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Lignocelulozni materiali so obnovljivi naravni vir, ki ga uporabljajo na različnih tehnoloških področjih. Težavna razgradnja lignina predstavlja oviro pri izkoriščanju ligninoceluloznega materiala. Kraljestvo gliv je bogat in neizkoriščen vir biotehnološko zanimivih encimov, med katerimi so tudi encimi, ki omogočajo razgradnjo lignina. Glavni encimi, ki sodelujejo pri razgradnji lignina so lignolitične oksidoreduktaze (lakaze, lignin peroksidaze, ter mangan peroksidaze). Cilj magistrske naloge je bil pripraviti vodne esktrakte 62 gliv nabranih v slovenskih gozdovih, ter s pomočjo testa oksidacije ABTS odkriti, ali vodni ekstrakti gliv vsebujejo encime, ki omogočajo razgradnjo lignina. Identificirali smo željene encimske aktivnosti v nekaterih vrstah gliv, ki še niso bile opisane v literaturi. Najvišje encimske aktivnosti smo določili pri glivah rodu Cantharellus, pri katerih smo podrobneje preverili tudi vpliv pH na encimsko aktivnost. Ugotovili smo, da imajo lakaze, lignin peroksidaze in mangan peroksidaze optimum delovanja večinoma v kislem in nevtralnem območju pH. Lignocelullosic material is renewable natural resource, that is used in different technological areas. Difficult degradation of lignin presents an obstacle for utilization of lignocelullosic material. The kingdom of fungi is rich and unexploited source of biotechnologically interesting enzymes, including lignin-degrading enzymes. Main lignin-degrading enzymes are ligninolytic oxidoreductases (laccases, lignin peroxidases, and manganese peroxidases). The aim of this master thesis was to prepare water extracts of 62 fungi from Slovenian forests and using ABTS oxidation test discover potential lignin-degrading enzymes. In certain fungal species we identified desired enzymatic activities, that were not yet described in the literature. We determined the highest enzymatic activities in fungi from the genus Cantharellus, for which we investigated the effect of pH on enzymatic activity in more detail. We found out that laccase, lignin peroxidase and manganese peroxidase have optimum activities in the acidic and neutral pH range.

Response surface methodology (central composite design of experiments) was employed to simultaneously optimize enzyme production and productivities of two ligninolytic enzymes produced by Ceriporiopsis subvermispora. Concentrations of glucose, ammonium tartrate and Polysorbate 80 were varied to establish the optimal composition of liquid media (OLM), where the highest experimentally obtained activities and productivities were 41 U L$^{−1}$ and 16 U L$^{−1}$ day$^{−1}$ for laccase (Lac), and 193 U L$^{−1}$ and 80 U L$^{−1}$ day$^{−1}$ for manganese peroxidase (MnP). Considering culture growth in OLM on various types of immobilization support, the best results were obtained with 1 cm beech wood cubes (BWCM). Enzyme activities in culture filtrate were 152 U L$^{−1}$ for Lac and 58 U L$^{−1}$ for MnP, since the chemical composition of this immobilization material induced higher Lac activity. Lower enzyme activities were obtained with polyurethane foam. Culture filtrates of OLM and BWCM were applied for dye decolorization. Remazol Brilliant Blue R (RBBR) was decolorized faster and more efficiently than Copper(II)phthalocyanine (CuP) with BWCM (80% and 60%), since Lac played a crucial role. Decolorization of CuP was initially faster than that of RBBR, due to higher MnP activities in OLM. The extent of decolorization after 14 h was 60% for both dyes.

"Available online 11 June 2022", The objective of this study was to assess the degradation rates of chrysene and benzo[a]pyrene, as well as the removal of aluminium and iron from contaminated soil collected in the upper layer (030 cm) in Lagos, Southwest Nigeria. Trametes versicolor was isolated from this soil and used in degradation experiments, with plantain peels as support. After 8 weeks, 82.0% of chrysene degradation was achieved by T. versicolor, and by adding support this increased to 91.0%. Benzo[a]pyrene was less degradable, with 38.0% and 49.1% of degradation, respectively. Trametes versicolor was also capable of accumulate 46.1% of aluminium and 57.2% of iron. By adding plantain peels, these amounts increased to 48.2% and 61.8%, respectively. At the same time, laccase was produced by Trametes versicolor on plantain peels, achieving 37.8 U/g of crude laccase during SSF at 30 °C for 3 weeks. Laccase degradation experiments were set up in packed-bed reactor (PBR), with a constant feed of 21.6 mL/day of laccase, with and without mediators. In 35 days, 75.9% degradation of chrysene was achieved by laccase. The highest degradation was observed with ABTS (2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid diammonium salt) as mediator, 87.9%. Benzo[a]pyrene degradation with laccase reached 35.6%, raising to 38.8 % with ferulic acid as mediator. In addition, 99.2% of iron and 99.6% of aluminium was removed by laccase, being the treatment for this last mediated with ABTS., This study was supported by the Portuguese Foundation for Science and Technology (FCT), Portugal under the scope of the research project PTDC/AAG-TEC/5269/2014, the strategic funding of UID/BIO/04469/2013 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 - Programa Operacional Regional do Norte. Ziva Vipotnik is a recipient of a fellowship supported by a doctoral advanced training (call NORTE-69-2015-15) - Doctoral Program in Applied and Environmental Microbiology (DP_AEM); operation NORTE-08-5369-FSE-000060; co-financed by North 2020 through the European Social Fund (ESF)., info:eu-repo/semantics/publishedVersion

Lakaze so zaradi sposobnosti oksidacije najrazličnejših substratov industrijsko zelo zanimivi encimi, obenem pa zaradi možnosti pretvorbe številnih fenolnih spojin igrajo pomembno vlogo pri varovanju okolja ter pri razvoju biosenzorjev. Senzorji na osnovi lakaz so pomembni za analizo kvalitete voda, kjer z njimi zaznavamo prisotnost strupenih fenolnih spojin, prav tako pa se uveljavljajo na področju analize antioksidantov v živilih. Z miniaturizacijo senzorjev zmanjšamo čas analize, stroške reagentov in količino odpadkov. V pričujočem delu sem submerzno gojila glive bele trohnobe Trametes versicolor, Trametes gibbosa in Dichomitus squalens, ki so znane proizvajalke izvenceličnih lakaz. V filtratih produkcijskih gojišč sem ovrednotila lakazno aktivnost ter njeno odvisnost od pH vrednosti. Izbrani filtrat z najvišjo vsebnostjo lakaz sem uporabila za reakcijo oksidacije v mikropretočnem sistemu, v katerega sem uspešno integrirala miniaturiziran pretočni spektrofotometrični detektor in senzor za raztopljeni kisik. Rezultati in-line meritev produkta oksidacije na izstopu iz mikroreaktorja so primerljivi z meritvami v konvencionalnem spektrofotometru, kar je dobra osnova za nadaljnji razvoj miniaturiziranega pretočnega biosenzorja na osnovi lakaz. Laccases are industrially relevant enzymes because of their ability to oxidize a wide variety of substrates. At the same time, they play an important role in environmental protection and biosensor development due to their ability to transform many phenolic compounds. Laccase-based sensors are important for water analysis, where they detect the presence of toxic phenolic compounds, and are also used in the food industry to detect antioxidants. By miniaturizing the sensors, we reduce analysis time, reagent costs and waste. In the present work, the submerged cultivation of the white rot fungi Trametes versicolor, Trametes gibbosa and Dichomitus squalens, which are known producers of extracellular laccase, was studied. Laccase activity in the filtrate of the production medium and its dependence on pH were evaluated. The filtrate with the highest laccase activity was used for the oxidation reaction in the microfluidic system, in which a miniaturized flow spectrophotometric detector and an oxygen microsensor were successfully integrated. The results of in-line measurements of the oxidation product at the outlet of the microreactor were comparable to the measurements in a conventional spectrophotometer, which provides a good basis for further development of a miniaturized laccase-based flow-through biosensor.

Signe Vadone (2019): Ganoderma lucidum 9621 ārpusšūnu ligninolītisko enzīmu aktivitātes noteikšana. Darbā noteikta un salīdzināta G. lucidum 9621 lakāzes un peroksidāžu aktivitāte četru dažādu piedevu šķidrajās barotnēs – ½ MEB(+ Mn2+; + 2% Lg; + 2% Lg + Mn2+). Veikta kvantitatīva ligninolītisko enzīmu aktivitātes noteikšana, izmantojot spektrofotometrijas metodes. Darbā tika salīdzināta dažādu glabāšanas apstākļu (+4˚C, -20˚C un liofilizācijas) ietekme uz G. lucidum 9621 ligninolītisko enzīmu aktivitāti un inkubācijas beigās noteikta sēņu micēlija biomasa. Noskaidrots, ka augstāko ārpusšūnu ligninolītisko enzīmu aktivitāti G. lucidum 9621 iegūst 6.-10. inkubācijas dienā un lielāka aktivitāte ir paraugiem, kuri inkubēti barotnēs ar lignīna piedevu. Ieteicamie apstākļi enzīmu glabāšanai tika noteikta sasaldēšana -20˚C un liofilizācija. Atslēgvārdi: Ganoderma lucidum, lignīna degradācija, ligninolītiskie enzīmi, lakāze, peroksidāzes., Signe Vadone (2019): Determination of Ganoderma lucidum 9621 extracellular ligninolytic enzyme activity. The activity of Ganoderma lucidum 9621 laccase and peroxidase activity in liquid media with four different addivives - ½ MEB(+ Mn2+; + 2% Lg; + 2% Lg + Mn2+) has been determined and compared. Quantification of enzyme activity using spectrophotometric methods was performed. The effect of different storage conditions (+4˚C, -20˚C and lyophilization) on the activity of G. lucidum 9621 enzymes, as well as the biomass of fungal mycelium at the end of the incubation was compared. It was cleared that the highest enzyme activity of G. lucidum 9621 is obtained from 6.-10. day of incubation and higher activity was on samples incubated in lignin supplemented medium. Freezing -20˚C and lyophilisation were determined as the best storage conditions for enzymes. Keywords: Ganoderma lucidum, lignin degradation, ligninolytic enzymes, laccase, peroxidases.

Svrha je ovog istraživanja bila izolirati i identificirati gljive izraženih lignolitičkih sposobnosti, autohtonih za južnu Srbiju. Dva izolata gljiva, identificirana kao Trametes hirsuta F13 i Stereum gausapatum F28, odabrana su za procjenu aktivnosti lignolitičkih enzima i učinkovitosti uklanjanja lignina iz piljevine bukve. Dobiveni rezultati pokazuju da su oba izolata dobar izvor industrijski vrijednih enzima, te da se mogu primijeniti u raznim biotehnološkim i industrijskim procesima. Oba su izolata pokazala aktivnost lakaze, mangan-peroksidaze i polivalentne peroksidaze, dok je aktivnost lignin peroksidaze zabilježena samo u izolatu S. gausapatum F28. U ovom je radu prvi put zabilježena sposobnost vrste S. gausapatum da proizvodi lignin peroksidazu. Izolat T. hirsuta F13 imao je veću aktivnost lakaze od izolata S. gausapatum F28, koji je pokazao veću aktivnost mangan-peroksidaze. Također, izolat T. hirsuta F13 imao je izraženiju aktivnost lakaze pri submerznom uzgoju nego pri fermentaciji na čvrstoj podlozi, što je rijetkost kod gljiva. Ovaj je podatak bitan za industrijske procese, u kojima se uglavnom koristi submerzna fermentacija. Ispitivanjem učinkovitosti uklanjanja lignina utvrđeno je da su oba izolata dobri razgrađivači lignina. Ukupni gubici lignina nakon pet tjedana inkubacije na piljevini bukve bili su: 33,8 % s pomoću izolata T. hirsuta F13 i 28,8 % s pomoću izolata S. gausapatum F28., The aim of this research is to isolate and identify fungi with high lignin-degrading abilities that are autochthonous to southern Serbian region. Two novel fungal isolates identified as Trametes hirsuta F13 and Stereum gausapatum F28 were selected to assess their ligninolytic enzyme activities and the efficiency of lignin removal from beech wood sawdust. Obtained results show that both isolates are good sources of industrially valuable enzymes with a potential for application in various biotechnological and industrial processes. Both isolates showed laccase, manganese-dependent peroxidase, and versatile peroxidase activities, while only S. gausapatum F28 had lignin peroxidase activity. This is the first record of the ability of S. gausapatum species to produce lignin peroxidase. T. hirsuta F13 showed higher laccase activity than S. gausapatum F28, while S. gausapatum F28 had higher manganese peroxidase activity. Also, T. hirsuta F13 exhibited much higher laccase activity under submerged cultivation conditions than solid-state cultivation conditions, which is rare for fungi. This is important for industrial processes since the submerged fermentation is a dominant technique in industry. The test of the efficiency of lignin removal showed that both isolates are efficient lignin decomposers. After five weeks of incubation on beech wood sawdust, the total lignin losses were 33.84 % with T. hirsuta F13 and 28.8 % with S. gausapatum F28.

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, $KH_2PO_4$, $MgSO_4$ · $7H_2O$ and $MnSO_4$ · $H_2O$ at three levels and pH at two levels with OA layout of L18 ($2^1 × 3^7$) 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 $KH_2PO_4$, $MgSO_4$ · $7H_2O$ and $MnSO_4$ · $H_2O$ 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 $L^{–1}$, $KH_2PO_4$ 3 g $L^{–1}$, $MgSO_4$ · $7H_2O$ 0.5 g $L^{–1}$ and $MnSO_4$ · $H_2O$ 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. Namen tega dela je bilo povečanje proizvodnje lakaz glive Pleurotus ostreatus PLAB z optimizacijo gojitvenega medija trdnega gojišča. Povečane aktivnosti lakaz smo pridobili s pomočjo načrtovanja eksperimenta po Taguchi ortogonalni matriki. Izbrali smo sedem faktorjev, od teh so bile vrednosti lignoceluloze, glukoze, kvasnega ekstrakta, peptona, $KH_2PO_4$, $MgSO_4$ · $7H_2O$ in $MnSO_4$ · $H_2O$ izbrane na treh nivojih in vrednosti pH na dveh nivojih. Za načrtovanje eksperimenta smo izbrali predlagano ortogonalno matriko L18 (21 × 37) in programsko opremo Minitab 17. Analiza rezultatov izvedenega eksperimenta je pokazala, da sta imeli lignoceluloza (20 %) in glukoza (10 g $L^{–1}$) pozitivni učinek, medtem ko $KH_2PO_4$, $MgSO_4$ · $7H_2O$ in $MnSO_4$ · $H_2O$ niso imeli pomembnega vpliva na produkcijo lakaz. Analiza rezultatov Taguchi ortogonalne matrike je pokazala, da so pH 6, lignoceluloza 20 %, glukoza 10 g $L^{–1}$, kvasni ekstrakt 6 g $L^{–1}$, pepton 15 g $L^{–1}$, $KH_2PO_4$ 3 g $L^{–1}$, $MgSO_4$ · $7H2_O$ 0,5 g $L^{–1}$ in $MnSO_4$ · $H_2O$ 0,1 g $L^{–1}$ optimalni pogoji za maksimalno produkcijo lakaz. Po modelu je bila napovedana produkcija lakaz 30,37 U $g^{–1}$ suhe snovi pri optimalnih pogojih, eksperimentalno smo dosegli aktivnost lakaz 29,15 U $g^{–1}$ suhe snovi, kar je v skladu s napovedano vrednostjo po modelu.

Darbā novērtēta lignocelulozi saturošu piedevu (kļavu lapas, dažādi apstrādāti kviešu salmi) ietekme uz L. edodes 3565 micēlija biomasas pieaugumu un ekstracelulārās lakāzes aktivitāti. Augstākā lakāzes aktivitāte (545.74±135.92 U/mL) un lielākais micēlija biomasas guvums (422.92±31.52 mg/100 mL) iegūts šķidrās iesala ekstrakta barotnēs ar hemicelulozi un celulozi nesaturošu kviešu salmu piedevu (0.50%), inkubējot uz rotācijas kratītāja (140 rpm). Inkubācijas laikā novērots: 1) pakāpenisks lakāzes aktivitātes pieaugums neatkarīgi no piedevas; 2) vides pH samazināšanās. Maltas kļavu lapas novērtētas kā micēlija blīvumu un radiālo augšanu veicinoša piedeva neatkarīgi no pamatbarotnes. Maltas brūnaļģes novērtētas kā barotni bagātinoša piedeva agarizētās iesala ekstrakta barotnēs. Novērota kultivēšanas temperatūras ietekme uz lakāzes aktivitāti un micēlija biomasas pieaugumu., Effect of lignocellulose additives (wheat straw, maple leaves) on extracellular laccase activity and mycelium yield was evaluated. Highest laccase activity (545.74±135.92 U/mL) and mycelium yield (422.92±31.52 mg/100 mL) was obtained in malt extract on rotatory shaker (140 rpm) cultures with wheat straw additive (0.50%) which did not contain hemicellulose and cellulose. The following observations were made during the cultivation period: 1) laccase activity gradually rises independently of additives; 2) pH of the medium decreases. Ground maple leaves facilitated an increase in mycelium density and radial growth regardless of medium. Seaweed showed to be medium enriching additive on solid malt extract medium. The influence of temperature on laccase activity and mycelium yield was observed.

Fitopatogena gljiva Cryphonectria parasitica uzrokuje rak kore pitomoga kestena (Castanea sativa). U Europi je bolest kontrolirana prisutnošću virusa Cryphonectria hypovirus 1 (CHV-1), koji smanjuje virulenciju i sporulaciju gljive, čime uzrokuje fenomen nazvan hipovirulencija. U ovom istraživanju u virulentne gljive unesena su tri izolata virusa CHV-1 koji pripadaju dvama podtipovima. Prisutnost virusa dokazana je izolacijom dsRNA i reverznom transkripcijom te amplifikacijom dvaju otvorenih okvira čitanja virusne cDNA (ORF-A i ORF-B). Uspoređena je aktivnost unutarstanične lakaze LAC-2 i izvanstanične lakaze LAC-1 u virulentnim i hipovirulentnim izolatima gljive. Rezultati su pokazali da virus CHV-1 ne utječe na aktivnost unutarstanične lakaze LAC-2, dok aktivnost izvanstanične lakaze LAC-1 ovisi o izolatu i podtipu virusa, te o genotipu gljive. Pytopathogenic fungus Cryphonectria parasitica causes blight of chestnut (Castanea sativa). In Europe the disease is controlled by the presence of virus Cryphonectria hypovirus 1 (CHV-1), which reduces fungal virulence and sporulation, causing the phenomenon called hypovirulence. In this research three CHV-1 isolates belonging to the two subtypes of the virus were transferred to virulent fungal strains. The presence of virus was confirmed by dsRNA isolation, reverse transcription and amplification of two viral cDNA open reading frames (ORF-A and ORF-B). The activity of intracellular laccase LAC-2 and extracellular laccase LAC-1 in virulent and hypovirulent isolates of the fungus was compared. The results have shown that the virus CHV-1 does not affect the activity of the intracellular laccase LAC-2, whereas the activity of the extracellular laccase LAC-1 depends on the subtype and isolate of the virus and genotype of the fungus.

Laccases have the ability to oxidize both phenolic and trough mediators non-phenolic lignin related compounds. When reacting on lignin, they can display both ligninolytic and polymerizing (cross-inking) abilities, which makes them very useful for their application in industries based on lignocellulose material. Most of the published papers and applications of laccase and laccase-mediator systems on lignocellulose material relate to the pulp, paper and textile industry. Recent research has been done in terms of laccase assisted biografting of phenols and other compounds on wood surface and use of laccase for adhesion enhancement in fiberboard production. They can be introduced to wood technology as environmentally friendly enzymes. The paper reviews the application of laccases in industries based on lignocellulose material and discusses the future outlook and development in the above mentioned fields., Enzimi lakaze imaju sposobnost oksidacije fenolnih spojeva uz pomoć medijatora i nefenolnih spojeva lignina. Kada reagiraju na lignin, mogu pokazati i ligninolitičke i polimerizacijske (unakrsno povezujuće) sposobnosti, što ih čini vrlo korisnima za primjenu u industriji utemeljenoj na lignoceluloznim materijalima. Većina objavljenih radova i primjena enzima lakaze i posredničkih lakaza-sustava na lignoceluloznim materijalima odnose se na celulozu, papir i proizvode tekstilne industrije. Nedavno su provedena istraživanja o kalemljenju fenola i drugih spojeva uz pomoć lakaza na površinu drva i o primjeni lakaza za poboljšanje adhezije u proizvodnji ploča vlaknatica. Lakaze se mogu upotrijebiti u drvnoj tehnologiji kao ekološki prihvatljivi enzimi. U radu se analizira primjena enzima lakaze u industriji utemeljenoj na lignoceluloznim materijalima i razmatraju se buduće perspektive i razvoj na spomenutim područjima.

Naudojant spektrofotometrinį metodą tirtas ADH IIG reaktingumas su skirtingais mediatoriais ir įvairiais alkoholiais. Nustatytos tariamųjų kinetinių parametrų KM ir Vmax reikšmės, bei paskaičiuotos katalitinės ir bimolekulinės alkoholių oksidacijos bei mediatorių redukcijos reaktingumo konstantos. Tirta FERO ir ABTS oksidacija katalizuojama L95 lakaze. Gautos pradinių reakcijos greičių priklausomybės nuo substratų koncentracijų. Rezultatų analizei pritaikius Michaelio-Menten lygtį, gautos tariamųjų KM ir Vmax reikšmės, iš kurių buvo paskaičiuotos katalitinės ir oksidacinės konstantos. Pamatuotos pradinio reakcijos greičio priklausomybės nuo buferinių tirpalų pH ir jų komponentų, bei nustatytos optimalios substratų oksidacijos reakcijos pH reikšmės. Naudojant deguoninį elektrodą buvo registruotas deguonies sunaudojimas vykstant L95 lakazės katalizuojamai FERO ir ABTS oksidacijai ir paskaičiuotas pradinis reakcijos greitis bei sunaudoto deguonies priklausomybės nuo substratų koncentracijų. Registruotas ir deguonies sunaudojimas vykstant ADH IIG katalizuojamai alkoholio oksidacijai ir lakazes katalizuojamai mediatoriaus (antrojo qADH substrato) regeneracijai. Darbą sudaro 6 dalys: įvadas, literatūros apžvalga, eksperimentinė dalis, rezultatai ir jų aptarimas, išvados, literatūros sąrašas. Darbo apimtis – 85 p. teksto, 50 paveikslų, 8 lentelės, 109 bibliografiniai šaltiniai. Reactivity of ADH IIG with different mediators and various alcohols were investigated by spectrophotometric method. Values of apparent kinetic parameters KM and Vmax were determined, catalytic and bimolecular alcohols oxidation and mediators reduction reactivity constants were calculated. The FERO and ABTS oxidation catalysed by L95 laccase were investigated. The initial reaction rate dependencies on the substrates concentrations were obtained. The analysis of the results was performed by applying Michael-Menten equation and the values of apparent KM and Vmax, as well as catalytic and oxidation constants were calculated. The dependencies of the initial reaction rate on the buffer solutions pH and their components were measured also the optimal pH of the substrates oxidation reactions were determined. The oxygen consumption was registered L95 laccase catalysed oxidation of FERO and ABTS by oxygen electrode and initial reaction rate was calculated, as so as oxygen consumption dependences on substrate concentrations. The oxygen consumption ADH IIG catalysed oxidation of alcohols and laccases catalysed regeneration of mediators (second qADH substrate) were registered. Structure: introduction, 3 chapters, conclusions, references. Thesis consist of: 85 p. of text, 50 pictures, 8 tables, 109 bibliographical entries.

U ovom završnom radu kombinirani su postupci mokre obrade na džins tkanini. Nakon odškrobljavanja tkanine provedeni su postupci obezbojavanja sredstvima na bazi kisika i pomoću lakaza. Praćen je utjecaj pojedinih sredstava na čvrstoću tkanine, promjene tona tkanine kao i aktivnost i iscrpljenje pojedinih sredstava. Za praćenje promjena korištene su analitičke, spektrofotometrijske metode i metode ispitivanja vlačne sile

Tirta vanilino, izovanilino, vanilino rūgšties ir vanilino alkoholio oksidacija, katalizuojama iš Polyporus pinsitus, Coriolopsis byrsina ir Trichaptum abietinum grybų išskirtomis lakazėmis. Naudojant spektrofotometrinį metodą atlikti šių junginių oksidacijos kinetiniai tyrimai. Naudojant skirtingas lakazes, gaunamos santykinių pradinių sugerties kitimo greičių priklausomybės nuo substratų koncentracijų. Rezultatai, gauti naudojant skirtingas lakazes, lyginami tarpusavyje. Didžiausias tirtų junginių santykinis sugerties kitimo greitis, kuris atitinka oksidacijos greitį, buvo stebimas su Polyporus pinsitus, o mažiausias – su Trichaptum abietinum lakaze., The oxidation of vanillin and its derivatives was investigated in presence of recombinant Polyporus pinsitus, Curiolopsis byrsina and Trichaptum abietinum laccases, extracted from Basidiomycetes family fungi. Kinetic measurements were performed by using spectrophotometric method. The dependences of relative initial rate of change of absorbance on substrates concentration were obtained for various laccases. The results obtained using different laccases, compared with one another. The highest relative rate of change of investigated compounds‘ absorption, which corresponds to oxidation rate, was observed with Polyporus pinsitus laccase, while the lowest relative rate – with Trichaptum abietinum laccase. Keywords: laccase, vanillin, isovanillin, vanillic acid, vanillyl alcohol.

Tirta rekombinantinės lakazės, išskirtos iš Myceliophthora thermophila (rMtL), katalizuojama substrato kalio heksacianoferato (II) (ferocianido) oksidacijos reakcija tarpininkaujant mediatoriams - ferocenui, 1,1-dimetilferocenui (DMFc) ir 3-(10H-fenoksazin-10-il) propioninei rūgščiai (PPA). rMtL katalizuojama ferocianido oksidacijos reakcija vyksta lėtai. Iš pradinio reakcijos greičio priklausomybės nuo substrato koncentracijos nustatyta rMtL ir ferocianido bimolekulinė reaktingumo konstanta kred. Pastebėta, kad į reakcijos mišinį pridėjus mediatoriaus, oksidacijos reakcijos greitis padidėja priklausomai nuo mediatoriaus koncentracijos. Pasiūlytas kinetinis modelis, aprašantis mediatoriaus sinergetinio veikimo procesus, apskaičiuoti kinetiniai parametrai., The oxidation reaction of potassium hexacyanoferrate (II) (ferrocyanide) catalyzed by the recombinant laccase from fungus Mycelliophthera thermophila (rMtL) in the presence of mediators ferrocene, 1,1-dimethylferrocene (DMFc) and 3-(10H-phenoxazine-10-yl) propionic acid (PPA) was investigated. The rMtL-catalyzed oxidation reaction of ferrocyanide is very slow. The bimolecular constant of rMtL and ferrocyanide reactivity kred was determined from initial reaction rate dependency on substrate concentration. It was noticed that addition of a mediator increases reaction rate and that the increase depends on the concentration of that mediator. The kinetic model describing processes of mediator‘s synergistic effect was suggested, kinetic parameters were calculated.

Tirta substratų oksidacija katalizuojama lakazėmis, išskirtomis iš grybų Trametes hirsuta (ThL), Coriolopsis byrsina (CbL), Polyporus pinsitus (rPpL) ir Trichaptum abietinum (TaL). Substratų oksidacijos kinetiniai tyrimai atlikti naudojant spektrofotometrinį ir spektrofluorimetrinį metodus. Gautos pradinių reakcijos greičių priklausomybės nuo fermentų ir substratų koncentracijų. Rezultatų analizei pritaikius Michaelio-Menten lygtį, gautos tariamųjų KM ir Vmax reikšmės, iš kurių buvo paskaičiuotos katalitinės ir oksidacinės konstantos. Pamatuotos pradinio reakcijos greičio priklausomybės nuo pH ir nustatytos optimalios substratų oksidacijos reakcijos pH reikšmės., The substrates oxidation catalysed by Trametes hirsuta (ThL), Coriolopsis byrsina (CbL), Polyporus pinsitus (rPpL) and Trichaptum abietinum (TaL) laccases were investigated. The kinetic measurements were performed by spectrophotometric and spectrofluorimetric methods. The initial reaction rate dependencies on the enzymes and substrates concentrations were obtained. The analysis of the results was performed by applying Michael-Menten equation and the values of apparent KM and Vmax, as well as catalytic and oxidation constants were calculated. The dependencies of the initial reaction rate on the pH were measured and the optimal pH of the substrates oxidation reactions were determined. Keywords: laccase, oxidation, the initial reaction rate, pH.