This paper presents a kinetic model of the laccase-aided chlorine dioxide bleaching of bagasse pulp. The kinetic model was based on the rate of reduction of adsorbed organic halogen (AOX). The effects of the laccase enzyme dosage, the mediator 1-hydroxybenzotriazole (HBT) dosage, and the reaction temperature on the AOX content of the bleaching effluent are discussed. Good fits were obtained for...

γ-Proteobacterium JB, an alkali-tolerant soil isolate, produced laccase (8X10 nkat/L) in M162 medium. The optimization of process conditions (pH, incubation time, agitation, and CuSO4 concentration) for laccase production during submerged fermentation was carried out using response surface methodology (RSM) based on a central composite design (CCD). Maximum laccase production achieved was 7.4 X...

The thermal denaturation of laccase from the Japanese lacquer tree (Rhus vernicifera) was studied by differential scanning calorimetry. The endotherms of holo-laccase, type 2-Cu-depleted laccase and apo-laccase were deconvoluted into two independent two-state transitions, providing evidence for a domain structure of the protein. The correlation of the two transitions with the bleaching of coppe...

The current study includes isolation of laccase producing fungus from compost soil and characterization of the laccase enzyme. In our study, 11 fungal isolates were isolated by serial dilution. They were cultivated on potato dextrose agar (PDA) plate with indicator compound 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) to screen for the laccase production ability. Out of 11 iso...

Laccase enzymes are now commercially available, and a laccase/mediator combination is currently marketed for indigo dye bleaching in textile manufacturing; replacing traditional chemical-based processes with enzymatic technology reduces the need for effluent treatment. However, an inexpensive source of these enzymes will be needed to enable wider application of this technology. In the present w...

The present study focused on laccase production, characterization, and its involvement in chlorophyll decolorization. Extracellular laccase, with the highest activity of 11 U/ml on day 8, was efficiently produced from Trametes hirsuta in 5 l bioreactor with optimized media comprising dual carbon sources, glucose and water hyacinth. A laccase was then purified from the supernatant to homogeneity...

A locally isolated white rot fungal strain Trametes versicolor IBL-04 produced high laccase activities in solid state bio-processing of corn cobs. Addition of glucose and yeast extract (C: N ratio; 25:1) enhanced laccase synthesis. Addition of Tween-80 and CuSO4 enhanced laccase production to 1012 U/mL under optimized process conditions. Laccase was further purified to 2.89-fold (specific activ...

Zinc tetraaminophthalocyanine-Fe3O4 nanoparticle composites were prepared by organic-inorganic complex technology and characterized. It has been proved that the ZnTAPc dispersed randomly onto the surface of Fe3O4 nanoparticles to form molecular dispersion layer and there was a relatively strong bond between central zinc cation and oxygen. The nanoparticle composite took the shape of roundish sp...

Endocrine-disrupting genistein was treated with the white rot fungus Phanerochaete sordida YK-624 under ligninolytic condition with low-nitrogen and high-carbon culture medium. Genistein decreased by 93% after 4 days of treatment and the activities of ligninolytic enzymes, manganese peroxidase (MnP) and laccase, were detected during treatment, thus suggesting that the disappearance of genistein...

A novel laccase-producing white-rot fungus, Marasmius sp. BBKAV79 (Genbank Accession Number-KP455496, KP455497), was isolated and subjected to purification, characterization and dye decolorization study. The purified enzyme was obtained with a specific activity of 0.226 U mg-1 protein and a final yield of 13.5 %. The enzyme was found to be a monomeric protein with a molecular mass of ~75 kDa as...