bluuebunny/crossref_metadata_2025_split huggingface dataset:
Limited enzymic degradation of proteins: A new approach in the industrial application of hydrolases
Authors: Adler‐Nissen Jens 
Published: July 2010

AbstractThe industrial importance of hydrolases exceeds that of other classes of enzymes. A major application area for hydrolases is for the dissolution of biopolymers such as starch, pectin, cellulose and protein; in many cases it has been the desire to achieve as complete a solubilisation as possible. However, with food proteins, it has been demonstrated that a limited controlled hydrolysis may give rise to particularly interesting functional and organoleptic properties. The degree of hydrolysis (DH) is defined as the percentage of peptide bonds cleaved and is used as the controlling indice for the hydrolysis of food proteins. For a given enzyme‐substrate system, at least five independent indices can be defined: S (substrate concn), E/S (enzyme/substrate ratio), pH, T (temperature) and t (time). The advantage of the DH‐concept is that of these five variables, four (S, E/S, T, t) can be replaced by DH, i.e. within certain limits of S, E/S, T and t, the properties of a particular protein‐enzyme system are solely dependent on DH and pH of the hydrolysis. Empirically, this is demonstrated for soya‐protein isolate hydrolysed with Alcalase and theoretically the same result can be derived from the fact that there is substrate saturation throughout the reaction. These theoretical calculations are the basis for the so‐called θ(h)‐method, by which the significance of a particular hydrolysis indice can be studied. For each empirically derived hydrolysis curve, the hydrolysis time corresponding to any DH is found. Over a complete DH interval the proportion between the hydrolysis time for each DH is then calculated. If this term, denoted θ(h), is the same for all DH, the properties of the hydrolysates are independent of variations in the hydrolysis indice under study. A statistical procedure must be used to determine if θ(h) is constant or not. The θ(h)‐method is thus a valuable tool in the practical optimisation of industrial hydrolysis processes as the hydrolysis reaction curve under varying process conditions can be precalculated. The procedure may possibly be of interest in the hydrolysis of other biopolymers.
Use of immobilised cells with special emphasis on the formation of products formed by multistep enzyme systems and coenzymes
Authors: Mosbach Klaus 
Published: July 2010

AbstractDespite the increasing number of reports in the literature on the immobilisation of cells or enzymes for the production of compounds of more complex nature involving multistep enzyme systems and coenzymes, no such systems are yet known to be used commercially on a large‐scale basis (vaccine production by microcarrier‐attached animal cells being an exception). Various systems that have been described are reviewed including plant and animal cells. Special emphasis is given to the choice to be made between the use of immobilised cells or immobilised enzyme sequences. In this context alternative regeneration methods for coenzymes are discussed. Special attention is brought to the potential for such biosyntheses with immobilised‐permeabilised cells. It is likely that the list of immobilised cells‐enzymes used at present and restricted to single enzymic steps will be extended in the not too distant future by more complex systems.
Biomethanation: Its future development and the influence of the physiology of methanogenesis
Authors: Melchior Jean‐Luc , Binot Roger , Perez Inocenta Aguilar , Naveau Henry , Nyns Edmond‐Jacques 
Published: July 2010

AbstractBioconversion of organic matter into methane by anaerobic bacteria is a process better understood each day. The technology of biomethanation takes advantage of this in a number of ways, three of them being examined in this paper.First, when biomethanation is conducted under continuous, completely mixed conditions without active biomass recycle, a bottleneck may arise from the limited number of methanogenic bacteria present in the digestion mixed liquor. As the specific methane production rate was shown to be also limited, the resulting overall methane production must remain low. ‘Second generation’ methane digesters are being designed so as to trap the methanogenic bacteria within the digester, a fact which was demonstrated by the accumulation in the methane digestion mixed liquor of coenzyme F420.Second, when the feedstock for biomethanation consists of insoluble organic matter, the preliminary solubilisation of this insoluble matter is often rate‐limiting. It was shown that the inverse of conversion varies linearily with the inverse of mean residence time, which allowed the calculation of ‘ultimate’ conversion. Application of this technique to the individual components of a complex feedstock, determined independently, allowed us to identify problems of rate limitation and of bacterial competency. Two‐step methane digestion systems should help to overcome this second bottleneck.Third, monitoring of the biomethanation process needs major improvements. Even simple analytical methods such as dry organic matter or chemical oxygen demand determinations suffer major drawbacks and may lead to erroneous estimated efficiencies. A graph is proposed which attempts to correlate heats of combustion, mean oxidation stages and specific chemical oxygen demands with efficiencies with the aim of detecting anomalous values.
Animal cell technology: An overview
Authors: Spier Raymond E. 
Published: July 2010

AbstractThe review focuses attention on the different kinds of equipment which are used to grow large quantities of the two types of animal cells; the monolayer or surface‐dependent cell and the suspension or surface‐independent cell. The methodologies used to obtain reliable performance are described as are some examples of the application of microprocessors to monitor and control operational parameters. The kinds of products which are currently obtained from animal cells are listed and the future potential of genetically engineered animal and prokaryotic cells is discussed.
Use of microcarrier culture for the production of herpes simplex virus (type 2) in MRC‐5 cells
Authors: Griffiths Bryan , Thornton Barry 
Published: July 2010

AbstractThe ultimate aim of this work is the production of a subunit vaccine of herpes simplex virus (HSV). The first step was towards the development of a high‐yielding process for the production of HSV in tissue cells. The microcarrier system was evaluated for this purpose as it is a unit process with good scale‐up potential and is a monolayer‐growth method, essential for HSV production. Details are given of a closed perfusion system with environmental control which was capable of growing MRC‐5 cells to densities in excess of 105 cm−2 (3 × 106 cm−3). However, it has proved difficult, so far, to obtain good titres of HSV in this system. A novel approach to the production of HSV antigen with cell membrane‐associated antigens was tried. Preliminary trials in a guinea‐pig model indicated that these membrane‐associated antigens afforded protection against genital infection with HSV‐2.
Modern developments in mutagenesis
Authors: Saunders Gunter , Allsop Aileen , Holt Geoffrey 
Published: July 2010

AbstractMutants of Penicillium chrysogenum and Streptomyces clavuligerus have been isolated on the basis of increased sensitivity to far ultraviolet light far (u.v). In the former case the strain was also sensitive to a wide range of other mutagens, including alkylating agents and ionising radiations, but proved not to be hypermutable by any of these, whereas in S. clavuligerus two strains were hypermutable relative to their wild‐ type progenitor when treated with far u.v. In addition, various environmental conditions, including liquid holding and treatment with caffeine, isoniazid and nalidixic acid, increased mutant yield. The results obtained clearly show that induced mutation frequency can be enhanced both by mutation of genes involved in DNA repair and by modification of environmental conditions during or after mutagenic treatment. The importance of this and other modern developments in mutagenesis for the design of rational industrial strain‐improvement programmes is discussed.
Thermal crystallisation of amorphous calcium phosphate to α‐tricalcium phosphate
Authors: Kanazawa Takafumi , Umegaki Takao , Uchiyama Naoki 
Published: July 2010

AbstractDehydration and thermal change in amorphous calcium phosphate (ACP) have been studied by thermogravimetry, differential thermal analysis and X‐ray diffractometry. ACP retained water up to about 773 K. Immediately after the dehydration, a high‐temperature form of calcium phosphate, α —Ca3(PO4)2 (α ‐TCP), was obtained by ignition of ACP precipitated from the solution with a high degree of supersaturation. The kinetics of thermal crystallisation of α‐TCP from ACP were also studied.
Comparison of intermittent and continuous loading of stationary fixed‐film reactors for methane production from wastes
Authors: van den Berg L.(Bert) , Kennedy Kevin J. 
Published: July 2010

AbstractIntermittent loading of a stationary fixed‐film reactor (approximately 35 dm3) with bean‐blanching or pear‐peeling waste allowed the same or higher loading rates and rates of methane production as continuous loading. Slug‐loading one‐or two‐times daily or continuous loading for 7 out of 24 h allowed loading rates of up to 26 kg Chemical Oxygen Demand (COD) day−1 m−3 and rates of methane production of up to 3.5 m3 day−1 m−3 packing void volume, the latter almost 30% higher than during continuous (24 h) loading. The efficiency of converting COD into methane decreased noticeably at high intermittent loading rates. During one‐or two‐times daily loading large amounts of hydrogen were also produced during the first 1–2 h after loading.
Chemistry and pharmacology of β‐adrenoceptor antagonists
Authors: Smith Leslie H. 
Published: July 2010

AbstractThe development of β‐adrenoceptor antagonists from the β‐stimulant isoprenaline is discussed. Routes of synthesis for the two series of agents that have emerged, the arylethanolamines and the aryloxypropanolamines, are outlined. The various biological screens that are used to define the pharmacological indices of the β‐adrenoceptor antagonists are described and the relevance of these is discussed. The structural requirements for a given pharmacological profile are outlined briefly and this is then related to the drugs clinically available. The clinical indications in which β‐blockers are currently used and the future directions of β‐adrenoceptor research are indicated.
Synthesis of some new oxazoloquinolines and stilbyloxazoloquinolines
Authors: Hammam A. S. , Yanni A. S. , Khalil Z. H. , Abdel‐Hafez A. A. 
Published: July 2010

AbstractA new series of 2‐aryl(alkyl)oxazoloquinolines (IV) were prepared by the reaction of 7‐amino‐8‐hydroxyquinoline with aromatic (or aliphatic) aldehydes in the presence of piperidine as a catalyst. Interaction of 2‐methyloxazolo[4,5‐h]quinoIine with aromatic aldehydes in the presence of piperidine as a catalyst gave 2‐stilbyloxazolo [4,5‐h]quinolines. The structural configuration of the prepared compounds was determined by elemental and spectral analysis.
A comparison of rates of disproportionation and transalkylation of m‐xylene
Authors: Aneke L. E. 
Published: July 2010

AbstractThe relative rates of toluene transalkylation, disproportionation and benzene transalkylation of m‐xylene over a catalyst consisting of 72% HY zeolite, 18% β‐AlF3 and 10% (all w/w) Cu have been studied at a temperature of 723K, reciprocal space velocity of 352 g h−1 mol−1 and at total pressures varying between 101 and 911.93 kPa. The catalysed disproportionation of m‐xylene is fastest and this has been explained in terms of the greater basicity of m‐xylene over either benzene or toluene, whereas the catalyst is acidic. Thus m‐xylene would be expected to adsorb more strongly on the catalyst.
N‐alkylated‐4,5‐diamino‐1,8‐dihydroxyanthraquinones: Dyes for polyester fibres
Authors: Fisher Alan , Lee Chi‐Sun , Peters Arnold T. 
Published: July 2010

AbstractThe synthesis of a series of N‐mono‐and bis‐alkylated derivatives of 4,5‐diamino‐1,‐8‐dihydroxyanthraquinone is described. These compounds dye synthetic polymer fibres in blue to greenish‐blue shades of good fastness properties; bis‐alkylation results in decreased substantivity, but excellent dyes result from the use of mixtures of mono‐and bis‐alkylated derivatives.
Variation in cell‐wall strength of Klebsiella pneumoniae NCTC 418 with change in agitation speed in a chemostat system
Authors: John Wase D. A. , Nesaratnam Suresh T. , Blakebrough Norman 
Published: July 2010

AbstractKlebsiella pneumoniae (NCTC 418) was grown in a chemostat with impeller speeds between 700 and 1000 rev. min−1. An inverse relationship between impeller speed and the cell‐wall strength of the organism was found and explained.
Effect of carbon‐oxygen and carbon‐sulphur surface complexes on the adsorption of mercuric chloride in aqueous solutions by activated carbons
Authors: Lopez‐Gonzalez Juan De Dios , Moreno‐Castilla Carlos , Guerrero‐Ruiz Antonio , Rodriguez‐Reinoso Francisco 
Published: July 2010

AbstractSeveral activated carbons obtained from commercial sources have been tested for their ability to remove mercuric chloride (HgCl2) from aqueous solutions. The chemical nature of the surface of the activated carbons was changed by introducing carbon‐oxygen and carbon‐sulphur surface complexes. The influence of these types of complexes on the adsorption of HgCl2 by the activated carbons has been studied. It seems that the existence of hydroquinonic, phenolic and hydrosulphide groups on the surface of the carbon reduces Hg(II) to Hg(I). However, there was an increase in the adsorption of Hg(II) when sulphide or hydrosulphide groups were present on the surface of the carbon. The effect of the pH of the solutions on HgCl2 adsorption was also studied; when the pH was changed from 1 to 7 there was an enhancement of the adsorption of HgCl2 by the activated carbons.
Structure‐activity relations of β‐adrenergic agents
Authors: Main Brian G. 
Published: July 2010

AbstractA review of the structure‐activity relations in aryloxypropanolamine β‐adrenoceptor drugs is presented. The effect of substitution in various parts of the molecule on β1/β2 selectivity and degree of partial agonism is discussed. Cardiac (β1) selectivity is achieved by hydrophilic compounds with either p‐amide substitution in the aryl ring, or a hydrogen bonding group in the amine side chain. Lipophilic compounds with branched chains tend to be β2 selective. Partial agonist activity may also be controlled by hydrogen bonding groups in the side chain and by aromatic substitution. Here 3,4‐dihydroxyl groups give full agonists, mono‐and des‐hydroxy (OH) groups partial agonists. The size of any o‐substituent is critical and a plot of Taft's steric factor versus partial agonism gives a linear relation. By manipulation of the above factors all combinations of selectivity and agonist activity may be achieved.
Electrokinetic behaviour of coal particles suspensions
Authors: Caoca José , Bueno Julio L. , Sastre Herminio 
Published: July 2010

AbstractMeasurements of the zeta potential of coal suspensions have been carried out by micro‐electrophoresis. The influence of colloidal particles concentration, temperature, pH and ionic strength on two types of Spanish coals have been studied. Experimental results are discussed in terms of the adsorptive properties of coal surface and with regard to the formation of aggregates by coagulation.
Studies on fermentation‐broth rheology of a penicillium strain with cellulose as substrate
Authors: Manchanda A. C. , Jogdand V. V. , Karanth N. G. 
Published: July 2010

AbstractThe rheological behaviour of cellulose fermentation broths of Penicillium funiculosum culture has been investigated. The shear stress‐shear rate behaviour is explained satisfactorily by a power law model, although there appear to be small yield stresses, particularly at high substrate concentrations.
Effect of the presence of a syntan on the dyeing properties of nylon 6
Authors: Guthrie John , Cook Christopher C. 
Published: July 2010

AbstractThe effect of treatment of undyed nylon 6 with a synthetic tanning agent, Cibatex PA (Ciba‐Geigy), on the rate of absorption of C.I. Acid Red 13 has been studied. The observed reduction in the rate of dyeing becomes more pronounced with increasing concentration of syntan present on the fibre before the coloration process. For pretreated nylon, the rate of dye uptake is at a maximum after a dyeing time which is dependent on the concentration of syntan; for untreated nylon, the maximum rate of dye uptake occurs after very low dyeing times. The belief that the syntan is initially present on the fibre as a ‘ring’ or deposit in the outer regions of the fibre is supported by the observation that hot aqueous treatments of syntanned nylon, which would be expected to increase the diffusion of the syntan into the interior of the polymer matrix, tend to greatly reduce the time at which the maximum rate of dye uptake is observed.
Hydrogenation of benzene to cyclohexene on an unsupported ruthenium catalyst: Physical and chemical characterisation of iron‐poisoned catalysts in relation to their catalytic performance
Authors: Ingemar Odenbrand C. U. , Andersson S. Lars T. 
Published: July 2010

AbstractThe physical and chemical characteristics of an unsupported Fe‐Ru catalyst, used in the hydrogenation of benzene to cyclohexene, has been investigated. The chemical composition was determined by X‐ray diffraction and ESCA. The catalyst consists of an Fe‐Ru alloy and hydrous iron oxides. The texture of the catalyst was determined by adsorption measurements and by microscopy. With increased iron content the BET surface area and the pore volume decreases. The decrease in surface area affects all pore‐size intervals uniformly. The surface area measured by H2 adsorption decreases more rapidly than the BET surface area. The macroscopic particle size is constant up to an iron content of 15–20%. At higher contents their size decreases rapidly. The decreased Ha coverage on the catalyst surface on addition of iron was correlated to an increased yield of the desired intermediate cyclohexene. The chemisorption of benzene is also decreased by iron and, at poisoning levels above the optimal, planar adsorption of benzene is probably sterically hindered, whereas cyclohexene adsorption is less affected. This results in a decreased yield of cyclohexene at iron contents above the optimal. Hydrogenation of benzene to cyclohexene, performed in an alkaline aqueous phase, is shown to be influenced by diffusion. The catalyst particles (6–14 μm diameter) are large enough to make the overall rate limited by pore‐diffusion processes at 390 K. The maximum yield of cyclohexene has been correlated to the calculated effectiveness factor. The influence of poisoning and mass transfer, on the process, has been separated.
Hydrogenation of ethyne catalysed by supported solutions of tris‐(triphenylphosphine)chlororhodium (I)
Authors: Gil Figueroa Jesus M. , Winterbottom John M. 
Published: July 2010

AbstractThe hydrogenation of ethyne and propyne, catalysed by supported solutions tris‐(triphenylphosphine) chlororhodium (I) [RhI(PPh3)3Cl] has been studied in a fixed bed reactor at 1 atmosphere total pressure over the temperature range 60–90°C. A number of silica gel supports and reaction solvents, of different co‐ordination strengths, including molten triphenylphosphine itself were examined to determine their effect on catalyst activity and selectivity. Optimum liquid loadings were observed for each support and the presence of excess triphenylphosphine was essential to the promotion and maintenance of any catalyst activity and the optimum molar ratio PPh3/RhI (PPh3)3Cl =70. The catalyst was 100% selective for ethene formation, but suffered progressive deactivation. The use of strongly co‐ordinating solvents and microporous supports gave rise to longer catalyst life, at the expense of catalyst activity. Propyne also hydrogenated with 100% selectivity to propene, but without noticeable deactivation. It is concluded that strong co‐ordination of ethene is a likely cause of catalyst deactivation, whereas propene, conversely, co‐ordinates very weakly and does not hydrogenate. The best catalyst activity is achieved with a combination of a macroporous support and a weakly co‐ordinating solvent, but in this situation the catalyst is most easily poisoned when ethyne is hydrogenated.
Adsorption of copper nitrate from solution on silica gel
Authors: Choudhary Vasant R. , Vaidya Subhash H. 
Published: July 2010

AbstractAdsorption of copper nitrate from aqueous solution on to silica gel at different concentrations and temperatures has been investigated. Effect of precalcination temperature of silica gel and that of pH of the solution on the adsorption have also been studied. The adsorption was due to ion exchange and followed the Freundlich isotherm.
Catalytic decarbonylation of furfural in a fixed‐bed reactor
Authors: Coca Jose , Morrondo Eduardo S. , Sastre Herminio 
Published: July 2010

AbstractThe oxidative decarbonylation of furfural was studied in a fixed‐bed reactor. Mixtures of Mn, Zn, Cd, Sr and K oxides supported on spherical and cylindrical alumina were used as catalysts. In this paper the effect of the temperature and feed flow on the reaction yield for the catalysts tested and hence optimum reaction conditions are reported. Catalysts employed in this work are compared with Pd‐catalysts, frequently used for the decarbonylation of furfural.
Ethanol production by immobilised yeast and its CO2 gas effects in a packed bed reactor
Authors: Cho Gyu Hoen , Choi Cha Yong , Choi Yang Do , Han Moon H. 
Published: July 2010

AbstractImmobilised yeast trapped in an alginate matrix demonstrated maximum activity at 30°C and showed no pH effect between 3 and 7. Substrate inhibition was observed at glucose concentrations above 8% but the immobilised cells retained 70% of their maximum activity at 20% glucose concentration. The operational stability of immobilised cells was lower in simple glucose solution than in the activation medium in which only 20% of the activity was lost after 10 days operation. Inactivated immobilised yeast beads were reactivated by incubation in activation medium without a significant increase in cell numbers in a bead. During the operation of the immobilised yeast in a packed bed reactor, CO2 gas accumulation adversely affected the reactor performance. An ideal plug flow reactor, not taking into account the formation of CO2 gas bubbles and the presence of mass transfer resistance, was simulated using a kinetic model for the production of ethanol and the simulation results were compared with the actual reactor performance to determine the CO2 gas effect, quantitatively. Up to 45 % of the substrate conversion was lost due to the accumulation of CO2 gas bubbles in all cases.