Synthesis and characterization of phenylsiloxane‐modified bismaleimide/barbituric acid‐based polymers with 3‐aminopropyltriethoxysilane as the coupling agent

The preparation and characterization of phenylsiloxane (PhSLX)‐modified N,N′‐bismaleimide‐4,4′‐diphenylmethane (BMI)/barbituric acid (BTA) (10/1 mol/mol) oligomers are described. 3‐Aminopropyltriethoxysilane (APTES) was used as the coupling agent. The resultant hybrid BMI/BTA‐APTES‐PhSLX polymers were characterized primarily using thermogravimetric analysis in combination with differential scanning calorimetry and Fourier transform infrared measurements. The thermal stability of the BMI/BTA oligomer was improved significantly by incorporation of a small amount (20–30 wt%) of the copolymer of PhSLX and APTES (PASi). After adequate post‐curing reactions, the PASi‐modified BMI/BTA oligomers (HYBRID20 and HYBRID30 containing 20 and 30 wt% PASi, respectively) exhibited greatly reduced thermal degradation rates in the temperature range 300–800 °C and an increased level of residues at 800 °C as compared to the native BMI/BTA oligomer. This was further confirmed by thermal degradation kinetic studies, in which the activation energies for the thermal degradation reactions of the cured PASi‐modified BMI/BTA oligomers were shown to be higher than that of the pristine BMI/BTA oligomer. © 2012 Society of Chemical Industry     

Functional stabilization of cellulase by covalent modification with chitosan

Chitosan was linked to cellulase (EC 3.2.1.4) from Trichoderma viride by covalent conjugation to periodate‐activated carbohydrate moieties of the enzyme. The modified enzyme contained about 1.5 mol of polymer per mol of protein. The specific activity of the conjugate prepared was 39.8% of the native cellulase. The optimum pH and temperature for cellulase remained unaltered after modification. The thermostability was increased by 8.9 °C for the cellulase–chitosan complex. Thermal inactivation at different temperatures ranging from 65 °C to 80 °C was markedly increased for the polymer‐modified enzyme. The stability within the pH range 1.0–3.2 was also improved for the modified enzyme. © 2001 Society of Chemical Industry     

Dye bleaching and phenol precipitation by phthalic anhydride‐modified horseradish peroxidase

The phenol precipitation and dye bleaching capabilities of phthalic anhydride–modified horseradish peroxidase C (PA–HRP) were compared with those of native HRP C and ethylene glycol‐ bis‐(succinic acid N‐hydroxysuccinimide ester)–modified HRP (EG–HRP) reported previously. Removal efficiency (percentage of phenol removed from solution under experimental conditions) was determined for native HRP and both modified forms. Removal efficiencies at 37 °C were very similar, with >95% removal in each case. Removal efficiencies were less at 70 °C overall (range 25–45%) but PA–and EG–HRP removed up to 50% more phenol than native HRP. The three HRP forms showed similar dye bleaching performance at 37 °C in the presence of H₂O₂ and accelerators (up to 86% colour removal). PA–and EG–HRP showed slightly greater bleaching abilities at 65 °C than native HRP for some of the dye/accelerator combinations tested. Modified HRPs performed better in 40% (v/v) mixtures of dioxane or dimethylformamide. © 2000 Society of Chemical Industry     

Optimisation of a serine protease coupling to Eudragit S‐100 by experimental design techniques

A full factorial design was used to study the influence of four different variables, namely polymer concentration, carbodiimide concentration, time of reaction and blocking agent concentration, on the coupling of a serine protease into a soluble–insoluble polymer (Eudragit S‐100). All of the four factors studied have played a critical role in the protease coupling. Response surface methodology was used as an optimisation strategy to attain a conjugate with high activity yield and operational stability at 60 °C. Under optimised conditions (Eudragit, 2.5% w/v, carbodiimide, 0.2% w/v, coupling time, 1 h and blocking agent concentration, 0.05%), the conjugate activity yield was about 45% and its operational stability at 60 °C was increased by 1.7 times. After reusing the conjugate for five cycles, the remaining activity was still 72% of the initial value when compared with the native enzyme. Several tests confirmed that the enzyme was covalently crosslinked to Eudragit, which represents an improvement in the carbodiimide coupling of proteases into soluble–insoluble polymers. Copyright © 2005 Society of Chemical Industry     

Immobilization of α-Amylase to Temperature-Responsive Polymers by Single or Multiple Point Attachments

Temperature-responsive N-isopropylacrylamide (NIPAAm) polymer (PNIPAAm) with a free carboxyl functional end group and a copolymer (NIPNAS) of NIPAAm and N-acryloxysuccinimide (NAS) were synthesized and used for immobilization of α-amylase. The enzyme forms covalent bonds with the former polymer by single point attachment and with the latter polymer by multiple point attachment. Such a difference influences the enzyme activity and properties of the immobilized enzymes. The polymers are temperature-sensitive with lower critical solution temperatures (LCST) of 34·7 and 36·0°C for NIPNAS and PNIPAAm, respectively. The immobilized enzyme exhibited an LCST of 35·5°C for NIPNAS-amylase and 37·1°C for PNIPAAm-amylase. They precipitated and flocculated in aqueous solution above the LCST and redissolved when cooled below that temperature. The activity of the immobilized enzyme depended on the pH of the coupling buffer, with 8·0 being the optimum value. The specific activities of the immobilized enzymes were 87% and 108% compared with that of free enzyme with soluble starch as the substrate for NIPNAS-amylase and PNIPAAm-amylase, respectively. By characterizing the properties of the immobilized enzymes and comparing with those of free enzyme, no diffusion limitation of substrate was found for the immobilized enzymes and they are more thermal stable than the free enzyme. Within the two immobilized enzymes, NIPNAS-amylase showed better thermal stability and reusability. Repeated batch hydrolysis of soluble starch can be carried out efficiently with the immobilized enzymes by intermittent thermal precipitation and recycle of the enzyme. © 1997 SCI.     

Synthesis of fatty esters by polyethylene glycol-modified lipase

Monomethoxypolyethylene glycols (PEG) of molecular masses 1900 and 5000 were activated using p-nitrophenyl chloroformate to form PEG–nitrophenyl carbonates (activated PEG) with high yield (96–98%). The activated PEG was covalently attached to Candida rugosa lipase. Increasing the molar ratio of activated PEG to the enzyme increased the degree of lipase modification. These modified lipases exhibited specific ester synthesis activities on organic solvents compared with native lipase. The degree of activity enhancement depended on the size of activated PEG used and the degree of modification of the enzyme. Maximal activity was attained after exhaustive of modification. The effects of different solvents, reaction temperature, and fatty acids on the esterification activity and the stability of the modified enzyme were investigated. The optimum esterification temperature (40° C) and preference of fatty acids as acyl donors of the modified lipase were very similar to those of the native enzyme. The modified lipase exhibited higher activity non-polar solvents than in polar solvents, and showed higher temperature, solvent and storage stability then the native lipase.     

Synthesis and characterization of PMMA composites activated with starch for immobilization of L‐asparaginase

Poly (methyl methacrylate) (PMMA)–starch composites were prepared by emulsion polymerization technique for L‐asparaginase (L‐ASNase) immobilization as highly activated support. The hydroxide groups on the prepared composites offer a very simple, mild and firm combination for enzyme immobilization. The pure PMMA and PMMA‐starch composites were characterized as structural, thermal and morphological. PMMA‐starch composites were found to have better thermal stability and more hydrophilic character than pure PMMA. L‐ASNase was immobilized onto PMMA‐starch composites contained the different ratio of starch (1, 3, 5, and 10 wt %). Immobilized L‐ASNase showed better performance as compared to the native enzyme in terms of thermal stability and pH. K_m value of immobilized enzyme decreased approximately eightfold compared with the native enzyme. In addition to, immobilized L‐ASNase was found to retain 60% of activity after 1‐month storage period at 4 °C. Therefore, PMMA‐starch composites can be provided more advantageous in terms of enzymatic affinity, thermal, pH and storage stability as L‐ASNase immobilization matrix. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43421.     

Immobilization and stabilization of <Emphasis Type="Italic">Pseudomonas aeruginosa</Emphasis> SRT9 lipase on tri(4-formyl phenoxy) cyanurate

Lipase was extracted and purified from Pseudomonas aeruginosa SRT9. Culture conditions were optimized and highest lipase production amounting to 147.36 U/ml was obtained after 20 h incubation. The extracellular lipase was purified on Mono QHR5/5 column, resulting in a purification factor of 98-fold with specific activity of 12307.81 U/mg. Lipase was immobilized on tri (4-formyl phenoxy) cyanurate to form Schiff’s base. An immobilization yield of 85% was obtained. The native and immobilized lipases were used for catalyzing the hydrolysis of olive oil in aqueous medium. Comparative study revealed that immobilized lipase exhibited a shift in optimal pH from 6.9 (free lipase) to 7.5 and shift in optimal temperature from 55 °C to 70 °C. The immobilized lipase showed 20–25% increase in thermal stability and retained 75% of its initial activity after 7 cycles. It showed good stability in organic solvents especially in 30% acetone and methanol. Enzyme activity was decreased by ∼60% when incubated with 30% butanol. The kinetic studies revealed increase in K _M value from 0.043 mM (native) to 0.10 mM for immobilized lipase. It showed decrease in the V _max of immobilized enzyme (142.8 μmol min⁻¹ mg⁻¹), suggesting enzyme activity decrease in the course of covalent binding. The immobilized lipase retained its initial activity for more than 30 days when stored at 4 °C in Tris-HCl buffer pH 7.0 without any significant loss in enzyme activity.     

Partial purification and characterization of acylester hydrolase from Lupinus mutabilis

An alkaline acylester hydrolase was partially purified from germinated seeds of Lupinus mutabilis. Hydrolytic activity was absent in the crude extract of ungerminated lupine seed, but it increased and peaked at the fourth day in the germinating seedling. The purification scheme involved homogenization, centrifugation, acetone precipitation, anion exchange chromatography, pH precipitation, and hydrophobic interaction chromatography. The acylester hydrolase was purified 126-fold, and the overall activity yield was 10%. The molecular weight estimated by sodium dodecylsulfate-polyacrylamide gel electrophoresis was 60 kDa. The enzyme had an isoelectric point of 6.2 and showed maximal activity at pH 8.0. The enzyme showed good stability between pH 5.0 and 9.0. In the pH range 7.0–7.5, enzyme precipitation was observed. The enzyme was stable from 0 to 25°C for 5 h and at 45°C lost 50% of its activity in the same period of time. At higher temperatures, the enzyme showed low thermal stability. However, the highest initial activity was found to be at 45°C. Nonionic surfactants and cholic acid enhanced the activity of the enzyme. The activity was reduced by the addition of toluene and isooctane and increased by the addition of diethyl ether, acetonitrile, methanol, and pyridine. The activity was reduced by 37% in the presence of 1 mM Cu²⁺ ions. The enzyme-hydrolyzed triolein showing no positional specificity.     

Purification and properties of β-amylase produced by bacillus polymyxa

1,4-α-D -glucan maltohydrolase (β-amylase, EC.3.2.1.2.) produced by Bacillus polymyxa was isolated and purified. Some of its properties were examined and compared with those of a typical plant β-amylase. Hydrolysis of periodate oxidised amylose demonstrated an exo mechanism of substrate attack similar to that of sweet potato β-amylase. The effect of sulphydryl reagents on enzyme activity was similar to that reported for plant β-amylases. Consistent with the observation that the enzyme has an exo mechanism of action, it also failed to degrade Schardinger cyclodextrins. These latter compounds acted as inhibitors of the enzyme. The optimum temperature for activity was 37 °C. The enzyme was quite stable at temperatures up to and including 37 °C; 90% of the original activity remained after storage at 37 °C for 6 days. However, the stability decreased rapidly when exposed to temperatures above 37 °C; only 20% of the activity remained after 1 h at 45 °C. The hydrolase exhibited a rather sharp optimum at pH 6.8 for stability at 37 °C. However, the enzyme was quite stable in the pH range 6.4–7.2 at 20 °C but it was shown to be less stable in acidic conditions than the corresponding plant enzymes.     

Esterification of wheat straw hemicelluloses in the N,N‐dimethylformamide/lithium chloride homogeneous system

The esterified hemicelluloses were prepared under homogeneous reaction conditions in the system N,N ‐dimethylformamide/lithium chloride by reacting the native hemicelluloses with various acyl chlorides (C₃—C₁₈) in the presence of 4‐dimethylaminopyridine as a catalyst and triethylamine as a base within 30 min at 70–75°C. The products obtained were characterized by means of Fourier transform IR chromatography, gel permeation chromatography, thermal analysis, and solubility. The degree of substitution of esterified hemicelluloses was controlled between 0.38 and 1.75 as a function of experimental conditions. Under an optimum reaction condition xylose unit/acyl chloride (molar ratio 1 : 3, tetraethylammonium % 160, 75°C, 30 min), about 95% hydroxyl groups in native hemicelluloses were esterified. The molecular weight measurements showed a minimal degradation and hydrolysis of the products. The thermal stability of the products was also increased by modification. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 74: 2301–2311, 1999     

Characterization of a chemically modified β-amylase immobilized on porous silica

β-Amylase was coupled to a periodate oxidized dextran by reductive alkylation in the presence of sodium cyanoborohydride. The loss of activity (57%) during the cross-linking of the enzyme was the result of steric hindrance near the catalytic site. In order to verify this hypothesis, the residual activity was determined with substrates of variable molecular size. The residual activity was inversely proportional to the particulate size of the substrate. Increases in residual activity, of up to 53% were obtained using an orientated chemical modification in the presence of a substrate which protects the catalytic site. Native and dextran-conjugated β-amylase were immobilized on an amino activated silica by a classical method using glutaraldehyde for the native enzyme and by reductive alkylation for the modified enzyme. The relative activity of the enzymes obtained after this insolubilization was very high for the modified amylase, 45% for a medium enzyme concentration, compared with 4% at the same concentration for the native enzyme. This difference can be attributed to the variation of the length of the space arm between the silica and the enzyme. The soluble β-amylase dextran conjugate had a superior thermoresistance to that of the native enzyme; its optimal temperature of activity was 5°C higher than that of the native enzyme. This stabilization may be attributable to a rigidification of the protein structure. Immobilization of both native and modified enzymes on a amino silica resulted in thermostabilization of the enzymes. The optimal temperature of activity was 70°C for the native immobilized β-amylase (some 10°C higher than that of the native enzyme) and 75°C for the chemically modified, and subsequently immobilized, β-amylase. The immobilized forms of the enzymes were used for 14 days at 55°C in continuous substrate processing. The greater eflciency of the chemically modified β-amylase was demonstrated by a four-fold increase in maltose production compared to the classical method of immobilization. A kinetic study confirmed the stabilization of the β-amylase by a reduction of the rate constant of inactivation of the different modified enzymes.     

Electro‐active oligomers containing pendent carbazolyl or indolyl groups as host materials for OLEDs

Oligoethers containing electroactive carbazolyl, indolyl or 2‐phenylindolyl fragments were synthesized and characterized by NMR spectroscopy, elemental analysis and gel permeation chromatography. The oligomers represent amorphous materials of high thermal stability with glass transition temperatures of 107–161°C. The electron photoemission spectra of layers of the synthesized oligomers showed ionization potentials of 5.9–5.95 eV. Some of the derivatives were tested as host materials in phosphorescent OLEDs with iridium(III) [bis(4,6‐difluorophenyl)‐pyridinato‐N,C2′]picolinate as the guest. The device based on oligomer containing carbazolyl fragments exhibited the best overall performance with a turn‐on voltage of 3.5 V, maximum power efficiency of 4.1 lm/W and maximum brightness of 937 cd/m². © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

Chitosan and N‐carboxymethylchitosan: I. The role of N‐carboxymethylation of chitosan in the thermal stability and dynamic mechanical properties of its films

Chitosan (degree of deacetylation of 90.2%) and N‐carboxymethylchitosan (N‐CMCh) (degree of substitution of 18.5%) were analyzed using thermogravimetric analysis in order to determine their thermal stability. Also, their films were evaluated using scanning electron microscopy (SEM) and mechanical and dynamic mechanical analysis (DMA). Both polymers showed a thermal degradation peak at T_m ～ 250 °C, with T_onset and weight loss of 175 °C and 62% and 190 °C and 35% for chitosan and N‐CMCh, respectively. N‐CMCh showed a second thermal degradation peak at T_m = 600 °C, with an additional weight loss of 25%. Kinetic thermal analysis showed a slower process of degradation at 100 °C for N‐CMCh compared with chitosan, and an activation energy 13 times higher for the former, confirming the higher stability of N‐CMCh. Analysis of chitosan and N‐CMCh films showed that the latter support a high tension, with lower elasticity, and, as revealed by DMA, N‐CMCh has a more compact film structure, with a crossing arrangement of N‐CMCh fibers, as compared with the chitosan films which were determined from SEM analysis to have fibers in one direction only. Copyright © 2006 Society of Chemical Industry     

Silica nanoparticles modified with vinyltriethoxysilane and their copolymerization with N,N′‐bismaleimide‐4,4′‐diphenylmethane

The synthesis and characterization of the vinyltriethoxysilane‐modified silica nanoparticles were investigated. It was shown that the vinyltriethoxysilane molecules had been successfully grafted onto the silica nanoparticles. The native and silane‐modified silica dispersions in N‐methyl‐2‐pyrrolidone with the total solids contents within the range 1–6 wt % exhibited dramatically different flow behaviors. The polymerization of N,N′‐bismaleimide‐4,4′‐diphenylmethane (BMI) initiated by barbituric acid in the presence of the native or vinyltriethoxysilane‐modified silica nanoparticles were then carried out in γ‐butyrolactone (total solids content = 20%). The higher the level of silica, the better the thermal stability of the BMI/silane/silica composite particles. The silane‐modified silica particles significantly improved their dispersion capability within the continuous BMI oligomer matrix. Furthermore, the degree of dispersion of the vinyltriethoxysilane‐modified silica particles in the BMI oligomer matrix decreased with the weight percentage of silica based on total solids increased from 20 to 40 wt %. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: Sci 103: 3600–3608, 2007     

Synthesis and characterization of novel polyaspartimides derived from 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl and various diamines

A novel bismaleimide, 2,2′‐dimethyl‐4,4′‐bis(4‐maleimidophenoxy)biphenyl, containing noncoplanar 2,2′‐dimethylbiphenylene and flexible ether units in the polymer backbone was synthesized from 2,2′‐dimethyl‐4,4′‐bis(4‐aminophenoxy)biphenyl with maleic anhydride. The bismaleimide was reacted with 11 diamines using m‐cresol as a solvent and glacial acetic acid as a catalyst to produce novel polyaspartimides. Polymers were identified by elemental analysis and infrared spectroscopy, and characterized by solubility test, X‐ray diffraction, and thermal analysis (differential scanning calorimetry and thermogravimetric analysis). The inherent viscosities of the polymers varied from 0.22 to 0.48 dL g⁻¹ in concentration of 1.0 g dL⁻¹ of N,N‐dimethylformamide. All polymers are soluble in N‐methyl‐2‐pyrrolidone, N,N‐dimethylacetamide, N,N‐dimethylformamide, dimethylsulfoxide, pyridine, m‐cresol, and tetrahydrofuran. The polymers, except PASI‐4, had moderate glass transition temperature in the range of 188°–226°C and good thermo‐oxidative stability, losing 10% mass in the range of 375°–426°C in air and 357°–415°C in nitrogen. © 1999 John Wiley & Sons, Inc. J Appl Polym Sci 73: 279–286, 1999     

One‐Pot Lipase Entrapment Within Silica Particles to Prepare a Stable and Reusable Biocatalyst for Transesterification

In order to enhance the reusability, Rhizomucor miehei lipase was entrapped in a single step within silica particles having an oleic acid core (RML@SiO₂). Characterization of RML@SiO₂ by scanning and transmission electron microscopy and Fourier transform infrared studies supported the lipase immobilization within silica particles. The immobilized enzyme was employed for transesterification of cottonseed oil with methanol and ethanol. Under the optimum reaction conditions of a methanol‐to‐oil molar ratio of 12:1 or ethanol‐to‐oil molar ratio of 15:1, stirring speed of 250 revolutions/min (flask radius = 3 cm), reaction temperature of 40 °C, and biocatalyst concentration of 5 wt% (with respect to oil), more than 98 % alkyl ester yield was achieved in 16 and 24 h of reaction duration in case of methanolysis and ethanolysis, respectively. The immobilized enzyme did not require any buffer solution or organic solvent for optimum activity; hence, the produced biodiesel and glycerol were free from metal ion or organic molecule contamination. The activation energies for the immobilized enzyme‐catalyzed ethanolysis and methanolysis were found to be 34.9 ± 1.6 and 19.7 ± 1.8 kJ mol^?1, respectively. The immobilized enzyme was recovered from the reaction mixture and reused in 12 successive runs without significant loss of activity. Additionally, RML@SiO₂ demonstrated better reusability as well as stability in comparison to the native enzyme as the former did not lose the activity even upon storage at room temperature (25–30 °C) over an 8‐month period.     

Temperature‐dependent permeability of polyelectrolyte complex capsule membranes having N‐isopropylacrylamide domains

As a microcapsule with temperature sensitivity, poly(methacrylic acid)–polyethylenimine complex capsules containing N‐isopropylacrylamide units were designed. Two kinds of copolymers of methacrylic acid and N‐isopropylacrylamide were synthesized by free‐radical copolymerization. Partly crosslinked poly(methacrylic acid)–polyethylenimine complex capsules containing the methacrylic acid–N‐isopropylacrylamide copolymers were prepared at 40 or 25°C. The permeation of phenylethylene glycol through the capsule membranes was investigated. Permeability of the capsules prepared at 25°C increased monotonously with increasing temperature from 10 to 50°C. Permeability of the capsules prepared at 40°C also increased with increasing temperature up to 25°C but decreased above 30°C. Also, the degree of swelling of the membranes prepared at 40°C decreased above 30°C. Differential scanning calorimetry measurement showed that N‐isopropylacrylamide units underwent more efficient transition in the capsule membranes prepared at 40°C than in the membranes prepared at 25°C. The capsule membranes prepared at 40°C might have domains in which N‐isopropylacrylamide units are concentrated, whereas these units should distribute uniformly in the capsule membranes made at 25°C. Such a difference in distribution of N‐isopropylacrylamide units might result in the different permeation property of the capsule membranes. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 77: 2703–2710, 2000     

Lipase covalently attached to multiwalled carbon nanotubes as an efficient catalyst in organic solvent

Lipase was covalently attached to multiwalled carbon nanotubes (MWNTs). Structural changes of the lipase upon attachment onto MWNTs were analyzed through circular dichroism and FTIR spectroscopy. The conjugate was utilized for the resolution of a model compound (R,S)‐1‐phenyl ethanol, and the reaction medium was n‐heptane. The enzymatic resolutions were carried out at temperatures from 35 to 60°C. The results show that the lipase attached onto MWNTs has significantly affected the performance of the enzyme in terms of temperature dependence and resolution efficiency. The activity of MWNT–lipase was less temperature‐dependent compared with that of the native lipase. The resolution efficiency was much improved with MWNT–lipase. MWNT–lipase retained the selectivity of the native lipase for (R)‐1‐phenyl ethanol. The consecutive use of MWNT–lipase showed that MWNT–lipase had a good stability in the resolution of (R,S)‐1‐phenyl ethanol. © 2010 American Institute of Chemical Engineers AIChE J, 2010     

Immobilization of invertase onto dimer acid‐co‐alkyl polyamine

Invertase was immobilized onto the dimer acid‐co‐alkyl polyamine after activation with 1,2‐diamine ethane and 1,3‐diamine propane. The effects of pH, temperature, substrate concentration, and storage stability on free and immobilized invertase were investigated. Kinetic parameters were calculated as 18.2 mM for K_m and 6.43 × 10^?5 mol dm^?3 min^?1 for V_max of free enzyme and in the range of 23.8–35.3 mM for K_m and 7.97–11.71 × 10^?5 mol dm^?3 min^?1 for V_max of immobilized enzyme. After storage at 4°C for 1 month, the enzyme activities were 21.0 and 60.0–70.0% of the initial activity for free and immobilized enzyme, respectively. The optimum pH values for free and immobilized enzymes were determined as 4.5. The optimum temperatures for free and immobilized enzymes were 45 and 50°C, respectively. After using immobilized enzyme in 3 days for 43 times, it showed 76–80% of its original activity. As a result of immobilization, thermal and storage stabilities were increased. The aim of this study was to increase the storage stability and reuse number of the immobilized enzyme and also to compare this immobilization method with others with respect to storage stability and reuse number. © 2004 Wiley Periodicals, Inc. J Appl Polym Sci 93: 1526–1530, 2004