bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calculation of entropy change accompanying growth of Escherichia coli K‐12 on succinic acid
Authors: Battley Edwin H. 
Published: December 2004

AbstractThe ΔS of one unit carbon formula weight of Escherichia coli K‐12 cells, when grown on succinic acid, was calculated to be −80.13 J/deg. This value could then be used to calculate the entropy change accompanying the anabolism and metabolism of succinic acid to be 30.82 J/deg and 32.40 J/mol deg, respectively. The entropy of one unit carbon formula weight of dried E. Coli K‐12 cells is calculated to be 94.40 J/deg, which when divided by the mass of these cells becomes 3.90 J/g deg. The corresponding entropy of succinic acid is 2.77 J/g deg, making it apparent that the entropy per unit mass of the cells is greater than that of the substrate. It might be thought that because the cells appear to be so much more complex than the substrate, the cells should have a lesser entropy per unit mass than the substrate. That this does not appear to be true leads to the conclusion that the macromolecular organization (informational content?) of the cells contributes only in a very minor way to the total physical entropy of cells. © 1993 John Wiley & Sons, Inc.
Analysis of substrate protection of an immobilized glucose isomerase reactor
Authors: Houng Jer‐Yiing , Yu Hong‐Yang , Chen Kuo‐Cheng , Tiu Carlos 
Published: December 2004

AbstractThe effect of substrate protection on enzyme deactivation was studied in a differential bed and a packed bed reactor using a commercial immobilized glucose isomerase (Swetase, Nagase Co.). Experimental data obtained from differential bed reactor were analyzed based on Briggs‐Haldane kinetics in which enzyme deactivation accompanying the protection of substrate was considered. The deactivation constant of the enzyme‐substrate complex was found to be about half of that of the free enzyme. The mathematical analysis describing the performance of a packed bed reactor under the considerations of the effects of substrate protection, diffusion resistance, and enzyme deactivation was studied. The system equations for the packed bed reactor were solved using an orthogonal collocation method. The presence of substrate protection and the diffusion effect within the enzyme particles resulted in an axial variation of effectiveness factor, ηD, along the length of the packed bed. The axial distribution profile of ηD was found to be dependent on the operation temperature, Based on the effect of substrate protection, a better substrate feed policy could be theoretically found for promoting productivity in long‐term operation. © 1993 John Wiley & Sons, Inc.
Mathematical modeling of growth and alkaloid production in Claviceps purpurea batch fermentation
Authors: Miličić S. , Velušček J. , Kremser M. , Sočič H. 
Published: December 2004

AbstractAn new systematic approach for describing Claviceps purpurea growth and ergot alkaloid production during batch fermentation is presented. The model is based on microbial life, as the main characteristic for microbial development during fermentation process. The aging process of the microorganism is represented by life function, defined in microbial life space. The life space is defined as a measure in which the observer follows the development of a biosystem through physiological and morphological changes of a microorganism. As a consequence of such approach the relativistic theory is recognized. To validate the model developed, a test on growth and alkaloid synthesis data from an industrial batch fermentation was performed. © 1993 John Wiley & Sons, Inc.
Production of indole alkaloids by selected hairy root lines of Catharanthus roseus
Authors: Bhadra Rajiv , Vani Sundeep , Shanks Jacqueline V. 
Published: December 2004

AbstractHairy root cultures of Catharanthus roseus were established by infection of seedlings with Agrobacterium rhizogenes 15834. Approximately 150 transformants from four different. C. roseus cultivars were screened for desirable traits in growth and indole alkaloid production. Five hairy root clones grew well in liquid culture with doubling times similar to those reported for cell suspensions. Fast growing clones had similar morphologies, characterized by thin, straight, and regular branches with thin tips. The levels of key alkaloids, ajmalicine, serpentine, and catharanthine, in these five clones, also compared well with literature data from cell suspensions, yet HPLC and GC‐MS data indicate the presence of vindoline in two clones at levels over three orders of magnitude greater than the minute amounts reported in cell culture. These results suggest that further optimization may result in hairy roots as a potential source of vindoline and catharanthine, the two monomers necessary to synthesize that antineoplastic drug, vinblastine. © 1993 John Wiley & Sons, Inc.
Dissolution of sulphur particles by Thiobacillus ferrooxidans: Substrate for unattached cells
Authors: Shrihari  , Bhavaraju S. R. , Modak Jayant M. , Kumar R. , Gandhi K. S. 
Published: December 2004

AbstractThe growth of Thiobacillus ferrooxidans on sulphur is known to proceed through the attachment of cells to the sulphur particles. Experiments, However, show that the cells in the liquid phase, which are not attached to the sulphur particles, also grow. It has been shown through the use of a two‐compartment membrane reactor that this increase is partially due to the release of ions, corresponding to partially oxidized of sulphur, into the solution by the attached cells. The main soluble ion has been found to the thiosulphate, but traces of sulphite have also been detected. © 1993 John Wiley & Sons, Inc.
Mechanism of microbial flotation using Thiobacillus ferrooxidans for pyrite suppression
Authors: Ohmura Naoya , Kitamura Keiko , Saiki Hiroshi 
Published: December 2004

AbstractMicrobial desulfurization might be developed as a new process for the removal of pyrite sulfur from coal sluries such as coal–water mixture (CWM). An application of iron‐oxidizing bacterium Thiobacillus ferrooxidans to flotation would shorten the periods of the microbial removal of pyrite from some weeks by leaching methods to a few minutes. The floatability of pyrite in flotation was mainly reduced by T. ferrooxidans itself rather than by other microbial substances in bacterial culture as additive of flotation liquor. Floatability was suppressed within a few seconds by bacterial contact. The suppression was proportional to increasing the number of cells observed between bacterial adhesion and the suppression of floatability. If 25% of the total pyrite surface area covered with the bacteria, pyrite floatability would be completely depressed. Bacteria that lost their iron‐oxidizing activities by sodium cyanide treatment were also able to adhere to pyrite and reduced pyrite floatability as much as normal bacteria did. Thiobacillus ferrooxidans ATCC 23270, T‐1, 9, and 11, which had different iron‐oxidizing abilities, suppressed floatability to similar‐levels. The oxidizing ability of bacteria did not influence the suppressing effect. These results showed the mechanism of the suppression of pyrite floatability by bacteria. Quick bacterial adhesion to pyrite induced floatability suppression by changing the surface property from hydrophobic. The quick adhesion of the bacterium was the novel function which worked to change the surface property of pyrite to remove it from coal. © 1993 John Wiley & Sons, Inc.
Instability caused by high strength of cheese whey in a UASB reactor
Authors: Yan J. Q. , Lo K. V. , Pinder K. L. 
Published: December 2004

AbstractThe anaerobic digestion of cheese whey was studied in a UASB reactor. The profiles of the reactor, i.e., the distributions of the substrate concentration and pH under different operating conditions were developed. From the concentrations of substrates measured at various levels above the bottom of the reactor, two reaction stages, namely acidogenesis and methanogenesis, were distinguished. The instability caused by high influent concentration was interpreted as the accumulation of VFAs in the acidogenic stage beyond the assimilative capacity of the methanogenic stage. A range of stable operating conditions was predicted from the results of the profile measurements. The optimal influent concentration was found to be between 25 and 30 g COD/L at an HRT of 5 days for system stability. Other options fro stability control were discussed. © 1993 John Wiley & Sons, Inc.
A statistical analysis of the effect of substrate utilization and shear stress on the kinetics of biofilm detachment
Authors: Peyton Brent M. , Characklis W. G. 
Published: December 2004

AbstractOne of the least understood processes affecting biofilm accumulation is detachment. Detachment is the removal of cells and cell products from an established biofilm and subsequent entrainment in the bulk liquid. The goal of this research was to determine the effects of shear stress and substrate loading rate on the rate of biofilm detachment.Monopopulation Pseudomonas aeruginosa and undefined mixed population biofilms were grown on glucose in a RotoTorque biofilm reactor. Three levels of shear stress and substrate loading rate were used to determine their effects on the rate of detachment. Suspended cell concentrations were monitored to determine detachment rates, while other variables were measured to determine their influence on the detachment rate. Results indicate that detachment rate is directly related to biofilm growth rate and that factors which limit growth rate will also limit detachment rate. No significant influence of shear on detachment rate was observed.A new kinetic expression that incorporates substrate utilization rate, yield, and biofilm thickness was compared to published detachment expressions and gives a better correlation of data obtained both in this research and from previous research projects, for both mono‐ and mixed‐population biofilms. © John Wiley & Sons, Inc.
Rheological properties of mammalian cell culture suspensions: Hybridoma and HeLa cell lines
Authors: Shi Yaun , Ryu Dewey D. Y. , Ballica Rabia 
Published: December 2004

AbstractData on viscous (η′) and elastic (η″) components of the complex viscosity versus oscillatory angular frequency (0.01 to 4.0 rad/s) with increasing strains were obtained for hybridoma cell (62′D3) and HeLa cell (S3) suspensions in PBS at 0.9 (mL/mL) cell volume fraction using a Weissenberg rheogoniometer equipped with two parallel plate geometry at ambient temperature. Both cell suspensions exhibited shear thinning behavior. From the measured viscoelastic properties, the yield stress was calculated. Hybridoma cell suspension (15 μm as the mean diameter of cells) showed the yield stress at 550 dyne/cm2 that was 1.8 times higher than the value of HeLa cell suspension (22 μm mean diameter) as measured at the oscillatory angular frequency, 4.0 rad/s. The apparent viscosities of HeLa cell suspension at four concentrations and varying steady shear rate were also determined using the Brookfield rotational viscometer. The yield stress to steady shear test was about 130 dyne/cm2 for HeLa cell suspension at 0.9 (mL/mL) cell volume fraction. The apparent viscosity was in the range about 1 ∼ 1000 Poise depending on the cell concentration and shear rate applied. A modified semiempirical Mooney equation, \documentclass{article}\pagestyle{empty}\begin{document}$ \eta = \eta _0 \exp [K\dot \gamma ^{ - \beta } \phi /(1 - K''\sigma \phi _c /D)] $\end{document} was derived based on the cell concentration, the cell morphology, and the steady shear rate. The β, shear rate index, was estimated as 0.159 in the range of shear rate, 0.16 to 22.1 s−1, for the cell volume fractions from 0.6 to 0.9 (mL/mL). In this study, the methods of determining the shear sensitivity and the viscous and the elastic components of mammalian cell suspensions are described under the steady shear field. © 1993 John Wiley & Sons, Inc.
The adsorptive immobilization of phospholipids D mediated by calcium ions
Authors: Lambrecht Romy , Ulbrich‐Hofmann Renate 
Published: December 2004

AbstractImmobilization of phospholipase D from cabbage was studied with the aim of stabilizing the enzyme for its use in synthesis of phospholipids. It was shown that phospholipase D can be immobilized by adsorption to polymeric carriers containing long chain anchor groups such as octadecyl, octyl, or other alkyl residues. Starting from the crude enzyme, phospholipase D activity is preferentially bound (up to 100%) in competition with contaminating proteins. A prerequisite of high binding rates is the presence of calcium ions, which play a mediating role in the adsorption process. The maximum activity of the carrier‐enzyme complexes depends upon the calcium concentration in the immobilization process and the carrier material (≥10mM CaCl2 with octadecyl‐Si40, ≥40 mM CaCl2 with octyl‐sepharose and butyl‐fractogel). Immobilization of phospholipase D to octyl‐sepharose was shown to result in a distinctly increased storage stability and an enlarged pH‐optimum range for the catalytic activity. Operational stability of different phospholipase D‐carrier complexes was compared. © 1993 Wiley & Sons, Inc.
Mathematical model for the luminol chemiluminescence reaction catalyzed by peroxidase
Authors: Li Lin , Arnold Mark A. , Dordick Jonathan S. 
Published: December 2004

AbstractA kinetic model that accurately describes intensity vs. time reaction profiles for the chemiluminescence reaction between luminol and hydrogen peroxide, as catalyzed by horseradish perioxdase, is derived and evaluated. A set of three differential equations is derived and solved to provide intensity time information for the first 200 seconds of the reaction. The model accurately predicts intensity‐time profiles when literature values are used for all but one of the reaction rate constants. Furthermore, the model predicts a nonlinear curve for plots of light intensity versus the initial hydrogen peroxide concentration. Experimental data confirm that such plots are nonlinear. Finally, a linear double‐reciprocal plot is predicted by the model and the experimental data verify this relationship. © 1993 Wiley & Sons, Inc.
Viability testing and characterization of germination of fungal spores by automatic image analysis
Authors: Paul G. C. , Kent C. A. , Thomas C. R. 
Published: December 2004

AbstractFungal spores are used in the laboratory for culture maintenance and at laboratory and other scales as inocula for fermentations. The spore swelling and germination processes constitute a major part of the lag phase, and the subsequent culture morphology and productivity can be greatly influenced by the initial concentration and condition of the spores. An image analysis method has been developed for assessing the viability and the germination characteristics of fungal spores in submerged cultures. Structural variations during germination, i.e., swelling, germ tube formation, and germ tube elongation, are measured in terms of distributions of spore volumes and of germ tube lengths and volumes. These measurements are fully automatic and give a very rapid assessment of spore viability. This image analysis method might be used as a tool in culture maintenance and for determining the quality of inocula for fungal fermentations. © 1993 John Wiley & Sons, Inc.
Solid‐State nuclear magnetic resonance investigation of solvent dependence of tyrosyl ring motion in an enzyme
Authors: Burke Paul A. , Griffin Robert G. , Klibanov Alexander M. 
Published: December 2004

AbstractTyrosyl ring motions in α‐lytic protease were investigated by solid‐state deuterium nuclear magnetic resonance (NMR) spectroscopy in lyophilized enzyme powder, in powder suspended in organic solvents, and in aqueous crystals. Ring flipping rates were determined by examining deuterium quadrupole echo line shapes. Of the four Tyr residues in the enzyme, one was flipping at the slow (≤103 s−1) and one at the fast (≥107 s−1) exchange limit of the line shape experiment in all the environments tested. Flipping rates of the remaining two Tyr residues depended markedly on the solvent, with the lowest flipping rates (≤103 s−1 for both residues) observed in the enzyme powder, whether dry or suspended in hydrophobic tert‐butyl methyl ether. In hydrophilic dioxane and acetonitrile, the mobility of these residues increased to 104 and 105 s−1. The latter rate rose further to 106 s−1 in the hydrated hydrophilic solvents and to ≥107 s−1 in aqueous crystals. The deuterium spectrum of native α‐lytic protease was compared with that of the enzyme whose active center was covalently modified with an inhibitor, which binds next to Tyr‐123, constraining its ring. This experiment revealed that water addition to acetonitrile specifically increased the flipping rate of this active center residue. Librational motions (“wobbling”), estimated by their effect on spin–lattice relaxation times, were slowest in the anhydrous solvents, intermediate in the hydrated solvents, and fastest in the aqueous crystals. Thus, α‐lytic protease is more rigid in organic solvents than in water, as judged by mobility of its tyrosyl residues. Water stripping by hydrophilic solvents did not increase enzyme rigidity, nor were there clear correlations between mobility and either enzymatic activity or solvent dielectric constant. © 1993 John Wiley & Sons, Inc.
Micelle‐supported electroenzymology: Succinate dehydrogenation by escherichia coli fumarate reductase in decylubiquinone and octyl glucoside micelles
Authors: Kinnear Kathleen T. , Monbouquette Harold G. 
Published: December 2004

AbstractThe concept of micelle‐supported electroenzymology is demonstrated using a system consisting of the membrane enzyme Escherichia coli fumarate reductase (FRD), the amphiphilic coenzyme analogue decylubiquinone (DU), the micelle‐forming surfactant n‐octyl glucoside (OG), and a gold electrode. The OG micelles provide a hydrophobic, membrane mimetic medium for FRD and DU to exchange electrons while the gold electrode serves to regenerate DU. When succinate is presented to the FRD/DU/OG micelle system, electroenzymatic oxidation of succinate to fumarate occurs as evidenced using cyclic voltammetry. DU is shown to be the only electroactive species in the system; and as increasing amounts of succinate are added, the expected increase in the peak anodic (oxidative) current and decrease in the peak cathodic (reductive) current are observed. The peak anodic current approaches a limiting value with succinate concentration in qualitative agreement with simple Michaelis–Menten enzyme kinetics. When the strong competitive inhibitor oxaloacetate is added, enzymatic oxidation of succinate is inhibited as indicated by no change in the peak anodic and cathodic currents with increasing succinate concentration. © 1993 John Wiley & Sons, Inc.
Intracellular pH‐based controlled cultivation of yeast cells: II. Cultivation methodology
Authors: Sureshkumar G. K. , Mutharasan R. 
Published: December 2004

AbstractIntracellular pH (pHi) was measured on‐line in a bioreactor using a fluorescent pHi indicator, 9‐aminoacridine, and controlled fed‐batch cultivations of yeast cells based on pHi (FB‐pHi) were performed. In FB‐pHi cultivations, automated glucose additions were made to the culture in response to culture pHi. The average ethanol (an‐aerobic product) yield was significantly lower [0.12 g g−1 glucose in fed‐batch pHi cultivations with 100 ppm glucose additions (FB‐pHi‐100 cultivation) vs. 0.48 g g−1 glucose in batch] and cell yield was higher (0.54 g g−1 glucose in FB‐pHi‐100 cultivation vs. 0.3 g g−1 glucose in batch) compared to batch cultivation. An expression has been derived to calculate changes in pHi from measured fluorescence values when the cell concentration increases during growth. Cultivations based on pHi, performed with different magnitudes of glucose addition (100, 50, and 10 ppm additions), showed that lower magnitudes of glucose addition resulted in lower ethanol yields while cell yield remained unaffected. The ratio of specific oxygen uptake rate to specific glucose uptake rate (OUR/GUR) increased with decreased in magnitude of glucose additions in FB‐pHi cultivations, suggesting that the culture aerobic state was higher when the magnitude of glucose addition was lower. The average cell productivity in FB‐pHi cultivations was 29% higher than in batch cultivation. Cells were also cultivated at high OUR conditions, and the results are compared with other cultivations. © 1993 John Wiley & Sons, Inc.
Alginate–chitosan coacervation in production of artificial seeds
Authors: Tay Ling‐Fong , Khoh Leng‐Khim , Loh Chiang‐Shiong , Khor Eugene 
Published: December 2004

AbstractSurvival of secondary embryoids of winter oilseed rape (Brassica napus ssp. oleifera cv. Primor) has been used as an assay for the development of artificial seeds involving complex coacervation of alginate (polyanion) with chitosan (polycation). Germination frequency of 100% was achieved for encapsulated embryoids when alginate formed the inner matrix and chitosan the outer layer. When the matrix makeup was reversed, there was no germination of embryoids. The artificial seeds produced were hardened in dilute alkaline solutions of NaOH and Ca(OH)2. An optimum setting time could be selected based on a quantitative measurement of resistance of hardened capsules to compression and the germination frequency of the encapsulated embryoids. © 1993 John Wiley & Sons, Inc.
Controlled release process to recover heterologous glycosylphosphatidylinositol membrane anchored proteins from CHO cells
Authors: Kennard M. L. , Food M. R. , Jefferies W. A. , Piret J. M. 
Published: December 2004

AbstractA semicontinuous process has been developed to recover heterologous proteins at increased concentrations and purities. Proteins attached to mammalian cell membranes by glycosylphosphatidylinositol (GPI) anchors can be selectively released into the supernatant by the enzyme phosphatidylinositol–phospholipase C (PI–PLC). Chinese hamster ovary (CHO) cells, genetically engineered to express the GPI anchored, human melanoma antigen (p97), were used as a model system. These cells were grown in protein containing growth medium. During a brief harvesting phase the medium was replaced by phosphate buffered saline (PBS) containing 10 mU/mL of PI–PLC and the GPI anchored protein was cleaved from the cell surface and recovered in soluble form at up to 30% purity. After harvesting, the cells were returned to growth medium where the protein was re‐expressed within 40 h. The growth rate, viability, and protein production of cells, repeatedly harvested over a 44‐day period, were not adversely affected. This continuous cyclic harvesting process allowed recovery of a heterologous protein at high purity and concentrations and could be applied to the recovery of other GPI anchored proteins and genetically engineered GPI anchored fusion proteins. © 1993 John Wiley & Sons, Inc.