase mediator system.

This pilot investigation aimed to evaluate the removal efficiency and the underlying biocatalytic pathways of immobilized fungal laccase during the oxidative biotransformation of a non-phenolic metabolite, 3,5-dichloroaniline (3,5-DCA) derived from dicarboximide fungicides. The maximum loading of laccase on the microporous support surfaces could reach 36.4mg/g. The immobilized laccase on the microporous support surfaces exhibited excellent thermal stability, pH adaptability, storage stability, and reusability compared to free laccase. The ILMS assay indicated that the immobilized laccase efficiently removed studied 3,5-DCA (99-100%) in the aqueous medium, within 72h in the presence of catechol. In this study, we identified three coupling reaction products during the removal of 3,5-DCA through an ILMS assay. Based on the identified coupling reaction products, we proposed the reaction pathway for the biotransformation of 3,5-DCA by immobilized laccase, which was shown to be potentially useful in the sustainable environmental remediation of aniline metabolite (i.e., 3,5-DCA) derived from dicarboximide fungicides.

Effect of pH on the Dehydrogenative Polymerization of Monolignols by Laccases from Trametes versicolor and Rhus vernicifera.

Dehydrogenative polymerization of coniferyl alcohol (CA) and sinapyl alcohol (SA) was conducted using commercial laccases, fungal laccase from Trametes versicolor (LacT) and plant laccase from Rhus vernicifera (LacR), at pH 4–7 to investigate how the enzymatic polymerization of monolignols differs between these two laccase systems. The enzyme activity of LacT was the highest at pH 4, whereas that of LacR was the highest at pH 7. A dehydrogenation polymer (DHP) was obtained only from CA in both laccase systems, although the consumption rate of SA was higher than that of CA. 1H–13C HSQC NMR analysis showed that DHPs obtained using LacT and LacR contained lignin substructures, including β-O-4, β-O-4/α-O-4, β-β, and β-5 structures. At pH 4.5, the β-O-4 structure was preferentially formed over the β-O-4/α-O-4 structure, whereas at pH 6.5, the β-O-4/α-O-4 structure was preferred. The pH of the reaction solution was more vital to affect the chemical structure of DHP than the origin of laccases.

Laccases—Versatile Enzymes Used to Reduce Environmental Pollution

The accumulation of waste and toxic compounds has become increasingly harmful to the environment and human health. In this context, the use of laccases has become a focus of interest, due to the properties of these versatile enzymes: low substrate specificity, and water formation as a non-toxic end product. Thus, we begin our study with a general overview of the importance of laccase for the environment and industry, starting with the sources of laccases (plant, bacterial and fungal laccases), the structure and mechanism of laccases, microbial biosynthesis, and the immobilization of laccases. Then, we continue with an overview of agro-waste treatment by laccases wherein we observe the importance of laccases for the biodisponibilization of substrates and the biodegradation of agro-industrial byproducts; we then show some aspects regarding the degradation of xenobiotic compounds, dyes, and pharmaceutical products. The objective of this research is to emphasize and fully investigate the effects of laccase action on the decomposition of lignocellulosic materials and on the removal of harmful compounds from soil and water, in order to provide a sustainable solution to reducing environmental pollution.

Solid-State Fermentation of Chestnut Shells and Effect of Explanatory Variables in Predictive Saccharification Models.

In this study, chestnut shells (CNS), a recalcitrant and low-value agro-industrial waste obtained during the peeling of Castanea sativa fruits, were subjected to solid-state fermentation by six white-rot fungal strains (Irpex lacteus, Ganoderma resinaceum, Phlebia rufa, Bjerkandera adusta and two Trametes isolates). After being fermented, CNS was subjected to hydrolysis by a commercial enzymatic mix to evaluate the effect of fermentation in saccharification yield. After 48 h hydrolysis with 10 CMCase U mL−1 enzymatic mix, CNS fermented with both Trametes strains was recorded with higher saccharification yield (around 253 mg g−1 fermented CNS), representing 25% w/w increase in reducing sugars as compared to non-fermented controls. To clarify the relationships and general mechanisms of fungal fermentation and its impacts on substrate saccharification, the effects of some independent or explanatory variables in the production of reducing sugars were estimated by general predictive saccharification models. The variables considered were lignocellulolytic activities in fungal fermentation, CNS hydrolysis time, and concentration of enzymatic hydrolysis mix. Multiple linear regression analysis revealed a very high significant effect (p < 0.0001) of fungal laccase and xylanase activities in the saccharification models, thus proving the key potential of these enzymes in CNS solid-state fermentation.

Substitution of the Methionine Axial Ligand of the T1 Copper for the Fungal-like Phenylalanine Ligand (M298F) Causes Local Structural Perturbations that Lead to Thermal Instability and Reduced Catalytic Efficiency of the Small Laccase from Streptomyces coelicolor A3(2).

Many industrial processes operate at elevated temperatures or within broad pH and salinity ranges. However, the utilization of enzymes to carry out biocatalysis in such processes is often impractical or even impossible. Laccases (EC 1.10.3.2), which constitute a large family of multicopper oxidases, have long been used in the industrial setting. Although fungal laccases are in many respects considered superior to their bacterial counterparts, the bacterial laccases have been receiving greater attention recently. Albeit lower in redox potential than fungal laccases, bacterial laccases are commonly thermally more stable, act within broader pH ranges, do not contain posttranslational modifications, and could therefore serve as a high potential scaffold for directed evolution for the production of enzymes with enhanced properties. Several examples focusing on the axial ligand mutations of the T1 copper site have been published in the past. However, structural evidence on the local and global changes induced by those mutations have thus far been of computational nature only. In this study, we set out to structurally and kinetically characterize a few of the most commonly reported axial ligand mutations of a bacterial small laccase (SLAC) from Streptomyces coelicolor. While one of the mutations (Met to Leu) equips the enzyme with better thermal stability, the other (Met to Phe) induces an opposite effect. These mutations cause local structural rearrangement of the T1 site as demonstrated by X-ray crystallography. Our analysis confirms past findings that for SLACs, single point mutations that change the identity of the axial ligand of the T1 copper are not enough to provide a substantial increase in the catalytic efficiency but can in some cases have a detrimental effect on the enzyme’s thermal stability parameters instead.

Extracellular proteases and laccases produced by Pleurotus ostreatus PoB: the effects of proteases on laccase activity.

Laccases are enzymes produced by plants and white rot fungi, such as Pleurotus ostreatus, with industrial applications. Fungal laccases have been widely studied, and investigations, such as those involving recombinant DNA technology or adding inducers, have been made to increase laccase production. On the other hand, it has been proposed that extracellular proteases could decrease laccase activity when both types of enzymes are produced by P. ostreatus. The aim of this work was to evaluate the effects of proteases on the activity of extracellular laccases produced by P. ostreatus PoB in submerged culture. Results showed that P. ostreatus PoB produced alkaline, acidic, and neutral proteases. Protease activity was quantified, and the highest activity at alkaline pH (9.0) was 5.63 IU/L (192 h), that at acidic pH (2.0) was 3.38 IU/L (192 h), and that at neutral pH (7.0) was 6.20 IU/L (312 h). The protease activity decreased in the presence of different protease inhibitors, as phenylmethylsulfonyl fluoride (PMSF), EDTA, pepstatin A, and a cocktail of protease inhibitors. Laccase activity was determined in cultures with and without protease inhibitors. In the control culture (without inhibitor), the highest laccase specific activity was 99.88 IU/mg protein. In cultures with PMSF, pepstatin A, or a cocktail of protease inhibitors, laccase activity increased by approximately 1.35-fold (138 IU/mg protein) with respect to the control culture. The inhibitor EDTA did not produce a positive effect on extracellular laccase activity. These results suggest that laccase activity is affected by the actions of acidic and neutral extracellular proteases.

Relevance of Surface-Exposed Lysine Residues Designed for Functionalization of Laccase

Fungal laccases are oxidoreductases with low-specificity for substrates. The characterization of laccase's surface is a prerequisite used to obtain hybrid catalysts with new properties. Surface-exposed lysine residues are targets in immobilization reactions. In this work, LAC3-K0, an enzyme devoid of lysine, was used as a platform to detect potential surface-exposed sites suitable for replacement with a lysine residue. Seven sites were selected from a LAC3-K0 3-D model, and single lysine mutants (UNIKn, n = residue number) were obtained by site-directed mutagenesis. All mutants were expressed in Saccharomyces cerevisiae W303-1A and detected as functional secreted proteins by their ability to oxidize guaiacol or 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) on agar plates. All variants were active at acidic pH but presented no activity at neutral pH, as expected. Likewise, variants were stable a temperature between 15-55°C, and were completely inactivated at 70°C. Oxidation assays revealed that the replacement of one or two surface residues with lysine greatly affected enzyme activity and substrate specificity. The catalytic; parameters (KM^(app) and kcat^(app)) determined with ABTS were found to be different among the variants; Vmax^(app) was 1.5-2 fold higher in UNIK269 and triple mutant, with a KM^(app) of 0.27 and 0.30, respectively; kcat^(app )was 30.25 in UNIK238 and 32.34 in the triple mutant. The role of hydrophobic patches detected on the surface of LAC3-K0 was determined to be a favorable factor to be considered in the interaction of hybrid materials. All variants with uniquely surface located lysine created in this work can be in demand for obtaining laccases with a certain substrate specificity in the design of hybrid materials.

High electrochemical stability of hyperthermophilic archaeal multicopper enzyme adsorbed on gold electrodes compared to fungal laccase

Multicopper enzymes (MCEs) have attracted significant recent attention for use as biocathodes in enzyme-catalyzed fuel cells, mostly to facilitate the four-electron reduction of oxygen to water. Au is highly biocompatible and does not exhibit a carbon-like tendency for toxicity. Especially, the development of an implant-type enzyme fuel cells with noble electrodes, such as those made of Au, can assist in resolving health issues. In the present research, a direct electron transfer (DET)-type reaction featuring a hyperthermophilic archaeon multicopper enzyme (McoP) and a Trametes sp. laccase (Lac) adsorbed on bare Au electrodes was investigated. Quartz crystal microbalance (QCM) analysis was used to examine the adsorption behavior of McoP and Lac on Au electrodes. The obtained results indicated that the adsorbed McoP on Au exhibited stability against a higher potential electric field (+0.8 V vs. Ag|AgCl) and showed stable bioelectrocatalysis for oxygen reduction (main production of H2O2 with two-electron reaction), compared with Lac. The electron transfer rate of the McoP at the Au electrode interface was evaluated to be 10 s−1. This finding could urgently contribute for developing biocathodes in enzyme-catalyzed fuel cell, especially implant-type enzymatic fuel cells.

Bioactive Properties of a Novel Antibacterial Dye Obtained from Laccase-Mediated Oxidation of 8-Anilino-1-naphthalenesulfonic Acid.

Fungal laccase obtained from a Cerrena unicolor strain was used as an effective biocatalyst for the transformation of 8-anilino-1-naphthalenesulfonic acid into a green-coloured antibacterial compound, which can be considered as both an antimicrobial agent and a textile dye, simultaneously. The process of biosynthesis was performed in buffered solutions containing methanol as a co-solvent, allowing better solubilisation of substrate. The transformation process was optimised in terms of the buffer pH value, laccase activity, and concentrations of the substrate and co-solvent. The crude product obtained exhibited low cytotoxicity, antibacterial properties against Staphylococcus aureus and Staphylococcus epidermidis, and antioxidant properties. Moreover, the synthesised green-coloured compound proved non-allergenic and demonstrated a high efficiency of dyeing wool fibres.

Production of fungal laccase on pineapple waste and application in detoxification of malachite green

The main purpose of this work was to use pineapple crowns as substrate for optimizing laccase production by Trametes versicolor in lab-scale experiments. One-factor-at-the-time analysis and response surface methodology were used to optimize production. A single laccase with molecular weight of 45 kDa was the main protein produced. A maximal laccase activity of 60.73 ± 1.01 U/g was obtained in 7-day cultures, representing a 6.7-fold increase compared to non-optimized conditions. The optimized conditions were temperature: 28 °C; initial moisture: 90%; glucose: 8.38%; yeast extract: 2.86%. Combining activity and stability, the best conditions for using this laccase during the long periods required by large-scale processes are pH 4.0–5.0 and temperature of 40–50 °C. Under these conditions, the crude laccase was efficient in detoxifying the dye malachite green with a KM of 14.33 ± 1.94 µM and a Vmax of 0.482 ± 0.029 µM/min with 0.1 units/mL. It can be concluded that pineapple crown leaves can be effectively used as substrate by T. versicolor for producing laccase under solid-state culture conditions. Laccase is an industrially relevant enzyme and its production with concomitant valorization of pineapple crowns as substrate offers highly interesting perspectives.

A Review: Optimization of Fungal Laccase Production and their Potential Application in Effluents Treatment

A Review: Optimization of Fungal Laccase Production and their Potential Application in Effluents Treatment

Degradation of Synthetic Dyes with Plant-Produced Manganese Peroxidase and Commercial Laccase

Contamination of the environment directly impacts animal, plant, and human health, as well as agricultural production. A potential solution tested in this work incorporates the use of enzymes from fungi, manganese (Mn) peroxidase (MnP) and laccase, to degrade pollutants. Unfortunately, the MnP is too expensive to produce (more than US$24,000 per gram) to be used in remediation applications. MnP from a corn kernel biofactory can be produced in large amounts, and at &lt;US$5 per gram, would be cost-effective in this application and resolve pollution issues. Two formulations of recombinant MnP from the corn kernel production system and commercial fungal laccase have been tested for degradation of synthetic dyes in an aqueous environment. Numerous concentrations of four synthetic azo or anthraquinone dyes were used. All dyes were partially or completely degraded by both enzymes.

Optimization of Laccase Production, and Characterization of Lignin Degradation Products by Fusarium oxysporum JUMAD-053

The objective of this work was to optimize the culture conditions for laccase production in the presence of Kraft lignin by Fusarium oxysporum JUMAD-053, and to evaluate the biodegradation products of lignin. The fungal isolate that presented highest laccase activity had its production optimized by a statistical factorial design 3 3 in 15 experimental runs. F. oxysporum presented the highest constitutive laccase titer (5.37 U/mL). Statistical factorial design demonstrated a maximum laccase titer of 9.8 U/mL when assayed against ABTS under the conditions optimized: 1.125% (w/v) yeast extract, 0.5% (w/v) Kraft lignin and 10 days of cultivation. The maximum laccase titer when assayed on DMP was 8.4 U/mL, following the conditions optimized: 1.125% yeast extract, 0.25% Kraft lignin and 7 days of cultivation. The analysis of cultures led to identification of metabolites; two being aromatic: 2,6-dimethoxy benzoic acid and sesamin; also, fumonisin and long-chain fatty acids. As a result of the study, the maximum laccase activities of 9.8 and 8.4 U/mL measured from ABTS and DMP substrates, respectively. The search shows new sources of fungal laccase for obtaining new metabolites of biodegradation from Kraft lignin in culture medium. DOI: http://dx.doi.org/10.17807/orbital.v13i5.1623