bluuebunny/crossref_metadata_2025 huggingface dataset:
Heavy metals in the environment. Part I: Removal of cobalt from dilute effluent streams by fluidised bed electrolysis
Authors: Chaudhary Abdul J. , Grimes Susan M.
Published: July 2010

The fluidised bed cell is an electrolytic reactor which is designed to provide higher ion‐transfer conditions during electrolysis by breaking up the barrier layer at the cathode, thus enabling metals to be removed efficiently from dilute solutions. The effectiveness of the method as a means of removing metals from effluent to meet discharge consent levels is studied for the in‐situ removal of cobalt from dilute solution. The effects of cathode density, pH, reaction time, buffer solution composition, buffer concentration and agitation on the removal of cobalt are reported and expressed in terms of the percentage removal of cobalt (αCo), the efficiency for cobalt deposition (∞Co), and the energy consumption (WCo) for 1 kg of cobalt deposited. The results show that cobalt can, under optimised conditions, be removed from dilute solutions to a residual level of 0.2 ppm.
Enzymatic kinetic resolution of [3](1,1′)ferrocenophane derivatives
Authors: Izumi Taeko , Hino Toshimi , Ishihara Akira
Published: July 2010

Formyl‐ and hydroxymethyl‐ derivatives of [3](1,1′)ferrocenophane were enzymatically resolved with fermenting baker's yeast, immobilized lipase, and pig liver esterase.
Circulation liquid velocity, gas holdup and volumetric oxygen transfer coefficient in external‐loop airlift reactors
Authors: Choi Keun Ho , Lee Won Kook
Published: July 2010

The effects of the horizontal connection length (0.1 ± Le ± 0.5 m), the cross‐sectional area ratio of downcomer‐to‐riser (0.11 ± Ad/Ar± 0.53), and the superficial gas velocity on gas phase holdups in the riser and downcomer were studied. The circulation liquid velocity, the mixing performance and the volumetric mass transfer coefficient in the external‐loop airlift reactors were also measured. The horizontal connection length and Ad/Ar were major parameters which strongly affected the performance of external‐loop airlift reactors. Useful correlations in the external‐loop airlift reactors were obtained for gas holdups, the volumetric mass transfer coefficient, the circulation liquid velocity, and the mixing time.
Removal of 3—(3,4—dichlorophenyl)—1, 1 dimethylurea from aqueous solution by natural and activated bentonite
Authors: González‐Pradas E. , Villafranca‐Sánchez M. , Socias‐Viciana M. , Castillo‐Sánchez J. , Fernández‐Pérez M.
Published: July 2010

The adsorption of 3‐(3,4‐dichlorophenyl)‐1,1 dimethylurea (diuron) on bentonite desiccated at 110°C untreated, and acid treated with H2SO4 solutions over a concentration range between 0.25 M and 5.00 M, from aqueous solution at 30°C has been studied. In addition, adsorption of diuron on combined acid/heat treated samples (0.50 M and 2.50 M H2SO4/200°C and 400°C) has also been studied.

The experimental data points have been fitted to the Freundlich equation in order to calculate the adsorption capacities (K) of the samples; K values range from 0.92 μg g−1 for the untreated bentonite up to 974.42 μg g−1 for the 0.50 M H2SO4/400°C acid/heat treated bentonite. The removal efficiency (R) has also been calculated; R values ranging from 2.02% for the untreated bentonite up to 97.17% for the 0.50 M H2SO4/400°C acid/heat treated bentonite. The adsorption experiments show that bentonite heat treatment is more effective than bentonite acid treatment in relation to adsorption of diuron.
Thiophene Poisoning and reactivation of a supported nickel hydrogenation catalyst: The effect of temperature
Authors: Seoane X. L. , Arcoya A.
Published: July 2010

The extent and type of poisoning of an 8 wt% Ni/γ‐Al2O3 catalyst by thiophene has been examined in ethylbenzene hydrogenation reaction, between 403 and 523 K. The results suggest that at the higher temperatures the deactivation can take place through two different mechanisms. In one case, the formation of ‘Ni‐S’ surface species on the more active sites at the beginning of the reaction, produces a slow and irreversible poisoning. In the other, the planar adsorption of thiophene on the other sites produces a fast and reversible deactivation. At lower temperatures, the second mechanism seems to be predominant due to the fact that the hydrogenolysis activity diminishes.
Performance characteristics of a tower fermenter with mechanical foam control
Authors: Takesono Satoshi , Yasukawa Masami , Onodera Masayuki , Izawa Kohji , Yamagiwa Kazuaki , Ohkawa Akira
Published: July 2010

For a bubble column (BC) treating foaming liquids, the characteristics of a rotating‐disk mechanical foam‐breaker (MFRD) fitted to the BC were examined. The foaming behaviour of the BC and the foam‐breaking behaviour of the MFRD under various operating conditions were related to the changes in liquid hold‐up in the foam. The gas hold‐up in a mechanical foam‐control system (MFS) with the MFRD was confirmed to be greater than the gas hold‐up in a non‐foaming system (NS) including antifoam agent (AF). Comparison of the volumetric mass transfer coefficient between the MFS and the non‐foaming system, in terms of the specific power input, also demonstrated the superiority of mechanical foam control for oxygen transfer performance.
Scale‐Up studies of non‐aerated fed‐batch fermentation of dextransucrase and the industrial synthesis of dextran using the enzymatic route
Authors: Ajongwen N. J. , Barker P. E.
Published: July 2010

High activities of the enzyme dextransucrase were repeatedly produced using slowly agitated non‐aerated fed‐batch fermentations of Leuconostoc mesenteroides B‐512(F). Activities in excess of 24.0 U cm−3 were obtained consistently in a 16 dm3 laboratory fermenter using a 6 dm3 initial work volume. Yeast extract type was identified to be one of the important factors influencing the enzyme yield.

Studies on aerating the medium with different gases indicated that the presence of carbon dioxide in the medium favoured high enzyme production. Agitation rates did not appear to have significant effects on either cell growth or enzyme production. One type of antifoam (silicone antifoam) was observed to affect enzyme production but not the cell growth.

Scale‐up of the non‐aerated process was carried out up to a 1000 dm3 scale with enzyme broths containing up to 21.0 U cm−3 being produced. Two batches of the enzyme that were produced at the large scale were used for the first time to synthesize dextran at a 50000 dm3 industrial scale. The dextran yields were up to 95.5% of the conventional industrial yields and were achieved in much shorter reaction time intervals.
Medical genetics—genes and GPS for the 1990s
Authors: Bains William
Published: July 2010

DNA manipulation techniques have allowed the isolation and identification of many genes which cause disease in man. The same techniques are now being automated, and are on the threshold of application to more common and more complex genetic predispositions to diseases such as diabetes and schizophrenia. This article outlines the technology behind this development, and discusses some of the social, legal and ethical difficulties that widespread screening for genetic traits will raise. It is argued that these issues must be considered now, so that considered social responses to this technology are in place in the five years it is likely to take to develop.

The techniques of DNA manipulation that have led to recombinant proteins and biopharmaceuticals have also led to an unprecedented increase in understanding of human genetics, and a corresponding increase in the practical side of human genetics—medical genetic diagnosis. As a result, medical genetics is moving from a speciality of statisticians and cytologists into the mainstream of medicine, and will soon be the concern of every hospital, and probably of every GP. This offers huge benefits to patients, but also threatens misunderstanding and even the potential of abuse if this sophisticated understanding of our fundamental natures is used without precision.
Ozonation kinetics of iron and manganese in aqueous solution
Authors: Lin Sheng H.
Published: July 2010

Ozonation kinetics of iron and manganese in aqueous solution is experimentally investigated. The effects of pH, initial ion concentration and the ozone dosage on the kinetic rate parameters are examined. It has been found that ozonation of those ions in general follows zero order kinetics.
Properties of gelatin‐gum arabic coacervates composited with amino resins
Authors: Peker‐Baslara Sümer , Övez Bikem , Balcioǧlu Öilknur
Published: July 2010

Only a small percent of the formaldehyde added to the coacervation solution is actually utilized for crosslinking the gelatin and gum arabic in the dense coacervate phase, the rest remaining in the colloid‐poor solution. It was aimed to use this formaldehyde in the solution in a polymerization reaction with urea to form a composite film of gelatin‐gum arabic coacervate within a supramolecular structure of the urea‐formaldehyde resin. Part of the urea added reacts with formaldehyde used for crosslinking, opening up the polymer chains, and part reacts with free formaldehyde to form urea‐formaldehyde resin phase grafted onto the coacervated macromolecules. The physical properties of the composite film investigated in this work, i.e. water absorbance, water vapor sorption and permeability, are interpreted as a function of the structure evolving as a result of the competing crosslinking and polymerization reactions.
Role of Cu(II) and Zn(II) species on the anaerobic digestion of synthetic activated sludge
Authors: Mehrotra Anupama , Mehrotra Indu , Tandon Shiv N.
Published: July 2010

The effect of different concentrations of copper or zinc on the anaerobic biodegradability of sludge has been investigated. An attempt has been made to correlate the metal forms with the performance of the digester. The presence of organically‐bound copper is indicative of the deteriorated condition of the digester. However, an increased HNO3 extractable fraction is associated with the failure of the zinc‐spiked digesters.
Technetium—aspirin molecule complexes
Authors: El‐Shahawy Anwar S. , Mahfouz R. M. , Aly Aref A. M. , El‐Zohry Maher
Published: July 2010

Technetium‐aspirin and technetium‐aspirin‐like molecule complexes were prepared. The structure of N‐acetylanthranilic acid (NAA) has been decided through CNDO calculations. The ionization potential and electron affinity of the NAA molecule as well as the charge densities were calculated. Comparative studies of the electronic absorption spectra of acetylthiosalicylic acid (ATS) and aspirin (Asp) reveal the structure resemblance in which the acetyl carbonyl group is perpendicular to the plane of the corresponding organic acid. The studies of the electronic absorption spectra of NAA and anthranilic acid reveal the planarity of the NAA molecule. The electronic absorption spectra of Tc(V)‐Asp and Tc(V)‐ATS complexes have two characteristic absorption bands at 450 and 600 nm, but the Tc(V)‐NAA spectrum has one characteristic band at 450 nm. As a comparative study, Mo‐ATS complex was prepared and its electronic absorption spectrum is comparable with the Tc‐ATS complex spectrum.
Interaction of transport resistances with biochemical reaction in packed bed solid state fermenters: The effect of gaseous concentration gradients
Authors: Gowthaman M. K. , Ghildyal N. P. , Rao K. S. M. S. Raghava , Karanth N. G.
Published: July 2010

Mass transfer plays an important role in solid state fermentation (SSF) systems. Earlier work on SSF in tray bioreactors7 indicated that steep gaseous concentration gradients developed within the substrate bed, owing to mass transfer resistances, which may adversely affect the bioreactor performance. For all practical purposes these gradients have been eliminated using a packed bed column bioreactor with forced aeration. Gaseous concentrations (oxygen and carbon dioxide) and enzyme activities were measured at various bed heights for various air flow rates during the course of fermentation. The results indicated that concentration gradients were decreased effectively by increasing air flow rate. For example, the actual oxygen and carbon dioxide concentration gradients reduced from 0.07% (v/v) cm−1 and 0.023% (v/v) cm−1 to 0.007% (v/v) cm−1 and 0.0032% (v/v) cm−1 respectively when the air flow rate was increased from 5 dm3 min−1 to 25 dm3 min−1. This resulted in an overall improvement in the performance of the bioreactor in terms of enzyme production.
Performance of affinity biosensors with competitive displacement mechanism
Authors: Chen Jyh‐Ping
Published: July 2010

A mathematical model was developed for affinity biosensors where the detection principle is based on competitive displacement of a protein from an immobilized ligand. Two competing binding reactions between analyte and protein molecules in the bulk liquid phase, and immobilized ligand and protein molecules in the solid phase, were assumed to be in equilibrium. Theoretical calibration curves relating the signal generated, which is the total protein concentration detected in the bulk liquid phase, to the analyte concentration were calculated from this model. The simulated results indicated several important variables to consider when constructing the biosensor. The amount of responsive protein and immobilized ligand initially loaded and the relative binding strength of both the analyte and the ligand toward the protein will influence the biosensor's performance. Experiments have been carried out to verify this model, using bovine rennin as the protein, pepstatin‐agarose as the immobilized ligand, and pepstatin as the analyte. The experimental data agreed reasonably well with the simulated results from the model. This mathematical model seemed to be sufficient for describing the behavior of affinity biosensors based on competitive displacement and suitable for design purposes.
Amylolytic enzymes produced by Bacillus amyloliquefaciens MIR‐41 in batch and continuous culture
Authors: Castro Guillermo R. , Méndez Beatriz S. , Siñeriz Faustino
Published: July 2010

Bacillus amyloliquefaciens MIR‐41 has been isolated from natural sources and characterized using statistical methods. The strain showed three types of glucanase activities: α‐amylase, α‐glucosidase and pullulanase in defined medium and starch as carbon source. Extracellular activity of α‐amylase was approximately three times higher in continuous culture than in batch. Maximal productivity was found at a dilution rate of 0·16 h−1. Alpha‐glucosidase was expressed as a cell‐bound enzyme in batch culture, but in continuous culture was mostly extracellular. Pullulanase was cell‐bound in all cases. The expression of the enzymes was dependent upon the system and the dilution rate used. No cell lysis was detected in the chemostat as compared with batch cultures.
Analysis of volume change effects in a fluidized bed catalytic reactor
Authors: Shiau Ching‐Yeh , Lin Chin‐Jou
Published: July 2010

A mathematical model based on the concept of an improved bubble assemblage model is developed for calculating the conversion of a reaction system involving a volume change in fluidized beds. The influence of volume change on the hydrodynamic behavior of gas in the bed, such as bubble size variation, superficial gas velocity change, and volume fraction occupied by each phase, is also investigated. It is found that increasing stoichiometric coefficient values results in larger bubble size, higher superficial gas velocities, higher crossflow rate between emulsion phase and bubble phase, and greater volume fraction of bubble phase, but smaller volume fraction occupied by the emulsion phase as well as lower conversions.
Solubilization of hydrocarbons from oil sludge by synthetic surfactants
Authors: Janiyani K. L. , Wate S. R. , Joshi S. R.
Published: July 2010

Disposal of oil sludges poses an environmental pollution problem due to the presence of high molecular weight hydrocarbons which are hydrophobic and hence non‐biodegradable in nature. In‐situ transformation of hydrophobic hydrocarbons into hydrophilic moieties using surfactants and further degradation of solubilized hydrocarbons by microorganisms could be the viable solution for disposal of these sludges. Treatment of oil sludge with the synthetic surfactant polyoxyethylene sorbitan monooleate indicated the release of hydrocarbons in the aqueous phase. Increase in soluble chemical oxygen demand with increase in concentration of surfactant and contact time was observed indicating enhancement in solubility of hydrocarbons in the aqueous phase. The optimum ratio of sludge to surfactant was found to be 10: 1. While a two‐fold increase in solubility of hydrocarbons was observed due to agitation of sludge samples, variation in pH did not affect the solubilization.
Gas‐liquid transfer of atmospheric CO2 in microalgal cultures
Authors: Grima E. Molina , Pérez J. A. Sánchez , Garc Camacho F. Ía , Medina A. Robles
Published: July 2010

Transfer of CO2 in an aerated microalgal culture system has been studied. The CO2 absorption rate was not visibly affected by the kinetics of the reactions occurring in the culture medium. Biomass concentration in the bioreactor, within the interval studied, did not significantly affect the overall volumetric coefficient of CO2 transfer (K1a(CO2)). An expression has been proposed for the estimation of K1a(CO2) in the culture as a function of the effective power input to dispersion. Several empirical equations, found in the literature for estimation of the mass transfer parameters, were studied and those which best predicted experimental results are presented. The study concluded that empirical equations for a bubble diameter analogous to that found in the experiments should be used.
Studies on the Vilsmeier‐haack reaction. Part XIII: Novel heterocyclo‐substituted 4,4′‐bi‐pyrazolyl dithiocarbamate derivatives
Authors: Awad Ibrahim M. A.
Published: July 2010

5‐Imino‐3‐methyl‐l‐phenyl‐2‐pyrazoline‐4‐dithiocarbamic acid (I) underwent simultaneous formylation and dimerization reactions with the Vilsmeier reagent giving 4‐[5′‐imino‐3‐(1″‐formyl‐2″‐dimethylaminoethenyl)‐3′‐methyl‐1′‐phenyl‐1′H‐pyrazolo‐4′‐dithiocarbamyl‐2,4‐dihydro‐3‐imino‐5‐methyl‐2‐phenyl‐1‐pyrazoline]dithiocarbamate (II) which hydrolysed with sodium hydroxide to give 4‐[3′‐(1″‐formyl‐2″‐hydroxyethenyl)‐3′‐methyl‐1‐phenyl‐1′‐H‐pyrazolo‐4′‐dithiocarbamyl‐1′‐pyrazoline]dithiocarbamate‐5,5′‐dione (IV). Treatment of II and/or IV with morpholine, piperidine, piperazine, hydroxylamine, hydrazine hydrate or phenylhydrazine afforded the corresponding dipyrazolo‐4,4′‐dithiocarbamate derivatives with different heterocyclic systems at the 3‐position. The structures of these compounds were confirmed by microanalysis data, IR and 1H‐NMR spectrometry. All synthesized compounds have been screened in vitro against Gram‐positive and Gram‐negative bacteria, and fungi.
Alkylnaphthalene succinimides as multifunctional additives
Authors: Mohamed M. M. , Naga H. H. Abou El , Meneiry M. F. El
Published: July 2010

Alkylnaphthalene succinimides are synthesised and evaluated as flow improvers, pour point depressants and ashless dispersant additives for fuels and crankcase lubricating oils. The synthesis is based on reacting alkylated naphthalene with maleic anhydride in the presence of the following amines: ethylene diamine, diethylene triamine and tetraethylene pentamine. Chlorinated paraffin wax is used as an alkylating agent for naphthalene. Results showed that magnitude in pour point depression as well as cold filter plugging point depression for the tested fuels are highly related to the molecular weight of alkylnaphthalene succinimides. As ashless dispersant additives, results showed that the magnitude of dispersive power for the tested oils is related to the amine compound used.
Study of a continuous separation process for 2‐furyl oxirane
Authors: Uhlemann Jens , Borredon Elisabeth , le Lann Marie‐Véronique , Casamatta Gilbert
Published: July 2010

The present work is a study on a continuous separation process for 2‐furyl oxirane from its reaction medium which is a quaternary mixture. Continuous process flowsheeting has been used in order to compare two different separation processes which are based upon solvent extraction and heteroazeotropic distillation. The improved production process totals five unit operations: synthesis of 2‐furyl oxirane; filtration of the reaction medium; heteroazeotropic distillation; synthesis of trimethylsulphonium bromide; and filtration of trimethylsulphonium bromide.
Electrolytic regeneration of bleach solution in the motion picture industry
Authors: Adaikkalam P. , Sathaiyan N. , Visvanathan S.
Published: July 2010

Cyclic voltammetric and galvanostatic experiments have been carried out with both synthetic and commercial bleach solutions with a view to regenerating the same. Maximum efficiency could be achieved if the oxidation is carried out below an anodic potential of 0·80 V vs SCE. The data obtained in galvanostatic experiments with RCE confirm the results of the earlier technique.
Effects of light, CO2 and inhibitors on the current output of biofuel cells containing the photosynthetic organism Synechococcus sp
Authors: Yagishita Tatsuo , Horigome Takashi , Tanaka Kazuko
Published: July 2010

The current output of the biofuel cells containing a marine alga, Synechococcus sp. and an electron transport mediator, 2‐hydroxy‐1, 4‐naph‐thoquinone (HNQ) was increased under illumination and in the presence of CO2. The inhibitory effects of carbonyl cyanide m‐chlorophenylhydrazone (CCCP), 3‐(3,4‐dichlorophenyl)‐1,1‐dimethylurea (DCMU), 2,5‐dibromomethylisopropyl‐p‐benzoquinone (DBMIB), phenylmercury acetate (PMA) and N,N′‐dicyclohexyl‐carbodiimide (DCCD) on the output current of fuel cells run in the light suggested that HNQ accepts electrons mainly at the site of ferredoxin‐NADP+ reductase (FNR) in the electron transfer chain. The inhibition of light‐induced generation of current output by CCCP indicates that the current is derived from photosynthetic oxidation of water. Endogenous glycogen in algae is required to sustain a steady current output from the fuel cells.
Novel substituted 2‐acetamido thiophene‐4‐styryl disperse dyes
Authors: Rangnekar Dinesh W. , Sabnis Ram W.
Published: July 2010

Ethyl 2‐acetamido‐3‐cyano‐5‐carbethoxy thiophene‐4‐acetic acid ester has been synthesised by the Gewald reaction of diethyl acetonedicarboxylate, sulphur and malononitrile, followed by acetylation. A variety of aryl and hetaryl aldehydes were condensed with this thiophene derivative in refluxing DMF in the presence of piperidine to yield novel styryl dyes. The fluorescence in solution and dyeing properties of these styryl dyes on polyester were studied.
Synthesis of thieno[2,3‐c]pyridines and related heterocyclic systems
Authors: El‐Kashef H. S. , Geies A. A. , El‐Dean A. M. Kamal , Abdel‐Hafez A. A.
Published: July 2010

1‐Isopropyl‐4‐piperidone (1) reacts with sulphur and active methylene nitriles to give thienopyridines (2a‐c). Compounds 2a, b react with CS2 in pyridine to produce pyridothienopyrimidines (3a, b) which upon methylation with MeI give S‐methylated derivatives (4a, b). Dibenzylidene compound (5) reacts with hydrazine hydrate, phenyl hydrazine, thiourea malononitrile or cyanoacetamide to give compounds 6–9 respectively. Piperidylidene malononitrile (10) reacts with benzaldehyde to give derivative 11 which undergoes an addition reaction with malononitrile to give 12 which is also obtained by reacting 1 with one mole of benzaldehyde and two moles of malononitrile.
Immobilization of aminoacylase by encapsulation in poly‐l‐lysine‐stabilized calcium alginate beads
Authors: Lee Kong H. , Lee Pat M. , Siaw Yew S.
Published: July 2010

Aminoacylase I (EC 3.5.1.14) encapsulated in calcium alginate beads stabilized with poly‐L‐lysine was used for the production of L‐phenylalanine by the hydrolysis of a racemic mixture of N‐acetyl‐DL‐phenylalanine. The immobilized aminoacylase was studied with respect to operational stability, thermal stability, effects of pH and temperature and kinetic constants. The leakage of enzyme from the stabilized beads was eliminated. The immobilized enzyme retained high biological activity. The Km and Vmax values for the stabilized beads were 11.11 mmol dm−3 and 0.076 μmol min−1 respectively. The optimum pH and temperature for the hydrolysis were 6.5 and 55°C respectively. Scanning electron micrographs revealed crosslinked structures on the surface of the beads. The operational performances of the beads in a batch reaction and a packed‐bed bioreactor for continuous reaction were investigated. With batch reaction, only about 5% of enzyme activity was lost within ten reaction cycles and there was no significant loss of activity over 600 h of continuous operation after equilibrium was reached, and a conversion yield of about 80% was obtained.
Lipase‐catalyzed resolution of 1‐hydroxymethyl‐2‐methylferrocene
Authors: Izumi Taeko , Aratani Satoshi
Published: July 2010

±‐1‐Hydroxymethyl‐2‐methylferrocene was optically resolved by transesterification with lipases using vinyl esters such as vinyl butyrate, vinyl caproate, vinyl octanoate and vinyl decanoate, as acyl donors.
Reaction steady states and stationary states in modelling semi‐batch enzyme hydrolysis
Authors: Powell Francis E. , Brooks Brian W.
Published: July 2010

Dimensionless material balance equations describing an uninhibited enzyme hydrolysis process in a semi‐batch reactor (i.e. fed‐batch reactor) are formulated; numerical solution of these equations provided concentration profiles of the enzyme‐substrate complex by using published kinetic parameters. The unrestricted values obtained are compared with estimates based separately on the reaction steady state and stationary state assumptions. Results are discussed in terms of the enzyme/substrate inventory used and it is found that the reaction steady state is a satisfactory approximation only when this ratio is sufficiently small. The stationary state may be a better approximation at other values, particularly when enzyme is added to substrate or when an empty tank is being filled. Reaction yields from semi‐batch and batch operations are compared. Processing takes longer in the semi‐batch operations and complete conversions are only practical in this mode when enzyme is added to substrate.
Effect of polymer matrix on penicillin acylase immobilization on copolymers of butyl acrylate and ethylene glycol dimethacrylate
Authors: Bryjak Jolanta , Trochimczuk Andrzej , Noworyta Andrzej
Published: July 2010

Copolymers of butyl acrylate and ethylene glycol dimethacrylate with various degree of crosslinking and aminolysis were used for penicillin acylase immobilization. The amount and activity of the bound protein decreased with the decrease of crosslinking when copolymers having nearly constant degrees of aminolysis were compared. The increase of the carrier amino group content increased the ability to bind the protein (by glutaraldehyde method) without a proportional rise of enzyme activity. The comparative studies of immobilization effect and performance of the derivatives showed 40% crosslinked EGDMA, having an amino group content of 0.67 mmol g−3, to be the carrier of choice. This selected carrier was tested for active protein immobilization by use of crude acylase preparation. It was shown that up to a protein concentration of 9 mg cm−3 in the immobilization mixture the active protein was preferentially bound to the polymer matrix. It was indicated also that the derivative stability was mostly affected by multipoint attachment of the enzyme to the carrier surface.
Cahn's perfect wetting theory in determining monolayer capacity
Authors: Spaull Allan J. B.
Published: July 2010

A thermodynamic method is developed to determine the monolayer capacity of an adsorbent from a first order transition in an adsorption isotherm. Using a number of examples, the value of the monolayer capacity determined by the thermodynamic method is compared with that determined by the BET method.
Inhibition of activity of urease in native form and immobilized on chitosan membrane by sodium fluoride
Authors: Leszko Maciej , Zaborska Wieslawa
Published: July 2010

The influence of sodium fluoride inhibitor on the activity of urease in native form and immobilized covalently on glutaraldehyde‐pretreated chitosan membrane was studied. Initially, in the presence of fluoride ions (I), a complex EI is formed which undergoes slow isomerization into a secondary form EI*. Both stages are represented on the progress curves. The dissociation constant of EI, Ki, for native and bonded urease were determined. The apparent rate constant as a function of the initial urea concentration for a given fluoride ion concentration was calculated, k = k ([I], [S]). It was found that sodium fluoride is a competitive slow‐binding inhibitor of urease. Hydrolysis of urea in the standard conditions, at pH = 7.0, at 25° and a constant ionic strength and variable concentrations of substrate and of inhibitor has been studied. The reaction was initiated by addition of enzyme and was observed over a period of 10 min. The rate of hydrolysis at any point of time for both forms of urease, free and bound, may be calculated from the inhibition constants Ki, K*i and apparent rate constant, k. It was found that immobilized urease is more resistant to the action of the inhibitor than the native one. This property offers potential for practical application.
Mass transfer and substrate utilization in biofilm reactors
Authors: Muslu Yilmaz
Published: July 2010

Mass transfer within microbial films is described using Monod‐type biological kinetics in terms of properties of packing material and the feed solution. For this purpose, computer techniques have been developed for the numerical evaluation of the normalized biofilm mathematical model. A second‐order partial differential equation, describing the mechanisms of dispersion phenomena inside the liquid layer, was then solved to determine the mass transfer coefficient. The application of the theory to earlier experimental data has also been demonstrated.
Screening of white rot fungi for the treatment of olive mill waste‐waters
Authors: Sayadi Sami , Ellouz Radhouane
Published: July 2010

Several white rot fungi were evaluated for their ability to decolorize olive mill waste‐waters (OMW). Among these, Phanerochaete chrysosporium showed the highest potential for the biological depollution of OMW. Approximately 65% of the color and 73% of the chemical oxygen demand (COD) were removed by P. chrysosporium strain HD. Phlebia radiata, Dichomitus squalens, Polyporus frondosus and Coriolus versicolor could also decolorize the OMW but to a lesser extent. The different abilities of these white rot fungi to decolorize OMW correlated with their rates of depolymerization of high molecular weight aromatics and the degradation of the low molecular weight aromatic compounds. Fourteen strains of P. chrysosporium were compared on the basis of their lignin peroxidase (LiP) production, OMW decolorization and residual material dry weight. High lignin peroxidase producer strains, such as strains HD and BKM‐F‐1767, showed the highest rates of OMW decolorization, P. chrysosporium strains 79–36 and FP 104297 (low LiP producer strains) did not exhibit any decolorization activity.
Kinetics of lipase‐catalyzed hydrolysis of lipids in biphasic organic—aqueous systems
Authors: Tsai Shau‐Wei , Chang Chun‐Sheng
Published: July 2010

A kinetic model has been proposed which is applicable to the hydrolysis of lipids by lipases in biphasic organic‐aqueous systems. An analytical rate equation, based on the interfacial substrate concentration, was derived and confirmed from previous experimental data. The equation may be reduced further to the Michaelis‐Menten form for the system by adding a water‐immiscible organic solvent (or using hydrophobic particles but for hydrophilic substrates). The reduced form cannot be obtained when the organic phase only contains the hydrophobic substrate. Moreover, the concept of substrate inhibition and certain conflicting expressions for the apparent maximum velocity and Michaelis‐Menten constant, that previous investigators claimed, have been clarified in the present study.
Influence of the physical‐chemistry properties of an acid‐activated bentonite in the bleaching of olive oil
Authors: González‐Pradas E. , Villafranca‐Sánchez M. , Gallego‐Campo A.
Published: July 2010

The bleaching process at 90°C of an olive oil from Jaen (Spain) using natural bentonite and bentonite acid treated with H2SO4 (over a concentration range between 0.50 M and 5.00 M) has been studied. The bleaching capacities of the bentonite samples were calculated by applying the Freundlich equation to the experimental data points corresponding to the bleaching process. The bleaching capacities (KF parameter) range from 2.5 × 10−7 for non‐treated bentonite up to 0.85 for 2.50 M H2SO4 treated bentonite. The bleaching capacity of the 5.00 M H2SO4 treated bentonite (KF = 0.81) is less than that of the 2.50 M H2SO4 treated bentonite.
Modelling of catalyst pellet poisoning for benzene hydrogenation
Authors: Rušić Davor , Zrnčević Stanka
Published: July 2010

Based on the kinetics of benzene hydrogenation, pore diffusion and catalyst deactivation, time‐dependent effectiveness behaviour of a single NiSiO2Al2O3 catalyst pellet where the chemical reaction rate is determined by pore diffusion was simulated for different conditions of operation.

Poisoning kinetics were measured in a series of differential reactor experiments at atmospheric total pressure at temperatures ranging from 403 to 473 K.

A computed effectiveness factor has been compared with experimental values for a catalyst pellet of industrial size. A good degree of correlation between theoretical prediction and the experimental results was found.
Biodegradation of wood‐pulp black liquor hydroxyacids by Micrococcus lylae
Authors: Mikulášová Mária , Pekarovičová Alexandra , Rybáriková Daniela , Košík Martin
Published: July 2010

When Micrococcus lylae grew on the black liquor from wood pulping, glucoisosaccharinic and acetic acids were completely used in 48 h, 2‐hydro‐xybutanoic acid decreased by 67%, lactic acid by 45% and glycolic acid by 38%. Conditions of the utilization of glucoisosaccharinic acid were optimized.
Aspects of the efficiency of calcium salts for the retention of sulphur in coal ash during combustion at 1200 k
Authors: Brady Mark E. , Burnett Michael G. , Galwey Andrew K.
Published: July 2010

Electron microprobe analyses were made of the residual ash particles remaining after combustion in air at 1200 K of samples of representative coals used in thermal power plants and of samples of Northern Ireland lignite. Local associations of sulphur and calcium in the small areas analysed (c. 10 μm) were ascribed to the formation of the relatively stable CaSO4. This correlation was not linear and it was concluded that locally CaO reacted preferentially with the acidic oxides of silicon and aluminium to form calcium alumino‐silicates. We recommend, therefore, that in assessing the amount of CaCO3 or Ca(OH)2 that must be added to a given fuel to achieve effective desulphurisation, due account must be taken of the ability of the constituent oxides in that coal to react with the additive.
Liquid‐phase oxidation accompanied by skeletal rearrangement of acetophenone and acetone by hydrogen peroxide in the presence of selenium dioxide
Authors: Shah Kamlesh J. , Chandalia Sampatraj B.
Published: July 2010

Treatment of acetophenone and acetone with hydrogen peroxide in tertiary butanol with selenium dioxide as catalyst gave phenylacetic acid and propionic acid with selectivities of 80% and 97%, respectively. The effects of various process parameters on the reaction rate and selectivity with respect to the acid have been investigated. The reactions were first‐order with respect to the substrates.
Preparation of needle‐like hydroxyapatite by homogeneous precipitation under hydrothermal conditions
Authors: Fujishiro Yoshinobu , Yabuki Hiroshi , Kawamura Kunio , Sato Tsugio , Okuwaki Akitsugu
Published: July 2010

Preparation of hydroxyapatite was carried out by a homogeneous precipitation technique using hydrothermal reactions of Ca(EDTA)2‐ and PO43‐ at 130–250°C and pH 4–10. Hydroxyapatite and monetite were formed above pH 6 and below pH 4, respectively. Needle‐like hydroxyapatite was formed at high temperatures above 130°C. The length of the needle‐like hydroxyapatite crystal increased with increasing working solution pH and temperature.
Effects of temperature and Cu2+ catalyst on liquid‐phase oxidation of industrial wastewaters
Authors: Chang Chiehming J. , Lin Jung‐Chou , Chen Chung‐Kuo
Published: July 2010

Wet air oxidation is a process in which partial oxidations arise in an aqueous medium. Elevated temperature and pressure have enhanced solvent power for both oxygen in air and organics in wastewaters. Oxidations have therefore been carried out either in a kinetic‐controlling or in a diffusion‐controlling operation. Spent caustic and neutralized wastewaters obtained from a petrochemicals‐manufacturing process, were employed in this study for wet oxidation in a semi‐batch reactor. Temperature was indicated by preliminary kinetic data to be the primary factor influencing a situation where there was little control by diffusion. The oxidation reactions of hydrocarbon organic compounds were demonstrated to be enhanced if Cu2+ was used as the catalyst. Designing and developing wet oxidation for processing industrial wastewaters was pursued in this present study by successfully adopting homogeneous kinetic models which were, subsequently, employed for calculating rate constants of oxidation reactions by correlating organics removal efficiency with oxidation time.
Epoxidation of methallyl chloride with t‐butyl hydroperoxide
Authors: Milchert Eugeniusz , Paździoch Waldemar
Published: July 2010

By applying a statistical method of experiment planning the optimum conditions of methallyl chloride epoxidation with t‐butyl hydroperoxide have been determined. The influences of the temperature, molar ratio of the methallyl chloride to t‐butyl hydroperoxide, catalyst concentration and reaction time on the selectivity of the synthesis of methylglycerol epichlorohydrine in relation to reacted t‐butyl hydroperoxide have been examined.
Pectinlyase immobilization on epoxy supports for application in the food processing industry
Authors: Spagna G. , Pifferi P. G. , Martino A.
Published: July 2010

The immobilization of a pectinlyase (PL, EC 4.2.2.3) contained in a commercial enzymic preparation was studied in view of its use for fruit pulp and juice processing. Two epoxy supports were tested for immobilization. These included Eupergit C (Rohm), a synthetic polymer, and γ‐alumina functionalized with γ‐glycidoxypropyltrimethoxysilane. In both biocatalysts, the catalytic response was not found to be high. The highest response in terms of immobilization yield and immobilized PL activity, however, was reported for Eupergit C (approx. 115 unit g−1 at optimum pH).
Production of enzymes from potato pulp using batch operation of a bioreactor
Authors: Klingspohn Uwe , Vijai Papsupuleti P. , Schügerl Karl
Published: July 2010

Trichoderma reesei strains MCG77 and Rut C30 were cultivated in batch operation in a stirred tank reactor on potato pulp (PP) consisting of starch, pectin, cellulose, and hemicellulose; potato pulp residue (PR) without starch and pectin; or enzymatic residue (ER), respectively, as substrate and potato protein liquor (PPL) as supplement. The enzyme mixtures produced by the fungi were characterized by four assays: with avicelase, CMCase, xylanase, and FP‐activities. Trichoderma reesei Rut C30 yielded higher activities than Trichoderma reesei MCG77. The enzyme activities and productivities obtained with PR are comparable to those obtained by other groups using pure cellulose and a synthetic nutrient solution in batch culture. An optimal operation strategy was derived to obtain maximum enzyme activity and productivity. After converting PR with the enzymes produced and using the residue, ER, as substrate for enzyme production, 85% (w/w) of the pulp was utilized.
Micro‐scale modelling of substrate removal kinetics in multicomponent fixed‐film systems
Authors: San H. A. , Tanik A. , Orhon D.
Published: July 2010

Modelling of fixed‐film reactors, as for suspended growth systems has to account for all the major components and biochemical processes responsible for the removal of substrate. Traditionally fixed‐film reactors are viewed as two‐component (substrate/biomass) systems interacting with the governing effect of molecular diffusion. Recent developments however have shown the importance of viability and product formation in the modelling of biological systems. This paper emphasizes these two new parameters and evaluates the kinetic relationships between the bulk substrate concentration and biofilm composition as it affects substrate removal and residual product formation.
Biosorption of metals by a waste biomass
Authors: Mattuschka Beate , Straube Gunhild
Published: July 2010

The binding of several metals by waste biomass of Streptomyces noursei was investigated. With respect to the binding capacity, the following order was observed: Ag > Cr > Pb > Cu > Zn > Cd > Co > =Ni. The sorption of metal ions increased with the increasing initial concentration of metal. The adsorption equilibrium of copper, lead and chromium sorption, and silver sorption at low concentration can be described by the Freundlich and Langmuir models. The possibilities for desorbing the metals from loaded biomass and the repeated use of biomass were investigated. The influence of various ions in water on metal sorption was tested. The metal capacity and selectivity of metal binding by biomass are important qualities for practical use.
Some implications of structural collapse during freeze‐drying using Erwinia caratovoraL‐asparaginase as a model
Authors: Adams G. D. J. , Irons L. I.
Published: July 2010

When the enzyme Erwinia caratovora L‐asparaginase was freeze‐dried in mixtures of lactose and sodium chloride, biological activity and protein structure were preserved during drying. However, by altering the ratios of the excipients in the formulation it was possible to obtain products which were pharmaceutically acceptable or unacceptable as assessed by the criteria of dried cake appearance, moisture content or ease of reconstitution.
Utilization of date products in production of oxytetracycline by Streptomyces rimosus
Authors: Abou‐Zeid Abou‐Zeid A. , Baeshin Nabeh A. , Baghlaf Ahmed O.
Published: July 2010

The carbon and nitrogen sources of a synthetic fermentation medium were substituted by equivalent amounts of date‐coat sugar extract and date‐seed hydrolysate. The addition of 1.0 g dm−3 urea and date‐seed lipid into the medium increased the efficacy for antibiotic formation. When the MgSO4, MnSO4, FeSO4 and ZnSO4 components of the medium were replaced by 0.5 g dm−3 date‐seed ash, antibiotic output was also increased.
Effect of polymer additives on hydrodynamics and oxygen transfer in a bubble column bioreactor
Authors: Kawase Yoshinori
Published: July 2010

The influence of polymer additives (polyethylene oxide and polyacrylamide) on the hydrodynamics and oxygen transfer in a bubble column bioreactor was examined. The addition of small amounts of these polymers has been known to cause significant drag reduction in turbulent flow circumstances. The gas hold‐up was slightly decreased and the liquid‐phase mixing was somewhat enhanced due to the addition of the polymers. The addition of polymer additives brought about a reduction of the volumetric oxygen transfer coefficient by about 40%. In dilute polymer solutions, large bubbles formed by bubble coalescence moved with high rise velocities in the presence of many small bubbles and the bubble size distributions were less uniform compared with those in water. The complicated changes in bubble hydrodynamic characteristics were examined to give possible explanations for oxygen transfer reduction.
Constant flowrate filtration of hybridoma cells suspensions
Authors: Favre Eric
Published: July 2010

The fouling mechanism of rotating sieves (also called spinfilters) in suspended mammalian cells reactors is still poorly understood, and their design is consequently largely empirical. A laboratory set‐up enabling constant flowrate filtration experiments is reported and its use described in order to study the fouling kinetics of 10 μm opening sieves by suspended hybridomas. Significant differences were obtained depending upon cell type and cell viability, under similar operating conditions. A roughly linear pressure drop increase, as predicted by constant flowrate incompressible cake filtration models, was obtained for most experiments. However, the influences of pumping flowrate and cell concentration on pressure drop evolution do not obey incompressible cake constant flowrate filtration laws; a surface colonization approach could possibly lead to a better description in that case.
Trifluoromethanesulphonic acid catalysed transalkylation between tetrabromobisphenol‐a and toluene for the production of 2,6‐dibromophenol
Authors: Effenberger Reinhard
Published: July 2010

The preparation of 2,6‐dibromophenol is described. This compound, useful as raw material for brominated poly(phenyleneoxide) and pyrogallol or derived pharmaceuticals/pesticides, was prepared in 80% (isolated) yield by a transalkylation reaction between tetrabromobisphenol‐A and toluene. The catalyst, trifluoromethanesulphonic acid, can be simply recovered and recycled. Perfluorinated resin sulphonic acid (NAFION‐H®, DuPont) did not effectively catalyse this transalkylation.
Regulation of the chlorine content in fresh, regenerated and coked PtRe/Al2O3 catalyst
Authors: Scelza Osvaldo A. , Baronetti Graciela T. , de Miguel Sergio R. , Silber Pablo , Castro Alberto A.
Published: July 2010

In bifunctional naphtha reforming catalysts the regulation of the chlorine content in order to equilibrate both catalytic functions (metallic and acidic) is one of the most relevant topics. In this paper a study of the chlorine regulation in fresh, regenerated and coked samples of a given commercial Pt (0.3 wt%)—Re (0.3 wt%)/Al2O3 catalyst is presented. Results show that an equilibrium chlorine content is reached when the samples are treated with an H2O—HCl mixture vaporized in a gas carrier (air or H2). This equilibrium content depends on the H2O/HCl molar ratio and the temperature of the regulation treatment. For fresh samples the equilibrium chlorine content does not depend on the nature of the gas carrier. Moreover, the retention capacity of chlorine by the support per unit of surface area is the same for fresh and regenerated samples. The presence of different amounts of coke on the surface does not modify the chlorine uptake with respect to the sample without coke.
Microbiological purification kinetics of wine‐distillery wastewaters
Authors: Romero L. I. , Nebot E. , Mart de la Ossa E. Ínez , Sales D.
Published: July 2010

Wine alcohol distilleries produce eight volumes of high‐strength waste (known as vinasse) from every volume of ethanol. The waste has an acidic character and a high organic content. Three adequate microbiological treatments (aerobic, mesophilic anaerobic and thermophilic anaerobic) for the purification of vinasses were examined. When around 90% biodegradable chemical oxygen demand (COD) removals were achieved in every treatment, optimum operating conditions had been attained, resulting in an optimum hydraulic retention times (HRT) of 8 days for aerobic, 6 days for mesophilic anaerobic, and 4 days for thermophilic anaerobic processes. The experimental results were compared with those obtained from a substrate utilization kinetic model. The model accurately predicted the performance of these processes, except at HRTs shorter than minimum, since these systems work under transient conditions. A comparison between kinetic coefficients obtained from the model showed that a thermophilic anaerobic process was the more efficient, since the process reached the same purification level, could be energy self‐maintaining and needed smaller process plants than the other two systems.