bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen plasma modification of wool fibre surfaces
Authors: Bradley R. H. , Clackson I. L. , Sutherland I. , Crompton J. A. , Rushforth M. A. 
Published: July 2010

AbstractA range of oxygen plasma treatments has been used to modify the surfaces of woven and fibrous wool samples. The resulting chemistry and composition have been characterised using X‐ray photoelectron spectroscopy (XPS). The extent of oxidation of di‐sulphide bonds to sulphur (SVI), in the form of sulphonic acid groups (−SO3H), by the plasma is shown to be only about 20–30% compared to 100% using a conventional wet chlorination process. However, the plasma does appear to react with surface carbon of the protein structure, leading to an increase in carbon‐oxygen functionalities. Total levels of surface oxygen achieved using the plasma technique are similar to those from the wet process.
Synthesis and application of novel sulpha drugs based on quinoxaline‐2‐one and/or quinoxaline‐2‐thione
Authors: Awad Ibrahim M. A. 
Published: July 2010

AbstractSome novel azo‐Sulpha drugs as 3‐methyl‐N‐azo‐(4′‐substituted heterocyclo‐benzene‐sulphamoyl) quinoxaline‐2‐ones (1‐11) and 3‐methyl‐N‐azo‐(4′‐substituted heterocyclo‐benzene‐sulphamoyl)‐quinoxaline‐2‐thiones (1′–11′) were synthesized by coupling 4′‐substituted heterocyclo‐benzene‐sulphamoyl diazonium acetates with 3‐methyl‐N‐(1H)‐quinoxaline‐2‐one and/or with 3‐methyl‐N(1H) quinoxaline‐2‐thione in acid medium. The corresponding iron (III) (1a‐11, 1′a‐11′a) copper (II) (1b‐1b′‐7b′) and mercury (II) (1c‐11c, 1c′‐11c) chelates were also prepared in a 1:1 metal‐to‐ligand ratio. The ligands and their chelates were characterized on the basis of microanalysis, UV, IR and H'‐NMR spectrometry and were tested in vitro for their antibacterial and antifungal activities.
Thermodynamic studies of weak aqueous sulfate solutions in solvent extraction systems
Authors: Juang Ruey‐Shin , Su Jenn‐Yih 
Published: July 2010

AbstractThe molalities and activity coefficients of various chemical species in the 0.5 M (H,Na,Me)SO4 aqueous solutions (Me = Cu, Co or Zn) were calculated by the Bromley and the simplified Pitzer methods for strong electrolyte solutions. The validity of the conventional constant ionic medium method applied to these extraction systems was studied. The thermodynamic constants of these trace metal extractions with di(2‐ethylhexyl)phosphoric acid (D2EHPA) were also evaluated, based on simple experiments and the calculated thermodynamic results.
Interfacial activity of 4‐alkylphenylamines and the rate of palladium(II) extraction
Authors: Wisniewski Maciej , Szymanowski Jan , Walkowiak Wladyslaw , Michalewska Malgorzata 
Published: July 2010

AbstractInterfacial tension isotherms were determined in hydrocarbon‐water systems for 4‐alkylphenylamines containing from 6 to 16 carbon atoms in their alkyl chains, and the surface excess isotherms were computed and interpreted using various adsorption isotherms.Palladium(II) was extracted with 4‐alkylphenylamines from 3 M HCI solutions. The maximum extraction rate of palladium(II) is observed for 4‐decyl‐ and 4‐dodecylphenylamines which exhibit good interfacial activity. Compounds soluble in the aqueous phase (4‐hexylphenylamine) or in toluene (4‐hexadecylphenylamine) extract palladium(II) slower than 4‐decyl‐ and 4‐dodecyl‐ phenylamines.
Bioprocess applications of model‐based estimation techniques
Authors: Massimo Christine Di , Lant Paul A. , Saunders Aidan , Montague Gary A. , Tham Ming T. , Morris A. Julian 
Published: July 2010

AbstractThe last decade has seen the development of a number of approaches for estimating those variables which are difficult to measure on‐line in industrial process situations. Whilst a range of techniques is available, a common element is the use of process knowledge in the form of a system model. In the case of bioprocess systems, although a large range of models has been presented in the literature, their use in estimation schemes on an industrial scale has been limited. A number of reasons can be identified for their low level of utilisation. Of particular significance is the uncertainty which exists in quantifying system performance and the process‐model mismatch which inevitably results. The level of ‘pre‐defined model’ uncertainty, together with the knowledge gained during the course of the fermentation, serves to dictate estimator structure. The paper considers a range of estimation strategies and contrasts, through industrial applications, their performance characteristics and utility.
Effect of temperature on fermentation kinetics of waste sulphite liquor by Saccharomyces cerevisiae
Authors: Rousseau S. , Rouleau D. , Yerushalmi L. , Mayer R. C. 
Published: July 2010

AbstractThe optimum operating temperatures for the maximum production of ethanol and the maximum utilization of substrate in batch fermentations of a waste sulphite liquor (WSL) as well as a synthetic medium using Saccharomyces cerevisiae were determined. The fastest consumption of substrate resulting in the shortest fermentation times of 13 h and 45 h was achieved at 35°C and 30°C for the synthetic medium and the WSL, respectively. The concentrations of ethanol in the two media were also maximum under these conditions: 11.6g dm−3 and 9.4 g dm−3 for the synthetic medium and the WSL, respectively. The productivities of biomass and ethanol increased with the increase of temperature and reached maximum values of 0.89 g dm−3 h−1 and 0.21 g dm−3 h−1 in the synthetic medium and the WSL, respectively. The inhibiting agents in the waste sulphite liquor affected the metabolic rates of microbial activities and prolonged the overall fermentation time while decreasing the productivities of biomass and ethanol. From analysis of the fermentation kinetics a mathematical model based on the Monod model was developed to describe the cellular growth and ethanol production. The model included inhibition terms for ethanol and the inhibiting agents in the waste liquor. The temperature dependence of the model parameters followed the Arrhenius law for temperatures between 15°C and 35°C. The activation energies (E) and the frequency constants (A) of these parameters were also determined.
A comparison of properties of inulinases of Fusarium oxysporum immobilised on various supports
Authors: Gupta Anil K. , Kaur Maninder , Kaur Narinder , Singh Rangil 
Published: July 2010

AbstractExtracellular inulinase was obtained after growing Fusarium oxysporum for 9 days on a medium containing an aqueous extract of Cichorium intybus roots. After partial purification, inulinase was immobilised by cross‐linking it with water insoluble protein supports prepared from flour of soybean and mungbean, and egg white. Inulinase was also immobilised by adsorbing it on DEAE‐cellulose. Inulinase immobilised on soybean and mungbean supports had a higher optimum temperature of 45°C as compared to 37°C of the free enzymes. Inulinase adsorbed on DEAE‐cellulose was thermally the most stable whereas the inulinase cross‐linked on soybean support was the least stable. Inulinase immobilised on DEAE‐cellulose and on supports obtained from mungbean and soybean had a pH optima of 5.5, 6.5 and 6.0, respectively. The Km values of various immobilised inulinases with inulin varied from 0.25 to 0.44 mmol dm−3.
Adsorption of 2,4‐D onto activated carbon: Application of Nth order approximation
Authors: Bhaskar Ganugapati V. , Bhamidimarri Rao S. M. 
Published: July 2010

AbstractAdsorption kinetics of 2,4‐dichlorophenoxyacetic acid (2,4‐D) onto activated carbon is presented in this paper. The equilibrium adsorption of 2,4‐D is described by a Freundlich type isotherm and the batch kinetic experiments are analysed using a surface diffusion model. The model equations are simplified by an nth order approximation and, when applied to the experimental data, the approximation predicted the film transfer and diffusion coefficients with a good accuracy.
Disperse dyes: 4‐hetarylazo derivatives from N‐β‐cyanoethyl‐N‐β‐hydroxyethylaniline
Authors: Peters Arnold T. , Gbadamosi Adam 
Published: July 2010

AbstractAminothiazoles, benzothiazoles, thiadiazoles and thiophenes were diazotised and coupled to N‐β‐cyanoethyl‐N‐β‐hydroxyethylaniline to give dyes which coloured polyester in orange to blue hues. The colour of the dyes is discussed with respect to the nature of the heterocyclic ring and substituents therein. Solvent effects on the visible absorption maxima of some of the dyes are also reported.
Production of vitamins, coenzymes and related biochemicals by biotechnological processes
Authors: Vandamme Erick J. 
Published: July 2010

AbstractVitamins and related biofactors belong to those few chemicals with a direct positive appeal to people. There is indeed a large need for extra vitamins, other than those derived from plant and animal food sources, due to unbalanced food habits or processing, food shortage or disease. Added vitamins are now either prepared chemically or biotechnologically via fermentation or bioconversion processes. Several vitamins and related biofactors are now only or mainly produced chemically (vitamin A, cholecalciferol (D3), tocopherol (E), vitamin K2, thiamine (B1), niacin (PP or B3), pantothenic acid (B5), pyridoxine (B6), biotin (H or B8), folic acid (B9) or via extraction processes (β‐carotene or provitamin A, provitamin D3, tocopherol, vitamin F‐group).However, for several of these compounds microbiological or algal methods also exist or are rapidly emerging. Others are produced practically exclusively via fermentation (ergosterol or provitamin D2, riboflavin (B2), cyanocobalamin (B12), orotic acid (B13), vitamin F‐group, ATP, nucleosides, coenzymes, etc. or via microalgal culture (β‐carotene, E, F). Both chemical and microbial processes are run industrially for vitamin B2 while vitamin C (ascorbic acid) is produced via a combination of chemical reactions and fermentation processes. A survey is given here of the current state of vitamin production, with emphasis on developments and strategies for improved biotechnological production and its significance, as compared to existing chemical processes.The screening or construction of vitamin hyperproducing microbial strains is a difficult task; pathway elucidation and metabolic (de)regulation need further study; r‐DNA technology has only recently been introduced; improved fermentation processes and immobilised biocatalysts bioconversions for the synthesis of chiral vitamin compounds or intermediates or derivatives are gaining importance; the recovery and purification of these vitamin compounds from their fermentation broths remains equally complex.
Modelling of hydrolysis controlled anaerobic digestion
Authors: Jain Sanjay , Lala Anil K. , Bhatia Suresh K. , Kudchadker Arvind P. 
Published: July 2010

AbstractA mathematical model of anaerobic digestion has been developed which considers the process as occurring through hydrolysis followed by a sequence of steps which have been considered together as a pseudo‐first order process. The Michaelis‐Menten equation has been modified to incorporate variable enzyme concentration. An immobilized reactor has been designed, fabricated and operated on cowdung feed to obtain data for estimating the model parameters by non‐linear regression. These model parameters were used to predict the performance of the reactor and good agreement between experimental and predicted values was observed. The model was further tested satisfactorily on data from the literature. From the parameters estimated it was concluded that hydrolysis was the slowest stage and that the mass transfer of hydrolytic enzyme from microbe to bulk was the rate controlling step in this stage. The hydrolysis reaction, represented by a modified Michaelis‐Menten equation, was reduced to first order in bulk enzyme concentration and zero order in substrate concentration thereby emphasizing the significance of bulk enzyme concentration.
Prediction of binary component isotherms for adsorption on heterogeneous surfaces
Authors: Al‐Duri B. , Khader Y. , McKay G. 
Published: July 2010

AbstractThe adsorption of three basic dyes onto peat has been studied as single and bisolute equilibrium isotherms. The Freundlich equilibrium isotherm, suitable for heterogeneous adsorption systems has been selected to describe the single component data. Furthermore, the extended Freundlich formula for binary systems has been used to describe binary system equilibrium. A very good agreement is obtained between experiment and theory. The dyes under investigation are: Basic Blue 3, Basic Red 22 and Basic Yellow 21 in their single phases and binary solutions, respectively, all onto peat.
Interfacial mass transfer in stripping of phenylalanine in a liquid‐liquid extraction process
Authors: Uddin Mohammad S. , Hidajat Kus , Lim Bee‐Gim , Ching Chi‐Bun 
Published: July 2010

AbstractStripping of L‐phenylalanine from organic phase containing ALIQUAT 336 (tri‐octyl‐methyl‐ammonium chloride) as complexing agent was studied using a stirred transfer cell. The study investigated the effects of concentration of the stripping agent, potassium chloride, in strip solution and temperature on mass transfer rates. A two‐film model based on organic and aqueous phases mass transfer resistances was proposed to estimate mass transfer coefficients and it predicted adequately the experimental time‐concentration data at different conditions studied. A comparison of mass transfer coefficients for stripping and previously published results on extraction for the same system was made.
Suspension culture of Nicotiana tabacum cells in a rotary‐drum bioreactor
Authors: Shibasaki Naomi , Hirose Kenji , Yonemoto Toshikuni , Tadaki Teiriki 
Published: July 2010

AbstractSuspension cultures of Nicotiana tabacum (tobacco) were studied using a rotary‐drum bioreactor and the effects of various operating factors on culture growth were investigated. Conditions of oxygen concentration, aeration and drum rotation rates required for optimum culture growth rate were determined. The results were compared with those obtained in an air‐lift bioreactor with a draft tube. The culture growth rates were higher in the rotary‐drum bioreactor than in the air‐lift bioreactor under the same conditions of aeration. The rotary‐drum bioreactor was superior to the air‐lift bioreactor in respect of oxygen mass transfer and the level of shear damage to N. tabacum cells.
Kinetic study of an enzymatic liquid—liquid reaction: The hydrolysis of tributyrin by Candida cylindracea lipase
Authors: Martinez Oswaldo , Wilhelm Anne‐Marie , Riba Jean‐Pierre 
Published: July 2010

AbstractThe objective of the work was to derive a kinetic model for the enzymatic hydrolysis of oils. The model reaction examined was the lipolysis of tributyrin by Candida cylindracea lipase. The kinetic model of Verger et al14 was adapted to the particular case of a standard, mechanically‐stirred tank in order to derive the reaction rate as a function of the variables ø, volume fraction of dispersed phase and N, speed of agitation. The validity of a literature correlation relating the mean drop diameter to ø, N and the interfacial tension was verified experimentally. The kinetic relationship was validated by a Lineweaver—Burk representation of the initial reaction rates determined and the kinetic constants were identified. For the system examined, the influence of stirrer speed was weak and limited to low values of ø (ø < 10%).
Solid aromatic products in methanol conversion to hydrocarbons
Authors: Sedran Ulises A. , Fígoli Nora S. 
Published: July 2010

AbstractThe influence of operative parameters on the formation of solid products in methanol conversion to hydrocarbons over amorphous silica—alumina catalysts was studied. Temperature was changed in the 330–430°C range and W/F ratios covered up to 4.65 h. The solid compounds identified were methyl‐substituted aromatics: 1,2,4,5‐tetramethylbenzene, pentamethylbenzene and hexa‐methylbenzene, the last two being the most important ones. Solid products normally represented around 30–40% of the total amount of aromatics formed. Essentially the same behaviour was observed on a zeolitic FCC catalyst.
Flow injection analysis with immobilized enzymes for process control of pullulan production by fermentation
Authors: Englbrecht Ursula , Schmidt Hanns‐Ludwig 
Published: July 2010

AbstractA flow injection system is described for the parallel determination of pullulan and glucose during a fermentation of the fungus Aureobasidium pullulans. The polysaccharide was hydrolyzed by pullulanase and amyloglucosidase, immobilized to controlled‐pore glass (CPG). The glucose produced was oxidized by glucose dehydrogenase and the NADH formed determined photometrically. The pullulan concentration was calculated from the difference to the response obtained for free glucose. The calibration curves for monomer and polymer were both linear between 2 mg dm−3 and 20 mg dm−3. Analysis of one sample for the determination of glucose and pullulan took about 10 min.
Reactive extraction of lactic acid with Alamine 336 in the presence of salts and lactose
Authors: San‐Martín Marta , Pazos Carmen , Coca Jose 
Published: July 2010

AbstractThe reactive liquid‐liquid extraction of lactic acid with Alamine 336 dissolved in toluene from aqueous solutions of 40.0 g dm−3 lactic acid was examined. Experiments were performed at 25 and 50°C for two amine concentrations of 20% and 40% v/v in toluene, and distribution coefficients were determined. Calculations based on the stoichiometry of the reactive extraction and the equilibria involved indicated that more lactic acid is transferred to the organic phase than would be expected from the stoichiometry of the reaction.The influence of salts and lactose on the lactic acid extraction was also investigated. Experiments were carried out at 25°C using, as aqueous phases, solutions of lactic acid (40.0 g dm−3) which contained sodium chloride and/or lactose at different concentrations. Results indicated that the extraction of lactic acid with Alamine 336 dissolved in toluene is not affected by lactose. If sodium chloride is present, less lactic acid is extracted by the organic phase and hydrochloric acid co‐extraction is observed.
On the permeation rate of copper extraction through liquid membranes
Authors: Shiau Ching‐Yeh 
Published: July 2010

AbstractThe understanding of the permeation rate of metal ions through liquid membranes is important for the design of such systems. In this paper, the permeation rates of copper ions through liquid surfactant membranes, including interfacial reaction rates and the diffusion rate of the copper ion, were analyzed using a model based on a mobilized hollow spherical globule configuration. The analysis shows that the extracting reaction is dominant at the external interface of the membrane and the stripping reaction is dominant at the internal interface; this means the reactions at both interfaces are not in equilibrium during the course of extraction. It also shows that the extraction rate, the diffusion rate and the stripping rate are not of equal value, especially at the early stage of the run.
Anaerobic treatment of leachates in UASB reactors
Authors: Berrueta José , Castrillón Leonor 
Published: July 2010

AbstractLeachates from the solid urban wastes landfill of Asturias were characterized and treated in upflow anaerobic sludge blanket laboratory reactors. The highest percentage of COD removal was 88% for a hydraulic retention time of 2–4 days. Gas production was close to the theoretical values, with CH4 content up to 88%. HCl was needed to keep pH neutral, and phosphate was added as nutrient. There was a refractory fraction to the biodegradation of 7%.
Spectrophotometric studies and analytical application of gold(III), yttrium(III) and palladium(II) chelates with 7‐(2‐pyridylazo)‐5‐chloro‐8‐hydroxyquinoline
Authors: Zuhri Ali Z. Abu , Rady Adel H. 
Published: July 2010

AbstractA spectrophotometric study of Au(III), Y(III) and Pd(II) complexes of a reagent 7‐(2‐pyridylazo)‐5‐chloro‐8‐hydroxyquinoline (PACHQ) is presented. Gold(III) forms a 2:1 (L:M) violet complex at pH 9.5 (50% ethanol), while Y(III) and Pd(II) form 2:1 (L:M) red complexes at pH 6.5 and 7.5 respectively. The stability of these complexes has been determined. Beer's law is valid over the concentration range 0‐7.87, 0‐8.89 and 0‐10.64μg ml−1 for Au(III), Y(III) and Pd(II) respectively. A number of foreign ions were tested for their interference. Synthetic solutions identical in composition to some Au(III) and Y(III) alloys are used to ascertain the suitability of the reagent.
Simultaneous saccharification and isomerization by immobilized glucoamylase and glucose isomerase
Authors: Hui Zhou , Wei Kong , Xiao Cha , Wei Li , Jiacong Shen 
Published: July 2010

AbstractGlucoamylase (GA) and glucose isomerase (GI), which are often used in industry to produce high‐fructose corn syrup, were immobilized on porous anilinosulphonic polystyrene beads and porous triethanolamine methyl polystyrene beads, respectively. The effects of the amounts of charged groups, the porosity of the carrier and the buffer concentration on the pH profile of immobilized glucose isomerase (IGI) were studied. The apparent pH optimum of the IGI shifted from pH 8.5 to pH 7.3, hence it is possible to carry out simultaneous saccharification and isomerization in a tubular reactor using immobilized glucoamylase (IGA) and IGI. This process is very difficult to accomplish using soluble GA and GI because of the large difference in the pH optima of the two enzymes.
Continuous aqueous phase extraction of proteins: Automated processing and recycling of process chemicals
Authors: Papamichael N. , Börner B. , Hustedt H. 
Published: July 2010

AbstractA two‐stage aqueous phase extraction of the enzyme fumarase from baker's yeast is described with respect to the recycling of the upper effluent phase from the secondary extraction. It was found that the binodal curve position was only slightly altered by the presence of protein at different load levels and that enzyme specific activity in the product was improved at higher total protein concentrations, which simplified the recycling strategy. On‐line enzyme and protein assays showed that disturbances during start‐up and desludging operations were reflected in variations in the protein concentrations in the various streams, but that the enzyme activities remained relatively stable. Recycling reduced the polyethylene requirements by 50% and that for potassium phosphate by 12%. A maximum saving of PEG (polyethylene glycol) of approximately 70% was achieved at optimum conditions of extraction, compared to a value of 90% predicted by a theoretical description of the system. An economic analysis of the recycled process showed significant advantages compared with a non‐recycled system, even though the capital outlay requirements for an automated, continuous system are much higher than for a manually run process.
Effects of substrate concentration on growth and lactic acid production by mixed cultures of Lactobacillus bulgaricus and Streptococcus thermophilus
Authors: Özen Sevgi , Özilgen Mustafa 
Published: July 2010

AbstractThe kinetics of growth and lactic acid production by mixed cultures of Lactobacillus bulgaricus and Streptococcus thermophilus were modeled with a set of modified logistic and Luedeking‐Piret equations. The specific growth rates and the inhibitory effect of each individual species on the mixed culture growth were found to be determined by the media composition. The kinetic analysis clearly showed that the contribution of each microbial species to the mixed culture growth process changed drastically when the substrate concentration was about 15%. This optimum initial substrate concentration was in agreement with the results of the previous studies and the optimum found by trial and error procedure in commercial yogurt production.