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Abstract Background White-rot fungi are known to naturally produce high quantities of laccase, which exhibit commendable stability and catalytic efficiency. However, their laccase production does not meet the demands for industrial-scale applications. To address this limitation, it is crucial to optimize the conditions for laccase production. However, the regulatory mechanisms underlying different conditions remain unclear. This knowledge gap hinders the cost-effective application of laccases. Results In this study, we utilized transcriptomic and metabolomic data to investigate a promising laccase producer, Cerrena unicolor 87613, cultivated with fructose as the carbon source. Our comprehensive analysis of differentially expressed genes (DEGs) and differentially abundant metabolites (DAMs) aimed to identify changes in cellular processes that could affect laccase production. As a result, we discovered a complex metabolic network primarily involving carbon metabolism and amino acid metabolism, which exhibited contrasting changes between transcription and metabolic patterns. Within this network, we identified five biomarkers, including succinate, serine, methionine, glutamate and reduced glutathione, that played crucial roles in co-determining laccase production levels. Conclusions Our study proposed a complex metabolic network and identified key biomarkers that determine the production level of laccase in the commercially promising Cerrena unicolor 87613. These findings not only shed light on the regulatory mechanisms of carbon sources in laccase production, but also provide a theoretical foundation for enhancing laccase production through strategic reprogramming of metabolic pathways, especially related to the citrate cycle and specific amino acid metabolism.

Background: White-rot fungi are known to naturally produce high quantities of laccase, which exhibit commendable stability and catalytic efficiency. However, their laccase production does not meet the demands for industrial-scale applications. To address this limitation, it is crucial to optimize the conditions for laccase production. However, the regulatory mechanisms underlying different conditions remain unclear. This knowledge gap hinders the cost-effective application of laccases. Results: In this study, we utilized transcriptomic and metabolomic data to investigate a promising laccase producer, Cerrena unicolor 87613, cultivated with fructose as the carbon source. Our comprehensive analysis of differentially expressed genes (DEGs) and differentially abundant metabolites (DAMs) aimed to identify changes in cellular processes that could affect laccase production. As a result, we discovered a complex metabolic network primarily involving carbon metabolism and amino acid metabolism, which exhibited contrasting changes between transcription and metabolic patterns. Within this network, we identified five biomarkers, including succinate, serine, methionine, glutamate and reduced glutathione, that played crucial roles in co-determining laccase production levels. Conclusions: Our study proposed a complex metabolic network and identified key biomarkers that determine the production level of laccase in the commercially promising Cerrena unicolor 87613. These findings not only shed light on the regulatory mechanisms of carbon sources in laccase production, but also provide a theoretical foundation for enhancing laccase production through strategic reprogramming of metabolic pathways, especially related to the citrate cycle and specific amino acid metabolism. [ABSTRACT FROM AUTHOR]

Laccases are vital players in the degradation of lignin, a complex polymer found in plant cell walls. They play a vital role in the ligninolytic activity of white-rot fungi, known for breaking down lignin the present study aimed to isolate a marine fungus with promising laccase-producing potential from the sediment. The present study collected sediment samples from mangrove sediment, Parangipettai area of Tamil Nadu, India. They were used to screen and isolate a promising marine fungus for laccase production. A total of 11 fungi were isolated. Among them, the isolate MSJM 06 showed the highest laccase activity (2.8 cm), The most potential strain, A. fumigatus was identified through LPCB, SEM and Molecular identification using ITS rRNA Sequencing and it was further selected for optimization and laccase production. Potential strains of MJMS-06 required 88 hours of incubation, 80 rpm agitation, pH 8, Temperature 37°C, 1.8% salinity, 1.5% starch as the carbon source was maltose and 0.7% peptone as the nitrogen source. [ABSTRACT FROM AUTHOR]

Bacterial laccases have proven to be a potential biocatalyst for various industrial applications due to their remarkable catalytic and stability properties. In this study, a novel thermostable laccase was produced from the bacterium Bacillus licheniformis VNQ by submerged fermentation. The specific activity of crude and purified laccase was found to be 13.17 U mg−1 and 83.47 U mg−1, respectively. The enzyme possessed a molecular mass of ∼48 kDa when characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum temperature and pH for enzyme activity was determined to be 55°C and 5.0, respectively. The enzyme was considered to be thermo-tolerant as it possessed a half-life of 4 h at 70°C. The enzyme was utilized for the oxidative biotransformation of in situ synthesized p -quinones to biologically active compounds, 1,4-naphthoquinone and its derivative. The obtained products were characterized using nuclear magnetic resonance (NMR) spectroscopy and gas chromatography–mass spectrometry (GC–MS) analysis. A high yield of naphthoquinones (74.93 ± 1.2%) with 1,4-naphthoquinone (60.61 ± 1.0%), and its derivative 2-hydroxy-1,4-naphthoquinone (14.32 ± 0.2%) was obtained at the optimized reaction conditions. • Production of thermostable laccase from thermophilic bacterial strain isolated from a geothermal location. • The enzyme possesses a half-life of 4 h at 70oC, thus suitable for the reaction processes performed at high temperature. • The enzyme obtained was utilized for the synthesis of naphthoquinone derivatives, popular bioactive compounds. • A high yield of 1,4-naphthoquinones (74.93 ± 1.2%) was obtained by optimizing the reaction conditions. [ABSTRACT FROM AUTHOR]

Pleurotus ostreatus and a newly isolated Ganoderma lingzhi strain were evaluated for their laccase secretion capacity by solid-state fermentation with different agricultural and forestry residues. There was a significant difference among fungi for biosynthetic potential. In principle, the laccase secretion capacity of P. ostreatus CY 568 was stronger than that from G. lingzhi Han 500. Different species of fungi had a preference for agricultural and forestry residues. The presence of cottonseed hull and Populus beijingensis were helpful for accelerating the rate of laccase enzyme production of P. ostreatus CY 568. Cottonseed hull and corncob were useful for improving the production of laccase from G. lingzhi Han 500. Continuous and stable laccase production was found on cottonseed hull by P. ostreatus CY 568 and G. lingzhi Han 500. Maximum laccase activity obtained from P. ostreatus CY 568 on Toona sinensis, Sophora japonica, Salix babylonica, Populus beijingensis, corncob, cottonseed hull, and straw of Oryza sativa was higher than that from G. lingzhi Han 500, and was nearly 1.16-fold, 1.59-fold, 3.32-fold, 1.39-fold, 1.08-fold, 1.08-fold, and 1.36-fold, respectively. These findings will be helpful for developing new productive strains and expanding more species for industrial application to obtain efficient and low-cost laccase. [ABSTRACT FROM AUTHOR]

Laccases are ligninolytic enzymes produced by different microorganisms, especially by fungi such as the white-rot fungus Pleurotus ostreatus. Chemical inductors have been used to promote laccase secretion due to the application of these enzymes in lignocellulosic biomass pretreatment. Cordyceps nidus ANDES-F1080 was previously described as a source of bioactive compounds that could influence the enzymatic production system of other fungi. For that reason, this study evaluates the effect of C. nidus’ ANDES-F1080 extracts on the laccase activity of P. ostreatus ANDES-F515. To achieve this objective, C. nidus ANDES-F1080 was grown in four different substrates: two artificial-based and two natural-based culture media. Metabolites were extracted from C. nidus ANDES-F1080 using water and methanol as solvents. Biochemical characterization of these extracts was performed to complement the analysis of their effect on laccase activity. Our results revealed an enhancement on the laccase activity of P. ostreatus ANDES-F515 grown in natural-based cultures when C. nidus’ ANDES-F1080 extracts were supplemented. The best laccase activities registered values around 10,575 ± 813 U·L−1.

Pyridine is a heterocyclic aromatic compound present in pyridine raffinate, an organic discharge of the pyridine manufacturing industry. Besides pyridine, raffinate also contains formaldehyde, picolines and phenolics. Earlier, we isolated Gamma proteobacterium from timber soil for laccase production and optimized the involved process parameters. Here, we studied the optimization of process parameters for biodegradation of pyridine raffinate with the help of mathematical modeling [central composite design with response surface methodology (CCD-RSM) and artificial neural network (ANN)]. The results predicted ANN to be a better tool for optimization of pyridine raffinate degradation. CCD was used to develop the best fit second-order polynomial quadratic regression equation. Prediction of degradation percentage for pyridine raffinate was done using the equation which was found to be 71.60% at temperature 36.76°C, pH 7.45 and inoculum concentration 1.96 mL/10mL. The predicted response was experimentally validated in the wet lab to verify the degradation efficiency. The outcome was 65.76±2%, further confirmed by Gas Chromatography-Flame Ionization Detector (GC-FID). The result of GC-FID () data showed no trace of pyridine (Area 0%) which was reduced from initial area of 1.38% pyridine in raffinate sample. [ABSTRACT FROM AUTHOR]

In the past decade, Mexican coasts have received an enormous influx of macroalgae species, producing serious environmental and public health concerns. Here, we developed a green methodology to generate a new polymer from the lignin contained in the macroalgae. The methodology consists in lignin extraction-by-boiling and its subsequent polymerization with a laccase-like enzyme from the green algae Tetraselmis gracilis (Tg-laccase). Mass spectrometry revealed the presence of guaiacyl (G), p-hydroxyphenyl (H), and sinapyl alcohol as the main monolignols in the lignin from Sargassum sp. On the other hand, MALDI-TOF spectra shows an increase in the size of the lignin chain after enzymatic polymerization process with Tg-laccase. Besides, the characterization of the novel polymer -using 1H NMR, FTIR, SEC-FPLC, and UV/Vis- allowed establishing that during the polymerization process there is a decrease in the number of phenolic groups as well as loss of aromatic protons, which allowed proposing a polimerizacion mechanism. This methodology could be promising in the development of a new lignin-based polymer and would open a new direction for the environmental management of the macroalgae on the Mexican beaches. [ABSTRACT FROM AUTHOR]

Repeated batch semi-solid fermentation (sSF) process using wheat straw substrate and fungal growth of Ganoderma lucidum on solid substrate was studied for production of laccase. pH showed significant effect on laccase production. Highest laccase activity with pH controlled to 5.0 in batch sSF was 15257.2 ± 353.4 U L− 1 on 9th day. In repeated batch process at pH 5.0, insoluble biomass substrate and fungal growth were reused after liquid part of medium was replaced with glucose, ammonium phosphate (best nitrogen source) and combined glucose and ammonium phosphate solution separately. Refilled to 80% w v− 1 of initial soluble sugar of first batch resulted in highest laccase production with peak activity after 4 days from replacement. Production of enzyme increased from 15257.2 U L− 1 in first batch to cumulative 90164.4 U L− 1 in 29 days after six repeated batches, productivity increased from 1680.2 to 3110.3 U L− 1 day− 1 (∼ 1.9 times) due to reductions in inhibitory effects and time required for fungal growth. Utilization of wheat straw in repeated batch sSF was supported by composition analysis and morphological changes (scanning electron microscopy) of substrate. Economic production of laccase using agricultural residues in repeated batch sSF could be possible. [ABSTRACT FROM AUTHOR]

The objective of this work was to increase laccase production by Pleurotus ostreatus PLAB through culture medium optimization using solid state culture conditions. Increased laccase activity was obtained through design of experiments (DOE) using the Taguchi orthogonal array (OA). Seven factors, viz. lignocellulose, glucose, yeast extract, peptone, KH2PO4, MgSO4 7H2O and MnSO4 H2O at three levels and pH at two levels. OA layout of L18 (21 x 37) was selected for the proposed experimental design using Minitab 17 software. Data analysis showed that lignocellulose (20 %) and glucose (10 g L1) had positive effect, whereas KH2PO4, MgSO4∙7H2O and MnSO4∙H2O did not have significant effect on laccase production. Taguchi OA analysis showed that pH 6, lignocellulose 20 %, glucose 10 g L-1, yeast extract 6 g L-1, peptone 15 g L-1, KH2PO4 3 g L1, MgSO4∙7H2O 0.5 g L-1 and MnSO4∙H2O 0.1 g L-1 were the optimal conditions to maximize laccase production. The model predicted a 30.37 U g-1 dry wt., which agreed with the experimentally obtained laccase activity 29.15 U g-1 dry wt. at optimal conditions.

Brewers’ spent grain (BSG) is the main solid by‐product of the brewing process and is typically disposed of as cattle feed. In this study, BSG was evaluated as a substrate for the production of polyphenols and the lignin‐degrading enzyme laccase using fungal solid‐state fermentation by Trametes versicolor. Laccases are finding increasing applications in the food industry and polyphenols have benefits for human health. After 14 days of fermentation with T. versicolor, there was a 3.4‐fold increase in the extraction of total polyphenols compared with untreated BSG. Using BSG as the sole source of carbon and nitrogen, maximum laccase activity was achieved after seven days of treatment with an activity of 560 U/L. Based on these results, BSG is suggested to be a good lignocellulose waste material to produce value‐added products such as the enzyme laccase and polyphenols. Copyright © 2018 The Institute of Brewing & Distilling [ABSTRACT FROM AUTHOR]

Improving laccases continues to be crucial in novel biotechnological developments and industrial applications, where they are concerned. This review breaks down and explores the potential of the strategies (conventional and modern) that can be used for laccase enhancement (increased production and upgraded biochemical properties such as stability and catalytic efficiency). The challenges faced with these approaches are briefly discussed. We also shed light on how these strategies merge and give rise to new options and advances in this field of work. Additionally, this article seeks to serve as a guide for students and academic researchers interested in laccases. This document not only gives basic information on laccases, but also provides updated information on the state of the art of various technologies that are used in this line of investigation. It also gives the readers an idea of the areas extensively studied and the areas where there is still much left to be done. © 2017 American Institute of Chemical Engineers Biotechnol. Prog., 33:1015-1034, 2017 [ABSTRACT FROM AUTHOR]

In order to screen more microorganisms for the biodegradation of tobacco stalk and explore its application value in the reusing of tobacco stalk. One bacterium strain H02 was screened out from soil for detecting its selective degradation of lignin in tobacco stalk and relative higher laccase production when fermentation with tobacco stalk in liquid state. The identification of 16S rDNA sequence indicates that the bacterium is belonged to Bacillus sp. It showed the highest laccase enzyme activity of 332.41 U/mL at 10 d after fermentation and the removal ratio of lignin, cellulose and hemicellulose were 15.68%, 5.58% and 19.66% respectively. In shortly, it can be inferred that this may provided a new approach for the reusing of tobacco stalk. [ABSTRACT FROM AUTHOR]

Rapeseed meal (RM) is an abundant and cheap by-product of oil extraction process. RM is a rich source of nitrogen, carbon, and minerals. Thanks to these features, RM has a striking potential for eco-friendly production of high value products in biotechnological processes. In this study, the possibility of using a low-cost medium based on the water soluble fraction of RM for laccase production by the fungus Pleurotus ostreatus has been evaluated and compared with the use of synthetic complex media. RM-based medium (RMM) led to extracellular laccase production comparable to that obtained in the presence of synthetic media. Moreover, the use of a raw material highly reduced the production costs. To further reduce cost and improve activity production the effect of the addition of nitrogen source, pure aromatic compounds and lignosulphonate, a low cost by-product of wood based industries, was evaluated. The optimized medium led to a laccase production level of more than 100,000 U/L at a cost of about 0.19*10-3 cent€/U. The obtained results demonstrate the effective recycle of a waste to produce an industrially relevant enzyme. [ABSTRACT FROM AUTHOR]

The objective of this work was to increase laccase production by Pleurotus ostreatus PLAB through culture medium optimization using solid-state culture conditions. Increased laccase activity was obtained through the design of experiments (DOE) using the Taguchi orthogonal array (OA). Seven factors, viz. lignocellulose, glucose, yeast extract, peptone, KH2PO4, MgSO4 ⋅ 7H2O and MnSO4 ⋅ H2O at three levels and pH at two levels with OA layout of L18 (2¹ x 37) were selected for the proposed experimental design using Minitab 17 software. Data analysis showed that lignocellulose (20%) and glucose (10 g L-1) had a positive effect, whereas KH2PO4, MgSO4 ⋅ 7H2O and MnSO4 ⋅ H2O did not have a significant effect on laccase production. Taguchi OA analysis showed that pH 6, lignocellulose 20%, glucose 10 g L-1, yeast extract 6 g L-1, peptone 15 g L-1, KH2PO4 3 g L-1, MgSO4 ⋅ 7H2O 0.5 g L-1 and MnSO4 ⋅ H2O 0.1 g L-1 were the optimal conditions to maximize laccase production. The model predicted a 30.37 U g-1 dry wt., which agreed with the experimentally obtained laccase activity 29.15 U g-1 dry wt. at optimal conditions. [ABSTRACT FROM AUTHOR]

Carbon sources and copper ion are the main influencing factors on the production of fungal laccase. To investigate the regulation of carbon source and copper ion in laccase production on the molecular level in tropical white-rot fungus PG15, a comparative analysis of gene expression patterns was performed by cDNA-amplified fragment length polymorphism (AFLP) technique. Selective amplifications with 120 primer combinations allowed the identification of 92 differentially expressed transcript-derived fragments (TDFs), ranging from 200 to 750 bp in size. The TDFs were from PG15 supplemented with different carbon sources and copper ion concentrations, majority of which downregulated laccase production. Twenty-one fragments that matched the database were functionally annotated and analyzed according to the up- and downregulation patterns identified by cDNA-AFLP. These fragments were probably involved in laccase production at the metabolism, signal transduction, transcription, or post-translation levels. This study provides the first catalog of genes involved in laccase production, together with their putatively functional annotations. These data provide potential candidates for improving laccase production in fungi by marker-assisted selection or genetic engineering. [ABSTRACT FROM AUTHOR]

Recent year, bacterial laccases are increasing interest in the field of industry and environmental applications especially decolorization of azo dyes. In industry, the dyes are present in stable nature including chemicals and lights. Due to these defects, the novel approaches are needed to removal of dyes before discharging into the environment. Among the various technologies, biological treatment methods and their strategies are very important, because of the decolorization and detoxification. Consecutively, biological mediated dyes removal are emerged with high potential especially microbes. Microbial laccases creates up new opportunities for their commercial applications. In this study, laccases were produced from Bacillus cereus (B. Cereus) and Pseudomonas parafulva (P. parafulva) by sub merged fermentation. For immobilization, the produced laccases were subjected to purify using 80% saturated ammonium sulphate and followed by dialysis. Then, crude laccases were immobilized through copper-alginate entrapment method. The maximum immobilized enzyme activity of the immobilized laccases were shown pH 8 at 50 °C and pH 7 at 40 °C for B. Cereus and P. parafulva respectively. In contrast, the normal enzyme activity was pH 10 at 40 °C and pH 8 at 40 °C were indicated for Bacillus cereus and P. parafulva respectively. Next, the free and immobilized laccases were performed the decolorization of three azo dyes T-blue, yellow GR and orange 3R, and exhibited that the 91.69 and 89.21% of Orange 3R were completely decolorized by both the B. Cereus and P. parafulva laccases when compared with free laccases enzymes. The confirmation of decolorization was monitored by UV–vis spectroscopy and FTIR spectroscopy, which clearly confirm the changes of peaks when compared with normal laccases. Finally, we have concluded that the B. Cereus and P. parafulva laccases are very important in azo dye decolorization and these used in future biological treatment of dyeing effluents. • Discovered the dye degrading bacteria from Western Ghats soil sample. • Purification of laccase enzyme from Bacillus cereus strain 1 and Pseudomonas parafulva strain 2. • Immobilized laccase enzyme for azo dye degradation ability. • Complete decolonization received after treatment of microorganisms. [ABSTRACT FROM AUTHOR]

This work represents the first report of isolation of potential laccase producers by air sampling using media supplemented with 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) and guaiacol for laccase production and secretion indicators. Nine fungal isolates showed positive reactions with 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) and guaiacol. The isolate named TEM H2 exhibited the largest and intensive oxidation zones with 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate) (85 mm) and guaiacol (66 mm) and therefore it was selected for detailed investigations. The strain was identified as Trametes trogii TEM H2 due to the morphological characteristics and the comparison of internal transcribed spacer ribosomal DNA gene sequences. The laccase production was screened in different liquid cultures. The best laccase production medium was determined as soluble starch yeast extract medium in which laccase production was reached to a maximum level (989.6 U l-1) on the 8th day of cultivation. Effects of different initial pH values on laccase production were tested. Optimum pH value for laccase production in soluble starch yeast extract medium was determined as pH 3.0 with 15425.0 U l-1laccase production at 12th day of cultivation. In addition, effects of eight inducers (veratryl alcohol, ferulic acid, 1-Hydroxybenzotriazole, syringic acid, 2,2-azinobis (3-ethylbenzothiazoline-6-sulfonate), 1 mmol l-1 CuSO4, 3% ethanol, guaiacol) were examined. Only cultures with 2,5-xylidine exhibited 1.9 fold increase in laccase activity reaching to 28890.0 U l-1. (© 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [ABSTRACT FROM AUTHOR]

Laccase production from Trametes versicolor was improved in the presence of the inducers ligninosulphonates, veratryl alcohol, and xylidine respectively two-, four-, and eightfold. The thermal inactivation of the produced laccase, after partial purification with ammonium sulfate was kinetically investigated at various temperatures (60-70 °C) and pH values (3.5, 4.5, and 5.5). The inactivation process followed first-order kinetics for all conditions tested, except for veratryl alcohol, for which a constant activity level was observed at the end of the inactivation, also after first-order decay. Enzyme thermostability was affected by the type of inducer used in the culture medium for the production of laccase and also by the pH of incubation mixture. Generally, laccase stability increased with pH increment, being more stable at pH 5.5, except with xylidine. At pHs 4.5 and 5.5, the three inducers significantly increased laccase thermal stability, with the higher effect being observed for pH 5.5 and ligninosulphonates, where increment of half-life times ranged from 3- to 20-fold, depending on the temperature. [ABSTRACT FROM AUTHOR]

Laccases are very interesting biocatalysts for several industrial applications. Its production by different white-rot fungi can be stimulated by a variety of inducing substrates, and the use of lignocellulosic wastes or industrial by-products is one of the possible approaches to reduce production costs. In this work, various industrial wastes were tested for laccase production by Trametes versicolor MZKI G-99. Solid waste from chemomechanical treatment facility of a paper manufacturing plant showed the highest potential for laccase production. Enzyme production during submerged cultivation of T. versicolor on the chosen industrial waste has been further improved by medium optimization using genetic algorithm. Concentrations of five components in the medium were optimized within 60 shake-flasks experiments, where the highest laccase activity of 2,378 U dm was achieved. Waste from the paper industry containing microparticles of CaCO was found to stimulate the formation of freely dispersed mycelium and laccase production during submerged cultivation of T. versicolor. It was proven to be a safe and inexpensive substrate for commercial production of laccase and might be more widely applicable for metabolite production by filamentous fungi. [ABSTRACT FROM AUTHOR]

White rot fungi (WRF) are suitable microorganisms for treating a broad range of organic pollutants and synthetic textile dyes because of their non-specific extracellular enzyme system. An indigenous novel strain, Pleurotus ostreatus IBL-02, was screened for its ability to decolorize four reactive dyes (Drimarene Brilliant Red K-4BL, Drimarene Golden Yellow K-2R, Drimarene Orange K- GL and Drimarene Blue K-2RL). Samples were removed after 10 days, centrifuged and supernatants were analyzed for determination of enzyme activities and percent dye decolorization. Flasks containing Drimarene Brilliant Red K-4BL showed 73% dye color removal after ten days with laccase production of 64 IU/ml, followed by 42 IU/ml manganese peroxidase (MnP) and only 1.0 IU/ml lignin peroxidase activity. The fungus also caused 53% decolorization of Drimarene Orange K-GL with 49 IU/ml, 18 IU/ml of laccase and MnP, respectively, but no LiP was detected. The maximally decolorized dye Drimarene Brilliant Red K-4BL was selected for subsequent enhanced laccase production and dye decolorization studies. Using modified medium IV (pH5; temperature, 35 °C) supplemented with glucose (2 g/100 ml) as carbon source, ammonium nitrate (0.06g/100 ml) as nitrogen source, copper (1 mM) as metal activator and ABTS (2 ml of 10 mM) as mediator, Pleurotus ostreatus produced 321 IU/ml of laccase to completely decolorize the Drimarene Brilliant Red K-4BL within 24hours. [ABSTRACT FROM AUTHOR]

Aims: To evaluate the production and stability of laccases by Pleurotus ostreatus in liquid co-cultures with Trichoderma viride as a function of infection time and agitation rate. Methods and Results: Pleurotus ostreatus cultures were infected with T. viride spores at 30 and 48 h. Maximal laccase volumetric activity was seen after 48 h (control cultures) or 72 h (co-cultures) of cultivation time. Only the cultures infected at 30 h showed an increased laccase volumetric activity compared to control cultures. After maximal laccase volumetric activity value was reached, a sharp decrease in it was observed in control cultures. Co-cultures exhibited a comparatively lower loss of activity. The influence of P. ostreatus and/or T. viride on the stability of laccase volumetric activity and isoenzyme pattern was evaluated. Trichoderma viride induced changes in the laccase isoenzyme pattern. Agitated cultures increased biomass growth and specific productivity threefold and sevenfold, respectively, to the static cultures. Conclusions: The laccase volumetric activity is very likely the result of the balance between biosynthesis and degradation/biotransformation rates occurring during the cultures. The individual presence of P. ostreatus or T. viride in the culture negatively affected the volumetric laccase activity. Significance and Impact of the Study: The evaluation of culture parameters that could influence Trichoderma–basidomycetes interaction and laccase production during submerged fermentation has not been reported. This study showed how laccase production in co-cultures of P. ostreatus and T. viride was influenced by the infection time and agitation/oxygenation conditions. [ABSTRACT FROM AUTHOR]

Aims: To select Trichoderma strains for enhanced laccase production in Pleurotus ostreatus or Agaricus bisporus cultures. Methods and Results: Laccase production by P. ostreatus and A. bisporus was evaluated in liquid (axenic) and solid (dual cultures) malt extract medium. Oxidation of ABTS, DMP and syringaldazine was evaluated in order to assess the potential of Trichoderma strains to enhance laccase production by basidiomycetes. Selected Pleurotus–Trichoderma interactions yielded higher increases in laccase volumetric activity and an additional laccase isoform was produced. By contrast, Agaricus–Trichoderma interactions lead to smaller increases on laccase volumetric activity, probably as result of repression (or degradation) towards one of the laccases isoforms. Conclusions: The strains of P. ostreatus and A. bisporus assessed in this work showed good potential as laccase producers. The Trichoderma-mediated biological stimulation of laccase production by P. ostreatus and A. bisporus is relevant in order to develop highly productive processes. Significance and Impact of the Study: Extracellular laccases from basidiomycetes are produced only in small amounts. It is therefore important to increase process productivity for potential industrial applications. The results from this study enable the selection Trichoderma strains capable of increasing laccase production by P. ostreatus or A. bisporus in dual cultures. [ABSTRACT FROM AUTHOR]

Abstract: The production of laccases during the lag, exponential and stationary phases of growth of Pleurotus ostreatus in submerged fermentation was evaluated. Laccase activity was positively correlated to the growth of the fungus. The specific growth rate was 0.02h−1 and the highest amount of dry biomass (7.8gl−1) was obtained after 480h of growth. Four laccase isoforms were secreted by the fungus, and tentatively named LI1, LI2, LI3 and LI4. LI2, LI3 and LI4 were produced during the stationary phase (between 408 and 456h approximately) while LI1 was produced during the lag, exponential and stationary phases of growth. Maximal laccase activity (12 200Ul−1) was observed at the beginning of the stationary phase (at 432h of growth). LI1 was purified by preparative isoelectric focusing and partially characterized. LI1 had a molecular mass of 43.7kDa as determined by SDS PAGE, a Km and Vmax of 90μM and 1.18ΔAbsmin−1 respectively and an isoelectric point of 2.3. LI1 showed activity over a broad range of pH and temperature, which may make it useful in the biodegradation of phenolic compounds present in wastewater from several industrial processes. [Copyright &y& Elsevier]

Abstract: The growth medium for Panus tigrinus laccase production was studied in shaken culture through response surface methodology. The impact of five crucial variables on enzyme production, including glucose and nitrogen concentrations and three distinct putative inducers, namely, copper sulphate, 2,5-xylidine and olive-mill wastewater was thoroughly investigated. Among them, 2,5-xylidine remarkably stimulated enzyme production while Cu2+ ions within the tested concentration range (0–0.25mM) had an opposite effect. The maximal laccase activity (about 2IU/mL on day 11) was observed in the medium containing glucose and nitrogen at concentrations of 12.5g/L and 20mM, respectively, and 0.25mM 2,5-xylidine as the sole inducer. A 35-fold increase in laccase activity was obtained with respect to the same medium where 2,5-xylidine had been omitted. With the medium thus optimised, further experiments were performed in a 3-L stirred-tank reactor (STR) leading to a laccase activity of 2200IU/L on day 9 with a productivity of 10.2IU/(Lh) and a specific activity of 26.7IU/mg protein. RT-PCR analyses of total RNA from both non-induced and putatively induced cultures conducted in STR showed that the transcript levels of only one out of two constitutively expressed laccase genes were markedly increased by the presence of 0.25mM 2,5-xylidine in the optimised medium. [Copyright &y& Elsevier]

Abstract: In this work, a thermostable laccase from the fungus Melanocarpus albomyces was produced in the efficient protein producer Trichoderma reesei in batch, fed-batch and continuous cultivations on lactose medium in a laboratory fermenter. The rate of consumption of base for pH control (DELTABAS) was measured in all the cultivations and was used as a control parameter in one fed-batch run and in a 1000h continuous cultivation. The dynamic DELTABAS control parameter can be used to maintain optimal production of secreted protein by fitting the rate of substrate feeding to the amount of substrate available to the growing fungus in the fermenter, thus maintaining growth limitation due to availability of carbon source while avoiding total carbon source depletion. The use of this parameter, capable of maintaining the biomass in a physiological state of imminent but not actual exhaustion of carbon source, was successful in both the fed-batch and continuous production of heterologous laccase. Laccase production in fed-batch and continuous runs was considerably improved in comparison to the batch cultivation, both in terms of volumetric productivity and yield on lactose. The DELTABAS-control algorithm was shown to be a useful research tool for process optimization. [Copyright &y& Elsevier]

Abstract: The establishment of the operational conditions for the continuous treatment process of the metal complex dye Grey Lanaset G (150mgl−1), in a fluidised bed bioreactor using air pulses with retained pellets of the white rot fungus Trametes versicolor has been carried out. Although the bioreactor operated under non-growth conditions, the fungus activity related to laccase production was maintained. The glucose consumption rate used to maintain the fungus was evaluated in 0.31±0.03gglucosed−1 DCW−1. The effect of the hydraulic retention time (HRT) on the decolourisation yield was also studied. Decolourisation was highly efficient (>80%) for the different HRTs ranging from 18 to 120h, and the dye removal rates ranged from 6.73 to 1.16mgl−1 h−1. No direct relationship between decolourisation and extracellular enzyme activity was found, and high enzyme activities were not necessary to obtain high decolourisation percentages. The treated effluent fulfils the environmental quality standards in relation to colour, so it could be discharged into a municipal wastewater treatment plant if necessary. [Copyright &y& Elsevier]

Abstract: The effects of the carbon and nitrogen sources, initial pH and incubation temperature on laccase production by the endophytic fungus Monotospora sp. were evaluated. The optimal temperature and initial pH for laccase production by Monotospora sp. in submerged culture were found to be 30°C and 8.5, respectively. Maltose (2gl−1) and ammonium tartrate (10gl−1) were the most suitable carbon and nitrogen source for laccase production. Under optimal culture medium, the maximum laccase activity was determined to be 13.55Uml−1, which was approximately four times higher than that in basal medium. This is the first report on laccase production by an endophytic fungus. [Copyright &y& Elsevier]

Laccases are ligninolytic enzymes produced by different microorganisms, especially by fungi such as the white-rot fungus Pleurotus ostreatus . Chemical inductors have been used to promote laccase secretion due to the application of these enzymes in lignocellulosic biomass pretreatment. Cordyceps nidus ANDES-F1080 was previously described as a source of bioactive compounds that could influence the enzymatic production system of other fungi. For that reason, this study evaluates the effect of C. nidus' ANDES-F1080 extracts on the laccase activity of P. ostreatus ANDES-F515. To achieve this objective, C. nidus ANDES-F1080 was grown in four different substrates: two artificial-based and two natural-based culture media. Metabolites were extracted from C. nidus ANDES-F1080 using water and methanol as solvents. Biochemical characterization of these extracts was performed to complement the analysis of their effect on laccase activity. Our results revealed an enhancement on the laccase activity of P. ostreatus ANDES-F515 grown in natural-based cultures when C. nidus' ANDES-F1080 extracts were supplemented. The best laccase activities registered values around 10,575 ± 813 U·L -1 ., Competing Interests: The authors declare that there are not conflicts of interest., (© 2020 The Authors.)