bluuebunny/crossref_metadata_2025_split huggingface dataset:
Production, purification and immobilisation of inulinase from Kluyveromyces fragilis
Authors: Gupta Anil K. , Singh Davinder Pal , Kaur Narinder , Singh Rangil 
Published: May 2005

AbstractKluyveromyces fragilis (NCIM 3217), Kluyveromyces marxianus (NCIM 3231), Hansenula polymorpha (NCIM 3377), Pichia fermentan (NCIM 3408), Pichia polymorpha (NCIM 3419) and Debaryomyces castellii (NCIM 3446) were grown on an inulin‐based growth medium. Only K. fragilis produced extracellular inulinase with a maximum after 36 h of growth at 25–27°C. Sucrose and fructose were weak inducers of inulinase as compared to inulin whereas with glucose the inulinase level was minimal. An aqueous extract of chicory roots containing 1% fructan was a better carbon source than inulin and peptone was the best nitrogen source for the production of inulinase. The maximum yield of inulinase was about 7 units cm−3 of medium. The invertase to inulinase ratio of 10 in the culture filtrate was reduced to 1·6 on purifying inulinase by ethanol precipitation followed by chromatography on Sephadex G‐200, DEAE‐cellulose and CM‐cellulose columns. Using this purification procedure, inulinase was purified 26‐fold. With inulin as substrate, the shape of the velocity curve was nearer to a sigmoidal pattern whereas with sucrose the curve was hyperbolic. The molecular weight of inulinase was determined as 250 ± 10 kDa. The crude and purified inulinase preparations did not release sucrose or oligosaccharides from inulin, indicating that the enzyme has primarily exo‐inulinase activity. Using the metal‐link chelation method, 40% of inulinase was immobilised on cellulose. Maximum activity of crude, purified and immobilised inulinase preparations was observed at 55°C. The half‐life of immobilised inulinase at 25°C was 5 days.
Enzymatic enantioselective hydrolysis of acyloxyferrocenophanes using lipases and esterases
Authors: Izumi Taeko , Aratani Satoshi 
Published: May 2005

AbstractEnantioselective hydrolysis of racemic acetate or butyrates of 1‐hydroxy [3](1,1′) ferrocenophane and endo‐1‐hydroxy [4](1,2) ferrocenophane using lipases, pig liver esterase and horse liver esterase resulted in the formation of (R)‐alcohols and (S)‐esters.
Selectivity aspects in the multi‐phase hydrogenation of α,β‐unsaturated aldehydes over supported noble metal catalysts: Part II
Authors: Satagopan V. , Chandalia Sampatraj B. 
Published: May 2005

AbstractThe hydrogenation of cinnamaldehyde to cinnamyl alcohol over a platinum on carbon catalyst could be intensified and made more selective in a two‐phase system using toluene and aqueous alkaline solution. Enhancement in the selectivity with respect to citronellol was noticed in the two‐phase hydrogenation of citronellal, while the reaction rate was marginally affected. Potassium hydroxide and sodium hydroxide were found to be efficient promoters.
Adsorptive recovery of water soluble essential oil components
Authors: Bohra Poonam M. , Vaze Abhay S. , Pangarkar Vishwas G. , Taskar Ajay 
Published: May 2005

AbstractMany essential oils are produced by the process of steam distillation. During this process valuable oxygenated components of the oil which have relatively higher solubility in water are preferentially lost in the distillate water. This loss is directly reflected in a lower yield and poor quality of the oil. Adsorption is extensively used for recovery of such valuable organics from dilute aqueous streams. This paper describes a preliminary study on the feasibility of adsorptive recovery. The following synthetic polymeric adsorbents were used in this work: Amberlite XAD‐2, XAD‐4 and XAD‐7. Equilibrium and column exahaustion studies were carried out for the adsorption of phenyl ethyl alcohol (PEA), linalool (LL) and eugenol (EG) and also of mixtures of PEA and LL, and EG and LL from dilute aqueous solutions. The results indicate that XAD‐4 is a relatively better adsorbent for all the three solutes studied.
A purification method for specific serine proteases using one‐step affinity chromatography
Authors: Grzywnowicz Krzysztof , Łobarzewski Jerzy 
Published: May 2005

AbstractA simple affinity chromatography procedure for specific isolation of serine proteases is described. The procedure was tested using enzymes from five microbial and one plant source. Feather keratin, covalently bound to controlled‐pore glass, was the support and magnesium chloride was used in the elution buffers instead of zinc chloride. This enabled one‐step isolation of serine proteases present in the biological materials used. The small (15 cm × 1 cm) controlled‐pore keratin‐glass column allowed high flow rates and protected the proteases from autodigestion during the chromatography process. The serine proteases were eluted from the column with good recovery (40–84·6%) and a purification efficiency between 5 and 7. The purified proteases were homogeneous by polyacrylamide gel electrophoresis.
Removal of metal ions from aqueous solution by activated carbons obtained from different raw materials
Authors: Budinova T. K. , Petrov N. V. , Minkova V. N. , Gergova K. M. 
Published: May 2005

AbstractThe adsorption of Pb2+, Cu2+, Zn2+ and Cd2+ from aqueous solution at 293 K by activated carbons obtained from different raw materials was studied. These carbons were prepared by water vapour pyrolysis of the raw materials—apricot stones, coconut shells and lignite coal. The influence of the solution pH on the adsorption processes has been studied. The presence of other metal ions in the solution decreases the adsorption of each of the ions. The selective adsorption of the metal ions is observed but the ones preferentially adsorbed do not completely prevent the adsorption of other ions. The chemical nature of the carbon surface and metal ions have great significance for the adsorption process.
Construction and performance characteristics of a metformin electrode based on the metformin phosphotungstate ion‐associate
Authors: Shoukry Adel F. , Rizk Mahmoud S. , Abdel‐Fattah Hussein M. , Issa Yousry M. , Atia Ehab M. 
Published: May 2005

AbstractA new metformin (Mf) ion selective PVC membrane electrode based on the ion‐associate of Mf with phosphotungstic acid was prepared. The electrode exhibited a mean calibration graph slope of 58 mV Mf concentration decade−1, at 25°C, within the concentration range 2·0 × 10−5−1·0 × 10−2 M MfCl. The change of pH within the range 4·0–11·0 did not affect the electrode performance. The standard electrode potentials were determined at different temperatures and used to calculate the isothermal coefficient of the electrode (0.000352 V°C−1). The electrode showed a very good selectivity for Mf with respect to a large number of inorganic and organic cations. The standard addition method and potentiometric titration were applied to determine Mf in pure solutions and in metformin‐containing tablets.
Contaminated and polluted land: A general review of decontamination management and control
Authors: Tadesse Behailu , Donaldson John D. , Grimes Sue M. 
Published: May 2005

AbstractAlthough land pollution is a major environmental concern it is probably the least understood source of pollution in terms of both transport of toxins and remediation. This paper deals with the current situation in legislation and land pollution remediation and highlights future requirements.
Commercial synthesis of α‐D‐cellobiosyl bromide heptaacetate
Authors: Goggin Katherine D. , Hammen Philip D. , Kuntson Kimberlee L. , Lambert Jack F. , Walinsky Stanley W. , Watson Harry A. 
Published: May 2005

AbstractA detailed commercial process for the synthesis and purification of the activated disaccharide, α‐D‐cellobiosyl bromide heptaacetate (1) was developed. Reaction of α‐D‐cellobiose octaacetate (CBO) with HBr in glacial acetic acid or in glacial acetic acid/methylene chloride combination affords α‐D‐cellobiosyl bromide heptaacetate in high yield and excellent quality. Process variables such as reaction solvent, reaction time, reaction temperature, HBr stoichiometry, isolation methods and product purification options were optimized for large‐scale synthesis. α‐D‐Cellobiosyl bromide heptaacetate was successfully prepared in a commercial manufacturing plant.
Solvent extraction of the trivalent lanthanides and yttrium by mixtures of 3,5‐diisopropylsalicylic acid and neutral organophosphorus compounds
Authors: Preston John S. , Du Preez Anna C. 
Published: May 2005

AbstractNeutral organophosphorus compounds containing a phosphoryl or thiophosphoryl group were found to cause appreciable synergistic shifts in the pH50 values for the extraction of the trivalent lanthanides and yttrium from chloride media by solutions of 3,5‐diisopropylsalicylic acid (DIPSA) in xylene. For the series of compounds with R = n‐butyl, the synergistic effect increases in the order (RO)3PS < (RO)3PO < (RO)2RPO < (RO)R2PO < R3PO. The synergistic effects are greater for lutetium(III) than for lanthanum(III) and, as a result, the separation across the lanthanide series (pH–pH) increases from only 0·17 pH unit for 0·25 M DIPSA alone to, for example, 0·85 pH unit for a mixture of 0·25 M DIPSA and 0·25 M triisobutylphosphine oxide (TIBPO). Mixtures of DIPSA and TIBPO give somewhat better separation factors between the light and middle lanthanide fractions (β = 3·0) than the commercial Versatic 10 acid (β = 2·6), and separation factors comparable to those of the latter extractant between the heaviest lanthanides (thulium to lutetium).
A dynamic model for rectangular capillary suction apparatus
Authors: Lee Duu‐Jong 
Published: May 2005

AbstractA model for the dynamic behaviour of wet front distance and liquid saturation in rectangular capillary suction apparatus (RCSA) is developed. Governing equations based on the mass/momentum balance are derived and solved numerically. The calculation shows that the effects of the intial conditions on system dynamics vanish rapidly, and the system will then evolve along a slow manifold independent of the initial conditions. When time is large, the dimensionless wet front distance with time is a straight line on a log–log plot with slope 1/2, and the liquid saturation under the inner cell will approach to a constant which depends only on the product of solid concentration and the averaged specific resistance if the RCSA is fixed. Optimum experimental conditions are suggested. A rapid method based on the model for estimating the averaged specific resistance of cake is proposed and compared with experimental findings.
Liquid phase oxidation of 3,4‐dihydroxybenzoic acid and the effect of the products on trihydroxy aluminium precipitation yields
Authors: Whittington Barry I. , Tran Tam , Trimm David L. , Armstrong Lyndon G. 
Published: May 2005

AbstractOrganic compounds are known to interfere with the precipitation of trihydroxy aluminium (gibbsite) in the Bayer process. Studies have been carried out of the effect of 3,4‐dihydroxybenzoic acid on precipitation and of the beneficial effect that can be achieved by oxidising the acid. Measurements of precipitate yields both in the presence of the acid and of products obtained by oxidising the acid were made. Oxidation in the presence of various metal ions was also examined. The yield of precipitate was found to decrease in the order Cu2+ (1·9 mM) > Fe3+ (2·2 mM) > blank (no added organics) > Mn4+ (44·3 and 2·3 mM) > Mn2+ (2·3 mM) > Mn2+ (44·3 mM) ≈ uncatalyset oxidation > Fe3+ (43·5 mM) > Cu2+ (38·2 mM) > untreated sample. This relative ordering was generally unaffected by reaction temperature or oxygen partial pressure. Soluble manganese salts were formed by partial dissolution of MnO2 in the alkaline solutions. These salts were required for oxidation of the 3,4‐dihydroxybenzoic acid to products which, collectively, did not poison the trihydroxy aluminium precipitation process.
Steam and carbon dioxide activation of Eucalyptus globulus charcoal
Authors: Arriagada Renán , García Rafael , Reyes Patricio 
Published: May 2005

AbstractThe partial gasification of Eucalyptus globulus charcoal, using carbon dioxide and steam as activating agents is studied. The influence of some preparation variables such as temperature and reaction time on textural, morphological and acid–base properties are given. The results obtained show that both activating agents produce microporous activated carbons and that a large increase in meso‐ and macroporosity is observed when steam and high burn‐off are used. It has been found that these activated carbons have weak acid sites and the effect of the burn‐off on the acid strength depends on the activating agent. Thus, the acid strength of these sites decreases with the burn‐off when steam is used, but no effect is observed when carbon dioxide is used.
The role of acetyl chloride in the chlorination of acetic acid
Authors: Mäki‐Arvela Päivi , Paatero Erkki , Salmi Tapio 
Published: May 2005

AbstractThe role of acetyl chloride as the active catalyst in the chlorination of acetic acid to mono‐ and dichloroacetic acids was examined by chlorinating acetic acid and monochloroacetic acid in the presence of acetyl chloride in semibatch and batch reactors. The reaction kinetics was autocatalytic when the acetyl chloride concentration was maintained constant by addition. If the acetyl chloride was added only at the beginning of the experiment the reaction rate decreased owing to the volatilization of acetyl chloride. The volatilization increased at high acetic acid conversions, since the solubility of acetyl chloride is lower in monochloroacetic acid than in acetic acid. The chlorination kinetics was described by a reaction mechanism consisting of acid‐catalysed acetyl chloride enolization followed by enol chlorination and chlorine exchange steps. According to the mechanism the enol chlorination proceeds in parallel to the formation of mono‐ and dichloroacetyl chlorides. This was verified in separate experiments, in which acetyl chloride was chlorinated in the presence and in the absence of an acidic enolizing agent, chlorosulphonic acid. The chlorine exchange reactions were verified by studying the acetyl chloride–monochloroacetic acid and the acetyl chloride–dichloroacetic acid equilibria. Chlorination of monochloroacetic acid in the presence of acetyl chloride revealed that dichloroacetic acid is formed mainly via the chlorination of acetyl chloride to dichloroacetyl chloride, which undergoes chlorine exchange with monochloroacetic acid.
New plastic membrane ion‐selective electrode for determination of trimethoprim
Authors: Aboudan Mahmoud , Issa Yousry M. , Shoukry Adel F. 
Published: May 2005

AbstractTrimethoprimium‐phosphomolybdata, (TM)3PM, was used as an ion‐exchanger in the construction of a TM‐responsive plastic membrane electrode. The calibration graph slope of the electrode is 56·5 mV per TM concentration decade when preconditioned by soaking in water, over a concentration range of 2·3 × 10−6–10−2 M with instantaneous response. The electrode has a life span of 24 h when soaked in 10−3 M TM solution and 5 days when soaked in distilled water. The working pH and temperature ranges of the electrode are 1·6–6·2 and 30–65·C, respectively. The isothermal coefficient of the electrode is 0·00091 V·C−1. The electrode is highly selective for TM towards inorganic cations, sugars and amino acids. It can be employed as a potentiometric sensor for determination of TM in pure solution and in tables.
Liquid‐phase mixing in external‐loop airlift bioreactors
Authors: Kawase Yoshinori , Omori Naoki , Tsujimura Masanari 
Published: May 2005

AbstractMixing time, circulation time and downcomer linear liquid velocity were measured in two sizes of external‐loop airlift bioreactors with Newtonian and non‐Newtonian fluids.The mixing time increased as a result of an increase of non‐Newtonian characteristics. However, the liquid circulation time was affected only slightly by non‐Newtonian flow behaviour. A semi‐empirical correlation for circulation time in external‐loop airlift bioreactors was proposed. The proposed correlation was compared with the present experimental results and those in the literature. Reasonable agreement was obtained between the predicted and experimental values of circulation times.The downcomer liquid velocity was almost independent of the downcomer‐to‐rise cross‐sectional area ratio. The correlation based on the concept of an eddy diffusivity predicted downcomer liquid velocities in Newtonian and non‐Newtonian fluids.
Kinetics of the catalysed decomposition of N2H by the ceramic superconductor YBa2Cu3O7–δ
Authors: Khalil Laila B. , Mourad Wedad E. , Rophael Magdy W. 
Published: May 2005

AbstractEvidence of the catalysed decomposition of N2H4 and its salts by a Y–Ba–Cu–O superconductor is presented. A thermostated aqueous suspension of the superconductor, treated with a solution of N2HCl−, produced nitrogen and hydrogen gases, whose volumes were measured at intervals in a gas burette. Two simultaneous reactions are suggested for the reaction between the N2H solution and Y–Ba–Cu–O. One is the reduction of Cu3+ ions in Y–Ba–Cu–O to Cu2+, producing nitrogen, and the other is the catalysed decomposition of N2H by Cu2+ ions in Y–Ba–Cu–O, producing nitrogen and hydrogen. The rates of hydrogen evolution at different initial concentrations of N2H are given. First‐order kinetics at the initial stages of the N2H/Y–Ba–Cu–O reaction were obtained. A comparison between the total nitrogen and hydrogen gases liberated from the reaction shows that the reduction reaction goes faster than the catalysed one. The rate of the catalysed reaction is increased as the initial concentration of the N2H solution increases.
Synergistic effects in the solvent extraction of some divalent metals by mixtures of versatic 10 acid and pyridinecarboxylate esters
Authors: Preston John S. , du Preez Anna C. 
Published: May 2005

AbstractPyridinecarboxylate esters were found to cause appreciable synergistic shifts in the pH50 values for the extraction of some divalent base metals by solutions of Versatic 10 acid in xylene. For n‐octyl 3‐pyridinecarboxylate, the synergistic shifts decreased in the order Ni > Co > Cd > Cu ≈ Fe > Mn > Zn, and for the commercial extractant Acorga DS5443A in the order Ni > Cu > Co > Fe > Cd > Mn > Zn. No synergistic effects were observed for divalent lead, calcium and magnesium. On the basis of the pH50 values obtained, several possible practical metal separations are suggested. No loss of metal‐loading capacity was found when the organic phases were contacted with 1 M sulphuric acid for prolonged periods at 30°C.The effect of changes in the structure of a series of isomeric octyl pyridinecarboxylates is reported for one of the smaller cations studied (copper), as well as for one of the larger cations (cadmium).
The synthesis of sucrose esters from telomer monocarboxylic acids
Authors: Donnelly Michael J. , Bu'Lock John D. 
Published: May 2005

AbstractGlycolipid biosurfactants possess excellent surfactant properties and can be useful model compounds for the synthesis of surfactants from materials available in large quantities. The incorporation of a long, branched alkyl group, which is a feature of glycolipids, into a synthetic surfactant was achieved by the transesterification of sucrose with the methyl ester of a selected telomer monocarboxylic acid mixture, in a solution reaction. Characterisation showed the product to be a mixture of mono‐ and diesters each comprising a different ratio of linear to branched alkyl chains in the substituted group. Surfactant properties of the mixture, and the chromatographically‐separated components, when evaluated in both distilled water and a salt solution, were found to be superior to a range of sucrose stearates. In addition the biosurfactant analogues were found to be more effective than surfactants derived from β‐keto alkyl esters of various sugars (including sucrose) but were not as efficient as these latter compounds.
Holdup measurements in a Scheibel column by means of an ultrasonic technique
Authors: Bonnet Julio C. , Sorrentino José A. 
Published: May 2005

AbstractAn ultrasonic technique developed by Bonnet and Tavlarides for dispersed phase holdup determination in liquid–liquid contactors has been applied in a 0·10 m diameter Scheibel extraction column. The column consists of three alternate mixing and packing sections of 0·03 and 0·055 m in height, respectively. The packings were built with polypropylene mesh with 96% voidage. The liquid–liquid systems were toluene (dispersed)/water (continuous) and MIBK (dispersed)/water (continuous); the Rushton‐type impellers were operated at 400, 500 and 600 rpm, and with four dispersed and continuous phase flow rates. In one of the mixing chambers two different holdup measuring devices were installed: two ultrasonic transducers and one controlled dispersion sampler. The values of dispersed phase holdup obtained by both methods were compared using statistical methods. It was found that at low agitation and for high interfacial tension, conditions for which the dispersion is not completely uniform, the difference was significant, whereas at high agitation and low interfacial tension the values obtained through both methods were statistically equal. This work demonstrates the applicability of the ultrasonic technique for holdup measurements to Scheibel columns, in which the only technique used so far was sampling. This ultrasonic technique allows us to solve the axial monitoring and control problems of these columns.
Liquid–liquid extraction of a recombinant protein with reverse micelles
Authors: Pires Mario J. , Cabral Joaquim M. S. 
Published: May 2005

AbstractRecombinant cytochrome b5 was extracted into the reversed micelle phase of an anionic surfactant (AOT) in octane and back‐extracted to a final aqueous phase. The extraction of the protein was controlled by an electrostatic mechanism, since it was dependent on the global charge of the protein. This was directly demonstrated by experiments with native and mutant cytochromes obtained by site directed mutagenesis. The back‐extraction of cytochrome b5 to a fresh aqueous phase was decreased by factors that reduced the size of the water pool of the organic phase, such as high salt concentrations (1–2 mol dm−3 NaCl) and low temperatures (4°C), probably because of an increase in a favourable interaction of this protein with the surfactant at closer distances.
Rate evolution of benzonitrile nitration under heterogeneous conditions
Authors: Andreozzi Roberto , Aquila Tullia , Caprio Vincenzo , Insola Amedeo 
Published: May 2005

AbstractThe development of the nitration process in heterogeneous mixtures of benzonitrile and mixed acids of different compositions is followed in a batch stirred isothermal reactor. Preliminary evaluation of the distribution of the chemical species between the organic and acid phases allows mathematical modelling of benzonitrile nitration under heterogeneous conditions to be achieved on the basis of the previously assessed homogeneous nitration kinetics.
Microbiological treatment of fertilizer solid waste material containing phenoxyalkanoic herbicides 2,4‐D and MCPP
Authors: Oh Kye‐Heon , Tuovinen Olli H. 
Published: May 2005

AbstractThe purpose of the work was to evaluate the feasibility of a biological treatment process for herbicide‐containing solid waste material from a fertilizer‐manufacturing plant. The waste contained approximately 1·5% (w/w) 2,4‐dichlorophenoxyacetate (2,4‐D) and 1·4% (w/w) 2‐(2‐methyl‐4‐chlorophenoxy)propionate (MCPP, mecoprop). Both herbicides could be dissolved from the bulk matrix (vermiculite) within 3 days of chemical leaching in aqueous solution. Upon subsequent inoculation of herbicide‐degrading bacterial consortia derived from soil samples adjacent to the plant, 2,4‐D was completely degraded in the presence of up to 5% (w/v) pulp densities. The biodegradation of MCPP was concurrent but incomplete. The degradation process was acid‐producing, and pH control enhanced the rates of herbicide degradation.