bluuebunny/crossref_metadata_2025 huggingface dataset:
Optimal separation of n‐paraffins from Kuwait kerosene using a molecular sieve adsorbent
Authors: Al‐Damkhi A. M. , Al‐Ameeri R. S. , Jeffreys G. V. , Mumford C. J.
Published: July 2010

A study has been made of the vapour‐phase adsorptive separation of n‐alkanes from Kuwait kerosene using zeolite molecular sieves (LMS‐5A). The object was to identify the optimum operating conditions, in terms of flow rate, adsorption temperature and zeolite particle size for the separation of n‐alkanes from kerosene, so that the remaining stock would also be of marketable quality. The effect of these conditions on the height of the mass transfer zone (HMTZ) and the dynamic capacity (Ad) of zeolite was also investigated.

The adsorptive separation process comprised one cycle of adsorption using a fixed bed of zeolite type‐5A. The bed was fed with kerosene vapour until equilibrium had been achieved, whereby the n‐paraffins were adsorbed and the denormalized material excluded. The processes were carried out isobarically at one atmosphere.

The optimum operating conditions were found to be a feed flow rate of 33.33 × 10−9 m3 s−1, an adsorption temperature of 643 K and a zeolite pellet fraction size of 1.0–2.0 × 10−3m. This yielded an HMTZ value of 0.206 m and an Ad of 9.653 × 10−2 kg n‐paraffins kg−1 zeolite. The data will serve as a basis for the design of commercial plant.
Removal of phenols by adsorption on fly ash
Authors: Kumar Satendra , Upadhyay S. N. , Upadhya Y. D.
Published: July 2010

Adsorption of phenol and cresol and their mixtures from aqueous solutions on activated carbon and fly ash has been investigated. The effects of contact time and initial solute concentration have been studied and isotherm parameters are evaluated. The Freundlich isotherm has been found to be more suitable for all the systems investigated.
Catalyst preparation and support effects for triglyceride hydrogenation over supported nickel
Authors: Chung Chun‐Shun , Winterbottom John M.
Published: July 2010

Nickel catalysts have been prepared by impregnation and precipitation methods on silica and charcoal. Metal loadings were in the range 1–40% w/w Ni on the support.

The catalysts were investigated by temperature programmed reduction (TPR) and subsequently reduced in the temperature range 200–500°C. Metal surface areas were measured via H2 and CO chemisorption and limited studies of the catalysts were carried out using X‐ray photon spectroscopy (XPS), X‐ray diffraction (XRD) and transmission electron microscopy (TEM) to determine the chemical and physical state of the nickel after reduction. Reduced catalysts were employed for triglyceride (soya bean oil) hydrogenation (1 atmos H2, 160°C) in a stirred reactor (1000 rpm) and reaction rates (catalyst activity) and product distributions were determined.

Charcoal supported catalysts were active and zero valent nickel was detected after reduction. However, surface areas were variable, the performance of such catalysts being affected by pore effects, agglomeration and possibly nickel–charcoal interaction.

Silica supported precipitated catalysts were of relatively high activity and metal surface if methanol washed before activation and inactive (irreducible) if only water washed.

Although silica supported precipitated catalysts were more active per unit weight of metal than charcoal supported counterparts, they were less active per unit metal area and gave rise to greater trans‐acid production. This may be due to triglyceride molecules excluding hydrogen from small nickel crystallites.
On‐line measurement and control of penicillin V production in a tower loop reactor
Authors: Lorenz Th. , Diekmann J. , Frueh K. , Hiddessen R. , Moeller J. , Niehoff J. , Schügerl K.
Published: July 2010

Penicillin V was produced in a 98‐dm3 tower loop reactor using a production strain of Penicillium chrysogenum in pellet form. By using control devices, the aeration, the only energy input in a tower loop reactor, decreased by an average of 75%. The amounts of precursor substance (phenoxyacetic acid), acid, base, ammonium sulfate and urea, added during the penicillin fermentation process, were reduced by applying an automatic analysing system to the process.
Extractive distillation of propanol–water mixtures employing less‐soluble and sparingly soluble salts as separating agents
Authors: Zaidi Syed A. H.
Published: July 2010

Extractive distillation of 1‐propanol and 2‐propanol from the respective organo‐aqueous mixtures employing less soluble (Na IO3, K2SO4, PbCl2) and sparingly soluble salts (Ca(OH)2, CaSO4, BaSO4, PbSO4, PbCO3) dissolved to saturation in the boiling liquid phase at atmospheric pressure has been examined. The 98% purification of 2‐propanol obtained with Ca++−, Pb++ and Ba++ salts suggests large perturbation of phase equilibria with relatively small salt concentrations (9 × 10−6 M for Pb++) on the 2‐propanol‐water system.
Role of pretreatments on enzymatic hydrolysis of agricultural residues for reducing sugar production
Authors: Tewari Harmesh K. , Singh Lokendra , Marwaha Satwinder S. , Kennedy John F.
Published: July 2010

The ability of agricultural residues, namely wheat straw, sugarcane bagasse, groundnut shell and corn‐cob, for supporting cellulase production in Trichoderma reesei QM 9414 and the effect of pretreatments by chemical and physical agents on enzymatic hydrolysis of the residues have been investigated. Crystalline cellulose was used for comparison. Wheat straw supported maximum cellulase activities (FPA 111.11 IU g−1 substrate; CMCase 277.77 IUg−1 substrate; cellobiase 12.04 IU g−1 substrate) under submerged fermentation conditions at the end of six, six and ten days of incubation, respectively. The pretreatment of lignocellulosic wastes using both chemical and physical agents improved the enzymatic hydrolysis of the substrates. However, the nature and duration of delignification process of the cellulosics varied with the substrate. The treatment of sugarcane bagasse, corn‐cob and wheat straw using sodium hydroxide at a rate of 0.5% w/v with autoclaving for 1.5 h, 1.5 h and 0.5 h, respectively, was found to be optimum and resulted in the formation of reducing sugars of the order of 896 mg 10 g−1 of sugarcane bagasse, 760 mg 10 g−1 of corncob and 632 mg 10 g−1 of wheat straw. Among the physical agents, grinding of the groundnut shell to a particle size of 60 mesh was observed to be the most effective for producing maximum reducing sugars.
Microbial mineral processing: The opportunities for genetic manipulation
Authors: Nicolaidis Anthony A.
Published: July 2010

Applications of microbiology to mining operations have been surveyed and evaluated. This has been carrried out with a view to seeking directions whereby genetical and molecular biological approaches could be applied to optimise ‘bio‐mining’ processes. Copper and uranium are currently recovered from their ores on a commercial scale (to a value of about US$1800 million annually worldwide) using bioleaching systems carried out in the open in biologically uncontrolled conditions. Possibilities also exist for applying bioleaching methods on an industrial scale for the extraction of a number of other metals from sulphide‐bearing concentrates. Molybdenum, cobalt and nickel are likely to be most suitable, principally because of their value. Biological ore beneficiation can be used to enhance the recovery of noble metals. Bioleaching systems offer a variety of desirable advantages compared to conventional methods but suffer principally in their relatively low leaching rates. Opportunities exist for the enhancement of bioleaching rates by genetic technologies. These approaches are outlined and discussed. Bioconcentration systems offer possibilities for metal recovery from dilute industrial waste streams and metal refinery effluents and for the heavy metal detoxification of polluted waters. Possible applications of genetic technologies to bioconcentration systems are proposed. Other uses for the mineral leaching thiobacilli, e.g. fossil fuel desulphurisation, are outlined and discussed.
Cross‐flow separation of yeast cell suspensions using a sintered stainless steel filter tube
Authors: Kavanagh Paul R. , Brown Donald E.
Published: July 2010

A new design of cross‐flow filtration unit, the Transep filter, has been investigated for the separation of slurries of Saccharomyces cerevisiae. Porous cylindrical sintered stainless steel tubes of 2 μm and 3 μm nominal pore size ratings were used as filter media. Filtration rates were measured for cell suspensions ranging from 3 to 25 kg m−3. The 3 μm filter produced particle‐free filtrates at average rates from 1.25 m3 m−2 h−1 which declined to half this value over the range of cell concentrations studied.
Preparation of diphenyl acetonitrile by phase transfer catalysis
Authors: Kasarekar Ravindra B. , Sawant Sudhirprakash B.
Published: July 2010

Preparation of diphenyl acetonitrile has been investigated by the reaction of diphenyl methyl bromide with aqueous sodium cyanide, using quaternary ammonium salts as phase transfer catalysts. The effect of catalyst, temperature, catalyst loading, and reactant concentration on the conversion of diphenyl methyl bromide to diphenyl acetonitrile has been studied. Suitable process conditions have been established for the production of diphenyl acetonitrile.
Adsorption of thiram from aqueous solution on activated carbon and sepiolite
Authors: Gonzáiez‐Pradas E. , Villafranca‐Sánchez M. , Socias‐Viciana M. , Del Rey‐Bueno F. , García‐Rodriguez A.
Published: July 2010

Adsorption of thiram on activated carbon and acid‐heat treated sepiolite from aqueous solution at 10° C, 20° C, 30° C and 40° C has been studied. The adsorption isotherms may be classified as L type of the Giles classification which suggests that there is no strong competition from the solvent for adsorption sites.

The experimental data points have been fitted to the Langmuir equation in order to calculate the adsorption capacities of the solids as well as their surface areas available to the thiram molecules. The removal efficiency (P) has been calculated for both adsorbents resulting that activated carbon is more effective (P = 98–100%) in removing thiram from aqueous solution than acid‐heat treated sepiolite (P = 14–52%).
The application of solar energy in water reuse
Authors: Prasad Gur
Published: July 2010

The application of photocatalysed oxidation in water reuse technology is described. Results with a sequencing batch reactor showed that 4 hours contact of the raw sewage with 0·5 mg dye sorbed g−1 fly ash in sunlight, under experimental conditions, significantly reduced the organic and bacteriological load and rendered it fit for use in irrigation or for discharge. The effect of variables such as contact time or amount of dye sorbed on COD, MBAS and MPN counts were investigated and the results interpreted in terms of enhanced photoactivity and biodegradation in the sorbed state. The process appears to be well suited to commercial exploitation as it is safe, quick and economical.
Suitability of spent hydrodesulphurisation (HDS) catalyst in low pressure distillate hydrocracking—a case study
Authors: Mittal Krishan G. , Gupta Sri C. , Agarwal Ravindra K. , Rai Jai R.
Published: July 2010

Low pressure hydrocracking (40–80 atm., 425°C and 0·5 liquid hourly space velocity is achieved economically on a low cost spent hydrodesulphurisation catalyst (cobalt—moly/alumina) using vacuum distillate of Indian crudes. Once through, conversion to products boiling below 371°C was in the range 40°69—43·04 wt % with the middle distillate amounting to 32·03–38·24 wt %.
Reactors for ethanol production using immobilised yeast cells
Authors: Qureshi Nasibuddin , Pai J. S. , Tamhane D. V.
Published: July 2010

Ethanol production by immobilised yeast cells in packed‐bed column reactors was significantly affected by the hold‐up of CO2 produced during the fermentation. Compartmentalisation of the reactor minimises CO2 hold‐up and prevents flotation of immobilised cell beads during operation and bead rupture during shut‐down conditions. In a reactor of dimensions 2·2 × 60 cm, a rate of ethanol production of 5·11 g h−1 at a dilution rate of 1·27 h−1 was achieved, when 18% (w/v) glucose solution was fed at the bottom at pH 5·5 and temperature 33–35°C. In larger reactors of sizes 4 ×; 40 cm and 8 × 80 cm the rates of ethanol production and CO2 hold‐ups were 5·11 and 5·37 g h−1 and 48·66% and 40·66% and 40·79% of the void volume at dilution rates of 1·27 h−1 and 1·67 h1, respectively. The CO2 hold‐ups in column reactors (4 × 40 cm) held in inclined (43° from horizontal) or horizontal positions were 41·33% and 46·67% of the void volume, respectively. Double and triple series reactors (each of dimensions 2·2 × 60 cm) showed better performance than a single verticle reactor (2·2 × 60 cm).
Mass transfer of sodium chloride in simulated crystallizing pond during the rainfall period
Authors: Huang Ting‐Chia , Juang Ruey‐Shin , Huang Tzung‐Huei
Published: July 2010

The mass transfer equation describing the transport phenomena of sodium chloride is derived for the simulated crystallizing pond during the rainfall period. According to the theoretical and experimental results, the dissolution rate of NaCl is shown to be controlled by the combination of salt transport including the diffusion and convection of solute in solution and surface dissolution reaction including the desorption and surface diffusion of solute. It is found that both the dissolution and convective mass transfer coefficients are proportional to the total rainfall quantity, and inversely proportional to the brine depth. The variation of dissolution mass transfer coefficient to the total rainfall quantity and brine depth is correlated from the experimental results. Correlation of the convective mass transfer coefficient is also obtained by using the numerical solution of the mass transfer equation.
Hydrolysis of sugar cane bagasse with hydrochloric acid, promoted by ultrasound
Authors: Schuchardt Ulf , Joekes Inés , Duarte Humberto C.
Published: July 2010

Ultrasound effectively promotes the hydrolysis of pre‐hydrolysed sugar cane bagasse using 38% concentrated hydrochloric acid. In combination with lithium chloride, ultrasonic promotions as high as 62% were observed. Of the three frequencies (25, 35 and 40 kHz) studied, the lowest promoted the hydrolysis most effectively but, when in combination with lithium chloride, reoligomerised the sugars. The higher frequencies of 35 and 40 kHz required larger concentrations of lithium chloride for complete conversion. Irradiation with 40 kHz also promoted subsequent acid hydrolysis of the sugar oligomers.
Separation of ethanol‐water mixtures using 3A molecular sieve
Authors: Cartón Angel , González Gerardo , Torre Angeles Iñiguez De La , Cabezas Jose Luis
Published: July 2010

An experimental study of 3A molecular sieve behavior, in order to obtain anhydrous ethanol, was developed. The adsorption of water in vapor phase was performed in an essentially isothermal fixed bed. 99·9 wt% ethanol was recovered operating with azeotropic distillation and different flow rates. A simple model in terms of a driving force and linear equilibrium was tested. Runs in liquid phase were also carried out, obtaining lower treatment capacities than when working in vapor phase.
Kinetics of naphthalene sulphonation with 96 wt % sulphuric acid
Authors: Nowicki Lech , Zarzycki Roman
Published: July 2010

An empirical approach to the kinetic investigation of naphthalene sulphonation with 96% sulphuric acid is presented. The best parameter estimates for the proposed kinetic model were obtained by non‐linear regression of experimental data.
Automated production scale affinity purification of monoclonal antibodies
Authors: Kenney A. C. , Chase H. A.
Published: July 2010

This paper describes the use of automation to improve the efficiency of affinity chromatography as a production technique. The use of automation in development of affinity processes is described together with an analysis of the benefits of automating production systems. The paper considers what factors are important in achieving an efficient affinity process on a production scale. The discussion is supported with data illustrating the use of immobilised Protein A to purify large quantities of monoclonal antibody from cell culture. The paper concludes with a brief discussion of possible future developments and extensions of automation in affinity processes.
Oxidation of anthracene in the liquid‐phase
Authors: Das C. K. , Das N. S.
Published: July 2010

Various processes for the oxidation of anthracene in the liquid‐phase have been reviewed with special consideration to the mechanistic pathways involved. The prospect of the processes with crude anthracene/less pure anthracene as feed‐stock has been emphasized.
Urease immobilization on an alkylamine derivative of titanium (IV)‐porous silica: Kinetics and operational stability
Authors: Martins Maria Barbara F. , Cruz Maria Eugenia M. , Cabral Juaquim M. S. , Kennedy John F.
Published: July 2010

For the purpose of immobilizing urease (urea amidohydrolase, EC 3.5.1.5) for routine determination of urea, a covalent bond immobilization method on titanium (IV) chloride activated silica supports1,2 was used. Several parameters were studied in order to optimize the residual activity upon immobilization and during operation. The kinetic constants of the immobilized enzyme form (Km=92 mmol dm−3, Vmax=752 μmole min−1 mg−1) are much higher than those of the free preparation (Km=31 mmol dm−3, Vmax=128 μmole min−1 mg−1). The optimum pH of the immobilized enzyme preparation was shifted to higher values, from pH 7·4 to 8. The optimum temperatures for the immobilized and free forms were 75 and 65°C, respectively. The activation energy of the immobilized form is four times smaller than that of the free, indicating less sensitivity to temperature. It was also observed that the immobilized enzyme exhibits a higher heat stability than the free enzyme. From these studies the conditions for optimal operation and retention of stability of the immobilized enzyme were determined. The enzyme immobilized on the alkylamine derivative of porous silica can be reused at 37°C for several hours a day with 100% retention of its initial activity for at least 1200 h of total life (i. e. operating time at 37°C plus stationary time at 4°C).
Ion exchange characteristics of ceric tungstate: Kinetics of exchange
Authors: Mikhail Etidal M. , Misak Nasr Z.
Published: July 2010

The kinetics of exchange of Cs+, Ag+, Zn2+ and Sc3+ on ceric tungstate were studied under particle diffusion control conditions at different temperatures. At the studied temperatures, the mobility of the monovalent ions in the prepared exchanger is higher than that of the multivalent ones, presumably due to weaker electrostatic interaction with the exchange sites. The activation energy data point to a substantial or complete dehydration of the ions diffusing in the narrow pores of the exchanger. The highest activation energy is displayed by Cs+ having the largest crystallographic radius.
Optimization of sucrose phosphorylase production by Leuconostoc mesenteroides
Authors: Vandamme Erick J. , Loo Jan Van , Simkens Eric , Laporte Andre De
Published: July 2010

Environmental optimization of the Leuconostoc mesenteroides ATCC 12291 sucrose phosphorylase fermentation process was undertaken. The effects of pH control, fermentation temperature and medium composition on growth, culture viscosity, sucrose utilization pattern and dynamics of enzyme fermentation were studied. Optimized fermentations were run at controlled pH 7 at 32°C yielding high enzyme levels. Applications of sucrose phosphorylase are discussed.
Development of a microcomputer‐based system for single‐stirred bioreactors and their cascade
Authors: Meyer H.‐D. , Kuhlman W. , Lübbert A. , Schügerl K.
Published: July 2010

A computer‐aided measuring and control system for bioreactors is presented. It is suited for the automation of a wide range of different fermenters. The hardware concept as well as the newly developed software package are described. The whole system was tested thoroughly during several yeast cultivation and ethanol production experiments in a single laboratory‐scale stirred tank bioreactor and in a cascade of three stirred bioreactors.
Effect of hydrodynamic stress on dunaliella growth
Authors: Silva Humberto J. , Cortifas Teresa , Ertola Rodolfo J.
Published: July 2010

The effect of hydrodynamic stress derived from gas bubble dispersion and broth mixing on Dunaliella growth was examined by growing the algae in two different vessels; a Roux bottle and a miniloop reactor. It was found that Dunaliella cells were increasingly sensitive to high specific bubble rates at modified orifice Reynolds numbers between 9.9.104 to 18.8.104 and liquid motion with Reynolds numbers between 712 and 1293. The addition of carboxymethylcellulose and agar to the cultures served to protect the microorganisms from the effects of shear stress.
Molecular mechanism of calcium sulfonate redissolution by micelles
Authors: Celik M. S. , Somasundaran P.
Published: July 2010

It has been suggested that redissolution of sulfonate/multivalent precipitates occurs by micellar solubilization. The molecular mechanism governing the redissolution process has not been identified. In this study, the solubilization constant, which is an indicator of the capacity of the micelles to solubilize the precipitate, is determined with the aim of elucidating the molecular mechanism involved in the redissolution process. The effects of ionic strength, alkyl chain length, temperature, n‐propanol and n‐dodecane on the solubilization constant are examined under a variety of conditions. In addition, counter‐ion binding to micelles and conductivity of micelles are determined for different sulfonates. Based on all these data, a mechanism involving the adsorption of Ca2+ on the micelle and the subsequent dissolution of calcium disulfonate to replenish the system is proposed to account for the precipitate redissolution.
Influence of gas distributor design on the oxygen transfer characteristics of an airlift fermenter
Authors: Bovonsombut Sittisin , Wilhelm Anne‐Marie , Riba Jean‐Pierre
Published: July 2010

The performances of two types of gas distributor (a perforated ring and a porous plate) in an airlift fermenter were compared in the measurement of gas holdup, overall mass transfer coefficient and mixing time, using four aqueous media containing different concentrations of four electrolytes, sugar and antifoam agent in order to simulate fermentation media.

In pure water, a 50% higher kLa value was found with the porous plate; this difference was emphasized by adding salts or organic compounds so that the kLa could become two or three times higher with the porous plate. The type of sparger seemed to have very little effect on holdup ratios and mixing times.
Continuous‐flow estimation of laccase activity in rotten grape juice by a computerized electrode
Authors: Zouari Nabil , Romette Jean‐Louis , Thomas Daniel
Published: July 2010

A continuous‐flow method for estimation of the degree of rot in grape has been developed which involves measuring the oxygen consumption in a mixture consisting of grape juice and quinol. For the automation of the system, assays were carried out with centrifuged and heated samples of grape juices. The feasibility of the system has been demonstrated.
Dissolution kinetics of ulexite in water saturated by sulphur dioxide
Authors: Alkan Mahir , Muhtar Kocakerim M.
Published: July 2010

The dissolution kinetics in SO2‐saturated water of ulexite, a sodium calcium borate, have been studied. The effect of particle size, gas flow rate and temperature were determined. Ulexite dissolution rates increased with decrease in particle size, with increase in temperature and were not affected by the flow rate of SO2. The activation energy for the dissolution was calculated as 58‐01 kJ mol−1.
Recovery of uranium by tannin immobilized on agarose
Authors: Nakajima Akira , Sakaguchi Takashi
Published: July 2010

Tannin, which is a ubiquitous and inexpensive material, was immobilized on agarose gel to produce an excellent adsorbent for uranium recovery from seawater. Optimal conditions for the immobilization of tannin on agarose gel by both the epichlorohydrin and cyanuric chloride coupling procedures were examined in detail. The resulting immobilized tannin has a highly selective ability to adsorb uranium and applicability in both column and batch systems. This adsorbent can recover uranium from natural seawater with high efficiency. The maximum adsorption capacities were 1850 μg uranium g−1 adsorbent for the tannin immobilized on agarose gel by the epichlorohydrin coupling procedure and 1062 μg g−1 adsorbent for that produced by the cyanuric chloride coupling procedure.
A comparison of immobilised protease activities
Authors: Jasim Munir A. , Hall George M. , Mann John , Taylor Keith D. A.
Published: July 2010

Five proteases, bromelain, ficin, papain, pepsin and trypsin were immobilised on cellulose supports by two different techniques using cyanogen bromide or glutaraldehyde. The degree of immobilisation was determined and the activity of the immobilised enzymes compared to that of the free enzymes using egg albumin as a substrate. The stability of each immobilised enzyme was determined by repeated hydrolysis of egg albumin and the most active enzymes used in sequence—the technique of multiple hydrolysis—in order to maximise hydrolysis. In terms of the degree of immobilisation, activity and stability of the enzymes cyanogen bromide was more effective than glutaraldehyde. For the individual enzymes pepsin, trypsin, ficin, bromelain and papain were most active, stable and immobilised to the greatest extent.
Immobilization of glucoamylase in porous glass fibers
Authors: Toldrá Fidel , Jansen Norman B. , Tsao George T.
Published: July 2010

Glucoamylase has been successfully immobilized in controlled pore glass fibers by a silane‐glutaraldehyde coupling method. Enzyme solution was continuously recycled through the glass fibers held in a fixed bed reactor. Different process parameters were tested. Reservoir volume and initial enzyme concentration both had a strong influence on final glucoamylase loading. The recycle rate affected the rate of loading but not the final amount of loaded enzyme. Glucoamylase was found to be nonuniformly distributed within the fibers with penetration depths never higher than 5.75 μm, half of the fiber radius. This factor could be important in improving the immobilized glucoamylase hydrolysis of dextrin syrups.
Scottish shale oil—production, occupational exposure and health effects
Authors: Scott Carleton B. , Irish Glenn E.
Published: July 2010

Expansion of shale oil production to commercial scale in Colorado, USA required an investigation of potential adverse health effects that could result from exposure to raw shale oil, intermediate streams and final products. Comparison of Scottish shale oil products, operations, occupational exposures and adverse health effects with shale oil products and operations planned for Colorado showed the importance of severe hydro‐treating of raw shale oil to remove biologically active molecules (believed to be mainly aromatic heterocyclics) that apparently were responsible for most of the adverse health effects experienced by Scottish shale oil workers, neighbors and users.
A simple model for the reaction of normal octane on pt/al2o3 catalyst
Authors: Ako Churchill T. , Susu Alfred A. , Gobina Edward N.
Published: July 2010

Design parameters were obtained from a simple model developed for the catalytic reaction of normal octane on platinum—alumina catalyst. The relevant equations were solved analytically and graphically. The model did not involve intramolecular and intermolecular mass transfer phenomena because of the particle size (0.1–0.4 mm); it took into account kinetic phenomena and was applied in predicting conversion—temperature and conversion—reactor length profiles. Conversion—temperature profiles obtained from the model compared favourably with those obtained experimentally.
Hydrolysis of sugar cane bagasse with hydrochloric acid: Separation of the acid by pervaporation. Evaluation of the bergius process
Authors: Schuchardt Ulf , Joekes Inés , Duarte Humberto C.
Published: July 2010

Polyester reinforced PTFE membranes with a nominal pore size of 0.02 μm are very effective in pervaporating HCl gas from hydrochloric acid solutions and cellulose hydrolysates. The efficiency of such membranes, which may be as high as 1.8x10−2 mmol HCl min−1 cm−2 at 40°C, is almost independent of the flow rate and the static pressure of the acidic solution but depends strongly on the acid concentration. At an acid concentration of 26% (w/v) the pervaporation of HCl is negligible at 40°C, but can be accelerated by increasing the temperature. A slow increase of temperature during the pervaporation process is proposed, as this promotes post‐hydrolysis of the sugars. Lithium chloride induces structural changes in the membrane which increase efficiency without compromising performance. The use of this new technology in conjunction with the original Bergius process could improve the performance of the latter and reduce its overall costs. The use of the improved process for the hydrolysis of sugar cane bagasse could double the yields of sugar or alcohol per hectare of planted sugar cane.
Fractionation of dextran using repetitive batch chromatography
Authors: Barker P. E. , England K. , Ganetsos G.
Published: July 2010

The fractionation of broad dextran fractions using preparative scale gel permeation chromatography has been carried out. A batch system was used, consisting of ten borosilicate columns, each of 5.1 cm i.d. and 70 cm long and packed with Spherosil XOB075 porous silica beads.

The repetitive injection technique was employed and the effects of feed, charge volume and concentration on the molecular weight distribution of the products were evaluated.
Acid catalysed pressure synthesis of n‐ethylbenzylamine from benzylamine and ethanol
Authors: Deka Dibakar C. , Nandi Dilip K. , Palit Sunanda K.
Published: July 2010

The synthesis of N‐ethylbenzylamine from benzylamine and ethanol in the presence of an acid catalyst has been carried out under pressure. Under optimum conditions (497 K, 6.3417 MPa, residence period 1 h, benzylamine to ethanol mol ratio 1:3 and benzylamine to hydrochloric acid mol ratio 1:1), the conversion of benzylamine to N‐ethylbenzylamine is 78.39%.
Air‐lift reactors in chemical and biological technology
Authors: Merchuk Jose C. , Siegel Marc H.
Published: July 2010

The principle of the air‐lift reactor is finding wide application in the fields of both chemical technology and biotechnology because it offers simple and effective mixing in three‐phase processes involving gases, liquids and solids. The air‐lift principle offers advantages of no moving parts, high gas absorption efficiency, good heat transfer characteristics and rapid mixing which are applicable in a range of industrial processes. This review considers specific aspects of air‐lift reactors emphasizing their function and relevance to particular applications. The two main groups of air‐lift reactor, baffled vessels and external loop reactors, have four main component parts in common, the riser, the downcomer, the base and the gas separator, all of which have distinct characteristics. The performance of these four components with respect to flow configurations, fluidization of suspended solids and mass transfer are discussed together with methods of evaluating mass transfer coefficients.
The effects of oxygen on β‐lactam biosynthesis by alginate entrapped streptomyces clavuligerus
Authors: Scott Robert I. , Sladen Susan , Maidment Mandy , Rashid Tahira , Pratsis Christos , Perry David
Published: July 2010

The physiology of Streptomyces clavuligerus has been studied by investigating oxygen uptake and β‐lactam (clavulanic acid) production by free and alginate entrapped cells. The specific oxygen uptake rate of cells entrapped in strontium or calcium alginate was only about 35% of the rate in free cells. This reduction in oxygen uptake was due to reduced internal diffusion of oxygen; in addition calcium, barium and strontium ions could also cause oxygen uptake in free cells to be inhibited. Measurements of the deformation of individual gel beads showed that maximum hardness was reached after 15 min exposure to 0.14 mol dm−3 Ca2+. Exposure of cells to Ca2+ for this time caused a 15% reduction in the rate of oxygen uptake. Levels of clavulanic acid produced by free cells were higher than those produced by immobilized cells; production was dependent on the degree of aeration of the cells.
Batch alcoholic fermentation modelling by simultaneous integration of growth and fermentation equations
Authors: Gòdia F. , Casas C. , Solà C.
Published: July 2010

The modelling of batch growth and fermentation data presents important disadvantages when numerically calculated specific rates are used. In this paper, the results obtained using a different technique, based on the integration of the differential rate equations in the modelling of batch alcoholic fermentation with Saccharomyces cerevisiae at different temperatures and initial sugar concentrations, are presented, and the use of both techniques is discussed.
Production of protease by bacillus subtilis using simultaneous control of glucose and ammonium concentrations
Authors: Kole M. M. , Draper I. , Gerson Donald F.
Published: July 2010

Batch, ammonium‐controlled and simultaneous glucose and ammonium controlled fermentations were compared for the production of protease by Bacillus subtilis NCIB 8054. During fermentations of B. subtilis, maximum protease production was obtained in the stationary phase. Protease production in fermentations controlled at 5 mmol dm−3 ammonium was 1.5 times greater than in uncontrolled batch fermentations. Simultaneous control of ammonium at 5 mmol dm−3 and glucose at 0.15 g dm−3 using controllers based on an ammonium electrode and an oxygen electrode, doubled protease production compared with fermentations having only an ammonium control and tripled protease production compared with uncontrolled batch fermentations. The protease yield on glucose and protease yield on ammonium was increased in fermentations with simultaneous glucose and ammonium control.
Studies on sulphatization—I. Sulphatization of manganese ore with pyrite
Authors: Nayak Binod Bihari , Parida Kulamani , Rao Sreepada Bhanojee
Published: July 2010

The sulphatization of low grade manganese ore with iron pyrites has been studied. The effect of reaction period, temperature, ratio of manganese to sulphur, particle size, surface area and packing density was investigated and the extent of sulphatization was reported as recovery of manganese sulphate. Under optimum heating time of 2 h at 600°C with finely powdered (−150±200 mesh BSS pyrite and −300±325 mesh manganese ore) reactants, the conversion to manganese sulphate was 82%.
A continuous‐flow method for the rapid determination of sanitary quality of grape must at industrial scales
Authors: Zouari Nabil , Romette Jean‐Louis , Thomas Daniel
Published: July 2010

A rapid method for the continuous‐flow determination of laccase activity in grape must has been developed. The system was automated and permitted online measurement with less than 5% error.

The feasibility of the system in industrial conditions was proved in vinification plants with grape musts and wines. The capacity of musts to consume oxygen during sulphur dioxide treatments was also followed.
Estimation of total aromatics in kerosene fractions by infrared spectroscopy—II
Authors: Ramaswamy Veda , Kothiyal Vimal , Singh Indra D. , Krishna Rajamani
Published: July 2010

A general equation for the quick and accurate estimation of total aromatics in straight run kerosene fractions is derived using i.r. absorbances at characteristic wavenumbers from aromatic concentrates of kerosene of different crude oils. The accuracy of the method is found to be ±5%. When compared with the FIA method the deviation was found to be within 5.5%.
Evaluation of acids and cellulase enzyme for the effective hydrolysis of agricultural lignocellulosic residues
Authors: Tewari H. K. , Marwaha S. S. , Kennedy J. F. , Singh L.
Published: July 2010

This paper reports the results of experimentation carried out to compare the ability of mineral acids (HCl and H2SO4) and cellulase enzyme (from Trichoderma reesei QM 9414) in the saccharification of corn‐cob, groundnut shell, sugarcane bagasse and wheat straw. With the exception of corn‐cobs, acids proved to be better saccharifying agents than the cellulase complex, but the former gave a poor substrate for alcoholic fermentation since the saccharified mashes contained large amounts of pentoses which are not metabolized by most strains of yeast. In addition, both acids and enzymes have been found to be substrate specific. Maximal saccharification of groundnut shell, sugarcane bagasse and wheat straw were obtained with sulphuric acid at 15.0, 5.0 and 5.0% (v/v) under 15, 15 and 15 psi pressure for 15, 30 and 30 min, respectively; whereas hydrochloric acid at 7.5% (v/v) with. autoclaving for 30 min at 10 psi resulted in maximum saccharification of corn‐cob. However, the order of susceptibility of substrates to enzymatic attack was corn‐cob > wheat straw > sugarcane bagasse > groundnut shell. Increase in enzyme concentration (1–4 IU ml−1) and treatment duration (12–72 h) improved saccharification, but increases in substrate concentration (>5.0%, w/v) had an inhibitory effect on the hydrolytic ability of the cellulase enzyme complex. Of the various substrate‐acid ratios tested, a ratio of 1:8 was found to be optimal for the eflcient hydrolysis of the substrates under study.
Porosity and texture of basic zirconium nitrate
Authors: Gimblett F. Gareth R. , Hussain Asiah , Sing Kenneth S. W.
Published: July 2010

Studies have been made of the development of texture and porosity in basic zirconium nitrate samples subjected to heat treatment at temperatures between 25 and 500°C. Scanning electron microscopy indicates that progressive disintegration of the amorphous material occurs over this temperature range, generating approximately spherical particles. Nitrogen gas adsorption studies, supplemented by mercury porosimetry measurements, show that these particles possess some microporosity (pore diameter < 2 nm), although the major factor controlling their adsorptive properties is an intrinsic mesoporosity related to a pore diameter within the range 2–50 nm and produced by the successive elimination of water and nitrato ligands with increasing temperature. Crystallisation occurs when the system is heated above 500°C, leading to the conversion of the amorphous material to the cubic variety of zirconia.
Effect of uv absorbers containing singlet oxygen quenching groups on the photochemical stability of crystal violet lactone and related colours
Authors: Oda Hironori
Published: July 2010

The photofading behaviour of Crystal Violet Lactone was investigated in solution. The contribution of singlet oxygen to that fading was suggested. UV absorbers containing nickel sulphonate quenching groups were prepared and the protecting effect of these compounds towards the photofading of colour materials derived from colour formers was examined in solution and in solid state. It was proposed that nickel salts of 2,2′‐dihydroxy‐4,4′‐dimethoxybenzophenone‐5‐sulphonic acid and its derivative can be applied as effective stabilisers against the photofading of indicator dyes in pressure (or heat) sensitive recording systems.
Characterization of a chemically modified β‐amylase immobilized on porous silica
Authors: Germain Pierre , Crichton Robert R.
Published: July 2010

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.
The cross‐flow filtration of an unstable β‐lactam antibiotic fermentation broth
Authors: Harris Tim A. J. , Reuben Bryan G. , Cox David J. , Vaid Aloke K. , Carvell John
Published: July 2010

A ceramic cross‐flow filter has been evaluated in a recycle loop connected to a bioreactor containing a viscous Streptomyces sp. broth. Because of the instability of the antibiotics formed, it would be advantageous to extract them continuously as they are produced.

The performance of the filter, under conditions of high viscosity and suspended solids, has been calculated. Resistance to filtrate flux, distribution of the antibiotic and sterilisability within the system were also examined.

An initial flux at a cross‐flow velocity of 4 ms−1 gave readings of 162 litres m−2 h−1, which dropped to 131 litres m−1 h−1 on subsequent runs because of ‘bedding‐in’. Fluxes were improved by an increase of cross‐flow velocity and, for short periods, by applying pressure. They were reduced by anti‐foam agents and the gradual build‐up of particle polarisation layers. Loop sterilisation and removal of the antibiotic in the filtrate stream were excellent.
Barium aluminate hydrates: Part V. 2BaO·Al2O3·2H2O and 2BaO·Al2O3
Authors: Ahmed A. H. Moinuddin , Glasser Lesley S. Dent
Published: July 2010

A new compound of formula 2BaO·Al2O3·2H2O has been synthesised and studied by infra‐red, X‐ray and thermal analytical techniques. This hydrate yielded another crystalline product, 2BaO·Al2O3, during dehydration.
Wollastonite as adsorbent for removal of Fe(II) from water
Authors: Singh A. K. , Singh D. P. , Panday K. K. , Singh V. N.
Published: July 2010

Wollastonite was used as an adsorbent for the removal of Fe(II) at different experimental conditions. The extent of removal is favourable at low concentration and low temperature. Maximum adsorption was noted at pH 4.0. The batch adsorption kinetics has been described by a first order rate expression, and the surface mass transfer coefficients and diffusion coefficients have been calculated at different temperatures. The intraparticle transport of Fe(II) within the pores of wollastonite is found to be the rate limiting step. The applicability of the Langmuir isotherm for the present system has been tested at different temperatures. Thermodynamic parameters indicate the exothermic nature of Fe(II) adsorption on wollastonite. The variation of adsorption with pH has been explained on the basis of interaction of iron species with negatively charged constituents of adsorbent.
Kinetics of saccharification of raw starch by glucoamylase
Authors: Matsumura Masatoshi , Hirata June , Ishii Satoshi , Kobayashi Jiroh
Published: July 2010

A kinetic model for saccharification of raw starch was derived by taking into account the structural features of glucoamylase. The kinetic parameters were determined by using the results of experiments on saccharification of raw sweet potato starch, which were carried out at various substrate and enzyme concentrations in a temperature range from 23 to 40°C. From analysis of the experimental results it was concluded that the adsorption of enzyme was strongly dependent on temperature, and that two subsites took part in glucose inhibition, which was more pronounced at low temperature. The proposed kinetic model successfully predicted the progress of saccharification up to a high conversion, and also the progress of ethanol production in a simultaneous saccharification and fermentation.
On the retention of n‐butylamine by crystalline and fibrous cerium(IV) phosphate
Authors: Arjona A. Mata , Rodríguez A. García , Bueno F. del Rey , Sánchez E. Villafranca , Conejo G. López
Published: July 2010

The retention of n‐butylamine dissolved in cyclohexane on both crystalline and fibrous cerium(IV) hydrogen phosphate has been studied. The products involved were characterized by thermogravimetry, derivative thermogravimetry, differential scanning calorimetry, IR spectroscopy and X‐ray diffraction. The experimental results obtained reveal that the adsorption of n‐butylamine from cyclohexane solutions results in a net increase in the lattice space of the crystalline variety of the phosphate. Integral enthalpies and entropies, isosteric heats and differential entropies of retention were calculated from the adsorption isotherms run at 10, 15, 20, 25 and 30°C. The results show that variation of the different thermodynamic parameters with the degree of coverage for the two types of phosphate to be rather different.
Characterization and application of glucose oxidase immobilized in silica hydrogel
Authors: Kojuharova Ani , Popova Yanka , Kirova Nadejda , Klissurski Dimitar , Simeonov Danail , Spasov Liubomir
Published: July 2010

The properties of glucose oxidase (EC1134) embedded in silica gel were investigated. The immobilized preparations retained 62% of the activity of the mobilized enzyme. The optimum pH value (5.8) and temperature (30°C) were the same for the immobilized as for the soluble enzyme, but immobilized glucose oxidase had higher thermal and pH‐stability. The constants of thermal and pH inactivation, and the Michaelis constants were calculated.

The effects of various cations and proteins on the activity of the immobilized enzyme were studied; NH4, K+, Mg2+ and gelatin all increased the relative activity of the preparations to 93–96% of the soluble enzyme.

Combined immobilized preparations of glucose oxidase and catalase were repeatedly used in the oxidation of D‐glucose and the preparation of calcium gluconate.