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Öğe Antioxidative and metabolic responses to extended cold exposure in rats(Akademiai Kiado Zrt, 2008) Yuksel, Sengul; Asma, Dilek; Yesilada, OzferIn this work, we investigated whether extended cold exposure increases oxidative damage and susceptibility to oxidants of rat liver, heart, kidney and lung which are metabolically active tissues. Moreover in this study the effect of cold stress on some of the lipid metabolic mediators were studied in rat experimental model. Male albino Sprague-Dawley rats were randomly divided into two groups: The control group (n = 12) and the cold-stress group (n = 12). Tissue superoxide dismutase (SOD), catalase (CAT), glutathion S-transferase (GST) and glutathion reductase (GR) activities and glutathion (GSH) were measured using standard protocols. The biochemical analyses for total lipid, cholesterol, trigliceride, HDL, VLDL and LDL were done on autoanalyzer. In cold-stress groups SOD activity was decreased in the lung whereas it increased in the heart and kidney. CAT activity was significantly decreased (except liver) in all the tissues in treated rats. GST activity of cold-induced rats increased in liver and heart while decreased in the lung. GR activity was significantly decreased (except in liver) in all the tissues in cold-stressed rats. GSH level was significantly increased in the heart but decreased in the lung of animals exposed to cold when compared to controls. It was found that among the groups trigliceride, total lipid, HDL and VLDL parameters varied significantly but cholesterol and LDL had no significant variance. In this study, we found that exposure of extended (48 h) cold (8 C) caused changes both in the antioxidant defense system (as tissue and enzyme specific) and serum lipoprotein profiles in rats.Öğe Bioremediation and Decolorization of Textile Dyes by White Rot Fungi and Laccase Enzymes(Springer International Publishing Ag, 2018) Yesilada, Ozfer; Birhanli, Emre; Geckil, Hikmet[Abstract Not Available]Öğe Bioremediation Applications with Fungi(Springer International Publishing Ag, 2018) Saglam, Necdet; Yesilada, Ozfer; Saglam, Semran; Apohan, Elif; Sam, Mesut; Ilk, Sedef; Emul, Ezgi[Abstract Not Available]Öğe A comparative study on decolorization of reactive azo and indigoid dyes by free/immobilized pellets of Trametes versicolor and Funalia trogii(Triveni Enterprises, 2015) Yildirim, Seval Cing; Yesilada, OzferThe objective of the present study was to investigate decolorization of Acid Blue 74 and Reactive Blue 198 dyes by free and immobilized white rot fungal pellets in order to confirm the possibility of practical application via repeated-batch cultivation. Decolorization studies were conducted using free pellets (FP), fungal cells immobilized on activated carbon (IFCAC) and pinewood (IFCP), and also fungal cells entrapped in alginate beads (FCEAB). No additional nitrogen and carbon source was used and high decolorization rates were achieved in only dye-contained media without pH adjustment. Acid Blue 74 was decolorized 96 and 94% within 2 hr by Trametes versicolor and Funalia trogii free pellets, respectively. These values were 87 and 84% for Reactive Blue 198, in this respect. Immobilization of fungal cells on pinewood increased the usability of pellets and the average decolorization efficiency of both dyes. The micro environment changed in the presence of pinewood and increased the stability of immobilized pellets. Decolorization was performed rapidly and efficiently. Laccase activity enhanced with availability of pinewood, and high laccase production with F trogii was obtained. After separation by sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE), the molecular weight of Trametes versicolor and F trogii laccase bands was determined 64 and 61 kDa approximately. Green bands were obtained by the activity staining process with laccase substrate (ABTS) after gel renaturation step.Öğe Cytotoxic and antimicrobial potential of benzimidazole derivatives(Wiley-V C H Verlag Gmbh, 2021) Kucukbay, Hasan; Uckun, Mustafa; Apohan, Elif; Yesilada, OzferNew benzimidazole derivatives were synthesized and their structures were characterized by spectroscopic and microanalysis techniques. The cytotoxic properties of ten benzimidazole derivatives, five of which were synthesized in our previous studies, were determined against the lung cancer cell line, A549, and the healthy lung epithelial cell line, BEAS-2B. Among the ten compounds tested, based on the 72-h incubation results, compound 12 was the most cytotoxic against the A549 cell line, whereas against the BEAS-2B cell line, it was as cytotoxic as cisplatin. The IC50 values of compound 12 were 3.98 and 2.94 mu g/ml for A549 and BEAS-2B cells, respectively. The cisplatin values were 6.75 and 2.75 mu g/ml for A549 and BEAS-2B cells, respectively. Compounds 10, 8, 7, and 13 showed toxic effects against A549 cells, but were less toxic against BEAS-2B cells than cisplatin. The antimicrobial activity of these compounds against pathogenic bacteria and yeasts was also evaluated based on their minimum inhibitory concentration (MIC) values. The compounds, except 12 and 13, generally showed higher antimicrobial activity against yeasts, compared with bacteria. Compound 12 showed better activity against Pseudomonas aeruginosa and Staphylococcus aureus than against Escherichia coli. Compounds 7, 8, and 11 were the most effective ones against the microorganisms, and yeasts were highly sensitive to these compounds with MIC values of 25-100 mu g/ml.Öğe Design of laccase-metal-organic framework hybrid constructs for biocatalytic removal of textile dyes(Pergamon-Elsevier Science Ltd, 2022) Birhanli, Emre; Noma, Samir Abbas Ali; Boran, Filiz; Ulu, Ahmet; Yesilada, Ozfer; Ates, BurhanThis study aims to present a simple and effective carrier matrix to immobilize laccase as opposed to complex and tedious immobilization processes and also to use it in the removal of textile dyes. For this purpose, Cobalt (Co) and Copper (Cu) based metal-organic frameworks (MOFs) were prepared and laccase was immobilized on two different MOFs via encapsulation. The characterization outcomes showed that laccase was well immobilized into MOF supports. Optimum pH and temperature were found for Lac/Co-MOF (pH 4.5 at 50 degrees C) and Lac/Cu-MOF (pH 5.0 at 50 degrees C). The Km (0.03 mM) and Vmax (97.4 mu mol/min) values of Lac/Cu-MOF were lower than those of Lac/Co-MOF (Km = 0.13 mM, Vmax = 230.7 mu mol/min). The immobilized laccases showed good reusability as well as improved resistance to temperature denaturation and high storage stability. For instance, the Lac/Co-MOF and Lac/Cu-MOF retained more than 58% activity after 4 weeks of storage at room temperature. Meanwhile, Lac/Co-MOF and Lac/Cu-MOF maintained 56.5% and 55.8% of their initial activity, respectively, after 12 reuse cycles. Moreover, thermal deactivation kinetic studies of immobilized laccases displayed lower k value, higher t1/2, and enhancement of thermodynamic parameters, which means better thermostability. Finally, the decolorization activities for the Lac/Co-MOF were 78% and 61% at the 5th cycle for Reactive Blue 171 andÖğe Dye removal by dead biomass of newly isolated Pleurotus ostreatus strain(Natl Inst Science Communication-Niscair, 2018) Dogan, Demet; Boran, Filiz; Kahraman, Sibel; Akmil-Basar, Canan; Yesilada, OzferDead biomass prepared from newly isolated Pleurotus ostreatus strain was tested for their efficiency in removal of indigo carmine. The effects of operational parameters such as contact time, initial dye concentration, amount of biomass, initial pH and agitation rate on removal were examined. The dye removal increased rapidly during the first 60 minutes (87%) and remained nearly constant between 60 - 120 minutes of adsorption (87 - 90%). The removal of dye by dead biomass of newly isolated P. ostreatus was clearly dependent on the initial dye concentration of the solution and dye removal was reduced from 83% to 53% as concentration was increased from 100 to 500 mg/L indigo carmine. Results were analyzed by the Langmiur, Freundlich, Dubinin-Redushkevich (D-R), Temkin, Frumkin, Harkins-Jura, Halsey, Henderson isotherm using linearised correlation coefficient. The kinetics of adsorption of IC have been discussed using six kinetic models, i.e., the pseudo first order model, the pseudo second order model, the Elovich equation, the intraparticle diffusion model, the Bangham equation, the modified Freundlich equation. In order to determine the best fit isotherm and kinetic models, three error analysis methods of residual mean square error (RMSE), chi-square (X-2) statistic and the average percentage error (APE%) were used to evaluate the data.Öğe The effect of various inducers and their combinations with copper on laccase production of Trametes versicolor pellets in a repeated-batch process(Tubıtak scıentıfıc & technıcal research councıl turkey, ataturk bulvarı no 221, kavaklıdere, ankara, 00000, turke, 2017) Birhanli, Emre; Yesilada, OzferThe aim of this study was to increase laccase production in Trametes versicolor ATCC 200801 pellets by using various inducers and their combinations under repeated-batch conditions. Because copper is an effective inducer for laccase production, the effect of Cu on laccase production in this strain was tested first. The optimal Cu concentration for the highest laccase production was 0.5 mM. Following this preliminary study, the effect of other inducers [2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS), syringaldazine, guaiacol, and 2,5-xylidine] on laccase production was determined. Copper was determined to be the most efficient inducer among the inducers used. Therefore, the synergistic effect of each inducer with Cu on laccase production in this strain was investigated. While the maximum laccase activity was 0.60 U/mL in stock basal medium (SBM) alone, the highest enzyme activities detected were 4.76 and 2.87 U/mL in SBM + 0.05 mM ABTS and SBM + 1 mM 2,5-xylidine, respectively. Maximum laccase activities obtained from the combination of the inducers were 33.61 and 26.49 U/mL in SBM + 0.5 mM Cu + 0.5 mM 2,5-xylidine and SBM + 0.5 mM Cu + 0.05 mM ABTS, respectively. These were the most efficient combinations for laccase production.Öğe ENHANCED PRODUCTION OF LACCASE BY FUNGI UNDER SOLID SUBSTRATE FERMENTATION CONDITION(North Carolina State Univ Dept Wood & Paper Sci, 2011) Boran, Filiz; Yesilada, OzferFunalia trogii and Trametes versicolor were grown on agro byproduct wheat bran moistened with various natural moistening agents, and their effects on laccase production under solid substrate condition were investigated. Laccase was the main enzyme detected under this condition. High levels of laccase activity were obtained with solid substrate cultures moistened with olive oil mill wastewater (OOMW) or alcohol factory wastewater (vinasse). Among the cultures without inducer, T. versicolor culture was detected as a more effective laccase producer than F. trogii culture. Copper and xylidine were used as laccase inducers, and copper induced laccase production more than xylidine. The maximum laccase activity was detected as 14.18 U/mL with F. trogii grown on wheat bran moistened with 5 mM CuSO4 center dot 5H(2)O added 25% vinasse. Azo dye decolorization activity of the supernatants from solid substrate cultures was also tested. While the use of 0.063 U/mL F. trogii laccase in reaction solution gave 66% decolorization in a minute, it was 14% for T. versicolor. This method can be a possible alternative for valorization of lignocellulosic materials and industrial wastewaters during solid substrate fermentation and for obtaining enzyme source with very high decolorization activity.Öğe Enhanced production of laccase in repeated-batch cultures of Funalia trogii and Trametes versicolor(Elsevier Science Bv, 2010) Birhanli, Emre; Yesilada, OzferThe biotechnologically important enzyme laccase (benzenediol: oxygen oxidoreductase: EC 1.10.3.2) is secreted by white rot fungi. However, these organisms produce insufficient amount of laccase for use in various biotechnological areas. The main aim of this study is to enhance the laccase production in the repeated-batch cultures of Funalia trogii ATCC 200800 and Trametes versicolor ATCC 200801 isolated in Turkey. In this study, laccase production in the repeated-batch cultures of F. trogii and T. versicolor pre-grown pellets were investigated under various conditions. Retention time, temperature, agitation, pH and the amount of pellets were found to be important for laccase production during repeated-batch studies. The culture filtrate showed one protein band. Zymogram gel also showed only one band of activity. The enzyme remained fully active when frozen for 300 clays. The immobilized fungi were also able to produce high amounts of laccase during reuse. It is possible to obtain high laccase amounts with free and immobilized repeated-batch cultures under the most appropriate culture conditions determined. Considering the various biotechnological applications of laccase, an enhancement in laccase production through the selection of appropriate culture conditions could facilitate the development of more economical and environmentally friendly processes. (C) 2010 Elsevier B.V. All rights reserved.Öğe ENHANCEMENT OF LACCASE PRODUCTION OF PRE-GROWN FUNGAL PELLETS IN WASTEWATER OF OLIVE OIL MILLS(Parlar Scientific Publications (P S P), 2011) Apohan, Elif; Yesilada, OzferPrevious works reported laccase production ability of batch cultures of white rot fungi in olive oil mill wastewater media (OOMW). Therefore, here, laccase production ability of repeated-batch cultures of Funalia trogii and Trametes versicolor pre-grown pellets in olive oil mill wastewater media (OOMW) was investigated and conditions for laccase production were optimized. The results indicated that high amounts of laccase could be obtained by using the best production conditions such as agitation, initial pellet amounts, initial pH, OOMW concentration and temperature. All these conditions were found to be important for laccase production. After optimization, the effect of various supplementary sources and inducer (glucose, malt extract, cheese whey and copper) on laccase production ability of these fungi and longevity of this production ability were examined in repeated-batch process. Presence of glucose, malt extract, cheese whey and copper positively affected the laccase production ability and longevity of the production. The fungal pellets also partially bioremediated the OOMW during laccase production and F. trogii pellets removed 33 % COD from OOMW effluent whilst T. versicolor removed 28 % in the first use.Öğe The evaluation of pre-grown mycelial pellets in decolorization of textile dyes during repeated batch process(Springer, 2010) Yesilada, Ozfer; Yildirim, Seval Cing; Birhanli, Emre; Apohan, Elif; Asma, Dilek; Kuru, FilizThis study was undertaken for the possibility of application of pre-grown pellets for biotechnological treatment of dyes and textile industry waste waters. Mycelial pellets of five different white rot fungi were tested for their dye decolorization activity. The pellets of Funalia trogii, Phanerochaete chrysosporium and Trametes versicolor were determined as the most effective ones. The decolorization ability of viable pellets was compared with the decolorization (adsorption) ability of dead pellets during repeated batch studies. Astrazon Black dye was decolorized effectively, about 90%, by viable pellets of all fungi during the first use. Viable F. trogii pellets were found as the most effective pellets. Upon pellet treatment not only a high decolorization but also reduced toxicity (antimicrobial activity) of the Astrazon Black dye was recorded. This type of decolorization activity with commercial or crude laccase was partially observed. Growing cells of F. trogii in batch system showed lower efficiency in color removal of mixed dyes compared to the pre-grown pellets in repeated batch system. The results in this study showed that mycelial pellets could effectively be used as an alternative to traditional physicochemical processes.Öğe Facile construction of a robust and recyclable laccase/metal-organic framework-808 with boosted stability for biodegradation of Reactive Blue 171 and Reactive Blue 198 from aqueous media(Elsevier, 2024) Bakar, Busra; Bugday, Nesrin; Birhanli, Emre; Boran, Filiz; Ulu, Ahmet; Yasar, Sedat; Yesilada, OzferLaccase enzyme sees application demand in many industries such as textile, food processing, wood processing, pharmaceutical, and chemical. However, it becomes difficult to maintain the enzymatic activity of laccase under harsh reaction conditions and even after several biocatalytic cycles. Therefore, suitably prescribed supports are crucial to ensure that the catalytic activity and reusability of the immobilized laccase are maintained at high levels. The present study highlights the development and dye decolorization application of an enzyme carrier matrix employing a Zr-based metal-organic framework (MOF), MOF-808, with hierarchical porosity for the immobilization of laccase from Trametes trogii . The immobilization efficiency for Lac/MOF-808 was found to be 70.83 +/- 1.98 %. Lac/MOF-808 exhibited optimal catalytic temperature at 60 degrees C, while the optimal catalytic pH was 4.5. Due to recoverable properties from the carrier matrix the recycle test was satisfactory for the Lac/MOF808, being reused 7 times without losses greater than 50 % of residual activity. Stored at 25 degrees C, Lac/MOF-808 retained 30 % of its activity during 4-weeks period. A kinetic study was carried out for Lac/MOF-808 monitoring the oxidation reaction of ABTS. The K-m value was 0.070 mM and the V-max was 87.7 mu mol min(-1) g(-1). Kinetic investigations, on the other hand, demonstrated a decrease in K m following immobilization, signifying a higher affinity for substrate. The Lac/MOF-808 maintained its decolorization efficiency even after eight reaction cycles, exhibiting a remarkable activity of 56.7 % and 77.2 % against Reactive Blue 171 and Reactive Blue 198, respectively. Hence, the described Lac/MOF-808 might be an ideal candidate for efficient dye decolorization applications.Öğe Immobilization of Trametes trogii laccase on polyvinylpyrrolidone-coated magnetic nanoparticles for biocatalytic degradation of textile dyes(Taylor & Francis Ltd, 2024) Bakar, Busra; Birhanli, Emre; Ulu, Ahmet; Boran, Filiz; Yesilada, Ozfer; Ates, BurhanHigh cost and low operational stability are the most important challenges limiting the possible use of laccase in the removal of textile dyes. To overcome these challenges, in this study, polyvinylpyrrolidone (PVP)-coated magnetic nanoparticles (MNPs) were produced and characterized. To our knowledge, this is the first study to explore the feasibility of immobilizing a Trametes trogii laccase enzyme on Fe3O4/PVP MNPs. The characterization of samples and the successful immobilization of laccase were verified by characterization methods. Besides, the biochemical properties and stability of the Fe3O4/PVP/Lac were evaluated in terms of optimum pH, optimum temperature, thermostability, thermodynamic and kinetic parameters, storage stability, operational stability, and decolorization efficiency of two different textile dyes. The optimum activities were recorded at pH 2.5 degrees C and 30 degrees C. The Fe3O4/PVP/Lac displayed remarkable thermal stability and activation energy for denaturation, enthalpy, Gibbs free energy, and entropy results confirmed the enhanced stability of Fe3O4/PVP/Lac against high temperatures. Meanwhile, the Fe3O4/PVP/Lac retained about 58% of its original activity after seven consecutive reuses, while it retained up to 25% of its original activity after 28 d of storage at room temperature. K-m and V-max for the Fe3O4/PVP/Lac were calculated to be 126 mu M and 211 mu mol/min, respectively. Finally, after 8 and 6 cycles of repeated use, the Fe3O4/PVP/Lac still decolorized 32.34% and 32.23% of Remazol Brilliant Blue R (RBBR) and Indigo Carmine (IC), respectively. As envisioned, this study suggests a promising way to solve the problems of high price and poor operational stability of the enzyme during biocatalytic decolorization of textile dyes in wastewaters.Öğe Innovation of Strategies and Challenges for Fungal Nanobiotechnology(Springer International Publishing Ag, 2016) Saglam, Necdet; Yesilada, Ozfer; Cabuk, Ahmet; Sam, Mesut; Saglam, Semran; Ilk, Sedef; Emul, EzgiNanotechnology involves the study and use of materials under the 100 nm scale, exploiting the different physiochemical properties exhibited by these materials at the nanoscale level. Microorganisms are the best model and role of action for the nano/biotechnological applications. This technology has become increasingly important for the biotechnology and the related sectors. Promising applications have been already employed in the areas of drug delivery systems using bioactive nanoencapsulation, biosensors to detect and quantify pathogens, chemical and organic compounds, alteration of food compositions, and high-performance sensors and film to preserve fruits and vegetables. Moreover, the taste of food and food safety can be improved by new nano-materials from the microbiological sources. The huge benefits from this technology have led to increases in the market investments in nanoscience and nanoproducts in several areas.Öğe Laccase immobilization on bacterial cellulose produced in a mulberry pomace waste extract medium: Characterization and use for dye decolorization(Wiley, 2023) Unlu, Fevziye; Boran, Filiz; Yesilada, Ozfer; Koytepe, SuleymanThe present study aimed to immobilize laccase on dry bacterial cellulose (BC) produced by Komagataeibacter xylinus B759 in mulberry pomace waste extract as a low-cost and natural waste by-product and to determine the effectiveness of the obtained laccase immobilized BC (Lac/BC) for textile dye decolorization. The highest BC yield obtained after optimization studies was as 1.70 g/L in pH 8.0 medium at 32 degrees C after 15 days. BC and Lac/BC structures were characterized by different instrumental techniques. A transition to more amorphous character was observed with the binding of the enzyme structure. The morphological properties and fiber structure of the BC and enzyme-linked cellulose structures were examined by SEM and AFM analyses. Obtained Lac/BC pieces were used for the decolorization of Reactive Blue 171 (RB 171) and Reactive Blue 198 (RB 198) diazo dyes during the repeated-batch process. As a result of using 12 pieces of Lac/BC, 93% and 98% decolorization values were obtained for the RB 171 and RB 198 dyes in the first use, while the color removal was still 83% and 51% at the 8th use, respectively. The results showed that BC produced in a mulberry pomace waste extract can be used for laccase immobilization and Lac/BC is an effective and promising system for textile dye decolorization.Öğe Laccase production and dye decolorization by Trametes versicolor: application of Taguchi and Box-Behnken Methodologies(Turkish Biochem Soc, 2014) Gedikli, Serap; Aytar, Pinar; Buruk, Yeliz; Apohan, Elif; Cabuk, Ahmet; Yesilada, Ozfer; Burnak, NimetullahObjective: The aim of this study was to investigate the laccase production of Trametes versicolor under submerged fermentation condition. Then, dye decolorization by laccase was optimized using Box-Behnken methodology. Methods: The optimal culture conditions for producing high amount of laccase were determined using Taguchi methodology. The experiments were designed with five factors (glucose, yeast extract, CuSO4, inoculum size and pH) at three levels with orthogonal array layout of L27 (3(5)). Then, the optimum conditions for high decolorization activity of Reactive Blue 49 by obtained crude laccase were also investigated using Box-Behnken methodology. Results: The optimum culture conditions for production of high amounts of laccase were detected as 2 g L-1 of glucose, 5 g L-1 of yeast extract, 2mM of CuSO4, 4% of inoculum amount and pH 5.5. Yeast extract was the most effective factor, followed by CuSO4, inoculum, glucose and pH. Under these conditions, predicted values were in a good agreement with the actual experimental one. The predicted results showed that the maximum of Reactive Blue 49 decolorization as 98% could be obtained under the optimum conditions of pH 2.95, initial dye concentration 55.6 mg L-1, enzyme amount 0.76 mL and reaction time 46.91 min. The validity and practicability of this statistical optimization strategy was confirmed with the relation between predicted and experimental values. Conclusion: The results suggested that Taguchi method can be used in the optimization of laccase production process. Production of laccase by Trametes versicolor 2008001 can be effectively used for enzymatic decolorization according to the results of decolorization experiments in optimal levels.Öğe Laccase production by newly isolated white rot fungus Funalia trogii: Effect of immobilization matrix on laccase production(Elsevier Science Bv, 2013) Birhanli, Emre; Erdogan, Selim; Yesilada, Ozfer; Onal, YunusThe laccase production performance of newly isolated Funalia trogii (F. trogii) immobilized on low-cost activated adsorbents prepared from apricot stone was investigated in inexpensive molasses medium and compared with free pellets. The adsorbents were apricot stone-based activated carbon (AC), Cu-impregnated apricot stone-based activated carbon (Cu-AC) and Fe-impregnated apricot stone-based activated carbon (Fe-AC). Cu-AC and Fe-AC were prepared by chemical activation. The values of BET surface area (S-BET), total pore volume (V-t), micropore surface area (S-mic) and micropore volume (V-mic) which show the pore properties of the activated carbons were 133 m(2) g(-1), 0.105 cm(3) g(-1), 108 m(2) g(-1) and 0.056 cm(3) g(-1) for Cu-AC and 145 m(2) g(-1), 0.112 cm(3) g(-1), 117 m(2) g(-1) and 0.061 cm(3) g(-1) for Fe-AC, respectively. F. trogii attached well on all of these adsorbents. However, the fungus immobilized on Cu-AC produced much higher levels of laccase than the others. The laccase activity obtained in 5 g L-1 molasses media after first cycle and mean laccase activity obtained after three cycles with fungus immobilized on Cu-AC were 29.23 U mL(-1) and 27.04 U mL(-1), respectively. These activities were only 0.25 and 0.39 U mL(-1) with free pellets. The crude laccase from immobilized culture could also decolorize the textile dyes. (c) 2012 Elsevier B.V. All rights reserved.Öğe Laccase-conjugated thiolated chitosan-Fe3O4 hybrid composite for biocatalytic degradation of organic dyes(Elsevier, 2020) Ulu, Ahmet; Birhanli, Emre; Boran, Filiz; Koytepe, Suleyman; Yesilada, Ozfer; Ates, BurhanIn this study, a novel immobilization support for laccase was developed to enhance enzyme stability, efficiency and reusability. Firstly, Fe3O4 magnetic particles were synthesized and modified by the co-precipitation route using thiolated chitosan (TCS). The support was characterized using several methods. Afterward, laccase was attached to the surface of functional support. The biochemical properties of the immobilized laccase were comprehensively investigated. It was observed that immobilized laccase achieved maximum activity at pH 4.0 and the optimum temperature was found to be 50 degrees C. After storage at +4 degrees C and similar to 25 degrees C for 4 weeks, the residual activity of the immobilized laccase was 87% and 80% of its initial activity, respectively. At 55 degrees C, the activity of immobilized lactase decreased to 73A% in 180 min and after reused 20 times, the relative activity of immobilized laccase still was approximately 50% of its initial activity. Moreover, the textile dye (Reactive Blue 171 and Acid Blue 74) decolorization activity of immobilized laccase was also tested and it showed long-term textile dye decolorization activity. These results are promising for the use of laccase in industrial and biotechnological applications. Therefore, this functionalized magnetic hybrid composite might be used to immobilize laccase, an industrially important enzyme. (C) 2020 Elsevier B.V. All rights reserved.Öğe Moringa oleifera leaves: could solvent and extraction method affect phenolic composition and bioactivities?(Taylor & Francis Inc, 2021) Bennour, Naima; Mighri, Hedi; Bouhamda, Talel; Mabrouk, Mahmoud; Apohan, Elif; Yesilada, Ozfer; Kucukbay, HasanThis study was carried out to evaluate the effect of extraction methods (direct maceration (DM) and successive maceration (SM)) and solvents (dichloromethane (DCM), ethyl acetate (EAc), butanol (But), and aqueous extraction (Aqu)) on the phenolic composition and biological activities of Moringa oleifera leaves cultivated for the first time in Tunisia. Total polyphenol content (TPC), total flavonoid content (TFC) and LC-MS analysis were performed for all extracts. Antioxidant potential by DPPH, metal chelating, and FRAP assays, antibacterial activity against Staphylococcus aureus (ATCC 29213) and Escherichia coli (ATCC 25922) by the minimum inhibitory concentration method (MIC) and cytotoxic properties against lung cancer cells (A549), were determined. Phenolic compounds and biological activities of M. oleifera leaves depend on the method and the solvent used for the extraction of these bioactive substances. The But extract prepared by SM method exhibited the highest amounts of TPC (103.06 +/- 0.5 mg GAE/g DE) and showed the strongest potential antioxidant (CI50 = 0.26 mg/mL on DPPH test), antibacterial (MIC = 250 mu g/mL) and cytotoxic activities (GI(50) = 69.9 mu g/mL). LC-MS analysis showed that 28 phenolic compounds of 33 tested standards were found in M. oleifera leaves. The But extract obtained by SM method exhibited the highest amounts of rutin, quercetin and syringic acid.
