bluuebunny/crossref_metadata_2025_split huggingface dataset:
Selective hydrogenation of styrene. II. Poisoning of Pd/Al2O3 by thiophene and pyridine
Authors: L'Argentiere Pablo C. , Fígoli Nora S. 
Published: July 2010

AbstractThe poisoning of a commercial Pd/Al2O3 catalyst by pyridine and thiophene during the selective hydrogenation of styrene to ethylbenzene was studied. It was found that the Pd electronic state is the main factor controlling the interaction between the metal and the poisons. Pyridine added to the non‐poisoned feed in a pulse produces a modification in the Pd electronic state and a decrease in conversion, but, within certain limits, inhibits the adsorption of more pyridine or thiophene molecules.
A mathematical model of a fluidized bed reactor for the continuous production of solvents by immobilized Clostridium acetobutylicum
Authors: Qureshi Nasibuddin , Maddox Ian S. 
Published: July 2010

AbstractA fluidized bed reactor has been employed for the continuous production of solvents from whey permeate using cells of Clostridium acetobutylicum immobilized by adsorption onto bonechar. Substrate diffusion equations have been developed for the bioparticles, and a mathematical model has been advanced to describe the operation of the reactor. The model was fitted to the experimental data using the concept that not all of the biomass within the reactor was active in solvent production. On this basis, less than 5% was ‘active’ biomass.
A pH‐controlled fed‐batch process for dextransucrase production
Authors: Brown Donald E. , McAvoy Alexander 
Published: July 2010

AbstractA fed‐batch culture of Leuconostoc mesenteroides has been operated from an initial volume of 4 dm3 using a sucrose/NaOH solution feed on demand with pH control. An enzyme concentration of greater than 300 DSU cm−3 was achieved in 15 h. A yield of 0.107 kg cells kg−1 sucrose feed was determined. The enzyme production was growth associated at 2.67 × 107 DSU kg−1 cells produced. Growth was shown to be linear and attributed to an unknown conservative trace nutrient limitation associated with the yeast extract.
Transient response of a solid‐liquid model biological fluidised bed to a step change in fluid superficial velocity
Authors: Poncelet Denis , Naveau Henry , Nyns Edmond‐Jacques , Dochain Denis 
Published: July 2010

AbstractThe evolution of a solid‐liquid model biological fluidised bed under a step change in fluid superficial velocity is described. During a transient step change, the fluidised bed divides into a top zone which remains at the initial porosity and a bottom zone which settles at the final porosity. The interface of discontinuity in porosity moves progressively upwards through the fluidised bed. The velocity at which the top of the fluidised bed expands or contracts and the upward velocity of the porosity transition interface depend only upon the initial and final states of the bed porosity and the fluid superficial velocity. This results in a linear evolution with time of the total bed height and the height of porosity transition interface. The proposed model is well suited to describe the transient response of low‐density particles in a fluidised bed, such as encountered in biological systems, to a sudden change of liquid superficial velocity. The model was validated experimentally.
Optimisation of production conditions for 4‐hydroxy‐2,6‐dioxabicyclo(3,3,0)octan‐8‐one[1S,4S,5R] by catalytic oxidation
Authors: Jacquet Fabienne , Rigal Luc , Gaset Antoine 
Published: July 2010

AbstractThe 4‐Hydroxy‐2,6‐dioxabicyclo(3,3,0)Octan‐8‐one[1S,4S,5R], monoketone, is obtained by catalytic oxidation of isosorbide—or 2,6‐dioxabicyclo(3,3,0)4,8‐octandiol[1R,4S,5R,8R]—in an aqueous solution with a stream of oxygen and in the presence of a platinum on carbon catalyst. Setting up sequentially two experimental designs made it possible to study the three main factors which influence the monoketone formation in the case of two reactors of different size and profile. Optimisation of selective and/or quantitative conditions is carried out by comparing response surfaces. Several functional configurations for a discontinuous reactor under agitation are proposed as a function of the constraints chosen.
Assessment of acid hydrolysates of peat as substrate for Scytalidium acidophilum ATCC 26774 fungus
Authors: Martin Antonio M. , Chintalapati Sharada P. , Hoover Ratnajothi 
Published: July 2010

AbstractThe acid‐resistant fungus Scytalidium acidophilum ATCC 26774 was cultivated in submerged fermentation in hydrolysates of Sphagnum peat moss produced with H2SO4, HCl, HNO3 and H3PO4 acids. Hydrolysis with H2SO4 produced the highest concentration of total carbohydrates and reducing sugars in the hydrolysates. However, when Scytalidium acidophilum ATCC 26774 was grown in undiluted hydrolysates, the H3PO4 medium produced the best mycelial growth. The H2SO4 medium produced the highest dry biomass concentration (3.5 g dm−3) obtained with water‐diluted, non‐supplemented peat hydrolysates. Supplementation of diluted H2SO4 hydrolysates with 3 g dm−3 yeast extract and 0.4 g dm−3 MgSO4 considerably enhanced the growth, up to 5.9 g dm−3 dry fungal biomass.The biomass composition of Scytalidium acidophilum ATCC 26774 grown in the medium which produced the best growth was determined, revealing a relatively high protein content of 37.5% of the dry mycelial weight.
Oxidative detoxification of aqueous bark extracts. Part I: Autoxidation
Authors: Field Jim A. , Lettinga Gatze , Habets Leo H. A. 
Published: July 2010

AbstractThe aqueous extracts of bark were studied as a model for wet debarking wastewater. These extracts are known to contain a high concentration of methanogenic toxic tannins. The objective of this study was to modify the native bark tannins (oligomers) with oxidative methods in order to decrease their methanogenic toxicity. The tannins were polymerized by autoxidation, forming colored high‐molecular‐weight tannins that were non‐toxic to methanogenic bacteria. The autoxidation of pine bark extracts provided complete detoxification. In the case of spruce bark, which was responsible for extracts of higher toxicity, the detoxification was either partial or complete depending on the specific sample of spruce bark from which the extract was prepared. The autoxidation of birch bark did not result in significant detoxification. Although the oligomeric tannins were effectively polymerized, birch bark extracts contain non‐tannin toxins which were not affected by the autoxidation and evidence that highly toxic intermediates were formed during the high pH autoxidation of birch bark extracts is presented.Autoxidative detoxification offers an interesting approach for pretreating coniferous bark wastewaters. The oxidation reactions of the pretreatment serve to detoxify the largely non‐BOD tannin fraction. Thus the methanogenic bacteria are not inhibited during the anaerobic wastewater treatment for removing BOD.
Morphological and metabolic changes in the yeast Kluyveromyces marxianus var. marxianus NRRLy2415 during fermentation of lactose
Authors: Walker Graeme M. , O'Neill Joseph D. 
Published: July 2010

AbstractOxygen availability has been identified as a major factor in governing the morphology of the lactose‐fermenting yeast, Kluyveromyces marxianus var. marxianus (formerly fragilis) NRRLy2415. In this particular strain, filamentous cells (F forms) predominate during the initial stages of aerobic propagation whilst budding yeast cells (Y forms) predominate during anaerobiosis. In other K. marxianus strains, and in Candida pseudotropicalis, budding cells predominate irrespective of oxygen availability. Increased cellular cytochrome contents and oxygen uptake rates accompanied Y to F (yeast to filamentous) transitions in K. marxianus NRRLy2415, suggesting that functional mitochondria are involved in controlling dimorphism in this yeast. This was further supported by the observation that respiratory inhibitors such as chloramphenicol prevented filamentation and promoted formation of respiratory‐deficient budding cells. During aerobic batch cultivation. K. marxianus displayed physiological variability in which cells were initially filamentous and respiratory but latterly were yeast‐like and fermentative, suggesting that growth rate as well as oxygen availability affected cell physiology. This was supported by the finding that during growth in lactose‐limited chemostat culture, the morphology and respiratory activity of K. marxianus varied with the specific growth rate of cells. I n addition, the fermentation rates of F and Y forms varied, although maximum ethanol yields were not significantly different between the two morphologies. These results have implications for the more eflcient conversion of lactose to ethanol in commercial fermentations of cheese whey.
Reverse osmosis of lactic acid fermentation broths
Authors: Schlicher Laura R. , Cheryan Munir 
Published: July 2010

AbstractLactic acid model solutions and fermentation broths were concentrated using a tubular thin‐film composite reverse osmosis membrane. Flux increased linearly with applied transmembrane pressure and was relatively unaffected by flow rate. Osmotic pressures of 1% lactate solutions were 280–560 kPa, depending on the pH or degree of dissociation. Rejections increased with applied pressure. Higher pH caused a slight decrease in flux (due in part to the higher osmotic pressure) and a significant increase in rejection. Above pH 5·6, rejections of lactate and residual sugars were > 97%. In contrast, with cellulose acetate membranes, flux was generally lower and lactate rejection was proportional to the degree of dissociation at lower pressures.
Liquid‐phase oxidation of p‐cresol and Substituted p‐Cresols by Air
Authors: Sharma Shreekumar N. , Chandalia Sampatraj B. 
Published: July 2010

AbstractThe liquid‐phase oxidation of p‐cresol and substituted p‐cresols by air under alkaline conditions using cobaltous chloride as a catalyst and methanol as solvent, has been investigated with a view to obtain the corresponding aldehydes with sufficiently high selectivities. In the case of p‐cresol, the effects of various process parameters on the reaction rate and selectivity with respect to the aldehyde have been investigated. The results obtained are likely to be useful for the development of processes for the production of industrially relevant products such as 4‐hydroxybenzaldehyde, vanillin and syringaldehyde by using p‐cresol as the starting material. Various alternative process schemes have been proposed and evaluated.
Reaction of chrysotile asbestos with phosphate ion in relation to toxicity
Authors: Awadalla Farouk T. , Habashi Fathi , Pag Michel 
Published: July 2010

AbstractChrysotile asbestos (Grade 7RF66) sorbs phosphate ion from aqueous solution of phosphoric acid, basic disodium phosphate, ammonium dibasic phosphate, sodium pyrophosphate, or sodium tripolyphosphate. The amount sorbed varies from 0·2 to 2·5% P2O5. The fiber treated with ammonium dibasic phosphate has appreciably low toxicity that is comparable to chrysophosphate obtained by the reaction of chrysotile asbestos with POCl3 gas, provided the latter is washed thoroughly with water to remove watersoluble ingredients.
Kinetics of continuous whey fermentation by Kluyveromyces fragilis
Authors: Moresi Mauro , Trunfio Antonio , Parente Eugenio 
Published: July 2010

AbstractContinuous whey fermentation by Kluyveromyces fragilis was studied in a 30‐dm3 stirred fermenter as a function of the dilution rate (D) and feed concentration of lactose (So). By using the concept of material and energy balances, it was possible not only to check the consistency of the experimental steady‐state responses, but also to develop an unstructured model based on a Monod‐type kinetic equation for cell growth and two independent linear equations for the consumption rates of lactose and oxygen. Moreover, a typical Lineweaver—Burk plot enabled the yeast specific growth rate to be described as that of an enzyme‐catalysed reaction in the presence of an unknown noncompetitive inhibitor (that was identified with a reference intermediate compound produced by the microorganism itself under partially anaerobic conditions and expressed in terms of ethanol equivalent). In this way, the experimental cell concentrations were reconstructed with a mean standard error of about 10%, thus confirming the capability of this model to provide a reliable basis for further scale‐up of this fermentation process.
Biomass production by thermophilic microorganisms simultaneously using reaction heat
Authors: Heinritz Brigitte , Gehrhardt Matthias , Baumann Frank , Rogge Gerlind , Hedlich Rolf 
Published: July 2010

AbstractAn energy‐economic use of reaction heat is possible only if thermophilic microorganisms convert carbon substrates into biomass at temperatures above 65°C.The thermophilic bacterium Bacillus stearothermophilus TP5 was isolated from a man‐made hot water reservoir. The highest specific growth rate of 1.6 h−1 was obtained in continuous cultivation (chemostat) on a glucose‐containing nutrient medium at 68°C, pH 6.8 and normal pressure. The highest values for the biomass production rate (3.2 g dm−3 h−1) and the biomass yield coefficient (0.39 gg−1) were obtained at a dilution rate of 1.3 h−1 (about 80% of the highest specific growth rate) under the above‐mentioned conditions. The biomass production rate of the thermophilic bacterium was higher in the chemostat than in the semicontinuous process at normal pressure. The biomass produced in the chemostat at a dilution rate of 0.4 h−1 contained 71% of protein and 8% of RNA and had an ash content of 6%. The optimum and maximum temperatures of growth were changed by raising the pressure inside the reactor.As a prerequisite for the energy‐economic use of the reaction heat, the specific heat production was determined by using a special calorimeter. The ratio of heat production to oxygen consumption (oxy‐caloric coefficient) was found to be 13.6 kJ g−1, which is close to the theoretical value deduced from mass‐ and energy‐balance theory.
Quantities relevant to the handling safety of greasy wool
Authors: Jones J. C. , Lucien F. 
Published: July 2010

AbstractGreasy wool has a very considerable propensity towards self‐heating, and two quantities relevant to such self‐heating—activation energy of oxidation and thermal diffusivity—have been measured for four samples of ‘as‐received’ greasy wool. For comparison, the same quantities for two cellulosic fibre materials—raw cotton and kapok—are also presented.
Recycling of salts in partition protein extraction processes
Authors: Greve Arend , Kula Maria‐Regina 
Published: July 2010

AbstractAqueous two‐phase extraction systems were developed to separate intracellular proteins from cell debris. To economize on the use of chemicals as well as to minimize environmental pollution, a closed mode of operation was sought. Various approaches to achieve recycling of salt from the primary lower phase containing 30–60% (w/w) of the added salt together with cell debris, proteins and nucleic acids were studied. Techniques assessed included microfiltration, heat treatment and the extraction with phase systems formed by aliphatic alcohols. With 20% (w/w) primary lower phase it was found to be possible to separate 95% of the salt in 3–4 theoretical steps using counter‐current extraction.
Continuous separation of particles from macromolecules in split‐flow thin (SPLITT) cells
Authors: Levin Shulamit , Giddings J. Calvin 
Published: July 2010

AbstractA split‐flow thin (SPLITT) cell with a perpendicular driving force of one gravity has been utilized for the rapid separation of micron‐sized particles from macromolecules. The procedure involves the simultaneous use of two transport mechanisms and thus two operating modes: a sedimentation process controls the displacement of the particles across the thickness of the thin channel, while diffusion controls the displacement of macromolecules. The theoretical equations for these two operating modes are summarized and it is shown how the two modes can be combined to yield specified recovery factors. The theory was tested on a mixture of 10 μm polystyrene latex beads and three different proteins. The observed separation was in excellent agreement with theory. Attempts to fractionate red blood cells and plasma proteins from whole blood were only partially successful as a consequence of the weak sedimentation of red blood cells. Various remedies to this problem are suggested, the most promising of which is the use of a SPLITT cell subject to mild centrifugal forces.
The hydrogenation of triglycerides using supported alloy catalysts. I. Silica‐supported Ni—Ag catalysts
Authors: Parry J. D. , Winterbottom J. M. 
Published: July 2010

AbstractSilica‐supported Ni‐Ag catalysts with a loading of 2·1·0.6% (w/w) total metal have been prepared using the precursors nickel dimethylglyoxime and silver nitrate by means of a simple impregnation method. The resulting catalysts were activated by calcination at 260°C in air, followed by hydrogen reduction at 450°C. They were then employed for soyabean oil hydrogenation at 1 bar H2 pressure and 160°C in a stirred batch reactor.Characterisation of the catalysts using temperature‐programmed reduction and electron microscopy indicated that alloying of nickel and silver had occurred, but metal particle composition, for a given overall composition, varied with metal particle size and smaller metal particles were nickel rich.The hydrogenation activity and selectivity measurements revealed that the catalysts were more active and selective than a commercial nickel catalyst. Furthermore, the specific activities of the alloy catalysts were a maximum for alloys in the range 70–90 at. % Ni. However, the supported alloy catalysts also gave rise to greater trans isomerisation than the commercial catalyst. This is attributed to hydrogen deficiency caused by large triglyceride molecules blocking hydrogen chemisorption on small nickel particles (10–50 Å in diameter), leading to enhanced cis‐trans isomerisation.
The hydrogenation of triglycerides using supported alloy catalysts. II. Silica‐supported Pd‐Cu catalysts
Authors: Parry J. D. , Winterbottom J. M. 
Published: July 2010

AbstractPalladium‐copper catalysts supported upon silica, containing 2–6% (w/w) total metal, have been prepared by (i) precipitation and (ii) impregnation methods. The catalysts were employed for the hydrogenation of soyabean oil at 1 bar H2 pressure and at 160°C in a stirred batch reactor.Temperature‐programmed reduction studies provided evidence of alloying of palladium and copper and metal surface area measurements exhibited evidence of a slight maximum in the metal surface area at around 90 at. % Pd content. In addition, it was observed that the presence of copper seemed to prevent sintering of palladium, giving a more stable or even enhancing metal surface area compared with palladium alone.Activity measurements showed that there was evidence of a maximum at around 80–90 at. % Pd content. However, selectivity measurements showed that the latter parameter was dominated by the presence of palladium and except at very high copper contents the superior selectivity of the latter for linolenate chain hydrogenation was hardly evident. It is thought that the palladium may cause the copper to be present largely as Cu°, which is not as effective as Cu1 in catalysing selective hydrogenation of multiply unsaturated species.
Large‐scale chromatography in industrial processing
Authors: Ganetsos G. , Barker P. E. 
Published: July 2010

AbstractAlthough chromatography has been established as a powerful analytical tool, its large‐scale application is not widely appreciated. In this short review the up‐to‐date developments in the scaling‐up of chromatographic processes are considered and the designs judged to offer the greatest potential and commercial viability are described paying special emphasis to liquid applications.Sufficient references are included to enable the interested reader to pursue the subject further.
Production of furfural by acid hydrolysis of corncobs
Authors: Riera Francisco A. , Alvarez Ricardo , Coca José 
Published: July 2010

AbstractHydrolysis of corncobs for producing furfural was carried out in a pressurized batch reactor using superheated water and diluted sulphuric acid as catalyst. The range of experimental conditions was T=140–200°C and P=350–1550 kPa. Yields of furfural are reported as a function of reaction temperature, particle size, acid concentration and liquid/solid ratio. Attention has been focused on the solid residue remaining after the hydrolysis process, so that it can be further used as a humic fertilizer after oxiammoniation treatment.
The internal architecture of anaerobic sludge granules
Authors: Morgan J. W. , Evison L. M. , Forster C. F. 
Published: July 2010

AbstractThe structural characteristics of well‐formed anaerobic granular sludges were examined using scanning electron microscopy and light microscopy of thin sections. Transverse sections were found to consist of randomly orientated filaments of Methanothrix soehngenii. These were tightly packed with little space between the individual filament sheaths, revealing a ‘honeycomb’ appearance. Sections cut from wax‐embedded granules were stained using a number of histochemical procedures. Detailed examination of the overall structure of the granules was possible, revealing the presence of filamentous bundles of Methanothrix surrounded by a matrix found to be carbohydrate in nature. Interpretation of serial sections through the depth of the granule allowed for the construction of a diagrammatic illustration of the internal structure. A relationship between the measured diameter of these microcolonies of Methanothrix and the distance from the centre of the granule was established. Together these results enabled a proposal to be made as to the possible mechanisms involved in the growth of granules. This supports previous suggestions relating to the involvement of Methanothrix and bacterial polymers.
Hydrodynamic and mass transfer parameter correlations for the rotating disc contactor
Authors: Korchinsky W. J. 
Published: July 2010

AbstractThe normal, fragmented manner in which various model hydrodynamic and mass transfer parameters are measured and correlated separately, in the vain hope that accurate predictions of extraction column performance will be eventually possible, is avoided here. The ‘forward mixing’ model parameters are all determined simultaneously, in experiments with two sizes of rotating disc contactor where all required measurements, including drop size distributions and continuous phase profile compositions, are made during solute transfer between phases. Accurate predictions from the derived correlations of dispersed phase hold‐up fraction, drop size distributions and extraction efficiency are the result.
A low cost adsorbent from spent bleaching earth. II—optimisation of the zinc chloride activation procedure
Authors: Pollard Simon J. T. , Sollars Christopher J. , Perry Roger 
Published: July 2010

AbstractA set of optimised preparative parameters has been established for the zinc chloride activation of spent bleaching earth. Continuous volumetric nitrogen adsorption and aqueous phase phenol isotherms are used to characterise a range of adsorbents prepared using the rotary furnace. A structural model is proposed for these clay‐carbon materials and the key factors affecting their adsorptive capacity are discussed.