bluuebunny/crossref_metadata_2025_split huggingface dataset:
Development of a pilot‐scale microfiltration harvest for the isolation of physostigmine from Streptomyces griseofuscus broth
Authors: Russotti Gregory , Göklen Kent E. , Wilson James J. 
Published: May 2005

AbstractA pilot‐scale microfiltration harvest was developed for the isolation of physostigmine from a mycelial fermentation broth. Complete permeation for this extracellular secondary metabolite was obtained during initial laboratory screening with a variety of crossflow filtration membranes but poor filtration flux made process feasibility uncertain. Modification of the fermentation medium improved fluxes from 10–20 dm3 m−2 h−1 to 60–80 dm3 m−2 h−1 which significantly reduced membrane area requirements, making the process feasible for larger scale implementation. A commercially‐available ceramic membrane with 0·2 μm pores was employed for the scale‐up of this step to the pilot plant; this membrane was found to provide flux similar to that of polymeric membranes and had superior regeneration characteristics. Optimum performance at bench scale was obtained using 70 kPa transmembrane pressure and 4·0 m s−1 crossflow velocity. The mycelial broth had a very high suspended solids concentration (30% (v/v)) which limited us to a two‐fold concentration before starting the diafiltration washes. The process was scaled‐up to the 200–400 dm3 scale, with good reproducibility and excellent membrane regenerability observed in a series of five experiments. An increase in membrane loading did result in a decreased average flux at the larger scale (47·6 dm3 m−2 h−1), which indicated the importance of this parameter. A centrifugal pump was substituted for a positive displacement pump upon scale‐up and performed well if provided with the appropriate suction head. Scale‐up in general was straightforward, provided proper attention was given to the hydraulic design of the system.
Color difference measurement and color removal from dye wastewaters using different adsorbents
Authors: Yeh Ruth Yu‐Li , Thomas Adrian 
Published: May 2005

AbstractPollution from textile mills is a problem of formidable dimensions and color removal is the most perplexing problem facing environmental engineers designing appropriate treatment facilities for textile wastewaters. The CIE colorimetric system has been used in this study to measure the color in the treatment of disperse‐red‐60 dye wastewater using different adsorbents. The color removal is determined by using the CIE 1976 L*a*b* (CIELAB) color difference equation. The effect of contact time and dosage on color and color removal has been investigated for various adsorbents, namely, powdered activated carbon, granular activated carbon, activated alumina, molecular sieves and diatomite.
Oxidative dehydrogenation of ethyl alcohol over vanadium pentoxide supported on magnesia
Authors: Said Abd El‐Aziz A. , Abd El‐Wahab Mohamed M. M. 
Published: May 2005

AbstractThe catalytic dehydrogenation of ethyl alcohol on vanadium pentoxide supported on magnesia was studied in a flow system. The catalysts were characterised by DTA, X‐ray, surface area and electrical conductivity measurements. The results revealed that the yield of acetaldehyde is strongly affected by the nature of compounds formed as a result of the interaction between MgO and V2O5. The Mg3V2O8 formed at a calcination temperature of 550°C is the most active and selective catalyst. The activity of this spinel was correlated with the creation holes and the position of the Fermi potential. On the other hand, the catalyst calcined at 650°C was accompanied by the formation of an MgV2O6 spinel, which exhibited low activity and low selectivity.
Enantioselective separation of basic amino acids on talc
Authors: Arrou Dominique , Baboulène Michel 
Published: May 2005

AbstractCertain amino acid derivatives (ε‐basic, anilide group) can be readily adsorbed onto various types of talc (steopac, SS20, C300, C400). For instance, talc is capable of adsorbing the amino acid esters but not the equivalent free amino acids. The types of talc which have high hydrophobicity (00, 15M00) were poor adsorbents. Two applications of these findings are presented: enhancement of the sensitivity of enzymatic tests in the presence of chromogenic substrates and enantioselective separation of ε‐basic amino acids (arginine, lysine, ornithine).
Preparation of 4‐bromophthalic anhydride by oxidation of 4‐bromo‐ortho‐xylene
Authors: Glukhovskii Naum , Effenberger Reinhard 
Published: May 2005

AbstractThe preparation of 4‐bromophthalic anhydride is described. This compound, useful as raw material for production of dianhydride monomers such as bisphthalic dianhydride, oxy‐bisphthalic dianhydride and several bisphenol dianhydrides for the specialty polyimide sector, was prepared via gas phase oxidation of 4‐bromo‐ortho‐xylene with air over a V–Ti–P catalyst in a yield of 85%. Oxidation of 3‐bromo‐ortho‐xylene gave only a 45% yield of 3‐bromophthalic anhydride. Mixtures of 4‐ and 3‐bromo‐ortho‐xylene gave, as expected, mixtures of 4‐ and 3‐bromophthalic anhydride which were enriched in the 4‐isomer (in comparison with the starting bromoxylene isomeric composition).
A method for estimating the state variables and parameters of fermentation systems
Authors: Maher Mostafa , Roux Gilles , Dahhou Boutaib 
Published: May 2005

AbstractA major difficulty in the monitoring and control of bioprocesses is the lack of reliable and simple sensors for following the evolution of the main state variables and parameters such as biomass, substrate, product and growth rate. An adaptive estimation algorithm is proposed to recover the state and parameters in bioprocesses. This estimator utilises the physical process model and the reference model approach. Experiments concerning estimation of biomass and product concentrations and specific growth rate, during batch, fed‐batch and continuous fermentation processes are presented. The results show the performance of this adaptive estimation approach.
Synthesis and evaluation of some fatty esters as plasticizers and fungicides for poly(vinyl acetate) emulsion
Authors: Sadek E. M. , Motawie A. M. , Hassan A. M. , Gad E. A. 
Published: May 2005

Abstractn‐Fatty alcohols (average molecular weight 187), prepared from n‐paraffins, were treated with a series of dibasic acids such as malonic, succinic, glutaric, adipic and phthalic anhydride to give the corresponding fatty esters. The prepared fatty esters were formulated with poly(vinyl acetate) emulsion and used as films or textile coatings. Tests such as rate of drying, mechanical properties and resistance to micro‐organisms were carried out. Samples of poly(vinyl acetate) plasticized with dibutyl phthalate were also prepared and evaluated for the purpose of comparison. The antifungal activity of these compounds was studied. The results obtained indicate that the prepared fatty esters can be used not only as plasticizers but also as fungicides and in some respects they are better than the conventional dibutyl phthalate plasticizer.
Methacrylic acid–acrylamide‐g‐poly(ethyleneterephthalate) fibres for urea hydrolysis
Authors: Elçin Y. Murat , Saçak Mehmet 
Published: May 2005

AbstractThis paper presents the results of urease immobilization onto methacrylic acid–acrylamide grafted poly(ethyleneterephthalate) fibres. The graft yield strongly affected the maximum activity of the immobilized enzyme up to a value of 70·2%. Higher grafting caused a decline in urease activity and led to the degradation of the fibres. The minor changes observed in Km and Vmax demonstrated that the conformational changes existed during immobilization were not extensive. However, 70·2% methacrylic acid–acrylamide‐g‐fibres containing urease were more stable towards acidic and alkaline pH, high temperature and storage conditions compared with free enzyme. Apart from the increase in stability to heat inactivation, the initial enzymatic activity of the urease–fibre system remained almost unchanged even after 40 repeated assays corresponding to 10 h of operation in 4 months, indicating the excellent durability of the system.
Hydrolysis of lecithin by phospholipase A2 in mixed reversed micelles of lecithin and sodium dioctyl sulphosuccinate
Authors: Morgado M. A. P. , Cabral J. M. S. , Prazeres D. M. F. 
Published: May 2005

AbstractThe hydrolysis of egg yolk lecithin was studied as catalysed by porcine pancreatic phospholipase A2 (phosphatide 2‐acyl‐hydrolase, EC 3.1.1.4) entrapped in reversed micelles of lecithin and sodium dioctyl sulphosuccinate (AOT) in isooctane. The influence of relevant parameters such as temperature, pH, water content, and buffer, AOT, lecithin, calcium and enzyme concentrations was investigated. The order in which the reactants were mixed showed a strong influence on catalytic activity. Higher activities were obtained if the enzyme, water and calcium were first solubilized and pre‐equilibrated in plain AOT reversed micelles before the addition of the substrate. Maximum activity was obtained at 750 mmol dm−3 calcium in the water pool of the micelles, which is an extremely high concentration when compared with the values reported in the literature. This was related to the formation of divalent chelates of calcium with AOT that compete with the binding of the co‐factor to the enzyme. Accordingly, the optimum concentration of calcium in the inner core of the micelles decreased from 750 to 500 mmol dm−3 when the AOT concentration was lowered from 15 to 10 mmol dm−3.
Mean residence time of gas in mechanically agitated gas–liquid contactors
Authors: Murugesan Thanapalan , Rathnam G. S. Venkat , Rao S. Panduranga , Rao P. Gangadhar 
Published: May 2005

AbstractIn the present study of gas–liquid contactors, mean residence/contact time was calculated from knowledge of superficial velocity and the gas phase hold‐up, for various gas rates and impeller geometry and speeds, and compared with values obtained from RTD measurements. A new correlation, involving Flow Number, Froude Number, system geometry and the physical properties, is proposed. This uses the authors data and those available in literature.
Solid‐phase acylating reagents. Part III. The reactions of a macroreticular acetyl polystyrenesulphonate with aniline in aqueous, dichloromethane, dimethylformamide, dioxan and ethyl acetate solutions and with acetone in aqueous solutions
Authors: Laird Robert M. , Pandit Subash 
Published: May 2005

AbstractThe effectiveness of a macroreticular matrix in reducing side‐reactions in the reaction of acetyl polystyrenesulphonate with aqueous aniline has been investigated. Results were comparable with those for the 2% cross‐linked resins and the use of four non‐aqueous solvents gave neither any improvement in the acetanilide yield nor in its purity. The synthesis of isopropenyl acetates by reacting the reagent with acetone was explored.
Characterization of biomass from a pilot plant digester treating saline wastewater
Authors: Omil Francisco , Méndez Ramón J. , Lema Juan M. 
Published: May 2005

AbstractThe evolution of biomass contained in a pilot‐scale digester treating wastewater from a sea‐food processing factory (15–45 g Chemical Oxygen Demand (COD) dm−3 and high salinity) was studied for 2 years. During this period, different effluents have been treated and several operational conditions were followed. Laboratory‐scale experiments were carried out to determine the sludge methanogenic activity and the salinity adaptation of the biomass which developed in the digester. During the different periods, sludge concentration remained between 10 and 12 g Volatile Suspended Solids (VSS) dm−3, a value that seems to be characteristic for this reactor. A global Organic Loading Rate (OLR) balance showed no significant change of biomass concentration inside the reactor, although a quite important growth of biomass (11·5% of OLR fed) was observed. Methanogenic activity assays indicated a sludge with a good activity (0·5–0·75 g COD g−1 VSS day−1) in a saline medium could be obtained from a low activity sludge (0·047 g COD g−1 VSS day−1). Toxicity assays showed the importance of antagonistic effects of other cations on the toxicity exerted by sodium.
Synthesis of fatty esters by polyethylene glycol‐modified lipase
Authors: Basri Mahiran , Ampon Kamaruzaman , Yunus Wan Md. Zin Wan , Razak Che Nyonya A. , Salleh A. Bakar 
Published: May 2005

AbstractMonomethoxypolyethylene glycols (PEG) of molecular masses 1900 and 5000 were activated using p‐nitrophenyl chloroformate to form PEG–nitrophenyl carbonates (activated PEG) with high yield (96–98%). The activated PEG was covalently attached to Candida rugosa lipase. Increasing the molar ratio of activated PEG to the enzyme increased the degree of lipase modification. These modified lipases exhibited specific ester synthesis activities on organic solvents compared with native lipase. The degree of activity enhancement depended on the size of activated PEG used and the degree of modification of the enzyme. Maximal activity was attained after exhaustive of modification. The effects of different solvents, reaction temperature, and fatty acids on the esterification activity and the stability of the modified enzyme were investigated. The optimum esterification temperature (40° C) and preference of fatty acids as acyl donors of the modified lipase were very similar to those of the native enzyme. The modified lipase exhibited higher activity non‐polar solvents than in polar solvents, and showed higher temperature, solvent and storage stability then the native lipase.
Determination of relative wettability of porous sandstones by imbibition studies
Authors: Grattoni Carlos A. , Chiotis Efstathios D. , Dawe Richard A. 
Published: May 2005

AbstractThe effective wettability of consolidated sandstone rocks has been determined using the Washburn equation by measuring the rate of imbibition of water, ethanol and their mixtures into cores and thin rectangular sections. The rocks behaved as low energy surfaces with a critical surface with a critical energy of spreading as defined by Zisman, of 28 mN m−1. This behaviour is believed to be caused by clay particles or organic material present on the pore surfaces. A discussion of the validity and limitations of the Eashburn equation for obtaining effective wettabilities in consolidated porous media is presented. The general conclusion is that effective wettability depends on the preparation and general conditions of the samples.
Hydrolysis of ricebran oil in a fluidised‐bed recycle reactor using immobilised lipase on nylon‐6
Authors: Padmini P. , Iyengar K. K. S. , Baradarajan A. 
Published: May 2005

AbstractA recycling fluidises‐bed Immobilised enzyme reactor for the hydrolysis of ricebran oil employing an inexpensive Nylon‐6 matrix as the immobilisation carrier is described. The catalyst has high initial activity and excellent long term stability. The tractor design exploits the fact that fluidisation permits the use of small catalyst particles, so overcoming the yield‐limiting diffusion‐associated problems encountered in the case of conventional fixed‐bed reactors. The conventional fluidised‐bed reactor did not plugging and high pressure drop problems typical of fixed‐bed reactors. Conversion yields of 72% were achieved in the reactor, which generally showed superior performance to that of a fixed‐bed design.
The cocurrent downflow contactor (CDC) as a fixed bed and slurry reactor for catalytic hydrogenation
Authors: Boyes Adrian P. , Chugtai Arshad , Khan Zaffer , Raymahasay Sugat , Sulidis Andrew T. , Winterbottom John M. 
Published: May 2005

AbstractThe Cocurrent Downflow Contactor (CDC) has been studied as a three phase reactor and in addition, chemically enhanced mass transfer studies have confirmed the very high gas hold‐up values previously indicated by photographic methods (εg = 0·5–0·6). Mass transfer measurements for the O2/H2O system have shown that volumetric mass transfer coefficients (kL a) are in the range 0·25–0·3 s−1 for unpacked and packed CDC reactors, while Co2+ ion‐catalysed sulphite oxidation exhibited enhanced (kL a) are in the range 0·25–0·3 s−1 for unpacked and packed CDC reactors, while Co2+ ion‐catalysed sulphite oxidation enhibited enhanced (kLa) values of 0·55 s−1 with interfacial areas in the range of 1000–6000 m2 m−3. A model first order reaction, the palladium‐catlysed hydrogenation of itaconic acid, was examined both in a small stirred batch reactor and in the CDC. Low degrees of mass tranfer resistances were observed (both gas–liquid and liquid–solid) especially in the case of the CDC when used as a slurry and fixed bed reactor, with liquid‐solid mass transfer resistances being the the range 1–10%. This was confirmed by energy of activation measurements in the range 30–45 kJ mol−1. The CDC was used in slurry and fixed bed form for the respective hydrogenation of the triglycerides, rapeseed and soyabean oils. The reaction was predominantly surface reaction rate controlled with energies of activation in the range 47–58 kJ mol−1, using palladium and nickel catlysts. Reaction selectivities were high, especially in respect of linolenate removal and the fixed bed CDC was slightly superior to the slurry reactor.
Affinity chromatography of glucose‐specific lectin using silica‐based support
Authors: Lee Wen‐Chien , Hsiao Cheng‐Chung , Ruaan Rouh‐Chyu 
Published: May 2005

AbstractFour silica‐based adsorbents were prepared from covalent attachment of four carbohydrates: i. e. maltose, cellobiose, N‐acetyl‐D‐glucosamine and p‐aminophenyl‐β‐D‐glucopyranoside, respectively. These adsorbents posses either terminal D‐glucose or N‐acetyl‐D‐glucosamine as the ligand on their surfaces with a ligand density ranging from 20 to 29·2 μmol g−1. The binding of the glucose‐specific lectin, concanavalin A (Con A), to the immobilized ligand on the silica surface depended on the configuration of the immobilized glucose and the linkage of the glucose to the support. Con A showed strong affinity for maltose‐immobilized silica, which contains terminal α‐D‐glucose, and p‐aminophenyl‐β‐D‐glucopyranoside‐immobilized silica. On the other hand, Con A showed no affinity for cellobiose‐immobilized silica, which contains terminal β‐D‐glucose groups, and N‐acetyl‐D‐glucosamine‐immobilized silica. The binding constants for the interactions between Con A and immobilized ligands were determined. The columns packed with the resultant affinity adsorbents were then adopted for the purification of Con A from Jack bean meal. As the diluted NaCl extract of Jack bean meal was applied to the column packed with maltose‐immobilized silica, a 13·2‐fold purification was achieved by stepwise‐elution.
Gelling of alginate fibres
Authors: Thomas Adrian , Gilson Christopher D. , Ahmed Tanveer 
Published: May 2005

AbstractEquipment was developed to measure the time for complete gelling of sodium alginate fibres in calcium chloride solution, taken as the time to achieve maximum tensile strength. The effects of fibre diameter, alginate concentration, alginate composition and calcium chloride concentration on gelling time were investigated. A diffusional model, developed to predict the gelling time, agreed with experimental results except for the effect of calcium ion concentration which was modelled empirically.
Recovery of vegetable tannins from divi‐divi pods
Authors: Pérez‐Tello Carlos , Quintana‐Hernéndez Pedro 
Published: May 2005

AbstractAn experimental survey was developed to determine optimal operational conditions when extracting tanning materials from mied divi‐divipods with a 10% (v/v) alcohol–water solution. The study included runs at both laboratory and pilot levels. The percentage of extracted tanning materials from samples was measured when varying the following variables: (1) temperature, (2) solvent to solute ratio, (3) extracting time, (4) type of solvent, (5) agitation, and (6)average particle size. The optimal values were as follows: 50°C, 120 cm3 of solvent: 1 g of divi‐divi, 20 min, 10% (v/v) ethanol–water, agitation on, and 0.087 cm average particle size. The maximum yield of extracted tanning materials was 54 by weight (dry basis) when divi‐divi pods up to 6 months old were used, but the tannic content in pods decreased by 15% and 32% after 12 and 42 months of storage respectively.
Application of membrane filtration to glutamic acid recovery
Authors: Huang Shaoxun , Wu Xingyan , Yuan Cengxiang , Liu Tiemin 
Published: May 2005

AbstractA method for recovery of glutamic acid from fermentation broth using microfiltration, diafiltration, and reverse osmosis has been proposed. Coupled with the technique of semi‐continuous isoelectric crystallisation, the method gave a product of 3·3% higher purity with 11.1% higher yield compared with the conventional method.
Physico‐chemical methods for characterization of the physiological state of microorganisms
Authors: Zentgraf Brigitte 
Published: May 2005

AbstractThe physiological state of microorganisms should be considered in biotechnology and biosciences since this influences the rate and efficiency of cellular processes. Physico‐chemical methods, such as biocalorimetry and laser flow cytometry, and other spectroscopic methods for determination of biochemical data, such as concentration of NADH, ATP and cytochrome c, are suitable for describing the physiological state.
Flat‐sheet and hollow fiber membrane bioreactors: A study of the kinetics and active site conformational changes of immobilized papain including sorption studies of reaction constituents
Authors: Ganapathi Sowmya , Butterfield D. Allan , Bhattacharyya Dibakar 
Published: May 2005

AbstractPapain, a sulfhydryl protease has been immobilized on flat‐sheet modified polysulfone membranes and hydroxyethyl cellulose coated polyethersulfone hollow fibers. Amidase activity of the enzyme in solution on the membranes has been assayed. Immobilized papain on the modified polysulfone membrane and the hollow fibers retains 12% and 25% of its activity (with 1 mmol dm−3 substrate) in solution, respectively. Loading experiments revealed decreased activity on the modified polysulfone membrane with increased enzyme loading. Adsorption experiments for the reaction product, p‐nitroaniline, have been performed and an attempt has been made to correct for this in activity calculations. Apparent Michaelis–Menten parameters were determined for the modified polysulfone and hollow fibers with both Km and Vmax being lower in the immobilized cases. Electron paramagnetic resonance study of the changes in active site conformation of an enzyme on a hollow fiber membrane are reported for the first time. Experiments using the sulfhydryl‐specific (1‐oxyl‐2,2,5,5‐teetrahyl‐Δ3‐pyrroline‐3‐methyl)methanethiolsulfonate spin label depicted the presence of two subpopulations of immobilized papain on the hollow fibers, one of them active and one denatured.
Production of L‐aminoacylase by fermentation of Pseudomonas sp. BA2
Authors: Santoyo Antonio Bódalo , Rodríguez Josefa Bastida , Carrasco José Luis Gómez , Gómez Elisa Gómez , Teruel María Luisa Asanza , Rojo Isabel Alcaraz 
Published: May 2005

AbstractThe growth and enzymatic production of Pseudomonas sp. BA2 a new L‐aminoacylase‐producing microorganism, were studied in a bench‐top fermenter. Multiple fermentations were carried out in order to determine the optical pH and temperature values. The influence of the substrate concentration on both growth and Laminoacylase activity was also investigated. The maximum growth rate and the greatest yield of enzyme were obtained when the fermentation was carried out at pH 7·5, 25°C and DOT ≥ 50%. N‐Acetyl‐DL‐alanine, at a concentration 20 g dm−3, was used as the sole carbon and nitrogen source. The fermentation process provided a maximum biomass concentration of 3·36 g dry weight dm−3. The highest L‐aminoacylase production (11429 U g−1 dry weight) was obtained after 39 h of cultivation. The results were a significant improvement over those previously reported.