| some properties of an endo-1,4-beta-d-xylanase from the ligniperdous fungus trametes hirsuta. | some properties of purified endo-1,4-beta-d-xylanase (1,4-beta-d-xylan xylanohydrolase, ec 3.2.1.8) from the ligniperdous fungus trametes hirsuta were investigated. the enzyme was stable between ph 4.0 and 8.0 were optimum activity at ph 5.0--5.5. the temperature optimum was 50 degrees c and the enzyme was stable for up to 30 min at 45 degrees c; however, it was denatured at higher temperatures. the km for 4-o-methylglucurono-d-xylan was 6.36.10(-3) equivalents of d-xylose per litre, the activat ... | 1978 | 27428 |
| studies on xylanase from basidiomycetes. selection of strains for the production of xylanase. | formation of extracellular xylanase was studied in 10 strains of wood-destroying fungi belonging to basidiomycetes during their submerged cultivation with willow sawdust. the highest enzyme activity was found in the fungus trametes hirsuta (wulf.) pilát. the effect of sources of carbon and nitrogen, cultivation time and initial ph of the cultivation solution on the formation of xylanase by the fungus trametes hirsuta was investigated. the highest production of the enzyme was reached during culti ... | 1975 | 234905 |
| on the specificity and mode of action of a xylanase from trametes hirsuta (wulf.) pilát. | the mode of action of the extracellular endo-(1 leads to 4)-beta-d-xylanase produced by trametes hirsuta on a (4-0-methyl-d-glucurono)-d-xylan and a modified, essentially neutral d-xylan from white willow (salix alba l.) has been studied. xylotetraose and xylohexaose, together with aldotetraouronic and aldohexaouronic acids, were the main products. the acidic oligosaccharides had a 4-o-methyl-d-glucopyranosyluronic acid group attached to the non-reducing d-xylosyl end-group. the action pattern o ... | 1979 | 526952 |
| purification of xylanase from the wood-rotting fungus trametes hirsuta. | xylanase (ec 3.2.1.8) was purified from a crude extracellular enzyme of the wood-rotting fungus trametes hirsuta by a four-step procedure involving precipitation with ammonium sulphate, gel filtration on bio-gel p-10, column chromatography on deae-sephadex a-50 and preparative electrophoresis on polyacrylamide gel. the isolated enzyme, electrophoretically homogeneous, was separated from beta-xylo-sylosidase and other hydrolytic enzymes studied. the analysis of the degradation products of water-s ... | 1976 | 1248782 |
| cloning, sequence analysis, and expression of ligninolytic phenoloxidase genes of the white-rot basidiomycete coriolus hirsutus. | two cdnas and two genomic dnas coding for the allelic forms of the ligninolytic phenoloxidase were isolated from the white-rot fungus coriolus hirsutus. the cloned genes were identified in genetic libraries by hybridization screening using four deoxyoligonucleotide probes which corresponded to the partial amino acid sequence of the purified enzyme. each cdna encoded the full-length of the phenoloxidase, a protein consisting of 499 amino acid residues, and its putative signal peptide of 21 amino ... | 1990 | 2394718 |
| [physiologically active substances from the fungus coriolus hirsutus (fr.) quel]. | the fungus coriolus hirsutus is able to synthesize physiologically active compounds with a high antioxidant activity. the level of the antioxidant activity is mainly determined by phenolic constituents and makes up 90-95% of ionol activity. the experiments carried out in test animals have shown hypolipidemic and hypocholesterolemic effects of the fungus alcohol extract. | 1994 | 7984552 |
| characterization and structural analysis of the laccase i gene from the newly isolated ligninolytic basidiomycete pm1 (cect 2971). | we have isolated and characterized the cdna and genomic dna coding for a phenoloxidase, laccase i, previously purified from culture supernatant of the newly isolated ligninolytic basidiomycete pm1 (cect 2971). a cdna library from basidiomycete pm1 was constructed, and laccase-encoding cdnas were identified by screening with antiserum raised against the purified enzyme. the lac1 gene coding for the laccase was identified in a partial genomic library by using the isolated cdna as a probe. nucleoti ... | 1993 | 8285710 |
| purification and characterization of a phenoloxidase (laccase) from the lignin-degrading basidiomycete pm1 (cect 2971). | a new lignin-degrading basidiomycete, strain pm1 (= cect 2971), was isolated from the wastewater of a paper factory. the major ligninolytic activity detected in the basidiomycete pm1 culture supernatant was a phenoloxidase (laccase). this activity was produced constitutively in defined or complex media and appeared as two protein bands in native gel electrophoresis preparations. no enzyme induction was found after treatment with certain potential laccase inducers. laccase i was purified to homog ... | 1993 | 8368848 |
| [laccase from coriolus hirsutus--a new marker enzyme for immunoenzyme analysis]. | a new immunochemical reagent is proposed which contains laccase, isolated from the culture liquid of the basidial fungus coriolus hirsutus, as a marker enzyme. the feasibility of immunolaccase conjugates for different variants of immunoassay, i.e. "sandwich", competitive and indirect, is demonstrated. the comparison of immunolaccase and immunoperoxidase conjugates showed that the absolute sensitivity of laccase-antibody conjugates was 3 times higher than that of antibody-peroxidase conjugates (7 ... | 1993 | 8516277 |
| the ligninolytic system of the white rot fungus pycnoporus cinnabarinus: purification and characterization of the laccase. | the white rot fungus pycnoporus cinnabarinus was characterized with respect to its set of extracellular phenoloxidases. laccase was produced as the predominant extracellular phenoloxidase in conjunction with low amounts of an unusual peroxidase. neither lignin peroxidase nor manganese peroxidase was detected. laccase was produced constitutively during primary metabolism. addition of the most effective inducer, 2,5-xylidine, enhanced laccase production ninefold without altering the isoenzyme patt ... | 1996 | 8919775 |
| phenolic substrates for fluorometric detection of laccase activity. | a fluorometric procedure has been developed for detection and estimation of laccase activity in fungal broth cultures. laccase solution was pretreated with catalase for 1 h at 37 degrees c and ph 5. homovanillic acid was then added and the reaction mixture incubated for a further hour at 37 degrees c. the fluorescence was then developed by addition of 0.1 m glycine buffer at ph 10. laccase preparations from pyricularia oryzae, coriolus hirsutus and pycnoporus cinnabarinus catalysed formation of ... | 1997 | 9271877 |
| ultrasensitive bienzyme sensor for adrenaline. | a biosensor consisting of an analyte-recycling two-enzyme system using laccase (coriolus hirsutus) and pqq-dependent glucose dehydrogenase in combination with the electrochemical detection of oxygen depletion at a platinum electrode was used for adrenaline determination in the nano- and subnanomolar concentration range. measurements were performed in a flow cell providing excellent baseline stability and fast recovery of the sensor. improved design of the polymer matrix resulted in a lower detec ... | 1997 | 9451785 |
| molecular analysis of a laccase gene from the white rot fungus pycnoporus cinnabarinus. | it was recently shown that the white rot basidiomycete pycnoporus cinnabarinus secretes an unusual set of phenoloxidases when it is grown under conditions that stimulate ligninolysis (c. eggert, u. temp, and k.-e. l. eriksson, appl. environ. microbiol. 62:1151-1158, 1996). in this report we describe the results of a cloning and structural analysis of the laccase-encoding gene (lcc3-1) expressed by p. cinnabarinus during growth under xylidine-induced conditions. the coding region of the genomic l ... | 1998 | 9572949 |
| purification and characterization of the constitutive form of laccase from the basidiomycete coriolus hirsutus and effect of inducers on laccase synthesis. | an isolate of coriolus hirsutus constitutively expresses substantial amounts of extracellular laccase on a defined growth medium. the most efficient inducer of extracellular laccase synthesis was syringaldazine, which increased the enzyme yield by 1000% at a concentration of 0.11 microm. the constitutive form of the enzyme was purified 312-fold. laccase from c. hirsutus, with an estimated molecular mass of 55 kda and pi of 4.0, is a monomeric glycoprotein containing 12% carbohydrate consisting o ... | 1998 | 9693088 |
| laccase from coriolus hirsutus as alternate label for enzyme immunoassay. determination of pesticide 2,4-dichlorophenoxyacetic acid. | a new label--laccase from the fungus coriolus hirsutus--was applied for solid-phase enzyme-linked immunosorbent assays of the pesticide 2,4-dichlorophenoxyacetic acid (2,4-d). two proposed assays are based on (1) competitive binding of antibody-laccase conjugate with immobilized 2,4-d-protein conjugate and 2,4-d in tested sample, and (2) competition of 2,4-d and 2,4-d-laccase conjugate for binding with immobilized antibodies. kinetic and concentration dependencies for these reactions were studie ... | 1999 | 10390810 |
| [optimization of conditions for cultivation of the basidiomycete coriolus hirsutus--producer of extracellular laccase]. | the effects of various factors on the biosynthesis of extracellular laccase (ec 1.14.18.1) by the basidiomycete coriolus hirsutus (wulf.: fr.) quel. no. 072 during submerged cultivation were examined. optimal parameters for cultivation in a fermenter of 10 l were determined: temperature, 28 degrees c; stirrer rotation speed, 160 rpm; and the inoculum volume, 15% of the working volume of the fermenter. the filtrate contained peroxidase, laccase, and phenol oxidase activities and displayed a high ... | 2000 | 10752081 |
| [certain biochemical and physicochemical properties of the inducible form of extracellular laccase from basidiomycetes coriolus hirsutus]. | an inducible form of extracellular laccase (ec 1.14.18.1) was isolated from the basidiomycete coriolus hirsutus. the induction was performed with 0.11 microm syringaldazine, a substrate of laccase. the inducible form of the enzyme consisted of two isoforms, laccase i1 and laccase i2, whose molecular weights were 69 +/- 2 and 67 +/- 2 kda, respectively. the isoelectric points of these isoenzymes were found to be 3.5 and 4.2, respectively. the optimum ph range for both laccases was 4.4-4.6, and th ... | 2000 | 10867944 |
| silver stained polyacrylamide gels and fluorescence-based automated capillary electrophoresis for detection of amplified fragment length polymorphism patterns obtained from white-rot fungi in the genus trametes. | silver stained denaturing polyacrylamide gels (pages) and fluorescent denaturing automated capillary electrophoresis (ce) were used to detect amplified fragment length polymorphism (aflp) patterns obtained from white-rot fungi belonging to the genus trametes. aflp fingerprinting detected by the fluorescence-based method as well as by silver staining showed a high discriminatory power in differentiating nine strains of trametes ochracea, nine strains of trametes hirsuta and ten isolates of tramet ... | 2000 | 10889313 |
| decolorization and detoxification of textile dyes with a laccase from trametes hirsuta. | trametes hirsuta and a purified laccase from this organism were able to degrade triarylmethane, indigoid, azo, and anthraquinonic dyes. initial decolorization velocities depended on the substituents on the phenolic rings of the dyes. immobilization of the t. hirsuta laccase on alumina enhanced the thermal stabilities of the enzyme and its tolerance against some enzyme inhibitors, such as halides, copper chelators, and dyeing additives. the laccase lost 50% of its activity at 50 mm nacl while the ... | 2000 | 10919791 |
| purification and characterization of a new member of the laccase family from the white-rot basidiomycete coriolus hirsutus. | laccase produced by coriolus hirsutus was purified to electrophoretic homogeneity by acetone precipitation, deae sepharose cl-6b, sephacryl s-200 hr, hitrap sp, and mono s chromatography. the purification was 14.5-fold with an overall yield of 32.3%. the enzyme is a monomeric glycoprotein with 11% carbohydrate content, an isoelectric point of 7.4, and a molecular mass of 73 kda. the n-terminal amino acid sequence showed low homology to those of the laccases of other white-rot basidiomycetes. spe ... | 2000 | 11147821 |
| screening of micro-organisms for decolorization of melanins produced by bluestain fungi. | a total of 17 fungi and four bacteria were screened for their ability to decolorize melanin, using isolated extracellular melanin of the bluestain fungus aureobasidium pullulans as substrate. on agar media, decolorization was observed by four fungal strains: bjerkandera adusta vtt-d-99746, galactomyces geotrichum vtt-d-84228, trametes hirsuta vtt-d-95443 and trametes versicolor vtt-d-99747. the four fungi were more efficient on nitrogen-limited medium than on complete medium. the melanin-decolor ... | 2001 | 11330716 |
| reactivity of trametes laccases with fatty and resin acids. | lipophilic extractives commonly referred to as wood pitch or wood resin can have a negative impact on paper machine runnability and product quality. the lipophilic extractives are composed mainly of fatty acids, resin acids, sterols, steryl esters and triglycerides. in this work, the suitability of laccases for the modification of fatty and resin acids was studied, using two model fractions. in the treatments, resin and fatty acid dispersions were treated with two different laccases, i.e. laccas ... | 2001 | 11341313 |
| temperature-induced changes in copper centers and protein conformation of two fungal laccases from coriolus hirsutus and coriolus zonatus. | the paper reports on two fungal laccases from coriolus hirsutus and coriolus zonatus and their type-2 copper-depleted derivatives. temperature-induced changes of the copper centers were characterized by optical and electron paramagnetic resonance (epr) spectroscopy, and the overall protein stability by differential scanning microcalorimetry. the intact enzymes showed highly cooperative thermal unfolding transitions at about 90 degrees c. type-2 copper depletion led to uncoupling of the domains c ... | 2001 | 11410296 |
| indigo degradation with purified laccases from trametes hirsuta and sclerotium rolfsii. | the degradation of the textile dye indigo with purified laccases from the fungi trametes hirsuta (thl1 and thl2) and sclerotium rolfsii (srl1) was studied. all laccases were able to oxidize indigo yielding isatin (indole-2,3-dione), which was further decomposed to anthranilic acid (2-aminobenzoic acid). based on the oxygen consumption rate of the laccases during indigo degradation, a potential mechanism for the oxidation of indigo involving the step-wise abstraction of four electrons from indigo ... | 2001 | 11500206 |
| laccases from basidiomycetes: physicochemical characteristics and substrate specificity towards methoxyphenolic compounds. | laccases from the basidiomycetes coriolus hirsutus, coriolus zonatus, cerrena maxima, and coriolisimus fulvocinerea have been isolated and purified to homogeneity and partially characterized. the kinetics of oxidation of different methoxyphenolic compounds by the fungal laccases has been studied. as laccase substrates, such methoxyphenolic compounds as 4-hydroxy-3,5-dimethoxycinnamic acid (sinapinic acid), 4-hydroxy-3-methoxycinnamic acid (ferulic acid), and 2-methoxyphenol (guaiacol) were used. ... | 2001 | 11563958 |
| comparative characterization of methods for removal of cu(ii) from the active sites of fungal laccases. | copper-containing sites of laccases isolated from the basidiomycetes coriolus hirsutus and coriolus zonatus were characterized by optical methods and epr spectroscopy. methods for preparation of fungal laccase derivatives free from type 2 copper ions were compared. the data of epr spectroscopy and spectrophotometric titration of copper sites showed that only a modified method based on the use of bathocuproine as a chelator for type 2 copper yielded laccase derivatives completely free from type 2 ... | 2001 | 11703175 |
| decolorization of textile dyes by laccases from a newly isolated strain of trametes modesta. | four ligninolytic fungi, trametes modesta, trametes hirsuta, trametes versicolor and sclerotium rolfsii, were compared for their ability to produce laccases. the fungal laccases were screened for their ability to decolorize eight synthetic dyes (anthraquinone, azo, indigo and triarylmethane). the decolorization rate depended both on the source of the enzyme preparation and on the structure of the dye. based on laccase production and dye decolorizing ability, t. modesta was selected for further s ... | 2002 | 11996335 |
| evaluation of white-rot fungi for detoxification and decolorization of effluents from the green olive debittering process. | wastewater produced by the debittering process of green olives (gow) is rich in polyphenolics and presents high chemical oxygen demand and alkalinity values. eight white-rot fungi ( abortiporus biennis, dichomitus squalens, inonotus hispidus, irpex lacteus, lentinus tigrinus, panellus stipticus, pleurotus ostreatus and trametes hirsuta) were grown in gow for 1 month and the reduction in total phenolics, the decolorization activity and the related enzyme activities were compared. phenolics were e ... | 2002 | 12111170 |
| [immunoenzyme analysis of decomposition of herbicides by soil and wood-rot fungi]. | the effect of herbicide atrazine was studied on the growth and development of a number of soil and wood decay fungi: white-rot basidiomycetes (cerrena maxima, coriolopsis fulvocenerea, and coriolus hirsutus), thermophilic micromycetes from self-heating grass composts (cellulolytic fungus penicillium sp. 13 and noncellulolytic ones humicola lanuginosa spp. 5 and 12), and mesophilic phenol oxidase-producing micromycete mycelia sterilia inbi 2-26. detection of atrazine in liquid fungal cultures was ... | 2002 | 12325298 |
| electroreduction of o(2) to water at 0.6 v (she) at ph 7 on the "wired" pleurotus ostreatus laccase cathode. | o(2) was electroreduced to water at 0.6 v (she) near neutral ph on the "wired" pleurotus ostreatus laccase cathode. we previously reported high-current density (5 ma cm(-2)), four-electron electroreduction of o(2) to water on a "wired" coriolus hirsutus laccase electrode at +0.7 v (she) in ph 5 in citrate buffer. since the enzyme was inhibited by chloride and because its activity declined steeply when the ph was raised to neutral, the rate of o(2) electroreduction in a physiological buffer solut ... | 2002 | 12392957 |
| dibenzyl sulfide metabolism by white rot fungi. | microbial metabolism of organosulfur compounds is of interest in the petroleum industry for in-field viscosity reduction and desulfurization. here, dibenzyl sulfide (dbs) metabolism in white rot fungi was studied. trametes trogii uamh 8156, trametes hirsuta uamh 8165, phanerochaete chrysosporium atcc 24725, trametes versicolor ifo 30340 (formerly coriolus sp.), and tyromyces palustris ifo 30339 all oxidized dbs to dibenzyl sulfoxide prior to oxidation to dibenzyl sulfone. the cytochrome p-450 in ... | 2003 | 12571066 |
| [fungal decomposition of oat straw during liquid and solid state fermentation]. | white rot fungi (coriolus hirsutus, coriolus zonatus, and cerrena maxima from the collection of the komarov botanical institute of the russian academy of sciences) and filamentous fungi (mycelia sterilia inbi 2-26 and trichoderma reesei 6/16) were grown on oat straw-based liquid and solid media, as well as in a bench-scale reactor, either individually or as co-cultures. all fungi grew well on solid agar medium supplemented with powdered oat straw as the sole carbon source. under these conditions ... | 2003 | 12625046 |
| purification, molecular characterization and reactivity with aromatic compounds of a laccase from basidiomycete trametes sp. strain ah28-2. | a recently isolated basidiomycete, trametes sp. strain ah28-2, can be induced to produce a high level of laccases when grown on a cellobiose-asparagine liquid medium. after induction by kraft lignin, two major isozymes were detected in the fermentation supernatant of the fungus. the principal component laccase a, which accounts for about 85% of the total activity, can be purified to electrophoretic homogeneity by three chromatographic steps: deae-sepharose ff, superdex-200 and mono-q. the soluti ... | 2003 | 12664149 |
| [isolation and characterization of humin-like substances produced by wood-degrading fungi causing white rot]. | three samples of high-molecular-weight humin-like substances were obtained by solid-phase cultivation of coriolus hirsutus and/or cerrena maxima on oat straw. the yield of humin-like substances amounted to 1.38-2.26% of the weight of the plant substrate consumed. these substances, produced both by individual and mixed cultures of the basidiomycetes, were shown to be similar in their structure and physicochemical properties. according to the data of ir and 13c-nmr spectroscopy, the substances con ... | 2003 | 12754826 |
| crystallization and preliminary x-ray analysis of a four-copper laccase from coriolus hirsutus. | laccase from the fungus coriolus hirsutus has been purified. crystals of the enzyme suitable for x-ray structure analysis have been obtained under optimized crystallization conditions using polyethylene glycol as a precipitant. the crystals belong to space group p2(1)2(1)2(1), with unit-cell parameters a = 50.65, b = 74.01, c = 124.83 a, and contain 40% solvent and a single molecule of laccase in the asymmetric unit. x-ray data were collected to 1.85 a at the copper edge and the four copper site ... | 2003 | 12876350 |
| grape seeds: the best lignocellulosic waste to produce laccase by solid state cultures of trametes hirsuta. | grape seeds were used by trametes hirsuta as a substrate for laccase production giving 23 ku l(-1), which was 10-fold the value attained in the cultures with no lignocellulosic waste addition. the dyes, indigo carmine and bromophenol blue, were easily decolourised (100% in 24 h) by the extracellular liquid obtained in such cultures, whereas methyl orange (65% in 24 h) and phenol red (36% in 24 h) were more resistant to degradation. this shows the specificity of laccase towards different dye stru ... | 2003 | 12882277 |
| polymerization of guaiacol and a phenolic beta-o-4-substructure by trametes hirsuta laccase in the presence of abts. | the reaction of the monomeric lignin model compound guaiacol and the beta-o-4-type dimer erol (1-(4-hydroxy-3-methoxyphenyl)-2(2-methoxyphenoxy)-propane-1,3-diol with laccase from trametes hirsuta was studied in the presence of the mediator abts (2,2'-azino-di[3ethylbenzothiazoline-6-sulfonic acid]). the product mixtures were analyzed by means of aqueous-phase size exclusion chromatography (sec) with 50 mm naoh as eluent. interestingly, in the laccase-catalyzed reaction with both substrates, the ... | 2003 | 14524712 |
| transformation of the white-rot basidiomycete coriolus hirsutus using the ornithine carbamoyltransferase gene. | an efficient transformation system for the basidiomycete coriolus hirsutus was developed. a double-auxotrophic mutant of c. hirsutus, deficient both in ornithine carbamoyltransferase (octase) and 3-isopropylmalate dehydrogenase (3-ipm dehydrogenase), was transformed to arg+ with each allelic type of the c. hirsutus genomic octase gene (arg1) newly cloned. the transformation frequency of 10(3)-10(4) transformants per mug dna per 10(6)-10(7) oidial protoplasts was reached. southern blots showed th ... | 2003 | 14586093 |
| [comparative stability assessment of laccases from the basidiomycetes coriolus hirsutus and coriolus zonatus in the presence of effectors]. | stability characteristics of the laccases of the basidiomycetes coriolus hirsutus and coriolus zonatus were measured comparatively at temperatures 25 and 40 degrees c in the presence of various effectors (proteins, salts, polyalcohols, polyacids, and polyelectrolytes). stabilization effects of cations on the laccases from c. hirsutus and c. zonatus decreased in the descending series cu2+ > mg2+ > ca2+ and ca2+ > mg2+ > mn2+, respectively. tween 20 caused insignificant stabilization of the two en ... | 2003 | 14593868 |
| novel laccase redox mediators: spectral, electrochemical, and kinetic properties. | the screening of potential redox mediators for laccase was performed using homogeneous enzyme preparations from coriolus hirsutus and coriolus zonatus. it was discovered that derivatives of 1-phenyl-3-methyl-pyrazolones were efficient substrates for the laccases. the characterization of two representatives of the 1-phenyl-pyrazolone class, sodium 1-phenyl-3-methyl-4- methylamino-pyrazolone-5-n(4)-methanesulfonate and 1-(3'-sulfophenyl)-3- methylpyrazolone-5, in the reaction catalyzed by laccase ... | 2003 | 14665736 |
| [phenyl pyrazolones--novel oxidoreductase redox-mediators for degradation of xenobiotics]. | an approach was developed to screening organic compounds for putative activity of redox mediators of oxidoreductases, including laccases and peroxidases, applicable for xenobiotic degradation. the study was carried out with a homogenous laccase preparation from the basidiomycete trametes hirsuta and horse-radish root peroxidase. compounds belonging to 1-phenyl-3-methylpyrazolones were selected. spectroscopic and electrochemical investigation of two of the compounds, sodium 1-phenyl-2,3-dimethyl- ... | 2004 | 15125193 |
| role of oxidative enzymatic treatments on enzymatic hydrolysis of softwood. | the impact of oxidative modification and partial removal of lignin by laccase-mediator treatments on the enzymatic hydrolysis of steam-pretreated softwood (sps) was evaluated. two mediators, n-hydroxy-n-phenylacetamide (nha) and its acetylated precursor, were oxidized by the laccase from trametes hirsuta, and their effects on the activity of cellulolytic enzymes and on the hydrolysis yield of sps were examined. both simultaneous and sequential combinations of laccase-mediator treatments with com ... | 2004 | 15129438 |
| stainless steel sponge: a novel carrier for the immobilisation of the white-rot fungus trametes hirsuta for decolourization of textile dyes. | alginate beads, polyurethane foam, nylon sponge and stainless steel sponge were tested as carrier materials for the white-rot fungus trametes hirsuta for laccase production under submerged fermentation conditions. stainless steel sponge was the best carrier material leading to the highest laccase activities of up to 800 u/l after 8 days of cultivation. these values are higher than those reported to date operating with inert supports and without inducer addition. in a 1-l bioreactor containing t. ... | 2004 | 15207297 |
| electrochemical redox transformations of t1 and t2 copper sites in native trametes hirsuta laccase at gold electrode. | mediatorless, electrochemically driven, redox transformations of t1 (type 1) and t2 copper sites in trametes hirsuta laccase were studied by cyclic voltammetry and spectroelectrochemical redox titrations using bare gold electrode. det (direct electron transfer) between the electrode and the enzyme was observed under anaerobic conditions. from analysis of experimental data it is concluded that the t2 copper site is in det contact with gold. it was found that electron transfer between the gold sur ... | 2005 | 15453829 |
| laccase from melanocarpus albomyces binds effectively to cellulose. | a laccase from the thermophilic fungus melanocarpus albomyces was shown to bind to softwood and pure microcrystalline cellulose. the binding isotherm fitted well the langmuir type one-site binding model. the adsorption parameters indicated that m. albomyces laccase binds with high affinity to cellulose with a relatively low maximum binding capacity, as compared to the values for various cellulases. the binding was shown to be reversible and not influenced by non-specific protein or 0.1-0.5 m na2 ... | 2004 | 15474046 |
| comparison of physico-chemical characteristics of four laccases from different basidiomycetes. | new strains of basidiomycetes producing extracellular laccases (trametes ochracea 92-78, and trametes hirsuta 56) have been found by screening of isolates of trametes fungi. the laccases from t. hirsuta 56 and t. ochracea 92-78 as well as two laccases from previously found and described strains of basidiomycetes, namely cerrena maxima and coriolopsis fulvocinerea, were purified to homogeneity. the standard redox potentials of type 1 copper in the enzymes were determined and found to be 780, 790, ... | 2004 | 15556280 |
| influence of redox mediators and metal ions on synthetic acid dye decolourization by crude laccase from trametes hirsuta. | in this paper, the effect of redox mediators on synthetic acid dye decolourization (sella solid red and luganil green) by laccase from trametes hirsuta cultures has been investigated. all the redox mediators tested, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (abts), 1-hydroxybenzotriazole (hbt) and remazol brilliant blue r (rbbr), led to higher activities than those obtained without mediators addition showing the suitability of the laccase/mediator system (lms) in the decolourization ... | 2005 | 15620733 |
| rat cytochrome p450-mediated transformation of dichlorodibenzo-p-dioxins by recombinant white-rot basidiomycete coriolus hirsutus. | rat cytochrome p450, cyp1a1, has been reported to play an important role in the metabolism of mono-trichlorodibenzo-p-dioxins (m-tricdds). to breed lignin (and m-tetracdds)-degrading basidiomycete coriolus hirsutus strains producing rat cyp1a1, an expression cassette [c. hirsutus gpd promoter-c. hirsutus gpd 5' portion (224-bp of 1st exon-8th base of 4th exon)-rat cyp1a1 cdna-lentinula edodes pria terminator] was constructed and inserted into pucr1 carrying the c. hirsutus arg1 gene. the resulti ... | 2005 | 15812643 |
| direct electron transfer reactions of laccases from different origins on carbon electrodes. | electrochemical studies of laccases from basidiomycetes, i.e., trametes hirsuta, trametes ochracea, coriolopsis fulvocinerea, cerrena maxima, and cerrena unicolor, have been performed. direct (mediatorless) electrochemistry of laccases on graphite electrodes has been investigated with cyclic voltammetry, square wave voltammetry as well as potentiometry. for all mentioned high potential laccases direct electron transfer (det) has been registered at spectrographic graphite and highly ordered pyrol ... | 2005 | 15941673 |
| polysaccharides from fruitbodies and mycelial culture of the fungus trametes hirsuta (wulf. ex fr.) lloyd. | the fruitbodies and mycelial culture of the wood destroying fungus trametes hirsuta (wulf. ex fr.) lloyd were investigated as a source of polysaccharides. four different polysaccharide fractions were isolated from these sources with the good yield 4.76% (pfa) and 1.18% (pfb)--(fruitbodies) and 2.33% (pmca), 3.25% (pmcb)--(mycelium) respectively. some chemical differences were found in the composition of isolated polysaccharides. some of them contained aminoacids as the structural components, esp ... | 1992 | 16092431 |
| decolourization of synthetic dyes by trametes hirsuta in expanded-bed reactors. | the present paper studies the decolourization of different synthetic dyes (indigo carmine, bromophenol blue, methyl orange and poly r-478) by the white-rot fungus trametes hirsuta at bioreactor scale under solid-state conditions, operating with ground orange peelings as a support-substrate. dye decolourization was performed in both batch and continuous mode. batch cultivation led to high decolourization percentages in a short time (100% for indigo carmine in 3h and 85% for bromophenol blue in 7 ... | 2006 | 16099017 |
| microbial decolorization of melanoidin-containing wastewaters: combined use of activated sludge and the fungus coriolus hirsutus. | a white rot fungus, coriolus hirsutus, exhibited a strong ability to decolorize melanoidin in cultures not supplemented with nitrogenous nutrients. addition of peptone to the cultures lowered the ability of the fungus to decolorize melanoidin, but that of inorganic nitrogens (ns), ammonium and nitrate did not bring about any marked reduction in the ability. these results suggest an inhibitory effect of organic n on melanoidin decolorization. therefore, for enhancing the decolorization of melanoi ... | 2000 | 16232717 |
| decolorization of heat-treatment liquor of waste sludge by a bioreactor using polyurethane foam-immobilized white rot fungus equipped with an ultramembrane filtration unit. | a bench-scale bioreactor using immobilized fungal cells equipped with an ultramembrane filtration unit was developed as a means of decolorizing brown color components (melanoidins) arising from the heat-treatment liquor (htl) of waste sludge. artificial htl containing 4200 color units of synthetic melanoidin supplemented with 1000 mg/l ethanol was first subjected to decolorization by the fungus coriolus hirsutus ifo4917 immobilized onto polyurethane foam cubes. then, the resultant biologically t ... | 2000 | 16232877 |
| laccase and mn-peroxidase production by coriolus hirsutus strain 075 in a jar fermentor. | the white-rot fungus coriolus hirsutus strain 075 excretes considerable amounts of laccase and mn-peroxidase into culture broth over a brief production time. the effects of agitation speed, temperature, aeration and inoculum amount on laccase production using a 10-l fermentor were studied. the optimum fermentation conditions were a 15% inoculum, an aeration rate of 0.88 vvm, an agitation speed of 160 rpm, and a temperature of 28 degrees c. by optimizing the fermentation conditions, the laccase a ... | 2002 | 16233231 |
| a laccase study by electrospray ionization fourier transform ion cyclotron resonance ms: copper depletion, glycoforms and stability. | the molecular properties and stability of a laccase from the white-rot fungus trametes hirsuta (thl) were studied to exploit the unique capability of electrospray ionization mass spectrometry (esi-ms) to monitor conformational and molecular-based heterogeneities and metal ion binding simultaneously. acid and organic solvents were applied as denaturing agents. in aqueous acidic solution, thl existed in two major forms, distinguished by their mass difference; in addition to these, two other forms ... | 2006 | 16317711 |
| electrochemistry and kinetics of fungal laccase mediators. | the screening of potential redox mediators for laccase was performed using homogeneous trametes hirsuta laccase. heterogeneous (electrochemical) and homogeneous (oxidation by laccase) reactions of the different types of the enhancers (mediators) of the enzyme were investigated. it was discovered that derivatives of phenyl-methyl-pyrazolones and benzoic acid, as well as n-hydroxynaphthalimide were efficient substrates for the laccase. the characterization of several representatives from each clas ... | 2006 | 16318928 |
| the endophytic fungus trametes hirsuta as a novel alternative source of podophyllotoxin and related aryl tetralin lignans. | the aryl tetralin lignans are synthesized by podophyllum sps. and are in great demand worldwide due to their use in synthesis of topoisomerase inhibitors. however, the sustained production of these aryl tetralin lignans requires large-scale harvesting from the natural environments, which has resulted in the plant-endangered status. in view of the difficulties in their total chemical synthesis, cultivation and failure of metabolic engineering approaches, there is a need to search for alternative ... | 2006 | 16375985 |
| regio- and stereoselective reductions of dehydrocholic acid. | dehydrocholic acid (dhca), an unnatural bile acid, is manufactured by oxidation of cholic acid. its biotransformation by two basidiomycetes (trametes hirsuta and collybia velutipes) is reported. these mycelia showed different affinities for the substrate and selectivities of attack: t. hirsuta in particular regio- and stereoselectively reduced the 3-keto group to yield 3 alpha-hydroxy-7,12-diketo-5 beta-cholan-24-oic acid (7,12-diketolithocolic acid) as the main product. a number of different ch ... | 2006 | 16504228 |
| effects of ph and cyclodextrins on pentachlorophenol degradation (mineralization) by white-rot fungi. | white-rot fungi (wrf) such as trametes hirsuta completely degrade (mineralize) pentachlorophenol (pcp) and many other organopollutants. this has led to them being used to decontaminate various substrates (e.g. soil) through biorememediation. however, because pcp is a biocide, it can inhibit fungal growth and thereby its own degradation. it was hypothesized that substrate ph might affect pcp degradation, because when the ph is lower than 4.7 (the pka for pcp) the phenol predominates, while at hig ... | 2006 | 16616987 |
| laccase activity from the fungus trametes hirsuta using an air-lift bioreactor. | to produce high laccase activities from the white-rot fungus trametes hirsuta in an in-house air-lift bioreactor (alb). | 2006 | 16706901 |
| specificities of a chemically modified laccase from trametes hirsuta on soluble and cellulose-bound substrates. | laccases could prevent fabrics and garments from re-deposition of dyes during washing and finishing processes by degrading the solubilized dye. however, laccase action must be restricted to solubilized dye molecules thereby avoiding decolorization of fabrics. chemical modification of enzymes can provide a powerful tool to change the adsorption behaviour of enzymes on water insoluble polymers. polyethylene glycol (peg) was covalently attached onto a laccase from trametes hirsuta. different molecu ... | 2006 | 16791729 |
| intron-dependent accumulation of mrna in coriolus hirsutus of lignin peroxidase gene the product of which is involved in conversion/degradation of polychlorinated aromatic hydrocarbons. | the homobasidiomycete coriolus hirsutus coding sequences of a lignin peroxidase (lip) gene (lip, containing six (i-vi) introns), a lip cdna (lipc), and three lipc derivatives containing one (i), three (i-iii), or five (i-v) introns were inserted into chromosome-integrating expression vector. these recombinant plasmids were introduced into c. hirustus monokaryotic strain. the transformant carrying the promoter-lipc-terminator cassette did not contain enough mrna molecules to be detectable by nort ... | 2006 | 16794306 |
| expression of the autofluorescent protein, dsred2, in the recombinants of the ectomycorrhizal basidiomycete, suillus grevillei, generated by agrobacterium-mediated transformation. | recombinants were generated from the ectomycorrhizal basidiomycete, suillus grevillei, through agroinfection using a binary vector carrying the hygromycin b resistance and the autofluorescent protein, dsred2, markers. dsred2 was driven by a cis-regulatory region of the glyceraldeyde-3-phosphate dehydrogenase gene (gpd) from the wood-rotting basidiomycete, coriolus hirsutus, which contains promoters and 5' gpd sequences with first through fourth exons and expressed for the first time in suillus s ... | 2006 | 16804705 |
| purification and characterization of cellobiose dehydrogenase from white-rot basidiomycete trametes hirsuta. | in order to save energy during the pulp making process, we tried to use white-rot basidiomycete, trametes hirsuta, which degrades lignin efficiently. but a decrease in paper strength caused by cellulolytic activity ruled this out for practical application. since the cellulolytic activity of the fungus must be decreased, we purified and characterized a cellobiose dehydrogenase (cdh) that was reported to damage pulp fiber. the cdh in the culture filtrate of c. hirsutus was purified by freeze-thawi ... | 2006 | 16861797 |
| electroenzymatic reactions with oxygen on laccase-modified electrodes in anhydrous (pure) organic solvent. | the electroenzymatic reactions of trametes hirsuta laccase in the pure organic solvent dimethyl sulfoxide (dmso) have been investigated within the framework for potential use as a catalytic reaction scheme for oxygen reduction. the bioelectrochemical characteristics of laccase were investigated in two different ways: (i) by studying the electroreduction of oxygen in anhydrous dmso via a direct electron transfer mechanism without proton donors and (ii) by doing the same experiments in the presenc ... | 2007 | 16920407 |
| [increase of the detoxification potential of basidiomycetes by induction of laccase biosynthesis]. | the effect of oxidoreductase inducers guaiacol and syringaldazine on the ability of coriolus hirsutus, coriolopsis fulvocinerea, cerrena maxima, and cocultivated coriolus hirsutus/cerrena maxima to degrade atrazine in submerged cultures was studied. all the basidiomycetes reduced atrazine concentration with and without syringaldazine or guaiacol. the degree of atrazine degradation was higher in induced cultures (77-98% vs. 68-94% without induction). of the four cultures, the highest detoxifying ... | 2006 | 17022458 |
| effect of protein structure on laccase-catalyzed protein oligomerization. | laccase-catalyzed oligomerization of proteins was studied using trametes hirsuta laccase (thl) and coactosin as a model system. the reaction mechanism was elucidated using free amino acids and the tripeptide gly-leu-tyr as substrates. matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (maldi-tof ms) and high-performance liquid chromatography (hplc) as well as oxygen consumption measurements and sds-page were used to study the reactions. of the 15 selected amino acids, t ... | 2006 | 17090138 |
| properties of native and hydrophobic laccases immobilized in the liquid-crystalline cubic phase on electrodes. | both native trametes hirsuta laccase and the same laccase modified with palmytic chains to turn it more hydrophobic were prepared and studied with cyclic voltammetry and raman spectroscopy. native laccase immobilized in the monoolein cubic phase was characterized with resonance raman spectroscopy, which demonstrated that the structure at the "blue" copper site of the protein remained intact. the diamond-type monoolein cubic phase prevents denaturation of enzymes on the electrode surface and prov ... | 2007 | 17151864 |
| [development of a novel enzyme-redox-mediator system based on a fungal laccase and ruthenium complexes]. | the laccase produced by the fungus coriolus hirsutus has been coordinatively modified with ruthenium complexes [ru(phpy)(phen)(mecn)2]pf6 and ru(bpy)2co3 under aerobic and anaerobic conditions. the amount of the complexes per enzyme molecule does not depend on the oxygen concentration, equaling 5 for [ru(phpy)(phen)(mecn)2]pf6 and 3 for ru(bpy)2co3. the ph dependence of the enzymatic activity, thermostability, and catalytical and electrocatalytical properties of the modified laccase are reported ... | 2006 | 17168291 |
| [laccase of the lignolytic fungus trametes hirsuta: purification and characterization of the enzyme, and cloning and primary structure of the gene]. | the main physicochemical characteristics of the major isoform of the laccase secreted by the fungu, trametes hirsuta 072 were studied. the enzyme belongs to the group of high redox potential laccases (e(t1) = 790 +/- 5), and it oxidizes with high efficiency various substrates of phenolic nature. the gene of this isoform was cloned, and its nucleotide sequence was determined. the length of the complete gene is 2134 bp. it comprises 11 exons and 10 introns. analysis of the amino acid sequence of t ... | 2006 | 17168293 |
| enzymatic coating of lignocellulosic surfaces with polyphenols. | upgrading of the surface characteristics could enhance the bulk properties of naturally abundant fiber-forming materials for better performance or create new value-added products. laccase can induce cross-linkage and covalent coupling of low molecular weight compounds onto lignocellulosic surfaces. for this purpose the 38-kda laccase from trametes hirsuta was purified and characterized. the best conditions for laccase-induced coating of flax fibers were determined. this evaluation was based on t ... | 2007 | 17260331 |
| catalytic activity of oxidases hosted in lipidic cubic phases on electrodes. | the monoolein-based liquid crystalline cubic phase was used as the matrix to incorporate redox enzymes--glucose (gox), pyranose (pyox) oxidases and laccase. thin layer of the cubic phase embedding gox or pyox activated glucose oxidation in the presence and absence of appropriate mediators. the electrodes exhibited unchanged voltammetric response to glucose for not less than six days. the potentials and ratio of catalytic to diffusion currents could be modified by choosing appropriate electroacti ... | 2007 | 17289444 |
| elucidating the mechanism of laccase and tyrosinase in wheat bread making. | cross-linking enzymes generate covalent bonds in and between food biopolymers. these enzymes are interesting tools for tailoring dough and bread structures, as the characteristics of the biopolymers significantly determine the viscoelastic and fracture properties of dough and bread. in this study, the influence of oxidative cross-linking enzymes, tyrosinase from the filamentous fungus trichoderma reesei and laccase from the white rot fungus trametes hirsuta, on dough and bread were examined. oxi ... | 2007 | 17602567 |
| decolouration of industrial azo dyes by crude laccase from trametes hirsuta. | the decolouration of several azo dyes, commonly used in the leather industry, by crude laccase obtained from trametes hirsuta cultivation was assessed. among the six dyes studied four showed a decolouration percentage higher than 50% in 4h, whereas the other two showed more resistance to degradation. these results show the ability of laccase towards different dye structures as well as its enormous potential for the decolouration of recalcitrant azo dyes. | 2007 | 17706354 |
| structure and characteristics of an endo-beta-1,4-glucanase, isolated from trametes hirsuta, with high degradation to crystalline cellulose. | trametes hirsuta produced cellulose-degrading enzymes when it was grown in a cellulosic medium such as avicel or wheat bran. an endo-beta-1,4-glucanase (theg) was purified from the culture filtrate, and the gene and the cdna were isolated. the gene consisted of an open reading frame encoding 384 amino acids, interrupted by 11 introns. the whole sequence showed high homology with that of family 5 glycoside hydrolase. the properties of the recombinant enzyme (reg) in aspergillus oryzae were compar ... | 2007 | 17928699 |
| identification of white-rot and soft-rot fungi increasing ethanol production from spent sulfite liquor in co-culture with saccharomyces cerevisiae. | to identify fungi that are capable of increasing ethanol production from lignocellulose in spent sulfite liquor. | 2008 | 18248376 |
| enzymatic removal of off-flavors from apple juice. | contaminating microorganisms such as actinomycetes, alicyclobacillus, and chlostridium can generate off-flavors in apple juices. such bacterial metabolites represent, besides phenol types such as guaiacol and 2,6-dibromophenol, a broad range of other chemicals, for example, geosmin, 2-methylisoborneol, or alpha-terpineol. a laccase from trametes hirsuta was purified, immobilized, and applied for the selective elimination of off-flavor substances in apple juice caused by microbial contamination. ... | 2008 | 18318500 |
| selection of newly isolated mushroom strains for tolerance and biosorption of zinc in vitro. | nine newly isolated mushroom strains were tested to assess both their zinc tolerance and potential for zinc removal from an aqueous solution. four strains of ectomycorrhizal fungi, namely clavariadelphus truncatus (t 192), rhizopogon roseolus (t 21), lepista nuda (t 373), and tricholoma equestre (t 174), along with five strains of white rot fungi, lenzites betulina (s 2), trametes hirsuta (t 587), ganoderma spp. (t 99), polyporus arcularius (t 438), and ganoderma carnosum (m 88), were investigat ... | 2008 | 18388466 |
| formation of protein-oligosaccharide conjugates by laccase and tyrosinase. | proteins and certain carbohydrates contain phenolic moieties, which are potential sites for modification of the function of the biopolymers. in this study, the capability of two different fungal oxidative enzymes, laccase from trametes hirsuta (thl) and tyrosinase from trichoderma reesei (trt), to catalyze formation of hetero-cross-linking between tyrosine side chains of alpha-casein and phenolic acids of hydrolyzed oat spelt xylan (hosx) was studied. formation of reaction products was followed ... | 2008 | 18422326 |
| effects of laccase and xylanase on the chemical and rheological properties of oat and wheat doughs. | the effects of trametes hirsuta laccase and pentopan mono bg xylanase and their combination on oat, wheat, and mixed oat-wheat doughs and the corresponding breads were investigated. laccase treatment decreased the content of water-extractable arabinoxylan (weax) in oat dough due to oxidative cross-linking of feruloylated arabinoxylans. laccase treatment also increased the proportion of water-soluble polysaccharides (wsnsp) apparently due to the beta-glucanase side activity present in the laccase ... | 2008 | 18558694 |
| laccase electrode for direct electrocatalytic reduction of o2 to h2o with high-operational stability and resistance to chloride inhibition. | laccase from trametes hirsuta basidiomycete has been covalently bound to graphite electrodes electrochemically modified with phenyl derivatives as a way to attach the enzyme molecules with an adequate orientation for direct electron transfer (det). current densities up to 0.5ma/cm(2) of electrocatalytic reduction of o(2) to h(2)o were obtained in absence of redox mediators, suggesting preferential orientation of the t1 cu centre of the laccase towards the electrode. the covalent attachment of th ... | 2008 | 18585029 |
| [micellar laccase-catalyzed synthesis of electroconductive polyaniline]. | a method of enzymatic synthesis of electroconductive polyaniline on the micelles of dodecylben-zenesulfonic acid sodium salt (dbsna) is proposed. the high potential laccase from the basidiomycete trametes hirsuta was used as a biocatalyst. the conditions for polyaniline synthesis were optimized (ph 4.0; reagent concentrations, 10-20 mm; and aniline/dbsna ratio, 2: 1). the resulting product was electrochemically active in the range of potentials from -200 to 600 mv, electroconductive, and capable ... | 2008 | 18663952 |
| a membrane-, mediator-, cofactor-less glucose/oxygen biofuel cell. | we report the fabrication and characterisation of a non-compartmentalised, mediator and cofactor free glucose-oxygen biofuel cell based on adsorbed enzymes exhibiting direct bioelectrocatalysis, viz. cellobiose dehydrogenase from dichomera saubinetii and laccase from trametes hirsuta as the anodic and cathodic bioelements, respectively, with the following characteristics: an open-circuit voltage of 0.73 v; a maximum power density of 5 microw cm(-2) at 0.5 v of the cell voltage and an estimated h ... | 2008 | 18846297 |
| [effect of coriolus hirsutus laccase on atrazine adsorption and desorption by different types of soil ]. | study of adsorption-desorption behavior of herbicide atrazine in soils of different geographical zones in the presence of coriolus hirsutus laccase was performed. laccase was shown to significantly increase adsorption coefficient and to facilitate irreversible adsorption of atrazine to soil. supposably, laccase catalyzes oxidative binding of atrazine to soil. | 2008 | 18924413 |
| enzymatic oxidation of manganese ions catalysed by laccase. | the principal possibility of enzymatic oxidation of manganese ions by fungal trametes hirsuta laccase in the presence of oxalate and tartrate ions, whereas not for plant rhus vernicifera laccase, was demonstrated. detailed kinetic studies of the oxidation of different enzyme substrates along with oxygen reduction by the enzymes show that in air-saturated solutions the rate of oxygen reduction by the t2/t3 cluster of laccases is fast enough not to be a readily noticeable contribution to the overa ... | 2009 | 18976793 |
| purification and characterization of a thermostable laccase with unique oxidative characteristics from trametes hirsuta. | a laccase was purified from trametes hirsuta. this laccase was classified as a "white" or "yellow" laccase. ph 2.4 was optimal for the oxidation of abts and ph 2.5 for dmp. dmp oxidation was optimal at 85 degrees c. the half-life of this laccase was 70 min at 75 degrees c, and 5 h at 65 degrees c. non-phenolic dyes, such as methyl red, were oxidized by purified laccase without mediators. the enzyme was not inhibited by cu(2+), mn(2+), or edta. these are atypical laccase characteristics that make ... | 2009 | 19221878 |
| [synthesis of electroconductive polyaniline using immobilized laccase]. | a new method for synthesis of the conductive complex between polyaniline (pani) and poly(2-acrylamido-2-methyl-1-propanosulfonic acid) (pamps) was proposed; in this method, the immobilized laccase from the basidiomycete trametes hirsuta is used as a biocatalyst for aniline oxidative polymerization. the conditions for laccase immobilization on cm cellulose by bifunctional woodward's reagent were optimized. the catalytic properties of immobilized and native laccases were compared. the immobilized ... | 2009 | 19235506 |
| oxidative enzymatic alkene cleavage: indications for a nonclassical enzyme mechanism. | an enzyme preparation of trametes hirsuta cleaves alkenes following neither the classical dioxygenase mechanism nor via a monooxygenase mechanism. a catalytic cycle for an alternative enzymatic alkene cleavage was proposed, whereby two oxygen atoms derived from two different oxygen molecules are incorporated into the product(s). | 2009 | 19323520 |
| kinetic and theoretical comprehension of diverse rate laws and reactivity gaps in coriolus hirsutus laccase-catalyzed oxidation of acido and cyclometalated ru(ii) complexes. | the reactivity of the acido ru(ii) complexes cis-[rucl(2)(ll)(2)], [ruco(3)(ll)(2)], cis-[ruco(3)-(bquin)(2)] (ll = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen); bquin = 2,2'-biquinoline) and cyclometalated ru(ii) derivatives of 2-phenylpyridine and 4-(2-tolyl)pyridine [ru(o-c(6)h(4)-2-py)(phen)(2)]pf(6) (1), [ru(o-c(6)h(3)-p-r-2-py)(bpy)(mecn)(2)]pf(6) (2), and [ru(o-c(6)h(3)-p-r-2-py)(phen)(mecn)(2)]pf(6) (3) (r = h (a), me (b)) toward laccase from coriolus hirsutus has been investigat ... | 2009 | 19351176 |
| effect of solvent phase transitions on enzymatic activity and structure of laccase from coriolus hirsutus. | the effect of solvent phase transitions on catalytic activity and structure of the active site of laccase produced by the basidiomycetes coriolus hirsutus 072 was studied. as shown by small-angle x-ray scattering, laccase exists in solution as a mixture of monomeric and aggregated particles in the percent ratio 85:15. this ratio did not change on phase transitions. a complex nature of laccase activity dynamics during thawing and further heating to 20 degrees c was shown. spontaneous oxidation of ... | 2009 | 19463091 |
| oxidation of glycerol by 2,2,6,6-tetramethylpiperidine-n-oxyl (tempo) in the presence of laccase. | glycerol has the potential of being a low-cost and extremely versatile building block. however, current transformation strategies such based on noble-metal-catalysts show several disadvantages including catalyst deactivation or negative environmental impacts. in this study glycerol was oxidized by 2,2,6,6-tetramethylpiperidine-n-oxyl (tempo) in the presence of laccase from trametes hirsuta. analysis of the reaction production indicated sequential oxidation to glyceraldehyde, glyceric acid and ta ... | 2009 | 19464170 |
| structure of native laccase from trametes hirsuta at 1.8 a resolution. | this paper describes the structural analysis of the native form of laccase from trametes hirsuta at 1.8 a resolution. this structure provides a basis for the elucidation of the mechanism of catalytic action of these ubiquitous proteins. the 1.8 a resolution native structure provided a good level of structural detail compared with many previously reported laccase structures. a brief comparison with the active sites of other laccases is given. | 2009 | 19465775 |
| enhanced saccharification of alkali-treated rice straw by cellulase from trametes hirsuta and statistical optimization of hydrolysis conditions by rsm. | a white rot fungus, identified as trametes hirsuta based on morphological and phylogenetic analysis, was found to contain efficient cellulose degrading enzymes. the strain showed maximum endoglucanase (eg), cellobiohydrolase (cbh) and beta-glucosidase (bgl) activities of 55, 0.28 and 5.0 u/mg-protein, respectively. rice straw was found to be a potentially good substrate for growth of t. hirsuta for cellulase production. statistical experimental design was used to optimize hydrolysis parameters s ... | 2009 | 19540109 |
| on the reactions of two fungal laccases differing in their redox potential with lignin model compounds: products and their rate of formation. | laccases (ec 1.10.3.2) are multicopper oxidases able to oxidize phenolic compounds such as lignin-related polyphenols. since the discovery that so-called mediators effectively extend the family of laccase substrates, direct interactions between lignin-like materials and laccase have gained much less attention. in this work, the aim was to characterize oxidation products formed in direct laccase-catalyzed oxidation of different guaiacylic and syringylic lignin model compounds with two different l ... | 2009 | 19702333 |
| kinetic and biochemical properties of high and low redox potential laccases from fungal and plant origin. | the electrochemical studies of laccase-mediator systems are aimed at understanding the mechanism of their redox transformation and their efficiency in both homogeneous and heterogeneous reactions; this topic has paramount application spanning from bleaching of paper pulp and the enzymatic degradation of lignin to the biosensors and biofuel cell development. in this paper four different laccases from trametes hirsuta (thl), trametes versicolor (tvl), melanocarpus albomyces (r-mal) and rhus vernic ... | 2010 | 20056172 |
| polymerization of lignosulfonates by the laccase-hbt (1-hydroxybenzotriazole) system improves dispersibility. | the ability of laccases from trametes villosa (tvl), myceliophthora thermophila (mtl), trametes hirsuta (thl) and bacillus subtilis (bsl) to improve the dispersion properties of calcium lignosulfonates 398 in the presence of hbt as a mediator was investigated. size exclusion chromatography showed an extensive increase in molecular weight of the samples incubated with tvl and thl by 107% and 572% from 28400 da after 17h of incubation, respectively. interestingly, ftir spectroscopy, (13)c nmr and ... | 2010 | 20176477 |
| laccase-based biosensor for the determination of polyphenol index in wine. | in this work we have developed and characterized the use of laccases from trametes versicolor (tvl) and trametes hirsuta (thl) as biocatalytic components of electrochemical biosensors for the determination of polyphenol index in wines. polyazetidine prepolimer (pap) was used as immobilizing agent, multi-walled and single-walled carbon nanotubes screen-printed electrodes as sensors (mwcnts-spe and swcnts-spe) and gallic acid as standard substrate. the amperometric measurements were carried out by ... | 2010 | 20188914 |
| monolayer anthracene and anthraquinone modified electrodes as platforms for trametes hirsuta laccase immobilisation. | surface modification techniques are essential to the construction of enzyme based elements of biofuel cells and biosensors. in this article we report on the preparation and characterisation of modified carbon electrodes which were used as supports for the immobilisation of laccase from trametes hirsuta. the electrodes were electrochemically modified with diamine or diazonium linkers followed by attachment of either anthracene or anthraquinone head groups using solid phase chemical methodology. t ... | 2010 | 20577679 |
| [a heterologous production of the trametes hirsuta laccase in the fungus penicillium canescens]. | a heterologous protein expression in the fungus penicillium canescens is described for the first time. the fungal strains producing trametes hirsuta laccase under control of a highly efficient promoter of the p. canescens gene bgas has been constructed. these strains efficiently transcribe the t. hirsuta 072 laccase gene with a correct intron splicing. activity of the secreted heterologous laccase in the culture liquid reaches 3 u/ml, accounting for 98% of the total laccase activity, which demon ... | 2010 | 20586288 |
| wood decomposing abilities of diverse lignicolous fungi on nondecayed and decayed beech wood. | we tested the decay abilities of 28 isolates from 28 lignicolous fungal species (basidiomycota, ascomycota and zygomycota) with the pure culture test. we used beech wood powder in varying moisture conditions and decay stages (nondecayed, intermediately decayed and well decayed) as substrates. the weight loss in wood powder was -0.2-17.8%. five isolates of basidiomycota (bjerkandera adusta, mycena haematopus, omphalotus guepiniformis, trametes hirsuta, trametes versicolor) caused high weight loss ... | 2011 | 21262989 |