bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanistic studies of proteases and lipases for the detergent industry
Authors: Aaslyng Dorrit , Gormsen Erik , Malmos Henrik 
Published: July 2010

AbstractThe wash performance of three specific proteases (asp, lys/arg and glu specific, respectively) is demonstrated to be comparable to that of commercial unspecific detergent proteases (Alcalase® and Savinase®). A hypothesis for the high performance of these specific proteases is proposed. The influence of pH and ionic strength on protease performance is discussed.The removal of oily stains by lipases in detergent solution is improved only slightly under acidic conditions, whereas pH values >> pKa of the fatty acids formed results in strongly enhanced removal. Wash trials with LipolaseTM show very little effect of the lipase after the first wash, but high effect after the second and subsequent washes. This is explained by lipolytic activity under drying. Maximum activity is found when the water content of the cotton swatches is between 10 and 40% (w/w).
Interactions between Polymers and Insoluble Materials in the Detergents' Matrices
Authors: Zini Paolo 
Published: July 2010

AbstractPolycarboxylated polymers have a strong tendency to adsorb on a large variety of surfaces. Among the surfaces of interest in detergency, insoluble materials in water are those which cause, in general, most of the washing problems.The insoluble materials may come from the intentional addition of them into the detergent (e.g. zeolites and abrasive ingredients) or may be formed during the washing process itself (e.g. Ca carbonate and Ca phosphate salts).
The behaviour of LAS in the environment
Authors: Berna José Luis , Moreno Alfonso , Ferrer Juan 
Published: July 2010

AbstractDuring the last few years a considerable amount of information about the biodegradation of linear alkylbenzene sulfonates (LASs) in real environmental situations has been made available. This paper reviews the existing LAS concentrations found today in the environment, using specific analytical techniques for this surfactant, as well as its mineralization and fate in compartments such as sludge amended soils. LAS is totally decomposed into carbon dioxide, water and inorganic sulfate without formation of stable metabolites, and no accumulation has been detected in the compartments studied. The highest degree of biodegradation (>95%) takes place in the processes (sewers and sewage treatment plants) showing the shortest half lives (1–10 h).
Non‐animal alternative toxicity tests for detergents: Genuine replacements or mere prescreens?
Authors: Balls Michael , Reader Sandra , Atkinson Karen , Tarrant Jane , Clothier Richard 
Published: July 2010

AbstractNon‐animal toxicity tests and testing strategies for use in identifying the potential toxic hazard of chemicals and products, and in providing information for use in risk and safety assessment, are in the course of development, validation and evaluation.Possible replacement alternatives to the rabbit Draize eye irritancy test are discussed, and results obtained for two in‐vitro tests developed by FRAME (the kenacid blue test and the neutral red release test), applied to 19 surfactants and 32 formulations, are discussed.It is concluded that there are now legal and moral requirements that relevant and reliable non‐animal tests should be developed and accepted for use whenever possible.
The methanogenic toxicity of wastewater lignins and lignin related compounds
Authors: Sierra‐Alvarez Reyes , Lettinga Gatze 
Published: July 2010

AbstractLignin derivatives are major components of wastewater streams generated in the chemical processing of wood. The objective of this study was to evaluate the inhibitory effect of various lignins isolated from forest industry wastewaters, and selected lignin model compounds, on methanogenic bacteria. The methanogenic inhibition was determined at 30°C in standard toxicity assays, utilizing anaerobic granular sludge as inoculum. The wastewater lignins differed considerably in their inhibitory activity. Some lignin samples were nontoxic, whereas others caused 50% inhibition at concentrations ranging from 3320 to 5950 mg COD dm−3. Experiments with ultrafiltered lignins revealed that the toxicity of the inhibitory lignin samples originated from the low molecular weight fraction. In additional studies with low molecular weight lignin model compounds, it was observed that the inhibitory activity of these compounds was related to the functional groups on the aromatic ring. Compounds with aldehyde groups or apolar substituents were highly toxic, whereas those with carboxylic groups only caused significant inhibition at high concentrations. These results indicate that low molecular weight lignin derivatives in forest industry wastewaters are potential inhibitors of anaerobic treatment systems.
Continuous aqueous phase extraction of proteins: Automated on‐line monitoring of fumarase activity and protein concentration
Authors: Papamichael Neophytos , Börner Bernard , Hustedt Helmut 
Published: July 2010

AbstractAutomated assay techniques are described for on‐line measurements of fumarase activity and total protein concentration, including in‐line sample dilution and sample multiplexing during continuous aqueous phase extraction. Fumarase was determined by following the conversion of L‐malate to fumurate at a wavelength of 250 nm, while the protein assay was based on the Biuret reaction. Actual assay times of 2 and 4 min were achieved for the fumarase and protein measurements, respectively, with an effective measurement cycle time of 2 min. Standard deviations of c. 3.2 and 2% of the measured values were calculated for the enzyme and protein values, respectively. The assay system was coupled to a computer to allow on‐line data visualization and storage.
Electrochemical ion exchange
Authors: Bridger Nevill J. , Jones Christopher P. , Neville Mark D. 
Published: July 2010

AbstractThis paper introduces electrochemical ion exchange (EIX) as a technique for the removal of ionic species from aqueous waste streams. The basic mechanistic principles behind EIX are presented and experimental procedures described. Typical experimental results for a number of applications are given. A comparison is made between EIX and electrodialysis and electrodialysis combined with conventional exchange.
Hydrolysis and esterification with immobilized lipase on hydrophobic and hydrophilic zeolites
Authors: Lie Ewa , Molin Göran 
Published: July 2010

AbstractHydrolysis and esterification in a triolein/oleic acid system were compared with Candida cylindracea lipase attached to celite, hydrophobic zeolite and hydrophilic zeolite. The hydrophilic zeolite blocked the hydrolysis but mediated the esterification. Esterification with celite or hydrophobic zeolite as carrier was poor.
Purification and kinetics of penicillin G acylase from a mutant strain of escherichia coli ATCC 11105
Authors: Erarslan Altan , Terzi Ibrahim , Güray Ayşe , Bermek Engin 
Published: July 2010

AbstractA mutant strain with high penicillin G acylase activity was derived from Escherichia coli ATCC 11105 by chemical mutagenesis, using N‐methyl‐N′‐nitro‐N‐nitrosoguanidine. Penicillin acylase was extracted from the mutant strain and highly purified by DEAE‐cellulose and hydroxyapatite column chromatography followed by preliminary precipitation steps. Vm and Km values of the enzyme (specific activity: 24·81 U mg−1, protein concentration: 0.56 mg cm−3) were found to be 22.73 U cm−3 mm−1 and 3.18 mmold m−3 penicillin G, respectively. The enzyme was shown to be uncompetitively inhibited by excess of substrate. The inhibition by phenylacetic acid was found to be competitive, and 6‐aminopenicillanic acid to be noncompetitive. Inhibition constants for excess of penicillin G, phenylacetic acid and 6‐aminopenicillanic acid were estimated as 74.20, 18.74 and 15.00 mmol dm−3 respectively, at pH 8.0 and 40°C. The activation energy of the enzymatic hydrolysis reaction of penicillin G was found to be 10.78 kcal mol−1. Optimal pH and temperature values of the enzyme were determined as 8.0 and 60°C. Complete loss of the enzyme stability occurred when the enzyme was incubated at pH 10.0 for 2 days or at 50°C for 2 h.
Effect of temperature on the removal of lead(II) by adsorption on China clay and wollastonite
Authors: Yadava K. P. , Tyagi B. S. , Singh V. N. 
Published: July 2010

AbstractThe removal of Pb(II) from aqueous solution by adsorption on china clay and wollastonite is an attractive process. The amount of Pb(II) removed by adsorption is highly dependent on the temperature of the adsorbate solution and favours low temperature. The equilibrium times were noted, i.e. 90 min for china clay and 120 min for wollastonite. The various rate parameters of the adsorption process have been determined at different temperatures. The activation energies were determined and found to be −5.345 kJ mol−1 and −8.730 kJ mol−1 for Pb(II)‐china clay and Pb(II)‐wollastonite systems, respectively. The adsorption isotherm was measured experimentally at various temperatures. The negative values of enthalpy change (ΔH = −77.95 kJ mol−1 and −16.40 kJ mol−1 for china clay and wollastonite, respectively) indicate the exothermic nature of the adsorption processes for both systems. The isosteric heats of the adsorption process have been determined at various surface coverages of the adsorbents used. The various thermodynamic parameters have been calculated to elucidate the mechanism involved in the adsorption process.
Synthesis and anticonvulsant properties of some novel quinazolinone
Authors: El‐Feky S. A. H. , El‐Samii Z. K. Abd 
Published: July 2010

AbstractSome quinazolinone thiosemicarbazone and 4‐thiazolidone derivatives were prepared and tested for their anticonvtdsant activity. 3‐(2‐methyl‐4‐(3H)‐quinazolinon‐3‐yl)‐4‐oxo‐thiazolin‐2‐yl‐(4‐chlorobenzaldehyde)‐hydrazone (4a) shows the maximum protecting activity against pentylenetetrazol‐induced seizures in albino mice.
The catalytic activity of the ceramic superconductor YBa2Cu3O7 − δ
Authors: Rophael Magdy W. , Khalil Laila B. , Malati Mounir A. 
Published: July 2010

AbstractThe superconductivity of the ceramic solid YBa2Cu3O7 − δ, prepared by heating Y2O3, BaCO3 and CuO at 920°C for 22 h, was checked by the Meissner effect. Chemical analysis established the formula of the compound prepared. A thermostated aqueous suspension of the superconductor, treated with a solution of H2O2, produced oxygen, whose volume was measured at intervals in a gas burette. From the initial rates of the first‐order reaction at different temperatures, the activation enthalpy and entropy were 16 kJ mol−1 and −210 J K−1 mol−1 respectively. The rates of gas evolution were similar to those obtained when a MnO2 sample was used as a catalyst. Neither the superconductor nor its semiconductor phase photocatalysed the decomposition of KMnO4 solution. Evidence of the catalysed decomposition of N2H+5 by the superconductor is presented.
Bioconversion of Lmalic acid into Llactic acid using a high compacting multiphasic reactor (HCMR)
Authors: Naouri Pascal , Bernet Nicolas , Chagnaud Patrice , Arnaud Alain , Galzy Pierre , Rios Gilbert 
Published: July 2010

AbstractBiotransformation of Lmalic acid into Llactic acid was studied in a fluidised bed reactor using cells of Lactobacillus sp. 89 and Leuconostoc oenos ATCC 23278 immobilised in a calcium alginate matrix. The reactor was used in a batch or a continuous manner under a non‐oxidising atmosphere. It was shown that 3 mm diameter beads loaded with 6 and 30 mg dry matter per gram of gel were the best operating conditions for Leuconostoc and Lactobacillus respectively. The optimal working conditions were as follows: pH = 3.0–5.0, temperature = 30°C for Lactobacillus and pH = 3.0, temperature = 25°C for Leuconostoc. No inhibition due to lactic acid was observed and the internal diffusional effects were negligible. The short catalyst life that was initially observed with both strains resulted from a depletion in NAD and Mn2+, two basic cofactors for malolactic enzymes. To prevent this detrimental effect, a regeneration process for biocatalyst was proposed.
Kinetic investigation of penicillin g acylase from a mutant strain of Escherichia coli ATCC 11105 immobilized on oxirane–acrylic beads
Authors: Erarslan Altan , Güray Ayse 
Published: July 2010

AbstractHighly purified penicillin G acylase from a mutant derivative of Escherichia coli ATCC 11105 was immobilized on oxirane–acrylic beads by covalent binding via oxirane groups. The highest specific activity, (322 U g−‐1 dry matrix at 40°C and at pH 8·0) was obtained by using an enzyme solution having 13·8 U mg−‐1 specific activity and 72·73 mg total protein. The efficiency of immobilization was 95·8%. Kinetic parameters of immobilized penicillin G acylase were determined at the same pH and temperature by a preparation having 8·1 mg bound protein. The Km value and substrate inhibition constant of the enzyme were found to be 11·36 mmol dm−‐3 and 680 mmol dm−‐3 penicillin G respectively. Phenylacetic acid and 6‐aminopenicillanic acid were estimated as the competitive and non‐competitive inhibitors of the enzyme and their inhibition constants were found to be 90 mmol dm−‐3 phenylacetic acid and 76·1 mmol dm−‐3 for 6‐aminopenicillanic acid. The activation energy of the hydrolytic reaction was calculated to be 7·75 kcal mol−‐1. The immobilized enzyme showed highest activity at pH 8·0 and at 55°C. The enzyme was stable when incubated at 4°C for one day at a pH range of 5·0 to 9·0. Thermal stability (over 30 min) was observed up to 40°C but decreased at higher temperatures and was almost absent at 60°C. A 95% conversion rate was observed at 28°C and at 40°C with 60 and 30 min operation times respectively. Operational stability of the enzyme was improved further with dithiothreitol treatment. Activity loss was around 5% following 20 cycles of repeated use of the enzyme at 40°C. No significant loss of activity was observed at 28°C when the enzyme was used,for 20 cycles. 6‐Aminopenicillanic acid in the reaction mixture was observed to be stable during conversion reactions which were carried out at both temperutures.
Effects of floating contactors on oxygen transfer and hydrodynamics in a bubble column
Authors: Kang Yong , Min Bung T. , Nah Jong B. , Kim Sang D. 
Published: July 2010

AbstractThis study investigates the adoption of floating contactors to promote the rate of oxygen transfer from non‐uniform air bubbles to liquid in a bubble column with continuous operation. The volumetric oxygen transfer coefficient and axial dispersion coefficient of a liquid phase have been analyzed based on the axial dispersion model. Attention was focused on the effects of the volume fraction of the floating contactors on the volumetric oxygen transfer coefficient, axial dispersion coefficient of a liquid phase, and gas phase hold‐up in the bubble column. The results have shown that the volumetric oxygen transfer coefficient and gas phase hold‐up can increase by up to 25% and 13%, respectively, while the axial dispersion coefficient of a liquid phase decreases by up to 30% by adding floating contactors in the column.
Enhancing oil recovery
Authors: Dawe Richard A. 
Published: July 2010

AbstractThe extraction of oil from oil reservoirs beneath the North Sea has stimulated an immense popular interest in oil exploration and production. The mass media cover many of the sensational aspects of the industry but the mechanisms of the production of oil from the reservoir are not often mentioned. This is partly because the reservoir is a huge heterogeneous volume hidden underground, but also because some background in science is required. The mechanisms of oil recovery depend to a great extent on what happens at the interface between the displaced and displacing fluids at the pore scale (μm) and the reservoir scale (km). Oil is left unrecovered in areas of the reservoir where the displacing fluid has not passed (by‐passed zones–sweep efficiency) and as droplets trapped in the pores in areas where displacement has occurred (microscopic residual oil–pore displacement efficiency). The physics at the interfaces, including the interplay between capillary, (interfacial tension, wettability), viscous and gravity forces is fundamental to an understanding of the retention of this residual oil (a common reservoir average estimate is over 60%) trapped by the capillary forces or by‐passed by the displacing gas or liquid due to inhomogeneity of the reservoir. The alteration of the balance of these forces is the key to enhancing the oil recovery, either by sweeping new areas of the reservoir or recovering some of the microscopically trapped oil.This article is written to provide some of the background to oil production in the context of enhanced oil recovery (EOR). It firstly covers oil recovery that is normally practised, then describes the EOR techniques currently under active development and finally discusses some of the problems that research must overcome before EOR can be successfully implemented with confidence.
Hydraulic characteristics of biological filters
Authors: Muslu Yilmaz 
Published: July 2010

AbstractRelationships between the removal efficiency and the hydraulic regimes of trickling filters were investigated. At low flow rates, where break‐up of liquid jets occurs and drops form, completely mixed conditions prevail. For large hydraulic loadings effluent concentrations were calculated by means of a dispersed plug flow model. The ranges of validity of these models were studied theoretically. The effects of drop formation and breakage of liquid jets on the substrate utilization are expressed in terms of hydraulic and physical properties of the media and liquid.
Studies on the dechlorination and detoxificaton of organochlorine compounds. I. PCBs and PCNs
Authors: Stojkovski Stojan , Markovec Ladislav M. , Magee Robert J. 
Published: July 2010

AbstractIn the analysis of organochlorines such as polychlorinated biphenyls (PCBs) and polychlorinated naphthalenes (PCNs), levels of, for example, PCB concentration are often expressed as a ‘total PCB’ value, using a straight GC pattern‐matching technique with electron capture detection. Such methods provide little information about the identity of the individual components. In the present study, preliminary investigations using dechlorination with a NiCl2/NaBH4 catalyst indicated that the technique offered a comprehensive method for the analysis of PCBs and PCNs, as well as a method of detoxification of the ‘priority pollutants’ . This paper reports the use of capillary column GC‐MS with an ion trap detector (ITDTM) for the analysis of a number of PCBs and PCNs, including the commercially produced Aroclor 1254 and 1221, employing this dechlorination technique.
A mathematical model for a biological fluidized bed reactor
Authors: Lin S. H. 
Published: July 2010

AbstractA physical model is given in the present report for representing a three‐phase biological fluidized bed reaction system which consists of microorganism‐coated particles, waste water and air. The system is assumed to be well fluidized. The physical model can be represented by two differential equations describing, respectively, the substrate axial dispersion and diffusion/reaction. Numerical values of the physical parameters are selected from the literature or estimated from semi‐empirical equations. The governing system equations are solved by an iterative finite‐difference scheme. The theoretical predictions are compared with several experimental measurements and the agreement between them found to be very good, validating the physical model reported here.
Determination of vanadium in steels using phenylfluorone and cetylpyridinium bromide
Authors: Tarek M. , Zaki M. , Abuo‐Zeid Said M. 
Published: July 2010

AbstractVanadium(V) was determined spectrophotometrically by reaction with phenylfluorone (I) at pH 8.8 in the presence of cetylpyridinium bromide to form a 1:2 vanadium‐I chelate. The molar absorptivity of the sensitised chelate was 7.0 × 104 dm3 mol−1 cm−1 at 550 nm and the sensitivity index was 0.7 ng cm−2. Beer's law was followed up to 0.37 ppm of vanadium. The interference of other metal ions was eliminated by electrolytic separation using a mercury cathode. The developed method was successfully applied for the determination of vanadium in steels.
Gas transfer in an external loop bioreactor with built‐in ultrafiltration
Authors: White C. , Morgan N. L. , Killick E. G. 
Published: July 2010

AbstractThe SGI Ultrafermenter is an external loop bioreactor with circulation through an ultrafiltration module allowing removal of medium and soluble products during fermentation. The contents are continually circulated during operation and the vessel is also equipped with a stirring turbine. The interaction of these two mixing agents on gas transfer was investigated. Both mechanisms produced similar increments in KLa over their working ranges, with values from approximately 0–700 h−1 at 200 dm3 h−1 airflow. The effects of these two mechanisms on KLa were approximately additive at low values but the combined mixing produced a maximum KLa value also in the region of 700 h−1. The power‐draw of mixing using the two agents was calculated and stirring was found to be 10–20 times more efficient than circulation.
A comprehensive study on the polarographic behaviour of α‐arylhydrazono‐3‐ketimino‐nitriles
Authors: Ismail M. I. 
Published: July 2010

AbstractThe polarographic behaviour of some α‐arylhydrazono‐3‐ketimino‐nitriles (Ia—h) in 50% ethanolic aqueous buffer is reported and discussed. The mechanism of electrode processes corresponding to the observed cathodic waves is proposed and confirmed by the aid of model compounds as well as through identification of controlled potential electrolysis products. The E1/2 and pKa values of the title compounds were evaluated and correlated to Hammett constants. The physical characteristics of the studied compounds in DMF regarding their redox potential (Δ1/2); electron affinity (EA); ionization potential (IP); electronic transition energy (ECT) and coulomb repulsion integral (J12) were computed. A linear correlation was shown to exist between Δ1/2 and ECT.
Anaerobic biodegradability and toxicity of eucalyptus fiber board manufacturing wastewater
Authors: Soto M. , Field J. A. , Lettinga G. , Méndez R. , Lema J. M. 
Published: July 2010

AbstractWastewater from eucalyptus fiber board manufacturing (EFBM) was characterized and studied for its treatability by anaerobic digestion. The characteristics of the wastewater (in mg dm−3), are as follows: COD (42 000), SS (550), SO (1200), PO.P (50), NH.N (15), VFA (710), phenol (20), p‐cresol (125), tannin COD (1460) and pH 2.8. Approximately 60% of the COD is composed of carbohydrates.The continuous treatment of EFBM wastewater resulted in 93% COD removal and 78% COD methanogenized, with influent COD values of 20 g dm−3 and OLR of 17 kg COD m−3 d−1. The biodegradation reached 94% of influent COD and 74% of influent ultraviolet absorbance (215 nm).EFBM wastewater supplied at 20 g COD dm−3 (1:1 tap water diluted) caused 50% methanogenic toxicity, which did not disappear when tannins were removed by adsorption on PVP (polyvinylpyrrolidone). The toxicity decreased to 25% once the wastewater was autoxidized with air at high pH values. However, the effluent of the continuously fed column didn't show methanogenic toxicity, therefore the main toxic compounds in the wastewater were removed during anaerobic treatment.