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In this work, a novel calix[4]resorcinarene-based ionic liquid (C4RA-2IL) was synthesized, structurally characterized, and statically coated on capillary column as stationary phase for capillary gas chromatography (GC). The column efficiency of the C4RA-2IL column is 3345 plates m−1, which are determined by n-dodecane at 120 °C. Based on its McReynolds constants, the C4RA-2IL column showed moderate polarity. Particularly, the C4RA-2IL column show high separation performance for a wide range of analytes and some difficult separation of meta/para-isomers. Moreover, it exhibited excellent selectivity for critical aromatic isomers of chloroaniline, bromaniline, iodoaniline, toluidine and xylidine isomers and shows advantageous separation capability over the commercial polysiloxane stationary phase. This work presents a promising future of calixarene-based ionic liquid as a new type of stationary phase in GC separations.

Fungal laccases catalyze a wide range of reactions that have fostered an escalating demand in diverse sectors. Higher productivity in a short period remains a major challenge that needs to be fulfilled for successful industrial applications. In the present study, statistical optimization methods were utilized for high-yielding laccase production by the fungus Trametes maxima IIPLC-32 that achieved 103 IU mL−1 activity and a 13.3-fold increase compared to that under unoptimized conditions. Optimization using the Plackett–Burman design (PBD) and Box–Behnken design (BBD) identified that glucose, xylidine, veratryl alcohol, CuSO4, and potassium phosphate significantly influenced the laccase production. Furthermore, it also revealed that glucose contributed maximally to the overall laccase production, followed by xylidine and veratryl alcohol. Mathematical models were used for kinetic analysis. Kinetics of biomass formation followed the logistic growth model (with the model parameter values of Xmax = 9.54 g L−1, μmax = 0.77 d−1, and R2 = 0.95). Laccase production kinetics followed the Luedeking–Piret model (with the model parameters of α = 0.12 IU mg−1, β = 1.57 IU mg−1 d−1, and R2 = 0.90), indicating that the laccase produced by Trametes maxima IIPLC-32 is partially growth associated. The logistic mass balance equation adequately described substrate utilization. The model parameters of Yx/s = 0.96 g g−1 and m = 0.05 g g−1 d−1 were retrieved from the logistic mass balance equation. The applicability of the enzyme produced from the optimized process was checked for the decolorization of remazol brilliant blue R, and the maximum decolorization efficiency of 92.3% was achieved within 8 h of reaction without the addition of a mediator.

Laccases (EC 1.10.3.2) are a class of multi-copper oxidases that have industrial value. In the present study, forty-five isolates of wild mushrooms were screened for laccase production. Eight of the isolates exhibited exploitable levels of substrate oxidation capacity. Isolate BPSM10 exhibited the highest laccase activity of 103.50 U/ml. Internal Transcribed Spacer (ITS) rRNA gene sequencing was used to identify BPSM10 as Pleurotus pulmonarius. The response of BPSM10 to two nutritional media supplemented with various inducers was characterized and the results indicated that Malt Extract Broth (MEB) supplemented with Xylidine increased laccase production by 2.8× (349.5 U/ml) relative to the control (122 U/ml), while Potato Dextrose Broth (PDB) supplemented with xylidine increased laccase production by 1.9× (286 U/ml). BPSM10 has the ability to decolorize seven synthetic dyes in a liquid medium. Maximum decolorization was observed of malachite green (MG); exhibiting 68.6% decolorization at 100 mg/L. Fourier-transform infrared spectroscopy (FTIR) was employed to confirm the decolorization capacity. The present study indicates that P. pulmonarius BPSM10 has the potential to be used as a potent alternative biosorbent for the removal of synthetic dyes from aqueous solutions, especially in the detoxification of polluted water. Keywords: Laccases, Decolorization, P. pulmonarius, Fourier transform-infrared spectroscopy

In this study, we collected and prepared ethanol extracts from 30 vegetable and fruit by-products and screened for antioxidant activities using three methods, including determination of total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay (DPPH assay), and ferric reducing/antioxidant power assay (FRAP assay). The coffee sediment (TN-16) and ginger peel extract (TN-17) showed vigorous activities and higher than those of other samples (p

This work aimed to develop zwitterionic cellulose with a versatile potential for removing anionic and cationic dyes. A grafting degree of 22% in a 3:2 ratio of the anionic and cationic groups was determined by elemental analysis. Spectroscopic characterization by carbon 13 Nuclear Magnetic Resonance (13C NMR) confirmed the zwitterionic functionalization of cellulose. Removal tests showed that zwitterionic cellulose could interact with different dyes (Congo red, Crystal violet, Mordant blue 9, Malachite green, Xylidine ponceau, and Reactive black 5), achieving from 2 to 14-fold of removal at tested conditions.

To improve the feed quality removal of lignin from plant biomass is essential. To improve the activity of laccase of white rot fungi, aromatic inducers are used. In this study three inducers [Resorcinol (5mM and 10mM), Xylidine and Anisaldehyde] to induce the production of laccase enzyme in the culture of fungus: Cyathus stercoreus. Resorcinol (10mM) was found to be the best inducer among the rest. The enzyme activity was observed highest on the 8th day of induction (226.7U/ml). Protein content was also increased with the age of the culture. 80% ammonium sulphate was suitable for precipitating the laccase enzyme for culture filtrate. The laccase production can be enhanced with inducers and can be further used for the removal of lignin from the plant biomass.

A novel bioreactor system (low cost and easily scaled-up) is presented for dye decolorization applying filamentous fungi. In this two-phase bioreactor, dyes were decolorized at 28°C in a first phase by immobilized fungi in spherical cartridges prepared with a high-density plastic polyethylene mesh and filled with wheat bran as substrate for growth. In a second phase the capacity of the ligninolytic enzymes (laccase and Mn-peroxidase) present in the extracellular extracts from the solid residues was exploited for decolorization at 50°C. Each sphere behaved as a small-scale bioreactor for cell-culture. This system allowed the decoupling of growth (sterile condition) and decolorization (non-sterile condition) stages. The ability to decolorize the azo dye xylidine and the triphenylmethane Malachite Green by two Argentinean strains of Trametes versicolor was evaluated. The highest decolorization rates were displayed by T. versicolor BAFC 2234. When both dyes were applied together in the bioreactor, after a first phase (100min) 73.5% of Malachite Green and 40% of xylidine decolorization was attained, while at the end of the second phase (240min) a 97% and 52% decolorization was observed. Laccase activity was detected in the decolorized solution, but no Mn-peroxidase activity. The easy change of the cartridges allows the continuous use of the bioreactor in the non-sterile decolorization of dye-containing effluents.

Laccases and laccase-mediator systems (LMS) are versatile catalysts that can oxidize a broad range of substrates coupled to the sole reduction of dioxygen to water. They possess many biotechnological applications in paper, textile, and food industries, bioethanol production, organic synthesis, detection and degradation of pollutants, and biofuel cell development. In particular, bacterial laccases are getting relevance due to their activity in a wide range of pH and temperature and their robustness under harsh conditions. However, the enzyme and the redox mediator's availability and costs limit their large-scale commercial use. Here we demonstrate that β-(10-phenothiazyl)-propionic acid can be used as an efficient and low-cost redox mediator for decolorizing synthetic dyes by the recombinant laccase SilA from Streptomyces ipomoeae produced in E. coli. This new LMS can decolorize more than 80% indigo carmine and malachite green in 1 h at pH = 8.0 and 2 h in tap water (pH = 6.8). Furthermore, it decolorized more than 40% of anthraquinone dye remazol brilliant blue R and 80% of azo dye xylidine ponceau in 5 h at 50 °C, pH 8.0. It supported at least 3 decolorization cycles without losing activity, representing an attractive candidate for a cost-effective and environmentally friendly LMS functional at neutral to alkaline pH.

A soluble terpolymer of aniline (AN), 2-pyridylamine (PA) and 2,3-xylidine (XY), poly(AN-co-PA-co-XY) and its nanocomposite with ZnO nanoparticles namely, poly(AN-co-PA-co-XY)/ZnO were synthesized by chemical oxidative polymerization employing ammonium persulfate as an oxidant. Nanocomposites of homopolymers, polyaniline/ZnO, poly(XY)/ZnO and poly(PA)/ZnO were also synthesized by following similar synthesis route. FTIR, XRD and SEM techniques were used to characterize the synthesized compounds. The synthesized compounds were chemically deposited on mild steel specimens by solvent evaporation method using N-methyl-2-pyrrolidone (NMP) as solvent and 10% epoxy resin (by weight) as binder. Anticorrosive properties of homopolymer nanocomposites, terpolymer and its nanocomposite coatings were studied in 0.1 M HCl by subjecting them to various corrosion tests which includes: free corrosion potential measurement (OCP), weight loss measurements, potentiodynamic polarization, and AC impedance technique. The surface morphology of the corroded and uncorroded coated steel specimens was evaluated using SEM. The corrosion protection performance of terpolymer nanocomposite coating was compared to the terpolymer and individual homopolymers nanocomposites coatings after 30 days immersion in corrosive medium.

The titration curve is not obvious during the potentiometric titration analysis of the sample containing xylidine, and there is interference noise. The Savitzky-Golay smoothing method is used to eliminate the local noise effect in the titration curve, and the first-order derivation curve is obtained. The method performs polynomial fitting and derivation on each data point in the titration curve by aliquoting the moving window, and obtains the most effective information while eliminating noise. According to the standard sample measurement result error optimization window width and polynomial fitting times, the titration curve is smoothed by five points to obtain the ideal measurement result. The analysis of the actual sample shows that the smooth derivation method can more accurately detect the titration end point of the titration curve, and is simpler, faster and more reliable than the mapping method.

Laccases are polyphenol oxidases produced by many fungi and have many applications in textile, food and beverage, and pulp and paper industries. Laccase production can be induced using aromatic or phenolic compounds that mostly affect the transcription of laccase-encoding genes. In this study, we analyzed laccase and biomass production by Agaricus blazei in the presence of different concentrations of nitrogen, copper, and inducers such as pyrogallol, veratryl alcohol, xylidine, vanillin, guaiacol, and ethanol. Laccase production by A. blazei U2-4 reached 43.8 U/mL in the presence of 2.8 g/L nitrogen and 150 μM copper. However, addition of copper to the cultivation medium decreased biomass production. Different compounds differentially induced laccase production by A. blazei. Moreover, different concentrations of these inducers exerted different effects on laccase activity. Ethanol (1.0 mM), guaiacol (0.5 mM), and vanillin (0.5 mM) were the best inducers and increased laccase activity by 120% (A. blazei U2-2), 30% (A. blazei U2-3), and 9% (A. blazei U2-4), respectively. In contrast, pyrogallol and xylidine decreased laccase activity but increased biomass production.

It is desirable to make effective use of solid wastes, as well as waste liquors, of the dye house generated from leather processing. The present study deals with the adsorption of Acid red 26 (Xylidine ponceau) dye using leather fibre waste (buffing dust) as substrate matrix by the means of ultrasound, magnetic stirring and conventional heating. The research examined the effect of various process parameters: ultrasonic power, concentration of dye, temperature and time. The dye uptake data have been fitted with Freundlich and Langmuir isotherms, indicating a useful dye adsorption process. A mechanism for dye adsorption in leather fibres has also been proposed. This study shows that it is possible to remove dyes from dye house effluent streams using leather waste fibres of buffing dust by means of ultrasound. Two different toxic wastes produced by the same industry can be effectively contained. This ‘Intra wastes interaction’ approach could reduce the burden of discarding wastes of other materials in the le...

Culture filtrates from the white rot fungus Trametes trogii were used for the degradation of two azo dyes: Xylidine and Methyl Orange. These culture filtrates showed a great potential for decolorizing even high concentrations of both azo dyes, without the addition of redox mediators, possibly due to the synergistic action of their high contents of laccase (104 U ml−1), accompanied by Mn-peroxidase (0.54 U ml−1), cellobiose dehydrogenase (0.45 U ml−1) and glioxal oxidase (0.38 U ml−1) activities. 75% of Methyl Orange (980 ppm) and 96% of Xylidine (480 ppm) were degraded after 24 h, degradation occurred after 6 days with a 94% of Xylidine removed (1440 ppm). Biodegradation products from Xylidine were determined by capillary electrophoresis followed by MALDI-TOF mass spectra. Neither aromatic amines nor colored quinones were detected, major metabolites being naphtalene sulphonate and xylene.

Laccase production from Trametes versicolor was improved in the presence of the inducers ligninosulphonates, veratryl alcohol, and xylidine respectively two-, four-, and eightfold. The thermal inactivation of the produced laccase, after partial purification with ammonium sulfate was kinetically investigated at various temperatures (60-70 °C) and pH values (3.5, 4.5, and 5.5). The inactivation process followed first-order kinetics for all conditions tested, except for veratryl alcohol, for which a constant activity level was observed at the end of the inactivation, also after first-order decay. Enzyme thermostability was affected by the type of inducer used in the culture medium for the production of laccase and also by the pH of incubation mixture. Generally, laccase stability increased with pH increment, being more stable at pH 5.5, except with xylidine. At pHs 4.5 and 5.5, the three inducers significantly increased laccase thermal stability, with the higher effect being observed for pH 5.5 and ligninosulphonates, where increment of half-life times ranged from 3- to 20-fold, depending on the temperature.

Optimization of the medium components for production of laccase by Paraconiothyrium variabile using response surface methodology was investigated. Initial screening by Plackett–Burman design was performed to select major variables out of eleven medium components, among which peptone, CuSO 4 , and xylidine were found to have significant effects on laccase production. After application of the steepest ascent to approach the proximity of the optimum point, a central composite design was employed to optimize the level of the selected variables. In optimum concentrations of the most effective parameters, including peptone, 2.2 g/L, CuSO 4 , 0.03 g/L, and xylidine 1.29 mM, extracellular laccase activity was enhanced from 970 U/L (in basal medium) to 16,678 U/L, which means a 17-fold increase in laccase production in the optimized medium. Supernatant of the optimized medium was used for decolorization of five synthetic dyes, among which 93% of Remazol brilliant blue R (with initial concentration of 600 mg/L) disappeared after 3 h treatment in the presence of 5 mM hydroxybenzotriazole.

Trametes hirsuta, a filamentous basidiomycete, was successfully cultivated in solid-state fermentation (SSF) on a mixture of pine wood chips and orange peel in a novel bioreactor that allows mixing of the inoculated solid material during the fermentation. Copper sulfate or xylidine (2,5-dimethylaniline) were added to enhance the production of enzymes, especially laccases. For comparison, Trametes hirsuta was also cultivated in submerged conditions. The effect of additives in SSF was low, whereas the choice of the solid material and the rotation of the reactor vessel showed a significant influence on the enzyme production. The space-time yields for the fermentations were calculated and showed that SSF on low-cost substrates can effectively produce extracellular enzymes at a sufficient rate by a cultivation method that requires only low technology equipment.

Lignin peroxidase (LiP) enzyme was purified from Kocuria rosea MTCC 1532. The enzyme was produced and subjected to purification by ion exchange chromatography followed by gel filtration chromatography; 79-fold purity was obtained. The molecular weight of LiP was determined to be 66 kDa. The pH optimum of the purified enzyme was 3.0, and the temperature optimum was found to be around 50°C. Purified LiP showed a much higher activity towards n-propanol than towards L-Dopa, 8-hydroquinone, mimosine, veratryl alcohol, and xylidine. The effect of inhibitor and metal ion on LiP activity was analyzed. Purified LiP was able to decolorize synthetic dyes from various groups, indicating that it is a versatile peroxidase.

In the present study we have purified the intracellular veratryl alcohol oxidase (VAO) enzyme from Pseudomonas aeruginosa strain BCH to evaluate its dye decolorizing potential. The enzyme was purified by ion exchange chromatography using DEAE cellulose followed by gel filtration chromatography using Biogel P-100. The molecular weight of the purified enzyme was estimated by polyacrylamide gel electrophoresis (PAGE) analysis. The VAO was purified up to 12 and 16.3-fold by ion exchange and gel filtration chromatography respectively. VAO was estimated to be about 85 kDa by SDS–PAGE. The optimum pH and temperature for purified VAO was 3 and 55°C respectively. The purified enzyme exerted its optimal activity with veratryl alcohol and also oxidized various other substrates, whereas diminished activity was noted in case of tryptophan and xylidine. The metal ions Mn++ and Hg++ were found to suppress the oxidase activity. The purified enzyme decolorized different dyes with variable decolorization rates and efficiencies. Decolorization mechanism of Remazol Black by purified enzyme was studies in detail using various analytical techniques like HPLC, GC–MS and FTIR. This study is useful for understanding the precise role of Pseudomonas aeruginosa strain BCH in the decolorization of textile dyes containing industrial wastewater.

We investigated the use of solid residues from Pleurotus ostreatus mushroom production in adsorbing and decolorizing different dyes. The solid residue used in this study was composed of hemicellulose and cellulose (52.81 %), acid-insoluble lignin (25.42%), chitin (6.5%), and water extractives (14.82%). After incubating 14% (wt/vol) solid residue in distilled water for 4 h, laccase and manganese peroxidase (MnP) activities were 0.5 U/g and 12 mU/g, respectively. Enzymatic decolorization percentages were up to 100 for azure B (heterocyclic dye) and indigo carmine (indigoid dye), 74.5 for malachite green (MG) (triphenylmethane dye), and zero for xylidine (azoic dye). The optimum temperature for decolorization was in the range of 26 ∼ 36°C for all dyes. Data obtained on adsorption (enzymatic decolorization was prevented with sodium azide) at different dye concentrations and in a pH range of 3 ∼ 7 were used to plot Freundlich isotherms. The spent fungal substrate (SFS) displayed large differences in adsorption capacity, depending on the dye tested. The highest adsorption capacity was observed at pH 3 for MG, while xylidine was slightly adsorbed at pH 3 and 4 and not adsorbed at higher pH values. Laccase and MnP production were affected by the presence of the dyes. The highest enzyme levels were observed in the presence of MG, when laccase and MnP increased 1.39- and 2.13-fold, respectively. Decolorization and adsorption to SFS are both important processes in removing dyes from aqueous solutions. The application of this spent substrate for wastewater treatment will be able to take advantage of both of these dye removal processes. An important problem in bioremediation processes involving microorganisms is the amount of time required for their growth. In this report, we used the spent substrates from mushroom cultivation in wastewater treatment, thus solving the problem of waiting for microorganisms to grow.

The binding of aromatic anions by bovine serum albumin at pH 6,6 and 3,5 and by insulin at pH 3,5, in 0.1 N phosphate buffers, has been measured by the equilibrium-dialysis method. The association constants and the affinities of the first anion have been calculated from the binding curves. Conclusions are drawn regarding the influence of the structure of anions on their affinities for proteins. The benzene derivatives present low affinities (nitro-and amino-benzoates, aminobenzenesulfonates, phthalate and salicylate). Higher affinities are obtained with naphthalene derivatives (naphthalenemono- and di-sulfonates, naphtholsulfonate, aminonaphthalenesulfonate), with indigosulfonates, with anthraquinonesulfonates and with simple azo-derivatives (monohydroxy-, dihydroxy-, amino- azobenzenesulfonates). The highest affinities are presented by : picric and flavianic acids, complex azo-derivatives (tropeolin, orange II, xylidine red, amaranth) and sulfonphthaleins (in increasing order, phenol red, thymol blue, bromcresol purple and bromphenol blue). It is concluded that: 1. affinity is proportional to the number of aromatic rings of the anion; 2. the introduction of some substituents like OH, NO2 and halogens in the aromatic rings increases affinity whereas other ones like NH2 and nitrogen heterocycles depress it; 3. the position of lateral substituents is relatively unimportant; 4. the relative order of affinities is similar for serumalbumin and for insulin. One can also remark that in aromatic compounds, affinity is generally in qualitative relation with the resonance of the molecules. There is no definite structural pattern of the anion conferring to it a special affinity for the proteins. In the contrary, the associations studied here are quite unspecific and do not correspond to well defined chemical combinations.

A method for the determination and confirmation of amitraz and its degradation product 2,4-dimethylaniline (2,4-DMA) in honey is reported. Determination of the two compounds was based on HPLC with UV detection and MS/MS (LC-MS/MS) after a liquid-liquid extraction with hexane and isopropyl alcohol. Chromatographic separation was achieved by using a C18 column with a gradient mobile phase consisting of 0.02 M ammonium acetate and ACN. Recoveries for fortified honey ranged from 83.4 to 103.4% for amitraz and from 89.2 to 104.7% for 2,4-DMA with RSD values lower than 11.6% for HPLC and LC-MS/MS methods. LOD was 6 microg/kg for amitraz and 8 microg/kg for 2,4-DMA, while LOQ was 20 microg/kg for amitraz and 25 microg/kg for 2,4-DMA in HPLC method. LOD was 1 microg/kg for amitraz and 2 microg/kg for 2,4-DMA, while LOQ was 5 microg/kg for amitraz and 10 microg/kg for 2,4-DMA in LC-MS/MS method.

The assessment of human exposure to specific isomers of dimethylanilines (DMA's) is of interest for the evaluation of potential exposure-health outcome relationships. Improved analytical methods will help in identifying the environmental sources of such exposures. The separation of all six DMA isomers by supercritical fluid chromatography (SFC), without derivatization, is reported within. Further, the combination of SFC with electrospray ionization/tandem mass spectrometry provides selective detection in crude extracts of spiked (40 ppb of 3,5-dimethylaniline) raw materials. The raw materials chosen for analysis are commonly used in the manufacture of consumer hair-dye products.

Lignin peroxidase was purified (72-fold) from Acinetobacter calcoaceticus NCIM 2890. The purified lignin peroxidase (55-65 kDa) showed dimeric nature. The maximum enzyme activity was observed at pH 1.0, between a broad temperature range of 50 and 70 degrees C, at H2O2 concentration (40 mM) and the substrate concentration (n-propanol, 100 mM). Purified lignin peroxidase was able to oxidize a variety of substrates including Mn2+, tryptophan, mimosine, L-Dopa, hydroquinone, xylidine, n-propanol, veratryl alcohol, and ten textile dyes of various groups indicating as a versatile peroxidase. Most of the dyes decolorized up to 90%. Tryptophan stabilizes the lignin peroxidase activity during decolorization of dyes.

In this work, the effect on laccase activity of adding xylidine, veratryl alcohol and copper sulphate to cultures of Coriolopsis rigida under submerged cultivation conditions have been investigated. The highest activities (approximately 6 × 105 nkat/l) were obtained when the inducers copper sulphate (2 mM) and xylidine (10 mM) were added simultaneously. In addition, operating in the optimal conditions, it was possible to maintain the sustained production of laccase (around 3 × 105 nkat/l) for successive repeated batch cultures in an expanded-bed laboratory scale bioreactor. On the other hand, in vitro phenol degradation by laccase obtained in the bioreactor was studied with/without an effective mediator 1-hydroxybenzotriazol (HBT). The presence of a radical mediator plays an important role inducing the degradation of phenol, and without mediator the polymerization of phenol was detected.

Two isoforms of laccase produced from the culture supernatant of Pycnoporus sanguineus were partially purified by phenyl-Sepharose chromatography. Molecular masses of the enzymes were 80 kDa (Lac I) and 68 kDa (Lac II). Optimum activity of Lac I was at pH 4.8 and 30 °C, and Lac II was at pH 4.2 and 50 °C over 5 min reaction. The K m values of enzymes toward syringaldazine were 10 μm (Lac I) and 8 μm (Lac II). Sodium azide inhibited Lac I (85%) and Lac II (75%) activities.

An extracellular laccase was isolated and purified from Pleurotus sajor-caju grown in submerged culture in a bioreactor, and used to investigate its ability to decolorize three azo dyes. The extracellular laccase production was enhanced up to 2.5-fold in the medium amended with xylidine (1 mM). Purification was carried out using ammonium sulfate (70% w/v), DEAE-cellulose, and Sephadex G-100 column chromatography. The enzyme was purified up to 10.3-fold from the initial protein preparation with an overall yield of 53%. The purified laccase was monomeric with an apparent molecular mass of 61.0 kDa. The purified enzyme exerted its optimal activity with 2,2-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate (ABTS) and oxidized various lignin-related phenols. The catalytic efficiencies kcat/Km determined for ABTS and syringaldazine were 9.2x10(5) and 8.7x10(5), respectively. The optimum pH and temperature for the purified enzyme was 5.0 and 40 degrees C, respectively. Sodium azide completely inhibited the laccase activity. The absorption spectrum revealed type 1 and type 3 copper signals. The purified enzyme decolorized azo dyes such as acid red 18, acid Black 1, and direct blue 71 up to 90, 87, and 72%, respectively. Decolorization ability of P. sajor-caju laccase suggests that this enzyme could be used for decolorization of industrial effluents.

The laccase activities of Penicillium simplicissimum H5 during solid-state fermentation with rice straw were studied. Degradation of lignocellulose was also followed. Results showed that all supplemental carbon sources inhibited the laccase activity in different degrees, while suitable concentrations of supplemental nitrogen sources remarkably enhanced the laccase activity. The enhancement of activity by the ordinary laccase inducers 2, 2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) and xylidine was not observed in this study. Lignocellulose degradation was improved when laccase activity was relatively low, suggesting a polymerizing function of laccase in lignin degradation by P. simplicissimum.

Dyes especially azo dyes are used extensively as coloring agents in the manufacturing process of inks, textiles, leathers, food and pharmaceuticals. Liver, bacterial (anaerobic and aerobic) and fungal enzymes metabolized azo dyes immediately and released corresponding amines with carcinogenic character. Thus, the metabolism and release of amine products from azo compounds are of considerable interest. The present study emphases on the qualitative and quantitative analysis of products released from xylidine ponceau 2R by extra cellular protein (ECP) of Streptomyces sp. SS07, in comparison with the chemical reduction. It has been observed that both enzymatic and chemical catalysis release considerable quantities of similar type of amine compounds. The extra cellular fluid protein of 0.7852 mg/mg of ECP, on treatment with xylidine ponceau 2R, releases 2,4- xylidine, 2,6-xylidine and 2-methyl 3-amino p-quinone as products at pH 9.2 and at 37 °C for a contact period of 24 h. The clear band obtained in nondenaturing polyacrylamide gel electrophoresis showed the pure nature of the enzyme used for the reduction of dye xylidine ponceau 2R. Further, HPLC and GC–MS analysis of the reaction products after extracted with chloroform, revealed that about 5–20% increase in the quantity of amine was released by ECP.

The possibility of using zeolites containing the 2,4,6-triphenylpyrylium cation as photocatalysts for the degradation of pollutants has been tested on aqueous xylidine (2,4-dimethylaniline) solutions as models for contaminated wastewaters. The influence of the photocatalyst and substrate concentrations on xylidine oxidation has been investigated in homogeneous solution, by performing a series of experiments chosen according to the experimental design methodology (Doehlert uniform array). The empirical models and the corresponding response surfaces obtained from data analysis have been used for simulating and predicting degradation efficiency. The results have shown that conversion increases with increasing amounts of photocatalyst and decreasing concentration of the model pollutant. The fluorescence of 2,4,6-triphenylpyrylium was quenched by xylidine with a rate constant k(q) of 3.1x10(9)M(-1)s(-1). This result suggests a direct electron transfer between the excited pyrylium salt and xylidine. Because of the limited stability of the photocatalyst in homogeneous media, a pyrylium containing Y-zeolite has been tested for the photocatalytic oxidation of xylidine under heterogeneous conditions. The results suggest that the supported catalyst has a much improved stability and that xylidine oxidation rates remain nearly constant during the whole reaction time. An additional advantage of the pyrylium containing zeolite photocatalyst is that it can be recycled and used for further experiments.

A Box-Wilson central composite design was applied to optimize copper, veratryl alcohol and l-asparagine concentrations for Trametes trogii (BAFC 212) ligninolytic enzyme production in submerged fermentation. Decolorization of different dyes (xylidine, malachite green, and anthraquinone blue) by the ligninolytic fluids from the cultures was compared. The addition of copper stimulated laccase and glyoxal oxidase production, but this response was influenced by the medium N-concentration, with improvement higher at low N-levels. The medium that supported the highest ligninolytic production (22.75 U/ml laccase, 0.34 U/ml manganese peroxidase, and 0.20 U/ml glyoxal oxidase) also showed the greatest ability to decolorize the dyes. Only glyoxal oxidase activity limited biodecoloration efficiency, suggesting the involvement of peroxidases in the process. The addition of 1-hydroxybenzotriazole (a known laccase mediator) to the ligninolytic fluids increased both their range and rate of decolorization. The cell-free supernatant did not decolorize xylidine, poly R-478, azure B, and malachite green as efficiently as the whole broth, but results were similar in the case of indigo carmine and remazol brilliant blue R. This indicates that the mycelial biomass may supply other intracellular or mycelial-bound enzymes, or factors necessary for the catalytic cycle of the enzymes. It also implies that this fungus implements different strategies to degrade dyes with diverse chemical structures.

Extracellular fluid protein (ECFP) of Streptomyces species SS07 has been used to reduce water soluble azo dyes and the carcinogenic amines released have been compared with that from chemical reduction. The effect of temperature, pH and contact time on the recovery of amines using ECFP was studied. The ECFP releases carcinogenic amines at a pH of 9.2 and a temperature of 37 °C for a contact period of 24 h. The reduction products were analyzed with HPLC and their structures confirmed by LC–MS and GC–MS. It was observed that both the ECFP and chemical reduction methods released similar type of amine products. In the case of dye samples, compared to chemical reduction, 5–20% increase in the release of carcinogenic amines by ECFP was observed. The percentage of amine products released by chemical reduction was higher for leather garment samples compared to ECFP treatment.

A quick, simple, and reliable HPLC method for analysis of lignocaine and its metabolite xylidine in aqueous humor was developed. Aqueous humor was precipitated by 30% 5-sulfosalicylic acid and acetonitrile, then buffered by 4 M phosphate buffer at pH 4.0, with bupivacaine as internal standard. The chromatographic method employed a reverse C18 silica AccQ-Tag column and gradient mobile phase AccQ-Tag Eluent A and acetonitrile for separation at 37°C. The sample molecules were quantified at 220 nm. The analytical recoveries ranged from 96–109% and inter-assay imprecision less than 3.5%. In the analysis of 200 aqueous humor samples, no xylidine was detected after lignocaine gel application.

The production of laccase by Trametes versicolor under semi-solid-state conditions has been studied. Several supports (polyurethane foam, wheat straw, barley straw, wood shavings and barley bran) have been tested in order to determine the most suitable for laccase production by the above-mentioned microorganism. Barley bran led to the highest activity levels, reaching maximum values of about 1200 U/l. In this stage of research, several factors affecting laccase production (veratryl alcohol, xylidine, fresh support and the initial C/N ratio) were investigated. Xylidine was shown to be the best inducer of laccase activity, attaining values of about 1700 U/l. Moreover, the addition of fresh support not only prolonged culture lifetime but also enhanced activity levels, reaching in all the cases values higher than 2000 U/l. In addition, the decolourisation of three structurally different dyes by cultures grown on the best operating conditions determined in the present study, was monitored in order to assess the degrading capability of the ligninolytic complex secreted by such cultures. The decolourisation of all the dyes tested was almost total (85–96%) after 6 days of incubation.

The inclusion compounds of binaphthol with three isomers of xylidine have been studied in terms of their structures and infra-red spectra. Competition experiments show that the selectivity of enclathration follows the trend: 2,6-xylidine > 2,3-xylidine ≈ 3,5-xylidine. The kinetics of desolvation have been analysed and the activation energies established.

While Ir diphosphine complexes are very active catalysts for the enantioselective hydrogenation of imines with good to excellent enantioselectivity, their deactivation is often a serious problem, leading to low catalyst productivity. Our study describes attempts to stabilize Ir catalysts with diop, bdpp and bppm ligands for the hydrogenation of different imines. The best results were obtained with complexes immobilised on silica gel and with bimetallic W–Ir and Mo–Ir complexes. In most cases, enantiomeric excesses as well as initial rates were only slightly affected while the stability of the catalysts was enhanced significantly.

The diol host, 1,1′-bis-(4-hydroxyphenyl)cyclohexane (DHPC) and a number of xylidine isomers as guests formed a series of inclusion compounds that gave rise to various host:guest ratios controlled by crystallization temperatures. For the host DHPC with a particular xylidine isomer, the number of guests included generally decreases as the crystallization temperature increases. The crystal structures of these host–guest compounds were elucidated using single-crystal X-ray diffraction. Their thermal stabilities were characterized by TG and DSC analysis. The selectivity of enclathration by the host was measured by carrying out a series of competition experiments. The kinetics of guest decomposition were studied using isothermal and non-isothermal methods and reconciled with the crystal structures.

Lysinibacillus sphaericus D3 cell-immobilized beads in natural gel sodium alginate decolorized the xylidine orange dye 1-(dimethylphenylazo)-2-naphthol-6-sulfonic acid sodium salt in the laboratory. Optimal conditions were selected for decolorization and the products formed were evaluated for toxicity by disc diffusion assay against common marine bacteria which revealed the non-toxic nature of the dye-degraded products. Decolorization of the brightly colored dye to colorless products was measured on an Ultra Violet-Vis spectrophotometer and its biodegradation products monitored on Thin Layer Chromatographic plate and High Performance Liquid Chromatography (HPLC). Finally, the metabolites formed in the decolorized medium were characterized by mass spectrometry. This analysis confirms the conversion of the parent molecule into lower molecular weight aromatic phenols and sulfonic acids as the final products of biotransformation. Based on the results, the probable degradation products of xylidine orange were naphthol, naphthylamine-6-sulfonic acid, 2-6-dihydroxynaphthalene, and bis-dinaphthylether. Thus, it may be concluded that the degradation pathway of the dye involved (a) reduction of its azo group by azoreductase enzyme (b) dimerization of the hydrazo compound followed by (c) degradation of monohydrazo as well as dimeric metabolites into low molecular weight aromatics. Finally, it may be worth exploring the possibility of commercially utilizing L. sphaericus D3 for industrial applications for treating large-scale dye waste water.

Positron annihilation lifetime spectroscopy (PALS) is applied to a series of bis(aniline)fluorene and bis(xylidine)fluorene-based cardo polyimide and bis(phenol)fluorene-based polysulfone membranes. It was found that favorable amounts of positronium (Ps, the positron-electron bound state) form in cardo polyimides with the 2,2-bis(3,4-dicarboxyphenyl) hexafluoropropane dianhydride (6FDA) moiety and bis(phenol)fluorene-based cardo polysulfone, but no Ps forms in most of the polyimides with pyromellitic dianhydride (PMDA) and 3,3',4,4'-biphenyltetracarboxylic dianhydride (BTDA) moieties. A bis(xylidine)fluorene-based polyimide membrane containing PMDA and BTDA moieties exhibits a little Ps formation but the ortho-positronium (o-Ps, the triplet state of Ps) lifetime of this membrane anomalously shortens with increasing temperature, which we attribute to chemical reaction of o-Ps. Correlation between the hole size (V(h)) deduced from the o-Ps lifetime and diffusion coefficients of O2 and N2 for polyimides with the 6FDA moiety and cardo polysulfone showing favorable Ps formation is discussed based on free volume theory of gas diffusion. It is suggested that o-Ps has a strong tendency to probe larger holes in rigid chain polymers with wide hole size distributions such as those containing cardo moieties, resulting in deviations from the previously reported correlations for common polymers such as polystyrene, polycarbonate, polysulfone, and so forth.

Xylidines are important precursors for the production of dyes, drugs, and various other products. Because of the high carcinogenic nature of some xylidine isomers it becomes very essential and relevant to develop suitable analytical procedures to separate isomers as well as enhance detection at very low concentrations. Micellar electrokinetic chromatography has been standardized at various influencing parameters such as pH, ionic strength, and micelle modifiers, and the optimum conditions have been ascertained for the best separation and sensitivity of standard mixtures. The applicability of the procedure in environmental samples is studied.

A series of soluble terpolymers was synthesized by oxidative polymerization of 2-pyridylamine, aniline, and 2,3-xylidine using ammonium persulfate as oxidant in 1 M HCl aqueous solution. The yield, intrinsic viscosity, and solubility of the terpolymers were studied by changing monomer ratio and the polymerization time. At a fixed xylidine content of 10 mol%, the yield and intrinsic viscosity of the terpolymers decrease with increasing pyridylamine content and remain almost constant with polymerization time. The resulting terpolymers were characterized by FT-IR, 1 H-NMR, wide-angle X-ray diAraction, and thermogravimetry. The results showed that the polymers are amorphous terpolymers and exhibit good solubility, decomposition temperature of 375‐495C, the maximum weight-loss rate of 0.9‐5.8%/min, high char yield of 65 wt.% at 700C in nitrogen, and thermal degradation activation energy of 25‐81 kJ/mol. The thermal stability of the terpolymers is generally higher in nitrogen than in air. # 2001 Elsevier Science Ltd. All rights reserved.

The reaction of α-tetrahydrofurylsuccinic anhydride with amines proceeds regiospecifically at room temperature with the formation of N-substituted 2-(α-tetrahydrofuryl)succinamic acids. On increasing the temperature the reaction direction is changed and the 3 isomer is mainly formed.

Kinetics of chemical oxidative dispersion polymerization of 3,5-xylidine (Xy) in aqueous medium with ammonium persulfate (APS) as an oxidant was studied by monitoring the amount of proton released from Xy monomer, which was obtained from the amount of potassium hydroxide (KOH) solution added to keep constant pH values using a pH stat. The initial polymerization rate (R) [mol/L/min] of Xy was expressed as follows: R = 1.65 (1 − α) [Xy] [APS], where α is the degree of ionization of Xy, and [Xy] and [APS] are concentrations of Xy and APS, respectively. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 4238–4246, 2000

Micron-sized monodispersed polystyrene (PS)/poly(3,5-xylidine) (PXy) composite particles were produced by chemical oxidative seeded dispersion polymerization of 3,5-xylidine at 20 °C with 1.6-μm-sized monodispersed PS seed particles in HCl aqueous solution, the pH of which was always kept at 2.5 with a pH stat. The composite particles produced consisted of a PS core and a PXy shell.

In a medium containing 40 g ethanol l−1, laccase production by Trametes versicolor was 2.6 unit per ml of the supernatant, which was over 20 times higher than that without ethanol. Laccase activity with ethanol was quite comparable to that with the well-known inducers such as veratryl alcohol, xylidine and guaiacol. With other white-rot fungi, Coriolus hirsutus and Grifola frondosa, ethanol had a similar stimulatory effect on laccase production.