Fungal laccase: copper induction, semi-purification, immobilization, phenolic effluent treatment and electrochemical measurement

The laccase activity induced by copper ions in Trametes versicolor by two inducers was studied and the aims were to show that it is possible to obtain a high laccase activity in almost 12 of the enzymesproduct using a basic culture medium but different copper concentration. Laccase was inducted by 2,5-xylidine and copper sulfate. Semi-purification of the crude laccase was carried out through precipitation and the column separation with NaCl gradient. In order to apply in an effluent treatment, laccase was immobilized on different vitroceramics supports, pyrolytic graphite and also on a carbon fiber electrode as biosensor. The maximum laccase activity was 40,774.0 U L-1 at the 12th day. The best support for immobilization was pyrolytic graphite (glutaraldehyde treated-94% efficiency). Total phenol removal in Kraft E1 effluent was 19% for immobilized pyrolytic graphite with the mediator present. The biosensor prepared with this material showed a good linear response to catechol. The optimization of laccaseactivity induction through the combination of 2,5-xylidine and cooper sulfate was obtained and led to its use in environmental remediation

Purification, characterization and application of laccase from Trametes versicolor for colour and phenolic removal of olive mill wastewater in the presence of 1- hydroxybenzotriazole

Laccase forms (L1 and L2) from Trametes versicolor CCT 4521 showed a molecular mass of 66 kDa and optimum temperature around 40oC. The optimum pH (4.0 and 5.0) and Km (28.6 and 5 ìM) values usingsyringaldazine as substrate were found for L1 and L2, respectively. The enzymes were able to oxidize several compounds and were strongly inhibited by sodium azide, L-cysteine and dithiothreitol. The 75%of the N-terminal sequences were identical in both forms and similarities around 40 - 60% of laccases from wood-degrading fungi were observed. The use of 1-hydroxybenzotriazole as a mediator increased the compounds oxidized by laccases in olive mill wastewater

Purification, characterization and application of laccase from Trametes versicolor for colour and phenolic removal of olive mill wastewater in the presence of 1-hydroxybenzotriazole

Laccase forms ( L1 and L2) from Trametes versicolor CCT 4521 showed a molecular mass of 66 kDa and optimum temperature around 40 degrees C. The optimum pH ( 4.0 and 5.0) and K-m ( 28.6 and 5 mu M) values using syringaldazine as substrate were found for L1 and L2, respectively. The enzymes were able to oxidize several compounds and were strongly inhibited by sodium azide, L-cysteine and dithiothreitol. The 75% of the N-terminal sequences were identical in both forms and similarities around 40-60% of laccases from wood-degrading fungi were observed. The use of 1-hydroxybenzotriazole as a mediator increased the compounds oxidized by laccases in olive mill wastewater.6101248125

Characterisation of a Novel White Laccase from the Deuteromycete Fungus Myrothecium verrucaria NF-05 and Its Decolourisation of Dyes

A novel ‘white’ laccase was purified from the deuteromycete fungus, Myrothecium verrucaria NF-05, which was a high laccase-producing strain (40.2 U·ml−1 on the thirteenth day during fermentation). SDS-PAGE and native-PAGE revealed a single band with laccase activity corresponding to a molecular weight of approximately 66 kDa. The enzyme had three copper and one iron atoms per protein molecule determined by ICP-AES. Furthermore, both UV/visible and EPR spectroscopy remained silence, indicating the enzyme a novel laccase with new metal compositions of active centre and spectral properties. The N-terminal amino acid sequence of the purified protein was APQISPQYPM. Together with MALDI-TOF analysis, the protein revealed a high homology of the protein with that from reported M. verrucaria. The highest activity was detected at pH 4.0 and at 30°C. The enzyme activity was significantly enhanced by Na+, Mn2+, Cu2+ and Zn2+ while inhibited by DTT, NaN3 and halogen anions. The kinetic constant (Km) showed the enzyme was more affinitive to ABTS than other tested aromatic substrates. Twelve structurally different dyes could be effectively decolourised by the laccase within 10 min. The high production of the strain and novel properties of the laccase suggested its potential for biotechnological applications

Laccase induction in fungi and laccase/N-OH mediator systems applied in paper mill effluent

There has been increasing interest in extracellular enzymes from white rot fungi, such as lignin and manganese peroxidases, and laccases, due to their potential to degrade both highly toxic phenolic compounds and lignin. The optimum cultivation conditions for laccase production in semi-solid and liquid medium by Trametes versicolor, Trametes villosa, Lentinula edodes and Botrytis cinerea and the effects of laccase mediator system in E-1 effluent were studied. The higher laccase activity (12756 U) was obtained in a liquid culture of T. versicolor in the presence of 1 mM of 2,5-xylidine and 0.4 mM copper salt as inducers. The effluent biotreatments were not efficient in decolorization with any fungal laccases studied. Maximum phenol reduction was approximately 23% in the absence of mediators from T. versicolor. The presence of 1-hydroxybenzotriazole did not increase phenol reduction. However, acetohydroxamic acid, which was not degraded by laccase, acted very efficiently on E-1 effluent, reducing 70% and 73% of the total phenol and total organic carbon, respectively. Therefore, acetohydroxamic acid could be applied as a mediator for laccase bioremediation in E-1 effluent. (c) 2005 Elsevier Ltd. All rights reserved.98115816

Biodecolorization screening of synthetic dyes by four white-rot fungi in a solid medium: possible role of siderophores

Aims: Four selected fungi were screened for their ability to decolourize a textile effluent and commercial reactive dyes in a solid medium. Methods and Results: Ligninolytic enzymes activities (lignin peroxidase, manganese peroxidase and laccase) and siderophores presence were monitored in decolourized plates. Results: The results showed low lignin peroxidase activity and no manganese peroxidase activity was detected for all fungi. Laccase activity was observed in Reactive Blue 19 decolourized plates by Trametes versicolor and Trametes villosa. Siderophores presence was observed in Trametes versicolor, Phanerochaete chrysosporium and Lentinus edodes decolourized plates. Conclusions: Lentinus edodes displayed the greatest decolourization ability both in terms of extent and rapidity of decolourization. Significance and Impact of the Study: The transformation observed for dyes open the possibility to study siderophores to treat dyes and textile effluents.331212

Fungal laccase: copper induction, semi-purification, immobilization, phenolic effluent treatment and electrochemical measurement

The laccase activity induced by copper ions in Trametes versicolor by two inducers was studied and the aims were to show that it is possible to obtain a high laccase activity in almost 12 of the enzymes product using a basic culture medium but different copper concentration. Laccase was inducted by 2,5-xylidine and copper sulfate. Semi-purification of the crude laccase was carried out through precipitation and the column separation with NaCl gradient. In order to apply in an effluent treatment, laccase was immobilized on different vitroceramics supports, pyrolytic graphite and also on a carbon fiber electrode as biosensor. The maximum laccase activity was 40,774.0 U L-1 at the 12(th) day. The best support for immobilization was pyrolytic graphite ( glutaraldehyde treated-94% efficiency). Total phenol removal in Kraft E1 effluent was 19% for immobilized pyrolytic graphite with the mediator present. The biosensor prepared with this material showed a good linear response to catechol. The optimization of laccase activity induction through the combination of 2,5-xylidine and cooper sulfate was obtained and led to its use in environmental remediation.6101255125

Phenols removal in musts: Strategy for wine stabilization by laccase

The potential of laccase from Trametes versicolor for phenolic removal in must for wine stabilization was evaluated through a combination of an analytical methodology (capillary zone electrophoresis) and kinetics of phenols removal as the total antioxidant potential variation. Total phenolic content, total antioxidant potential and polyphenols were monitored from 0 to 3 h of must treatment. The results indicated that the treatment of a red must with laccase affect mainly the phenolic compounds responsible for the must antioxidant properties. The treatment of white musts with laccase showed higher reduction in total phenol than in the total antioxidant potential. Phenol degradation by laccase was very fast for catechins, and slowly for stilbenes (cis- and trans-resveratrol) and derivatives of cinnamic (ferulic and caffeic) and benzoic (syringic, vanillic, and gallic) acids. It is possible to conclude in this case that the use of laccase in white wines is perfectly feasible. This would allow softer and ecologically correct treatments, which would diminish the cost of processing and avoid deterioration of wines for long storage times. (c) 2007 Published by Elsevier B.V.454173210210

Phenolic compounds and total antioxidant potential of commercial wines

Growing evidence of the role of free radicals and antioxidants in health and ageing has focussed great interest on these compounds. The relationship between the total antioxidant potential and the phenolic content of commercial wines was evaluated. A close relationship between total phenolic content and total antioxidant potential for all wines was observed. Capillary zone electrophoresis showed that, in red wines, gallic acid was the highest of the phenolic acids and (+)-catechin and (-)-epicatechin were the next most abundant phenolics. Also, these compounds were strictly correlated with the total antioxidant potential of wines. Total antioxidant potential, by bleaching of 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radical cations, using gallic acid as standard, could be a practical and simple measurement to evaluate the characteristics of different wines. Furthermore, capillary electrophoresis is a powerful and high-performing tool for evaluating principal antioxidant wine components. (C) 2003 Elsevier Science Ltd. All rights reserved.82340941