bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of Immobilisation on the Production of α‐Amylase by an Industrial Strain of Bacillus amyloliquefaciens
Authors: Argirakos George , Thayanithy Kuganakathasan , John Wase D. A.
Published: July 2010

The effect of immobilisation of an industrial strain of Bacillus amyloliquefaciens in calcium alginate beads on production of α‐amylase was investigated using lactose‐based media in shake flasks and in a 0.3 dm3 glass fermenter. Although the microorganism was a good α‐amylase producer in batch cultures of free cells, it was unable to produce the enzyme for extended periods either in repeated batch cultures, or in continuous cultivation. In each case, parallel tests with cells immobilised in calcium alginate beads gave still further reduced enzyme yields, and the free cells released into the broth from these beads probably contributed substantially to any amylase produced during these extended fermentations. After prolonged use, the core of the alginate beads accumulated hard insoluble material, with viable immobilised cells confined to a surface layer.
Preparation of Aluminum Hydroxide Gels by Precipitation: Effect of Proton Acceptors on Surface Area and Porosity
Authors: Bakoyannakis Demetris N. , Stalidis George A. , Zamboulis Demetris X.
Published: July 2010

This work has been undertaken to study the effect of varying chain length of primary amines on the preparation of aluminum hydroxide gels by precipitation. The aluminum hydroxide gels have been prepared by precipitation from ethanolic solutions of AlCl3.6H2O adding primary amines (propylamine, octylamine, dodecylamine) which acted as proton acceptors during the hydrolysis reaction and made the precipitation possible. The prepared samples were freezedried and activated to temperatures of up to 773 K. This technique produced in general amorphous samples of high specific surface area (up to 570 m2 g%−1). The specific surface area measured by nitrogen adsorption and the pore size distribution determined by mercury porosimetry were differentiated according to the chain length of the amine used. These differences were further enhanced on thermal activation to the aforementioned temperatures.
Induction of Granulation by Sulphonated‐Lignin and Calcium in an Upflow Anaerobic Sludge Bed Reactor
Authors: Guiot Serge R. , Rocheleau Sylvie , Hawari Jalal , Samson RéJean
Published: July 2010

The present study evaluates the capability of sulphonated lignin (S‐lignin) and calcium to promote anaerobic sludge granulation, which is of prime importance in the operation of upflow anaerobic sludge bed (UASB) ‐like reactors. One of two reactors fed with a synthetic sugar waste was stepwise supplemented with a spent liquor rich in S‐lignin from a neutral sulphite semi‐chemical pulping plant to reach an addition rate of 0.17 g S‐lignin per gram volatile suspended solid (VSS) per day. This resulted in biomass pre‐granulation (50–60% of the biomass aggregates had a size > 0.3 mm). No change was observed in the surface properties (hydrophobicity and zeta potential) of the bacterial aggregates. The S‐lignin‐fed sludge aggregated in an ordered and cluster‐like manner and exhibited a more compact ultrastructure than the control sludge. Moreover, the addition of S‐lignin slightly enhanced the metabolic activities of the biomass. Calcium ion addition following the S‐lignin treatment improved the size and the settleability of the aggregates and increased the solid retention time.
The Chemical and Physical Structure of Peat Bitumens
Authors: Leahy James J. , Birkinshaw Colin
Published: July 2010

Peat bitumen obtained by solvent extraction of Irish high moor peat was subjected to chemical, structural and rheological characterisation. The bitumen was fractionated on the basis of solubility in n‐heptane, toluene and ethyl acetate into wax, resin and asphaltene; each of these major constituent groups was further separated into sub‐fractions by column chromatography using solvents of increasing polarity. All materials were chemically characterised by C, H, N and O content and infra‐red spectroscopy. Molecular size distribution of the materials was determined by gel permeation chromatography and vapour pressure osmometry. Heats of fusion, measured using the differential scanning calorimeter, indicated that crystalline species were concentrated in the wax fraction. The rheological properties of the bitumen were investigated between 10 and 50°C, and the fractions were examined at 20°C. Following analysis as yield pseudoplastic fluids, flow behaviour was described in terms of yield stress, flow and consistency indices. The measured flow parameters were examined in the light of the structural implications of the calorimetry and the results of the chemical analysis. Carboxylic acids and esters which are found principally in the wax fraction are considered to be the dominating rheological influence in the bitumen, affecting physical behaviour through their ability to crystallise at low temperature and thus mechanically hinder flow, and through secondary bonding increasing viscosity in the liquid phase.
The Anaerobic Biodegradation of a Bagasse‐Based Paper‐Mill Waste in Fixed‐Film Reactor
Authors: Prasad Duggirala Yogendra
Published: July 2010

The high concentration of biodegradable constituents in waste‐water derived from bagasse‐based paper mills warrants the consideration of an anaerobic biotechnology process to recover biogas and reduce the pollution load. An anaerobic down‐flow fixed‐film bark reactor process was studied to treat waste‐water generated from bagasse‐based paper mills. At the anaerobic stage, 90–95% of the total chemical oxygen demand (COD) was removed at loading rates of 3–18 kg COD m%−3 day%−1 without supplying any nutrients or trace elements. A yield coefficient of 0.156 g cells (g COD) %−1 was calculated at a high COD loading rate of 18 kg COD m%−3 day%−1. With the anaerobic treatment process it is estimated that 1 m3 of bagasse waste‐water with a COD content of 13000 mg dm%−3 can produce about 3.5 m3 of methane. Intermittent checks on the system alkalinity revealed that feed neutralization to maintain alkalinity would be necessary with sodium bicarbonate at approximately 2500 mg dm%−3 for achieving steady‐state high treatment efficiency.
Silver Electrodeposition from Photographic Processing Solutions
Authors: Grau Javier M. , Bisang JoséM.
Published: July 2010

This paper describes the parameters that are important in the industrial practice of silver removal from photographic fixers. The experiments were performed under potentiostatic control using synthetic solutions. The current efficiency was analysed as a function of the cathodic potential taking into account the deposit quality. A cathodic potential of −0.5 V against a saturated calomel electrode is recommended. The conditions to prevent the darkening of the electrodeposit were investigated. The determination of silver concentration in the solution was made by direct potentiometry. The results obtained with synthetic fixers were corroborated by making the silver deposition from commercial fixers in an electrochemical reactor with rotating cylinder electrode intercalated in an electrolytic flow circuit in order to simulate practical conditions.
Stability of Lactobacillus bulgaricus immobilized in K‐carrageenan gels
Authors: Büyükgüngör Hanife
Published: July 2010

The future application of immobilized microorganism techniques will depend on the development of systems which are technologically applicable on an industrial scale. These techniques must permit high microbial concentrations and must allow mass transfer to take place with low diffusional limitations. In addition, the mechanical separation of the immobilized microorganisms must be achieved economically, K‐carrageenan was used as an ionotropic gel carrier for the immobilization of Lactobacillus bulgaricus (ATCC 11842), and the effects of gel stability on productivity and the rate of product formation were investigated. K‐carrageenan gels had higher mechanical and chemical stability than alginate gels. The storage stability of microorganisms immobilized in K‐carrageenan was good enough to retain biocatalytic activity during prolonged storage at 4°C.
Use of Aspergillus niger to improve filtration of olive mill waste‐waters
Authors: Hamdi Moktar , Ellouz Radhouane
Published: July 2010

The high levels of dry matter (70–200 g dm−3) and total suspended solids (TSS) of up to 50 g dm−3 which are present in olive mill waste‐waters (OMW) render these very difficult to filter. During filtration of the OMW viscous solution, a cake is formed by the TSS which decreases the kinetics of the process. Addition of pellets of the fungus Aspergillus niger modifies the cake porosity and thus improves the OMW filtration process. Improvement to the filtration is directly related to the quantity of A, niger added and is attributable to the fermentation of OMW by A. niger since the TSS are trapped by the fungal pellets. The degradation of pectin by A. niger pectinases may also be partly responsible for the increase in the filtration capacity.
Characterization and use of a penicillin acylase biocatalyst
Authors: Ospina S. Sonia , Lopez‐Munguia Agustín , Gonzalez Rosa Luz , Quintero Rodolfo
Published: July 2010

A complete characterization of a penicillin acylase biocatalyst is presented, including the determination of physicochemical and kinetic parameters. Stability studies are detailed in terms of both storage temperature and pH as well as operational stability after 150 batch reactions of two hours duration each. An Arrhenius‐type model was used to simulate the effect of pH on biocatalyst stability. A kinetic model is proposed to describe batch and continuous stirred tank reactors and to predict the long‐term behavior of the process.
Decoloration of indene—coumarone resins by catalytic hydrogenation
Authors: Coca José , Rosal Roberto , Diez Fernando V. , Sastre Herminio
Published: July 2010

The catalytic hydrogenation of indene—coumarone resins, a coal‐derived polymer, has been carried out using commercially available catalysts. Hydrogenation of the resins causes the saturation of double bonds and leads to decoloration of the product, increasing its market value. A nickel‐on‐kieselguhr catalyst (Süd‐Chemie G‐49‐BRS) seems to be the most active and gives the highest degree of decoloration. However the decolorated resins tend to recover spontaneously their former colour, the process being only slightly prevented by the addition of stabilizers.
Experimental simulation of the infinite slab in thermal ignition
Authors: Jones J. C. , Gray B. F. , Rahmati H.
Published: July 2010

A novel piece of apparatus is described which simulates rigorously the ‘infinite slab’ in traditional thermal ignition theory. The apparatus was applied to shavings of a particular type of wood, and the results are shown to be consistent with those from more conventional experiments using basket heating.
Long chain phenols—part 30: A rate study of the mannich reaction of phenols (with particular reference to 3‐pentadecylphenol)
Authors: Short Eric L. , Tychopoulos Vasiliki , Tyman John H. P.
Published: July 2010

The rate of the Mannich reaction between 3‐pentadecylphenol, di‐n‐propylamine and 40% aqueous formaldehyde in aqueous ethanol under basic conditions has been studied by an HPLC analytical technique following preliminary experiments with dimethylamine, diethylamine and morpholine. The effect of excess amine and excess formaldehyde, different temperatures and the influence of pH were investigated. Kinetic expressions involving the concentrations of the phenol, amine and formaldehyde have been obtained on the assumption of the participation of either (a) the aminal (methylene‐bis‐amine) or (b) the aminol (methylolamine) for five cases covering the various molar proportions of reactant used experimentally. Initially, to test the equations for reactions effected at constant water concentration, theoretical values of t (time) were obtained as the initial concentration (a) of the phenol was varied by increments by a/20 using trial values for the composite rate constant. In this manner the best visual fit between the experimental points and the theoretical curves was obtained. The rate constant corresponding to such a curve was subsequently refined using a least squares procedure to yield the value which minimised the sum of the residuals between the experimental and theoretical values. In all cases the sum of the residuals was smaller when the kinetic expression derived assuming participation of the aminal was employed. The latter assumption also led to a smaller dispersion in the values obtained for the composite reaction constant from the different experiments.
Multienzyme membranes for biosensors
Authors: Krysteva Milka A. , Yotova Lyubov K.
Published: July 2010

Artificial multienzyme complexes were prepared in which enzymes were covalently bound to polysaccharide structures activated with urea and formaldehyde. Double enzyme complexes of glucose oxidase and catalase, a glucose oxidase and invertase, were prepared by immobilization on to cellulose fabric. Also, catalase was covalently bound to soluble dextran. The resulting multienzyme systems were highly active and stable, making them suitable for use in measuring the concentrations of glucose and saccharose in solutions. The measurements were performed using an amperometric oxygen electrode and multienzyme membranes containing glucose oxidase and catalase for the first substrate, as well as glucose oxidase bound to cheese‐cloth and a ‘liquid’ membrane of dextran‐bound catalase. To determine the concentration of saccharose, a multienzyme membrane with bound glucose oxidase and invertase was used in combination with a ‘liquid’ dextran—catalase. The enzyme electrodes exhibited a measuring range of 0.1–5 mol dm−3 and a response time of 2–3 min.

The electrodes may be used for measuring saccharose and glucose concentrations both in fermentation broths and food products.
Hydrophile lipophile balance of hydroxyoximes in McGowan scale and their partition and extraction properties
Authors: Szymanowski Jan , Voelkel Adam
Published: July 2010

Hydroxyoxime hydrophobicity was characterized by hydrophile lipophile balance in McGowan scale, and the relationship's log partition coefficient vs HLBGa and extraction rate vs HLBGa were discussed. The effect of the alkyl length and structure upon hydroxyoxime hydrophile lipophile balance and partition coefficients can be qualitatively considered using the effective length of the alkyl. The partition data for homologous series can be predicted from HLBGa. Relationships between extraction rate and HLBGa do not support the traditional view of the extraction mechanism. It supports the idea of the mechanism change from the bulk aqueous to the interfacial mechanism with the increase in hydroxyoxime hydrophobicity.
Chemical‐biotechnological processing of pine bark
Authors: Penas D. Zuhri Vázquez , Yusty M. A. Lage , Liñares J. C. Parajó
Published: July 2010

Samples 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

Reichstein'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

The 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

Bagasse 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

Activities 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

An 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

A 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

A 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

Branched 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

The 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

Two 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

The 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

Fumaric 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

Extracellular 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

Basically, 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

The 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

The 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

Investigations 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

A 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

Adsorption 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

The 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

The 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

Aqueous 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

α‐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.
Alternate control‐structures and plant‐model mismatch for fed‐batch bioreactors
Authors: Menawat Anil S. , Balachander Jayaram
Published: July 2010

Optimal feedback control of a fed‐batch bioreactor may be implemented by regulating the feed rate or the feed concentration and either may be used to optimize the same performance index. The latter approach, however, offers several advantages. In two bioreactors operating to maximize the instantaneous product formation rate, one with feed rate and the other with feed concentration control, the same amount of nutrients are fed to both fermenters. At the end of fermentation the fermenter with feed concentration control produces higher antibiotic concentration in a lesser volume than the other. The feed rate strategy, however, is more tolerant of the errors in the model than its counterpart. Such robustness is because of the complex volume effects which are absent with feed concentration (the feed rate is constant). The feed concentration strategy uses more information described in the model and hence is more sensitive to the errors. When the volume dependence is removed by implementing the control in the mass variable forms instead of the commonly used concentration forms, the feed concentration strategy becomes more robust and consequently less sensitive to the modeling errors. An ability to implement the feed concentration structure in either the mass or the concentration forms allows for a choice between sensitivity and robustness. Higher sensitivity would be desirable during system identification studies where parameters are estimated from data, whereas higher robustness would be preferred during plant operation.
Removal of organic matter from crude wet‐process phosphoric acid
Authors: Hanna A. A. , Ali A. F.
Published: July 2010

The organic matter was removed from the crude wet‐process phosphoric acid, produced by treating the Egyptian phosphate ore with sulphuric acid, using fine powder charcoal. The optimum charcoal/acid weight ratio, the effect of the acid concentration and the temperature on the efficiency of removal were studied.

It is found that the percentage of the organic matter content decreases from 2·172 × 10−2, for the crude phosphoric acid, to 0.108 × 10−2 after treatment of 70 g acid with 600 mg fine powder charcoal. When the charcoal/crude acid weight ratio reaches 1%, the crude acid becomes free from the organic matter and its colour turns from dark‐brown into pale‐green. This green colour is due to the presence of Fe2+ ions.

Also, it is found that as the acid concentration decreases, the efficiency of the charcoal in removing organic matter increases. This may be due to the decrease of the acid viscosity, by dilution, which enables the charcoal particles to spread and penetrate more easily through the medium.

The results of the effect of temperature show that the efficiency of charcoal in removing organic matter increases as the temperature is raised. This increase is also attributed to an increase in the charcoal apparent activity due to the decrease in the acid viscosity with temperature, leading to less possibility of scaling and more net surface area available for adsorption.
Synthesis of some new 3‐(2′‐heterocyclicethyl)‐2‐methyl‐3,4‐dihydroquinazolin‐4‐one derivatives as antimicrobial agents
Authors: El‐Zohry Maher F. , Abd‐Alla Mohamed A.
Published: July 2010

3‐(2′‐Chloroethyl)‐2‐methyl‐3,4‐dihydroquinazolin‐4‐one was reacted with acetylacetone, ethyl acetoacetate and diethylmalonate in the presence of sodium ethoxide to afford the alkylation products IV, V and VI, Compounds IV, V and VI were reacted with hydrazine hydrate, phenylhydrazine, hydroxylamine hydrochloride, urea and thiourea to yield 3‐(2′‐heterocyclicethyl)‐2‐methyl‐3,4‐dihydroquinazolin‐4‐one derivatives VII‐XV. The structures of the synthesized compounds were elucidated by elemental analyses and spectroscopic (IR and XH‐NMR) analyses.

The prepared compounds were tested for their antimicrobial activities in comparison with tetracycline as a reference compound.
Enzymatic kinetic resolution of [2.2]para‐cyclophane derivatives
Authors: Izumi Taeko , Hinata Takafumi
Published: July 2010

Reduction of 4‐formyl[2.2]para‐cyclophane with bakers' yeast allows the ready preparation of the planar chiral alcohol and aldehyde in optical active forms. Racemic [2.2]para‐cyclophane derivatives of 4‐acetoxymethyl‐ and 4‐hydroxymethyl‐ were optically resolved with lipases by hydrolysis of the acetate or by esterification of the alcohol using vinyl esters in organic solvents.
Extraction of penicillin G from simulated media by an emulsion liquid membrane process
Authors: Lee Sang Cheol , Lee Won Kook
Published: July 2010

The extraction of penicillin G from simulated media was performed by water/oil/water (w/o/w) emulsion liquid membranes (ELMs) and studied under various operational conditions in a batch system. The degree of extraction achieved was between 80% and 95% under specific conditions. A concentration of greater than nine times the initial concentration of penicillin G in the external phase was obtained in the internal phase. The pH of the internal aqueous solution, containing a basic salt, was theoretically calculated on the basis of the amount of penicillin G transported into the internal phase. The calculated results agreed with the experimental data well and were used to select a suitable type and concentration of a basic salt in the internal phase to give a pH within the range 5 to 8 where penicillin G was stable after the termination of extraction. The extraction of penicillin G was successfully performed by the ELM process with sodium carbonate in the internal phase.
Inhibition of the growth of the red microalga porphyridium sp. by limitation of nutrient transfer
Authors: Rotem Avi , Merchuk Jose C. , Arad Shoshana (Malis)
Published: July 2010

The unicellular red alga Porphyridium sp. was cultured in a medium to which increasing concentrations of its cell wall polysaccharide were added. As the polysaccharide concentration in the culture medium increased, algal growth rate and maximum cell number progressively decreased. In a different series of experiments it was shown that the polysaccharide also inhibited the rate of carbon uptake by the cells and as a result photosynthesis was also inhibited. In‐vitro experiments showed that the mass transfer coefficient for nitrate, bicarbonate, phosphate and potassium decreased as the polysaccharide concentration increased. The data indicate that the polysaccharide inhibits nutrient transfer from the medium to the cells, resulting in a reduction of the growth rate.
By‐product gypsum from the tapioca starch process
Authors: Beretka Julius
Published: July 2010

By‐product gypsum derived from the tapioca starch process was calcined in the laboratory and evaluated for use in the manufacture of plaster of Paris and plaster products. The gypsum had a purity of about 98%, was fine (1 %, + 150μm) and had a low bulk density (600 kg/m3). The laboratory calcined material had a higher than normal water requirement of 120–130 ml/100 g, and a long setting time of 65 min. Specimens cast at a water/solids ratio of 1·0 had a low compressive strength of 2·4–3·4 MPa. However, the mechanical strength could be improved by the addition of water‐reducing admixtures, and a strength of 7·6 MPa was obtained at a water/solids ratio of 0·6 and a resulting density of 1190 kg/m3. The waste gypsum derived from the manufacture of tapioca starch appears to be suitable for the manufacture of plaster of Paris and plaster products after the incorporation of water‐reducing admixtures into the plaster slurry.
Influence of coating thickness on the barrier effect of marine paint binders: An assessment using impedance measurements
Authors: Sarli A. R. Di , Elsner C. I.
Published: July 2010

The influence of coating thickness on the barrier effect afforded for several paint binders, as a part of naval steel/organic coating/artificial sea water systems, by using electrochemical impedance spectroscopy and corrosion potential measurements was studied.

As a function of the immersion time, ionic resistance (Rm) and dielectric capacitance (Cm) for the membrane were determined employing non‐linear fit routines on the experimental impedance spectra. Simultaneously corrosion potential values for the substrate were measured. These results showed that most of the samples exhibited very good dielectric and barrier properties whilst they remained in contact with the electrolyte and that the corrosion potential changes were in agreement with those of the impedance spectra. The importance of producing coatings with both uniform chemical composition and thickness to avoid localized corrosion was emphasized.
Enzymatic resolution of planar chiral ferrocene derivatives
Authors: Izumi Taeko , Hino Toshimi
Published: July 2010

Racemic 3‐methyl, 2‐ethyl, 2‐bromo, and 2‐trimethylsilyl derivatives of formylferrocene were kinetically resolved by enantioselective reduction with a fermenting baker's yeast. Moreover, 2‐methyl, 3‐methyl, 2‐ethyl, 2‐bromo, and 2‐trimethylsilyl derivatives of hydroxymethylferrocene were optically resolved with lipases by transesterification using vinyl esters.