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Mytilus galloprovincialis female specimens were collected from two mussel farms located in two sites next to Castel dell’Ovo, a historical complex located in the Naples Bay. Such sites were named, respectively, A‐area and B‐area for the different microbiological parameters so that mussels from A‐area can be sold without purification, whereas mussels from B‐area must be purified before sale. The mussels were collected during the nonreproductive (summer 2009) and reproductive periods (autumn 2009). Gonadosomatic index, structural organization of the ovary, presence of apoptosis, estrogen receptors expression, as well as the bisphenol A (BPA) content in the ovaries, were evaluated. Ovaries from specimens collected in area B showed a different and significant distribution of the investigated biomarkers as well as of BPA content in respect to those measured in the A‐area specimens, confirming that mussels are valid sentinel organisms to biomonitor in the Naples bay too.

The degradation and mineralization of the nonionic surfactant octylphenol ethoxylate (OPEO), commercially known as Triton??? X-45, by the peroxymonosulfate (PMS)/UV-C process were investigated. Three different toxicity tests (Daphnia magna, Vibrio fischeri and Pseudokirchneriella subcapitata) as well as the Yeast Estrogen Screen (YES) bioassay were undertaken to evaluate the potential toxic and estrogenic effects of OPEO and its oxidation products. OPEO removal was very fast and complete after 7 min via PMS/UV-C treatment under the investigated reaction conditions (OPEO = 20 mg L???1 (47 ??M); TOC = 12 mg L???1; PMS = 2.5 mM; initial reaction pH = 6.5; applied UV-C dose = 21 Wh L???1). TOC removal also proceeded rapidly; a gradual decrease was observed resulting in an overall TOC removal of 84%. The toxic responses of PMS/UV-C treated OPEO solutions varied according to the test organism used in the bioassay. Daphnia magna was found to be most sensitive to aqueous OPEO, whereas Pseudokirchneriella subcapitata appeared to be the least sensitive one. Daphnia magna and Vibrio fischeri tests revealed that the inhibitory effect of OPEO decreased significantly during the course of treatment. On the other hand, PMS/UV-C oxidation products exhibited a high toxic effect towards Pseudokirchneriella subcapitata (around 60%). YES test results underlined the need for improving the PMS/UV-C treatment performance to remove the estrogenic activity of OPEO and its oxidation products.

A monolithic silica gel matrix with entrapped glucose oxidase (GOD) was constructed as a bioactive element in an optical biosensor for glucose determination. Intrinsic fluorescence of free and immobilised GOD was investigated in the visible range in presence of different glucose concentrations by time-resolved spectroscopy with time-correlated single-photon counting detector. A three-exponential model was used for analysing the fluorescence transients. Fractional intensities and mean lifetime were shown to be sensitive to the enzymatic reaction and were used for obtaining calibration curve for glucose concentration determination. The sensing system proposed achieved high resolution (up to 0:17 mM) glucose determination with a detection range from 0:4 mM to 5 mM.

Manuale di Fisica Medica per studenti di Svienze della vita

Manuale di Fisica per i Corsi di Laurea Scienze Biologiche, Scienze Biotecnologiche, Scienze Naturali, Scienze Ambientali, Scienze Geologiche, Beni Culturali, Scienze Agrarie, Informatica ed altri corsi di laurea triennali

The behaviour of an urease loaded membrane, obtained by chemically grafting butyl methacrylate (BMA) on a nylon sheet, has been studied under non-isothermal conditions. Hexamethylenediamine (HMDA) and glutaraldehyde were also used as spacer and binding agent, respectively. Results have shown that the catalytic activity of themembrane under non-isothermal conditions is increasedwhen compared with the one found under comparable isothermal conditions. In addition, it has been found that the presence of temperature gradients decreases the apparent Km and increases the apparent Vmax with respect to the same values obtained under isothermal conditions. The percentage activity increases induced by the presence of a temperature gradient have been found to decrease with increasing average temperature and urea concentration. Aparameter has also been identified correlating the percentage increase of enzyme activity under non-isothermal conditions with the hydrophobicity of the catalytic membrane, this parameter being the ratio between thermo-osmotic and hydraulic permeability. Results have been discussed in terms of reduction of diffusion limitations for substrate and products movement towards or away from the catalytic site by the process of thermodialysis. The usefulness of using non-isothermal bioreactors in industrial biotechnological processes and, in particular, in waste water treatment has been confirmed.

Lactose hydrolysis by β-galactosidase immobilized on two nylonmembranes, differently grafted, has been studied in a bioreactor operating under isothermal and non-isothermalconditions. One membrane (M1) was obtained by chemical grafting of methylmethacrylate (MAA); the other one (M2) by a double chemical grafting: styrene (Sty) and MAA. Hexamethylenediamine was used as a spacer between the graftedmembranes and the enzyme. Both membranes have been physically characterized studying their permeabilities in presence of pressure or temperature gradients. Under non-isothermalconditions, the increase in activity of membrane M2 was higher than that of membrane M1. The α and β coefficients, giving the percentage of activity increase when a temperature difference of 1°C is applied across the catalytic membranes, have been calculated. Results have been discussed with reference to the greater hydrophobicity of membrane M2 with respect to membrane M1, the hydrophobicity being a prerequisite for the occurrence of the process of thermodialysis.

A new hydrophobic and catalytic membrane was prepared by immobilizing β-galactosidase on a polytetrafluoroethylene (PTFE) membrane, double grafted by means of γ-radiation. Methacrylic acid (MAA) and 2-hydroxyethyl methacrylate (HEMA) were used as monomers to be grafted. 1-6 Hexamethylendiamine (HMDA) and glutaraldehyde (GA) were used as spacer and coupling agent, respectively. The membranes were characterized physically and biochemically. The values of the hydraulic and thermoosmotic permeability coefficients were calculated. The dependence of catalytic membrane activity on the temperature, pH and substrate concentration was studied. Lactose hydrolysis, performed under isothermal and non-isothermal conditions, confirmed the usefulness of employing non-isothermal bioreactors in industrial processes. In particular, characteristic parameters of the non-isothermal process, such as α and β, indicative of the efficiency increase of the yield of an enzymatic reaction when a difference of temperature of 1°C is applied across the membrane, were calculated. These values were compared with those obtained so far with other membrane systems.

When a catalytic membrane is employed in a non-isothermal bioreactor its activity increases as a direct function of the applied temperature gradient and decreases when both average temperature or substrate concentration increase. To know the physical cause responsible for this behaviour, substrate fluxes have been studied under isothermal conditions diffusion and non-isothermal conditions thermodialysis . Strong analogies between the behaviour of the catalytic membrane and the substrate fluxes produced by the process of thermodialysis have been observed. By introducing diffusive and thermodiffusive substrate fluxes in appropriate mass balance equations the substrate concentration profiles into the catalytic membrane have been deduced by computer simulation. In absence of catalysis and under non-isothermal conditions the profiles are higher than the ones corresponding under comparable isothermal conditions, while the contrary occurs in the presence of catalysis. The percentage increases of enzyme activity, calculated by the curves of the substrate concentration profiles, show the same temperature and concentration dependence than those actually observed with the catalytic membrane. The role of thermodialysis in affecting the enzyme activity in non-isothermal bioreactor has been discussed and demonstrated.

The catalytic behaviour under isothermal conditions of two different membranes loaded with b-galactosidase was . investigated. One membrane M was constituted by a nylon sheet grafted with methylmethacrylate by means of chemical 1 . . grafting. The other, M , was prepared by a double chemical grafting: the first one with styrene Sty and the second one with methylmethacrylate. Membrane activity was characterized as a function of temperature, pH and substrate concentration. The role of Sty in increasing membrane hydrophobicity has been discussed. Membrane M was found to be better suited for was found to be better suited for employment in non-isothermal bioreactors.

The growing body of experimental evidence on nonisothermal matter transport in artificial porous membranes until now has been alternatively interpreted within the frame of reference of one of three independent theoretical approaches. According to one, the force driving transport is due to transfer of momentum from thermal excitations to the medium; another assumes this force to be due to transported entropy balance; the third envisages distillation in vapor-filled pores as the particular transport mechanism occurring in hydrophobic membranes

A hydrophobic and catalyticmembrane has been obtained by grafting with γ-radiations a Teflonmembrane in presence of methylmethacrylate solution and by immobilizing on it, after treatment with glutaraldehyde, the β-Galactosidase enzyme. When employed in a non-isothermal bioreactor, the membrane showed an increase in catalytic activity proportional to the applied temperature gradients. The results have been explained in terms of distinct contributions from the process of thermodialysis and the conformational changes induced in the dynamic structure of the enzyme by the presence of heat flow. The increase of the yield of the process has been evaluated in terms of a coefficient α representing the percent increase of enzyme activity when a temperature difference of 1°C is applied across the membrane. The catalyticTeflonmembrane used here gave values of 20%, which are comparable to those obtained with other membrane systems, making this kind of membrane useful for practical applications in industrial processes.

The behaviour of the enzyme invertase, located on the cell wall of baker's-yeast cells and entrapped in a gelatin membrane, was studied under isothermal and non-isothermal conditions. The reaction rate linearly increased with the applied transmembrane temperature gradient, with reference either to the average temperature or to the temperature on the warm side of the catalytic membrane. These results were obtained both when the bioreactor was operated under conditions of closed volumes and when the substrate-containing solutions are recirculated. The mathematical relationships have been elaborated between the temperatures read in the working solutions and those on the two faces of the catalytic membrane. Since the temperature difference across the membrane is smaller than that indicated by the thermocouples, the observed effects are greater than expected. The potential advantages of the use of a non-isothermal bioreactor in processes of industrial interest are discussed.

Heat, flowing through material systems composed of condensed phases produces thermal radiation forces, giving thus rise to various effects, some of them probably relevant to biological membrane transport. We shall use a simple physical argument to prove that the heat flux Jq couples with momentum flux Jp, generating pressure in liquid and liquid-solid interfaces. A theorem due to Boltzmann, applied by Ehrenfest to the adiabatic case1, shall be our starting point.

In NaCl and KCl aqueous nonisothermal solutions K+ inverts its sense of migration within the physiological concentration range; Na+ behaves similarly at much lower concentrations. These findings are discussed in relation to solute-induced modifications of water structure and of their influence on thermal diffusion. A possible evolutionary model of a thermodiffusive mechanism for the sodium-potassium pump is also suggested.

Nonisothermal membrane transport has been experimentally studied in the system sodium chloride and potassium chloride aqueous solutions/AP-20 Millipore porous partition. Anomalous behavior is found in both solvent and solute fluxes. The concentration dependence of these fluxes exhibits sharp minima and maxima, respectively. The anomalous regions occur in concentration ranges strongly influenced by the nature of the cation and by (average) temperature. When these results are compiled with the ones relative to thermal diffusion in the same solutions, stringent proof of the close affinity of processes of heat-flux-mediated matter transport in homogeneous and nonhomogeneous (membrane) systems is obtained. The physical cause of the observed anomalies can be tentatively imputed to solute-solvent interactions and to their dependence on solute nature and concentration and on solution temperature. © 1982 American Chemical Society.

A monolithic silica gel matrix with entrapped glucose oxidase (GOD) was constructed as a bioactive element in an optical biosensor for glucose determination. Intrinsic fluorescence of free and immobilised GOD was investigated in the visible range in presence of different glucose concentrations by time-resolved spectroscopy with time-correlated single-photon counting detector. A three-exponential model was used for analysing the fluorescence transients. Fractional intensities and mean lifetime were shown to be sensitive to the enzymatic reaction and were used for obtaining calibration curve for glucose concentration determination. The sensing system proposed achieved high resolution (up to 0.17 mM) glucose determination with a detection range from 0.4 mM to 5 mM.

Micro-Attenuated Total Reflection (ATR) Fourier Transform Infrared spectroscopy was used to investigate sol–gel layers for biosensing applications prior and after glucose oxidase (GOD) immobilization. The changes occurring in sol–gel infrared spectrum after GOD immobilization were clearly evidenced confirming the retaining of the enzyme activity. Moreover, micro-ATR experimental technique allowed us to investigate the spatial distribution of enzyme concentration. The non-destructive nature of our approach also enabled to monitor the time stability of sol–gel layers and of embedded GOD. The temporal evolution of some peaks in infrared spectra of these sol–gel layers was compared with absorption and steady-state fluorescence measurements. The results reported here confirm that micro-ATR infrared spectroscopy can be usefully employed for a non- or minimally invasive detailed characterization of supports for enzyme immobilization.

In view of the heath problems induced by the presence into the environment of endocrine disruptors, laccase from Trametes versicolor was covalently immobilized on a chemically modified polypropylene membrane in order to remove phenol and its derivatives from polluted waters. Using phenol as substrate model the optimal immobilization conditions were determined. The immobilized laccase exhibited maximal enzyme activity at pH 5.5 and optimal temperature at 55 °C. These operative parameters have been compared with those obtained with the soluble laccase in order to ascertain the immobilization effect. When employed in a bioreactor operating under isothermal conditions the immobilized laccase was able to oxidize a wide range of phenolic substrates. In particular it was found that some phenol derivatives (2-CP, 3-CP, 4-CP, NP and chlorophene) were oxidized at a similar rate than phenol, other derivatives (paracetamol, 3-MP and chloroxyphenol) at a smaller rate, while others (2,4-DCP and BPA) at higher rate. When the catalytic membrane was employed in a non-isothermal reactor the reaction rate increased with the increase of the applied temperature difference. Practically the increase of the laccase oxidative power under the non-isothermal conditions followed the same sequence observed under isothermal conditions. Interesting enough, the percentage increase of enzyme reaction rate under non-isothermal conditions resulted higher in the cases in which the isothermal reaction rate was smaller. When the reduction of the production times by the presence of a temperature gradient is considered, the measured values strongly candidate the technology of non-isothermal bioreactors as a useful tool in processes of detoxification of waste waters polluted by endocrine disruptors of phenolic origin. © 2010 Elsevier B.V. All rights reserved.

A monolithic silica gel matrix with entrapped glucose oxidase was constructed as a bioactive element in an optical biosensor for glucose determination. Physicochemical and biochemical characterizations of the catalytic matrix were performed, and the intrinsic fluorescence of immobilised glucose oxidase (GOD) was investigated in the UV and visible range by performing steady state and time course measurements. In all cases, the silica gel matrix proved to be a suitable support for optical biosensing owing to its superior optical properties (e.g., high transmittance and reliable fluorescence and GOD absorption spectra after immobilisation). From steady state measurements, calibration curves were obtained as a function of glucose concentration. When time course measurements were performed, the silica gel support displayed a larger linear calibration range and higher sensitivity than other immobilisation systems. In addition, a glucose optical biosensor was developed and characterised using as catalytic element GOD immobilised on a gel disk bound to a bundle of optical fibres.

A novel packed-bed bioreactor, operating under isothermal and non-isothermal conditions, has been constructed. The core of the apparatus consisted in a polypropylene ring filled with beta-galactosidase immobilized on beads of polyacrylic acid, grafted with dimethylaminoethyl methacrylate. Phenylendiamine and glutaraldehyde were used as spacer and coupling agent, respectively. Two lateral nylon membranes held the enzyme beads into the ring and allowed the occurrence of the process of thermodialysis when the bioreactor was operating under non-isothermal conditions. Comparison of the enzyme activity under isothermal and non-isothermal conditions has shown that in the presence of temperature gradients the rate of lactose hydrolysis was increased, with a reduction of the apparent Km value. Under non-isothermal conditions the percentage increases of enzyme activity were found to decrease with the increase of the substrate concentration. The results have been explained within the frame of reference of the process of thermodialysis.

A hydrophobic and catalytic membrane has been obtained by grafting with γ -radiations a Teflon membrane in presence of methylmethacrylate solution and by immobilizing on it, after treatment with glutaraldehyde, the β-Galactosidase enzyme. When employed in a non-isothermal bioreactor, the membrane showed an increase in catalytic activity proportional to the applied temperature gradients. The results have been explained in terms of distinct contributions from the process of thermodialysis and the conformational changes induced in the dynamic structure of the enzyme by the presence of heat flow. The increase of the yield of the process has been evaluated in terms of a coefficient α representing the percent increase of enzyme activity when a temperature difference of 1°C is applied across the membrane. The catalytic Teflon membrane used here gave values of 20%, which are comparable to those obtained with other membrane systems, making this kind of membrane useful for practical applications in industrial processes.

Laccases are cuproproteins belonging to the group of oxidoreductases that are able to catalyze the oxidation of various aromatic compounds (particularly phenols) with the concomitant reduction of oxygen to water. They are characterized by low substrate specificity and have a catalytic competence which widely varies depending on the source. Additionally, laccases have also very peculiar optical properties due to their copper active sites which participate to the reduction processes. All these characteristics make laccases very flexible biotic element for biotechnological applications. During the years, a number of studies have been devoted at exploiting catalytic properties of laccases and very few at profiting of their optical properties. Some preliminary studies by absorption, fluorescence FT-IR and Raman spectroscopies of commercial laccases have evidenced their potential usefulness for optical biosensing of phenol compounds as cathecol. Moreover the sol-gel process offers a convenient and versatile method for preparing optically transparent matrices at room temperature that can represent a very convenient support for laccase immobilization. Also for immobilised enzymes the above-mentioned techniques have allowed a detailed characterization of their optical properties that confirmed the potentials of laccases in optical biosensors and represented a fundamental step in the designing of an optimised optical biosensing scheme.

The oxidative biodegradation of 2- and 4-chlorophenol (CPs) catalyzed by immobilized laccase from Trametes versicolor was conducted in a bed reactor. The effects of reaction conditions (reaction time, dosage of immobilized enzyme, flow rate, pH value and temperature, initial concentration) on CPs removal efficiency (RE) were investigated. By using in the immobilization solution an enzyme dosage of 2.5 mg free enz g carrier − 1 , the maximum ratio of laccase to PAN-beads is resulted 0.25 mg imm enz g carrier − 1 . RE values greater than 70% were obtained when 40 mL of 1 mM substrate solution were circulated for 90 min at 75 mL min−1 in the bed reactor filled with 12 g of laccase-PAN beads. The optimal pH for CPs biodegradation was 5 and it was not related to substituent position on aromatic ring. Experiments with immobilized laccase demonstrated good removal at high initial substrate concentrations and high thermal stability. The affinity of 2-CP was higher than that of 4-CP. Finally, the 2-CP was also biodegraded as tertiary mixtures with 2,3,4,5-tetrachlorophenol (TCP) and pentachlorophenol (PCP). The presence of TCP and PCP decreased the removal efficiency of 2-CP. The order of the relative degrading capacity becomes TCP > PCP > 2-CP.

Endocrine disruptor chemicals (EDCs), which are predominantly present in the environment, are able to mimic or antagonise the biological activity of hormones primarily through the interaction with specific receptors. The main consequences are adverse effects on the growth and development of reproductive organs, the induction of cancer and effects on neuronal differentiation. In this study, we investigated the ability of certain EDCs, Bisphenol A (BPA), Bisphenol B (BPB), Bisphenol F (BPF), 4-n Nonylphenol (NP) and Octylphenol (OP), belonging to a homogeneous group of phenol origin, to interfere with specific cellular processes, namely, proliferation, by using MCF-7 breast carcinoma cells, and differentiation, by using murine bone marrow dendritic cells. We correlated the data on cell growth with the stimulation of cell cycle progression, which could become a step in the development of cancer, and we established a proliferation ranking between the tested EDCs: NP > BPA > OP > BPB > BPF. In addition, we investigated the ability of NP, BPA and OP to induce the differentiation of dendritic cells, the powerful antigen-presenting cells of the immune system. The differentiation and activation of these cells could affect a well-regulated immune response and determine an allergic sensitisation. We found that BPA and NP were active in determining differentiation. (C) 2012 Elsevier Inc. All rights reserved.

Micro-Raman spectroscopy and interval Partial Least Square (iPLS) multivariate analysis have been used for determining glucose concentration in various commercial sport drinks. By employing a visible excitation light (633 nm), micro- Raman spectra in the 600-1600 cm -1 wavenumber shift region have been recorded, showing well defined and separated vibrational fingerprints of the various contained sugars (glucose, fructose and sucrose). Glucose content was quantified by using the iPLS analysis based on a model built by employing aqueous glucose solutions as reference samples. The estimated glucose concentrations are in good agreement with the values obtained by using a biochemical assay. These results represent a significant step towards the development of a fast, simple, cost-effective Raman-based method for glucose quantification in products of food and beverage industry, alternative to expensive, time-, sample- and chemicals-consuming biochemical assays currently used in production and quality control processes.

The investigation of materials suitable for enzyme immobilization in biosensing applications has a widespread interest. There are many studies on physico-chemical properties of these materials at macroscopic level but few studies have been devoted to examine and correlate these properties at microscopic level. FT-IR spectroscopy with Micro-Attenuated Total Reflection (Micro-ATR) approach can be extremely useful for understanding a variety of aspects of materials which can be used for optimising immobilization procedures. Moreover, this experimental approach is particularly simple to use (no sample preparation is required) and minimally invasive. Using a Perkin Elmer Spectrum One FT-IR spectrometer equipped with a mercury-cadmium-telluride detector and a micro-ATR element we investigated different materials used for immobilization procedures with various enzymes widely used for biosensing in environmental and clinical applications. In particular, composite membranes constituted by a chemically modified poly-acrylonitrile (PAN) membrane plus layers of tethered chitosan of different molecular weight have been examined. Also silica gel matrices without and with glucose oxidase have been investigated. Spectra have been analysed and the contribution of principal functional groups has been evidenced.

Novel bicomponent microfibrous mats containing targeted amount of reactive maleic anhydride groups were prepared by electrospinning of mixed solutions of poly(styrene- alt -maleic anhydride) and poly(styrene- co -maleic anhydride). Then, amino-functionalized P(St- alt -MA)/P(St- co -MA) mats were obtained by reaction with p -phenylenediamine. ATR-FTIR and XPS spectroscopy were used to characterize pristine and modified P(St- alt -MA)/P(St- co -MA) mats. On the next step, laccase from Trametes versicolor was covalently attached onto the modified mats; the average amount of immobilized enzyme was 40 ± 0.7 mg/g mat. The catalytic activity of the immobilized enzyme was studied in respect to bisphenol A (BPA) endocrine disruptor. The optimum activity of the immobilized enzyme was reached at maximum flow rate of 1.3 mL/s. After 90 min the BPA concentration was reduced by 60% and the catalytic activity of microfibrous mats remained stable for about 30 successive reuses. In addition, the relative activity of laccase immobilized on the microfibrous mats was displayed in a broader pH range as compared to that of the free one.

The diffusion of peritoneal dialysis (PD) at home is somewhat restricted by the difficulty of transport and storage of a large amount of dialytic solutions. This problem is exacerbated in the case of hemodialysis. With the aim of producing pure water to be used in preparing the solution for peritoneal dialysis, or for hemodialysis in general, as one example, we purified the spent dialysate solution from PD. Experiments were carried out with 24 dialysate solutions taken from 8 patients. Pure water was obtained by means of a thermodialysis process in a hollow fiber reactor operating under nonisothermal conditions. Results show that the yield of the nonisothermal process is dependent on the temperature difference applied across the hydrophobic membranes. The production of pure water per square meter of membrane and per hour was equal to 0.55 or 1.2 or 2.0 liters, with a temperature difference of 11 degrees C or 21 degrees C or 28 degrees C, respectively. These results encourage the use of the thermodialysis process in the production of pure water for clinical uses.

Changes in steady-state UV fluorescence emission from free or immobilized glucose oxidase have been investigated as a function of glucose concentration. Immobilized GOD has been obtained by entrapment into a gelatine membrane. Changes in steady-state UV fluorescence have been quantitatively characterized by means of optokinetic parameters and their values have been compared with those previously obtained for FAD fluorescence in the visible range. The results confirmed that greater calibration ranges are obtained from UV signals both for free and immobilized GOD in respect to those obtained under visible fluorescence excitation. An alternative method to the use UV fluorescence for glucose determination has been investigated by using time course measurements for monitoring the differential fluorescence of the redox forms of the FAD in GOD. Also in this case quantitative analysis have been carried out and a comparison with different experimental configurations has been performed. Time coarse measurements could be particularly useful for glucose monitoring in complex biological fluids in which the intrinsic UV fluorescence of GOD could be not specific by considering the presence of numerous proteins. �� 2007 by MDPI.

Laccase from Trametes versicolor was immobilized by diazotization on a nylon membrane grafted with glycidil methacrylate, using phenylenediamine as spacer and coupling agent. The behavior of these enzyme derivatives was studied under isothermal and nonisothermal conditions by using syringic acid as substrate, in view of the employment of these membranes in processes of detoxification of vegetation waters from olive oil mills. The pH and temperature dependence of catalytic activity under isothermal conditions has shown that these membranes can be usefully employed under extreme pH and temperatures. When employed under nonisothermal conditions, the membranes exhibited an increase of catalytic activity linearly proportional to the applied transmembrane temperature difference. Percentage activity increases ranging from 62% to 18% were found in the range of syringic acid concentration from 0.02 to 0.8 mM, when a difference of 1 degrees C was applied across the catalytic membrane. Because the percentage activity increase is strictly related to the reduction of the production times, the technology of nonisothermal bioreactors has been demonstrated to be an useful tool also in the treatment of vegetation waters from olive oil mills.

The inhibitory power of three different active Nylon membranes, separately loaded with three different protease inhibitors, was studied with the aim of reducing the increased elastase concentration occurring during hemodialysis or extracorporeal blood circulation in patients undergoing cardiopulmonary bypass. Chemical grafting was carried out to make the inert Nylon membrane suitable for the immobilization of the inhibitors. The behavior of immobilized alpha(1)-antitrypsin, bovine pancreatic trypsin inhibitor (BPTI), or elastatinal was separately studied. alpha(1)-Antitrypsin and BPTI were covalently immobilized by means of a diazotization process, whereas elastatinal was covalently attached via a condensation process mediated by glutaraldehyde. The inhibitory power of each membrane type was studied as a function of the amount of immobilized inhibitor and temperature. All active membranes have shown good inhibitory power. The most efficient membrane was that loaded with alpha(1)-antitrypsin, the less efficient that with BPTI.

Laccase from Rhus vernicifera was immobilised on a nylon membrane chemically grafted with glycidyl methacrylate (GMA). Hexamethylenediamine (HMDA) and glutaraldehyde (GLU) were used as spacer and bifunctional coupling agent, respectively. Quinol was used as substrate. To know how the immobilisation procedures affected the enzyme reaction rate the catalytic behaviour of soluble and insoluble laccase was studied under isothermal conditions as a function of pH, temperature and substrate concentration. From these studies, two main singularities emerged from the experimental data: (i) the narrower pH-activity profile of the insoluble enzyme in comparison to that of the soluble counterpart; (ii) the increase of the affinity of the immobilised enzyme for its substrate. The behaviour of the catalytic membrane was also studied in a non-isothermal bioreactor as a function of substrate concentration and size of the applied transmembrane temperature difference. It was found that, under non-isothermal conditions and keeping constant the average temperature of the bioreactor, the enzyme reaction rate linearly increases with the increase of the temperature difference. These results have been discussed in the frame of reference of the process of thermodialysis driving thermodiffusive transmembrane substrate fluxes, which add to the diffusive ones. The advantages of the catalytic process carried out under non-isothermal conditions have been thrown in relief through the evaluation of the reduction of the production times and of the percentage increases of the enzyme activity.

In view of the treatment of agricultural waste waters, urea polluted, a catalytic and hydrophobic membrane was constructed by immobilizing urease on a nylon sheet grafted with cyclohexyl methacrylate (CHMA). Hexamethylenediamine (HMDA) and glutaraldehyde (GA) were used as spacer and crosslinking agent, respectively. With reference to the soluble counterpart immobilized urease was found to exhibit (i) a shift of the optimum pH towards more acidic values; (ii) a shift of the optimum temperature towards higher temperatures; (iii) higher values of Km. The latter result indicated an apparent loss of affinity of immobilized urease towards urea. To recovery this affinity loss, the catalytic membranes were employed in a bioreactor operating under non-isothermal conditions. Under these conditions the catalytic membranes exhibited reaction rates higher and apparent Km smaller than those measured under comparable isothermal conditions. As a consequence, percentage increases of enzyme activity and reduction of the production times, proportional to the magnitude of the applied temperature difference were observed. Results have been discussed in the frame of reference of the process of thermodialysis. The technology of the non-isothermal bioreactors confirmed its usefulness also in the reduction of urea concentration in aqueous solutions.

Glucose oxidase (GOD) was immobilized on nylon membranes having three different pore diameters and chemically grafted with glycidyl methacrylate (GMA) or butyl methacrylate (BMA). Hexamethylenediamine (HMDA) and glutaraldehyde (GA) were used as spacer and coupling agent, respectively. The biochemical and electrochemical behaviour of the membranes has been studied as a function of pH, temperature and glucose concentration with reference to the grafted monomer and the membrane pore diameter. The behaviour of the soluble GOD has also been studied in order to see the modification induced by the immobilization process on the enzyme activity. It was found that the values of the biosensor sensitivity, maximum saturation current and electrochemical affinity increase with the membrane pore diameter, indipendently of the nature of the graft monomer. Opposite behaviour was found relatively to the extension of the linear response ranges and the average response times. With reference to the parameters increasing with the pore diameter it was found that membranes grafted with GMA had higher values than those of the membranes grafted with BMA. The contrary occurred to the values of the parameters decreasing with the increase of the pore diameter. Biochemical and electrochemical results have been discussed in terms of the different limitations to the diffusion of substrate and reaction products across the catalytic membrane introduced by the different pore diameters and by the different hydrophobicity of the graft monomers.

β-Galactosidase was immobilized on a nylon membrane chemically grafted with butylmethacrylate. Hexamethylenediamine was used as spacer and glutaraldehyde as coupling agent. The catalytic behaviour of the membrane was studied under isothermal and non-isothermal conditions. It was found that in the presence of temperature gradients, the catalytic membrane exhibited higher activity and greater affinity for the substrate. The increases of the enzyme reaction rate was found to be proportional to the intensity of the applied temperature gradient. Percentage increases of the activity were also found to decrease with the increase of the average temperature and concentration. All the results are phenomenologically discussed in terms of substrate traffic across the catalytic membrane induced by the processes of diffusion or thermodialysis under isothermal and non-isothermal conditions, respectively.