bluuebunny/crossref_metadata_2025_split huggingface dataset:
Chemical‐biotechnological processing of pine bark
Authors: Penas D. Zuhri Vázquez , Yusty M. A. Lage , Liñares J. C. Parajó 
Published: July 2010

AbstractSamples of Pinus pinaster were treated with NaOH solutions to obtain both a phenolic extract and a solid residue suitable for processing into different marketable end‐products. The experiments performed in the study of the alkaline extraction followed an incomplete factorial design. The independent variables considered and their variation ranges were: liquor/bark ratio (5.25–12.73), temperature (100–130°C) and NaOH concentration (1–3% w/v). The effect of these variables on the residue yield, the lignin content, the polysaccharide content and the glucan/polysaccharide ratio were assessed. The solid residues from the alkaline treatments were delignified using acetic acid and hydrogen peroxide and submitted to enzymatic saccharification. The composition and the susceptibility to hydrolysis of processed samples is discussed.
Transformation of Reichstein's compound S into prednisolone by immobilized mixed cultures
Authors: Ghanem Khaled M. , El‐Aassar Samy A. , Yusef Hoda H. 
Published: July 2010

AbstractReichstein's compound S was transformed into prednisolone in a single‐step fermentation using immobilized mixed cultures, entrapped in different gels or adsorbed on clay particles. Calcium alginate at a gel concentration of 2% gave the highest transformation activities and prednisolone yields. The entrapped mixed cultures could be repeatedly used in batch‐wise transformation for at least six times when suspended in diluted nutrient medium and for three times when suspended in distilled water; in the latter case the entrapped cultures required to be reactivated in nutrient medium for further reuse. Mixed cultures adsorbed on clay particles were successfully reused 18 times, with reactivation after the 9th and 15th uses. Continuous transformation of substance S into prednisolone by mixed cultures adsorbed on clay particles was more efficient than batch‐wise reused adsorbed cultures and was dependent on the daily working medium volume.
Cellulase activity of Trichoderma reesei immobilized on gauze covered with hydrophilic and hydrophobic copolymers
Authors: Xin Lu Zhao , Kumakura Minoru 
Published: July 2010

AbstractThe effect of the surface properties of the matrix for immobilized Trichoderma reesei on cellulase activities was studied. The immobilization was based on an adhesion method. The carriers were obtained by coating cellulosic gauze with hydrophilic and hydrophobic monomers using a radiation copolymerization technique. The cellulase activities of the organisms immobilized on the matrices coated with the copolymers were higher than those of the free organisms. Hydrophilic matrices allowed increased growth of the immobilized organisms with increased cellulase activity.
Pulping with organic acids: 3‐acetic acid pulping of Bagasse
Authors: Shukry Nadia , El‐Meadawy Sohair A. , Nassar Mona A. 
Published: July 2010

AbstractBagasse was subjected to acetic acid pulping; the effects of the addition of 0.5% H2SO4 to the pulping solutions (50, 70 and 90% acetic acid) and varying the liquor ratio, on pulp yield, delignification %, pentosan content and strength properties of the pulps obtained were evaluated. Addition of H2SO4 improved the delignification but at the expense of yield and pentosan content. The breaking length and burst deteriorated, whereas the tear was slightly improved. Raising the liquor ratio from 5:1 to 10:1 also reduced the strength properties of the pulps. Delignification of Casuarina was easier than bagasse. IR studies of the acetic acid lignins obtained from both raw materials showed that Casuarina lignins contained more syringyl nuclei than bagasse lignin; the latter resembled softwood lignins. Addition of H2SO4 to bagasse changed the syringyl‐deficient to guaiacyl‐deficient lignin. A relationship was found between the ease of delignification for both raw materials and the relative intensity of the bands corresponding to syringyl groups.
Studies on the β‐glucosidase and endo‐1, 4‐glucanase activities from Clostridium papyrosolvens
Authors: Lequerica Juan L. , Valdés Teresa , Pérez‐Martínez Caspar 
Published: July 2010

AbstractActivities of endo‐β‐4‐glucanase and β‐glucosidase from Clostridium papyrosolvens (CECT 747) were studied under different conditions. No indications were found for the presence of more than one β‐glucosidase after ion exchange and ammonium sulphate fractionation. β‐Glucosidase showed activity against p‐nitrophenyl‐β‐D‐glucopyranoside and cellobiose but was not inhibited by δ‐gluconolactone. Independent cellobiose phosphorylase activity could also be detected. The β‐glucosidase was essentially intracellular. By the use of stationary phase culture assays, enzyme induction at low concentrations of cellobiose was observed, whilst glucose had no effect. Regulation of endo‐β‐1,4‐glucanase and β‐glucosidase were compared.
A low cost microprocessor‐controlled electrofusion and electroporation system
Authors: McCormick Cyril A. , Toll Michael O. , Marshall William H. 
Published: July 2010

AbstractAn important recent development in the field of biotechnology has been the use of high electric fields to render cell membranes temporarily permeable (electroporation). Cells in this state are receptive to gene transfer or can be induced to fuse with each other (electrofusion) to form hybrid cells containing the combined characteristics of the parent cells. A major reason for fusing cells is to form hybridoma cells which secrete monoclonal antibodies. A problem for research workers has been the high price of some of the electrofusion equipment. This problem has been addressed by designing a device that is inexpensive (less than $800 Canadian) and can be assembled by an electronics technician. The system uses a Radio Shack CoCo III microcomputer which is programmed in BASIC and controls the electroporation voltage pulse amplitude (25–500 V) and duration (2–275 μs) to an electrofusion chamber; this yields electric field strengths of 0·25‐5 kV cm−1 for a 0·1 cm electrode spacing. The system is capable of delivering pulse currents up to 3 A. This paper provides technical details on how to construct an instrument that has greater flexibility at less cost than comparable commercially available instruments.
Asphalt stripping bacteria
Authors: Ramamurti K. , Jayaprakash G. P. 
Published: July 2010

AbstractA study of asphaltic pavements ranging in age from 3 to 42 years, taken from several locations in the State of Kansas (USA) revealed that bacteria belonging to the family Pseudomonadaceae and the genus Thiobacillus appear to play an important role in the deterioration of asphaltic materials. The pinhole effect on the stripping of asphalt from aggregate surface is described alongside the synergistic effect of moisture and bacteria on asphalt deterioration.
Spectrophotometric determination of ephedrine HCl, cinchonine HCl, chlorpheniramine maleate, atropine sulphate and diphenhydramine HCl by solvent extraction of reineckate complexes
Authors: El‐Shahat M. F. , Badei M. M. Abdel , Daifullah A. A. M. 
Published: July 2010

AbstractA spectrophotometric method for the determination of some alkaloids (namely ephedrine HCl, cinchonine HCl, Chlorpheniramine maleate, atropine sulphate and diphenhydramine HCl) as separate compounds as well as in pharmaceutical preparations through the formation of their ion‐pair (reineckate complexes) is described. These complexes were prepared and the final products were extracted with nitrobenzene in situ. The optimum conditions for complete extraction were evaluated by investigating the nature of solvent, pH, time of shaking, temperature and reineckate concentrations. The absorption spectra of the extracted organic layer were measured at 520 nm. The extraction constants were calculated and found to have a mean of log KE ≈︁ 2. The application of the present method was compared with the accepted pharmacopoeia method and the effects of some interfering ions were also studied.
Biodegradability of branched alkylbenzene sulphonates
Authors: Hashim M. A. , Kulandai J. , Hassan R. S. 
Published: July 2010

AbstractBranched alkylbenzene sulphonates (ABS) widely used surfactants in the 1950s and early 1960s were subsequently replaced by linear forms in response to evidence that the former are recalcitrant. Though banned in most countries, the use of branched ABS is still widespread in developing countries. In addition to being recalcitrant, they are xenobiotic and, in nature, the biodegradation process of these surfactants requires a lengthy period. This review elaborates the available information on the biodegradation of the branched ABS in relation to their chemical stability, degradation processes, stages of acclimatisation and the microorganisms involved.
Metabolic responses of microorganisms growing on inhibitory substrates in nonsteady state culture
Authors: Sokol W. , Migiro C. L. C. 
Published: July 2010

AbstractThe dynamics of metabolic activity of Pseudomonas putida cultured on phenol in a nonsteady state, resulting from simultaneous step increases (or decreases) in dilution rate and feed phenol concentration, were studied. Metabolic activity was determined by the uptake rate, defined as the mass of phenol degraded by a unit mass of bacteria in unit time. A minimum duration of nonsteady state was necessary to induce the metabolic pathway. The induction time for Pseudomonas putida cultured on phenol was approximately 30 min, irrespective of the type of disturbance applied.The Monod‐Haldane equation was applied to fit the experimental values of uptake rate and the best kinetic parameters were calculated by the nonlinear least squares technique. Values of the kinetic parameters differed both for each parameter and type of disturbance investigated. For simultaneous step increases in dilution rate and feed phenol concentration, the value of um in the transient state first increased monotonically approximately four times and then decreased monotonically to the new steady state value after three residence times. Values of Ks and Ki attained those at the new steady state after three residence times, the highest being approximately three times greater than those of the steady state prior to disturbance. For simultaneous step decreases in D and SO, values of um, Ks and Ki reached those at the new steady state values after four residence times.
Spectrophotometric determination of Ce(IV), Fe(III) and U(VI) using desferrioxamine B (desferal)
Authors: Hafez M. B. , Hafez N. 
Published: July 2010

AbstractTwo moles of desferrioxamine B (desferal) combines with one ion of cerium(IV), Fe(IV) and U(VI) to form intensely coloured chelates having molar absorptivities of 3.8 × 104, 5.5 × 104 and 1.9 × 104 mol−1 cm−1 at 443 nm, 293 nm and 376 nm respectively. The system follows Beer's law up to 1.5 μg ml−1. The effect of desferal concentration, pH, time and foreign species are studied. The results of analysis of simulated wastes are reported.
Surfactant interference on lipase catalysed reactions in microemulsions
Authors: Skagerlind Peter , Jansson Mikael , Hult Karl 
Published: July 2010

AbstractThe hydrolysis of palm oil with lipase as a catalyst was carried out in two different microemulsion systems. One system was based on a nonionic surfactant, pentaethylene glycol monododecyl ether (C12EO5) and the other system was based on an anionic surfactant, sodium bis(2‐ethylhexyl)sulphosuccinate (AOT). The yield of free fatty acid produced by the reaction was found to be much lower in the C12EO5 system compared to the AOT system. Radiochromatography showed that the low yield was due to enzymatic esterification on the nonionic surfactant.Kinetic measurements showed that the reaction rate is about ten times faster in the AOT based microemulsion than in the nonionic system. Differences in the microemulsion structure and interfacial tensions in the two systems were found to be of no significant importance for explaining this difference. Kinetic data of mixed surfactant microemulsions indicated that the observed difference in the reaction rates of the AOT and the C12EO5 microemulsion systems was a consequence of the C12EO5 surfactant competing with the substrate for the active site of the enzyme. The reason why C12EO5 surfactant inhibited the reaction, and AOT surfactant did not, was found to be related to differences in the structures of the hydrophobic part of the surfactant.
Fumaric acid production from hydrolysates of starch‐based substrates
Authors: Moresi M. , Parente E. , Petruccioli M. , Federici F. 
Published: July 2010

AbstractFumaric acid production by Rhizopus arrhizus from commercial hydrolysates of corn starch (i.e. glucose molasses) was studied at different initial concentrations of glucose (S) and C:N ratios (R) by performing a 32 factorial experiment.By using the response surface methodology and statistical analysis, fumaric acid (YF) and mycelial biomass (Yx) yields, as referred to the initial concentration of glucose and fumaric acid productivity (PF), were fitted to the only significant first‐order effects of S and R with mean percentage errors ranging from 11 to 15%. The resulting empiric models were used to determine the optimal values of S (100–130 g dm−3) and R (150–210 g‐atom C per g‐atom N) associated with YF and PF varying in the ranges 40–49% and 7–8.5 g dm−3 day−1, respectively. After establishing the validity of these data at the 95% confidence level, an optimal operating condition (S = 120 g dm−3 and R = 150) was further tested using other substrates (i.e. glucose and acid or enzymatic hydrolysates of cassava, corn and potato flours). Statistically significant improvements in the fumaric acid yield and productivity were determined with respect to the predicted values. Since the highest values of YF and PF were obtained from the acid hydrolysates of the starch‐based materials and such values were also found to be insensitive to the substrate used (at a probability level of 0.05), the above operating condition might be further employed to minimise fumaric acid production costs as a function of the feedstock used.
Hydrolysis of topinambur (Jerusalem artichoke) fructans by extracellular inulinase of Kluyveromyces marxianus var. bulgaricus
Authors: Manzoni Matilde , Cavazzoni Valeria 
Published: July 2010

AbstractExtracellular inulinase from Kluyveromyces marxianus var. bulgaricus catalysed the hydrolysis of pure inulin and the extracts of fresh and dried topinambur (Jerusalem artichoke). At an enzyme concentration of 10 IU g−1 of substrate the three substrates were hydrolysed respectively to 65–3, 77–3 and 83–9%. The relationship between the extent of hydrolysis, reaction time and enzyme concentration was studied and a kinetic model of hydrolysis was derived.
Processing of interfacial tension data in solvent extraction studies. Interfacial properties of various acidic organophosphorus extractants
Authors: Cote Gérard , Szymanowski Jan 
Published: July 2010

AbstractBasically, the interfacial tension data can be plotted as a function of logarithm C where C denotes the concentration of any form of the surface active species considered. The various relationships y vs In C are discussed here from a mathematical point of view and it is shown that ambiguities may arise from the use of the interfacial tension curves versus the total extractant concentration for the interfacial tension data interpretation. The method recommended in this work is based on the computation of the whole surface excess curves (Γ vs concentration of individual species). This is achieved by matching various adsorption equations (e.g. Szyszkowski or Temkin relationships) or empirical equations to the interfacial tension data (y vs C). The term dy/dln C can then be analytically calculated and introduced into the Gibbs equation [Γ = −(1/RT)dy/dln C] to derive mathematical expressions for the surface excess curves. To exemplify our approach, interfacial data are interpreted for dibutylphosphoric acid (HDBP), di(2‐ethylhexyl)phosphoric acid (HDEHP), di(hexoxyethyl)phosphoric acid (HDHOEP), 2‐ethylhexyl‐2‐ethylhexylphosphonic acid (HEH[EHP]) and di(2‐ethylhexyl)phosphinic acid (H[DEHP]) at various liquid‐liquid interfaces.
Use of bipolar membranes for ion exchange resin regenerant production
Authors: Bolton H. R. 
Published: July 2010

AbstractThe utilisation of electrodialysis bipolar membranes to prepare hydrochloric acid and sodium hydroxide from a sodium chloride solution was tested at West Thurrock Power Station. The product chemicals were then used to regenerate full scale ion exchange units on the site and the results compared to normal operation with commercial regenerants.The large scale pilot plant was found to operate satisfactorily and the quality of produced chemicals was in line with predictions.The adoption of on‐site, on‐demand production of regenerants could offer immediate advantages for remote installations which would otherwise be dependent on the transport of dangerous chemicals over long distances.In the longer term further advances in the selectivity of commercially available membranes and the prevailing cost of commercial regenerants are considered the key factors governing the future rate of implementation of this novel process.
The effect of cobalt on the activity of iron catalyst supported on magnesium hydroxide carbonate (MHC) in the ammonia synthesis
Authors: Kaleńczuk Ryszard J. 
Published: July 2010

AbstractThe effect of cobalt on the activity of the magnesium hydroxide carbonate supported iron catalysts for ammonia synthesis was studied. The addition of cobalt has been found to increase considerably the activity of the catalyst samples. A sample containing ca 20 wt% Co as metallic phase showed maximum activity in the ammonia synthesis (X‐ray fluorescence (XRFS) was used to analyze the sample compositions). The precursor reduction temperature proved an important factor affecting properties of the samples studied, and catalyst reduced at the relatively high temperature of 873 K was the most active. On the basis of the activity measurements, phase structure studies with the X‐ray diffraction (XRD) method, temperature‐programmed reduction studies, and a Mössbauer spectroscopic investigation, a conclusion has been drawn that the formation of an intermetallic iron‐cobalt compound is crucial to the catalyst activity. It has been postulated that this might be due to the surface restructuring by exposing the most active iron surface, Fe(111). Considering the support and promoter natures the catalysts studied can be called ‘super‐basic’. Negligible potassium addition (0.2 wt% K) in the form of KOH can cause very high increase in the catalytic activity in ammonia synthesis.
A study of biological filtration using flow‐through tracer techniques
Authors: Muslu Yilmaz , Saltabas Lütfü 
Published: July 2010

AbstractInvestigations were performed to determine substrate removal in biological filters with the aid of dispersion theory and first order reaction kinetics. Flow‐through tracer experiments were conducted to study the hydrodynamic dispersion. Dispersion numbers were then obtained by equating variances of the experimental and the theoretical C curves. An equation was derived to calculate dispersion numbers as a function of specific surface area and the mean velocity of the laminar film flow over the filter medium.
Concentration‐dependent diffusion of dye in adsorptive dyeing systems
Authors: Lin Sheng H. 
Published: July 2010

AbstractA concentration‐dependent dye diffusion model is extended in the present study to represent adsorptive dyeing systems. It is a revision of the previous one by incorporating the effect of external mass transfer resistance and concentration dependence of diffusion coefficient on the dye's diffusion process. The theoretical predictions using the extended model show excellent agreement with the observed data, significantly better than that of the previous one. It is also found that an adsorption equilibrium is achieved under most operating conditions due primarily to the fact that the dye diffusion within the pores is a considerably slower process than the dye adsorption.
Adsorption of heavy metal cations from aqueous solutions by wool fibers
Authors: Balköse Devrim , Baltacioǧlu Hayri 
Published: July 2010

AbstractAdsorption of metal cations by kivircik wool from aqueous NiCl2, CuCl2, ZnCl2, CdCl2, HgCl2 and Pb(NO3)2 solutions at 25°C and 50°C was investigated using atomic absorption spectroscopy. A fiber diffusion controlled adsorption rate model was used to predict the effective diffusion coefficients of metal ions in wool. It has been shown that wool is a potential adsorbent for removing toxic metal ions from contaminated water.
Permeation of 6‐nitro‐3‐phenylacetamide benzoic acid (nipab) and hydrolysis by penicillin acylase immobilized in emulsion liquid membranes
Authors: Miesiac I. , Schügerl K. , Szymanowski J. 
Published: July 2010

AbstractThe effects of various commercial and model surfactants of different structure and hydrophilicity were studied on water‐in‐oil (w/o) emulsion stability, potassium cation leakage and permeation of 6‐nitro‐3‐phenylacetamide benzoic acid in a model system using Penicillin acylase (EC 3.5.1.11) immobilized in a liquid membrane. Both emulsion stability, potassium leakage and permeation of organic substances depend upon hydrophilicity; of surfactants. Hydrophilic surfactants may be used to stabilize emulsions only in mixtures with hydrophobic emulsifiers. Additions of small quantities of hydrophilic surfactants to the system in which permeation occurs together within an enzymatic process may be advantageous. Both the rate of permeation and potassium transfer significantly increase when hydrophilic surfactants are present. There was no relationship observed between potassium cation transfer from the internal phase and emulsion stability in the storage lest.
Water denitrification by an immobilized biocatalyst
Authors: Čižinská Simona , Matějů Vít , Krejčí Jakub , Janoch Tomáš , Kyslíková Eva 
Published: July 2010

AbstractThe continuous denitrification of drinking water was performed by microorganisms from activated sludge chemically immobilized in a water‐soluble polymer. The influence of temperature, pH, input nitrate and dissolved oxygen concentrations on the process rate was studied. Nitrates were reduced on average from 25.8 to 6.8 mg dm−3 N3−‐N over a 100‐day operation.
The application of aqueous two‐phase systems to oligosaccharide synthesis by a‐mannosidase catalysed glycosyl transfer reactions
Authors: Bartlett Terence J. , Rastall Robert A. , Rees Nicholas H. , Adlard Maxwell W. , Bucke Christopher 
Published: July 2010

AbstractAqueous two‐phase systems formed from PEG and dextran have been applied to the synthesis of oligosaccharide by Jack bean α‐mannosidase in reverse. Whilst rates of synthesis and percentage yields weie similar in two‐phase systems and one‐phase aqueous buffer systems, a ten‐fold increase in yield of product per unit of enzyme was seen. In addition, the use of aqueous two‐phase systems offers potential process advantages over one‐phase systems for the synthesis of oligosaccharides.
Flow improvement of waxy western desert gas oil
Authors: El‐Gamal I. M. , Gad E. A. M. , Faramawi S. , Gobiel S. 
Published: July 2010

Abstractα‐Olefin‐maleic anhydride copolymers were prepared by reacting C12, C14, C16 and C18 olefins with maleic anhydride, respectively. The reaction products were then esterified with cetyl alcohol, purified, and characterized through weight average molecular weight, polydispersity and molecular weight distribution. The synthesized additives were tested as flow improvers for a heavy gas oil derived from the western desert waxy crude. The content, distribution, and average molecular weight of n‐paraffins in the tested gas oil were determined. Matching of the carbon atom number in the alkyl chain of α‐olefins with the average molecular weight of n‐paraffins in the gas oil composition was investigated. Storage stability of the treated distillate fuel was tested in terms of pour point depression for one month.