bluuebunny/crossref_metadata_2025_split huggingface dataset:
A rapid method for detecting bacterial contamination in the presence of Penicillium and Streptomyces antibiotic fermentations
Authors: McLaughlin J. , Bruno C. F. , Forrest T. 
Published: December 2004

AbstractContamination in antibiotic fermentation processes results in major economic and process problems. The detection and elimination of contamination is a continual objective for fermentation companies. While efforts continue to eliminate contamination by improving equipment and sterile techniques, it is still imperative to have a rapid method for detecting contamination in laboratory‐stage inoculum and seed tanks. This article describes the successful studies leading to the adoption of the BACTEC, an automatic bacterial detection system, as a supplemental detection technique. The BACTEC system detects contamination by incubating samples with a selected14C‐labeled substrate or substrates. The resulting metabolism of substrate produces 14C‐labeled CO2 which is then quantified and expressed as a growth index, permitting detection of contamination more rapidly at a much earlier time than is possible with conventional detection techniques that involve Phenol red dextrose broth, streak plates, and microscopic examination techniques.
Ion exchange chromatography of proteins—predictions of elution curves and operating conditions. II. Experimental verification
Authors: Yamamoto Shuichi , Nakanishi Kazuhiro , Matsuno Ryuichi , Kamijubo Tadashi 
Published: December 2004

AbstractThe applicability and validity of the model developed in Part I were confirmed experimentally. In this article, various proteins were eluted both by stepwise and linear gradient elution on DEAE ion exchangers under a variety of experimental conditions. Adsorption isotherms were measured as a function of ionic strength in batch experiments. The moment method was empolyed for the determination of various parameteres such as the gel‐phase diffusion coefficient and the longitudinal dispersion coefficient. By use of these parameters and the experimentally measured ionic strength of the peak position, the number opf plates was determined according to the method described in Part I. Theoretical elution curves were calculated with the experimentally measured adsorption eqluilibria and the number of plates. Good agreement was observed between theory an experiments. Various factors affecting the separation were investigated. It was found that the effect of the number of plates for salts, N′p, was negligible except the case of stepwise elution of high ionic strength buffer. When elution curves were symmetrical, the widths of the elution curves were inversely proportional to the square root of the number of plates of proteins, Np, as in other chromatographic techniques. A simple graphical method for prediction of the peak position in linear gradient elution described in Part I was found applicable when the elution curves were symmetrical. A useful correlation of prediction of the peak width in a linear gradient elution was proposed on the basis of the approximate solution derived in Part I of this study. This graphical method and correlation permit easy prediction of the peak position and peak width in linear gradient elution in the case of symmetrical elution curves.
Enzyme management in the iotech process
Authors: Sinitsyn A. P. , Bungay H. R. , Clesceri L. S. 
Published: December 2004

AbstractIn the Iotech process, steam explosion of wood chips potentials hydrolysis of the cullulose by enzymes. A small portion of the exploded wood is used as substrate for the production of enzymes for hydrolysis of the remaining wood. Explosions conditions degrade some of the hemicellulose, creating factors (probably related to furfural) that impair enzymatic hydrolysis and destablized the cellulases. Fortunately, simple washing with water paremits more rapid hydrolysis while enzyme stability is greatly improved. Enzymes can be recovered from the hydrolysis residue by adjusting the pH to neutrality, and additional enzymes from hydrolysis filtrate can be adsorbed on fresh exploded wood en route to hydrolysis. A simple mass balance calculation shows proportions of various activities in a mix of fresh and recycled enzymes.
Steady‐state approximation of enzyme activation and inhibition
Authors: Okamoto Masahiro , Takeda Youko , Aso Yoichi , Hayashi Katsuya 
Published: December 2004

AbstractThis article deals with the effects of the initial concentration of effector (inhibitor or activator) on the steady‐state approximation of enzyme kinetics. The results could be summarized as follows: (1) In competitive inhibition, the increase in the initial concentration of inhibitor led to the reduction of steady state time. (2) In noncompetitive and uncompetitive inhibitions, the steady state time was not changed with the increase in the initial concentration of inhibitor. (3) In nonessential activation, the increase in the initial concentration of activator led to the reduction of steadystate time. (4) It was specially noted that in nonessential activation, even if the reaction is in the steady‐state, activation constant (KA) can not be determined exactly unless the initial concentration of activator is very small.
Kinetics of multilayer immobilized enzyme‐filter reactors: Behavior of urease‐filter reactors in different buffers
Authors: Goldstein Leon , Levy Mordechai , Shemer Lev 
Published: December 2004

AbstractA sequential model which describes the kinetic behavior of multilayer immobilized‐enzyme filter reactors for systems obeying the Michaelis‐Menten scheme and various types of inhibition by product and by substrate is proposed. The model was varified experimentaly using a single enzyme‐filter‐substrate system—urease bound to nylon‐filter disks acting on urea—in different buffers to obtain the various inhibition patterns.
Solubility and selective crystallization of lactose from solutions of its hydrolysis products glucose and galactose
Authors: Bourne J. R. , Hegglin M. , Prenosil J. E. 
Published: December 2004

AbstractA high degree of conversion is desired when lactose is hydrolyzed to glucose and galactose. This produces, however, a high concentration of galactose, which is inhibitory for the enzyme catalyst (β‐galactosidase). The inhibition can be reduced by limiting the conversion per pass over the enzyme (e.g. to ca. 50%), separating unconverted lactose from the reactor effluent, and recycling it to the reactor inlet. (This allows the overall conversion to be raised to ca. 80–90%). The solubilities of lactose, glucose, and galactose have been determined at various temperatures and for sugar mixtures having different concentrations and degrees of hydrolysis. Various cooling crystallizations have defined convenient and simple processes for the selective separation of lactose from its hydrolysis products.
NO2 Sensor which uses immobilized nitrite oxidizing bacteria
Authors: Okada Tadashi , Karube Isao , Suzuki Shuichi 
Published: December 2004

AbstractA biosensor consisting of immobilized nitrite oxidizing bacteria and an oxygen electrode has been developed for the amperometric determination of NO2 (nitrogen dioxide) gas. The response time for the determination of NO2 was within 3 min. A linear relationship was observed between the current decrease and the NO2 concentration below 255 ppm. The minimum concentration for the determination of NO2 was 0.51 ppm. The current decrease was reproducible within ±4% of the relative error. The selectivity of the microbial sensor for NO2 was satisfactory. The current output of the sensor was almost constant for more than 24 days and 400 assays.
Precipitation, chelation, and the availability of metals as nutrients in anaerobic digestion. II. Applications
Authors: Callander I. J. , Barford J. P. 
Published: December 2004

AbstractThe relative importance of the individual effects of precipitation and chelation of metal ions in anaerobic digestion is assessed. Experimentally determined soluble metal ion levels are compared with predicted levels obtained by using a previously described methodology.1 It is found that soluble metal complexes may increase the level of soluble metals in the presence of CO and S2− by a factor of up to 104. The formation of a soluble complex may increase or decrease the availability of the metal ion in question for microbial uptake. Two case studies are presented, one using a defined medium and one a complex medium. It is possible, in the case of the defined medium, to accurately predict the free metal ion concentration using the methodology previously developed.1 While the identification of the presence of natural chelating compounds in a complex medium is not routinely possible, the significant discrepancy between the measured level of the soluble metal ion Fe2+ and the calculated level in the case studies presented indicates that natural chelating compounds may play a vital role in providing available metal ions to the microorganisms of an anaerobic digester.
A new sensor—the “filtration Probe”— for quantitative characterization of penicillin fermentation. III. An automatically operating probe
Authors: Nestaas Eirik , Wang Daniel I. C. 
Published: December 2004

AbstractThe filtration characteristics of the penicillin broth can be monitored semicontinuously using an automatic filtration probe. This probe operates aseptically and the broth samples (filtrate and filter cake) are recycled to the fermentor after each filtration. The collected data—filtrate volume and filter cake volume versus filtration time—can be related to the total biomass concentration in the fermentor.
Improving immobilized biocatalysts by gel phase polymerization
Authors: Kuu W. Y. , Polack J. A. 
Published: December 2004

AbstractA new method is presented for the treatment of gel‐type supports, used for immobilizing microbial cells and enzymes, to obtain high mechanical strength. It is particularly useful for ethanol fermentation over gel beads containing immobilized viable cells, where the beads can be ruptured by gas production and the growth of cells within the gels. This method consists of treating agar or carrageenan gel with polyacrylamide to form a rigid support which retains the high catalytic activity characteristic of the untreated biocatalysts. The size and shape of the biocatalyst is unaffected by this treatment. The method involves the diffusion of acrylamide, N,N′‐methylenebisacrylamide and β‐dimethylaminopropionitrile (or N,N,N′,N′‐tetramethyl‐ethylenediamine) into the performed biocatalyst beads followed by the addition of an initiator to cause polymerization within the beads. Treated gels have been used for the continuous fermentation of glucose to ethanol in a packed column for over two months. During this operation, the gel beads maintained their rigidity, and the maximum productivity was as high as 50 g h−1 L−1 gel. There was no appreciable decay of cell activity.
Rates of glucose oxidation with a column reactor utilizing a magnetic field
Authors: Sada Eizo , Katoh Shigeo , Shiozawa Masami , Matsui Ichiro 
Published: December 2004

AbstractRates of glucose oxidation were measured with the use of a fluidized‐bed column placed in a magnetic field and magnetite‐containing beads of immobilized glucose oxidase and catalase. Its performance was predicted from the volumetric coefficient for liquid‐phase mass transfer and the kinetic constants for glucose oxidation. Effusion of beads was negligible under the operating conditions employed.
Dynamics of biodegradation of 2,4‐dichlorophenoxyacetate in the presence of glucose
Authors: Papanastasiou A. C. , Maier W. J. 
Published: December 2004

AbstractIt has been observed experimentally that the biodegradation of 2,4‐dichlorophenoxyacetate (2,4‐D) is inhibited by the presence of glucose. However, this effect is masked by the fact that larger concentrations of active biomass are produced when glucose is available. The implication of such a “mixed” growth in a continuous flow system is that much higher dilution rates can be applied for an efficient chlorinated‐organic removal when other conventional substrates are present. The mean cell residence time is reduced and the area of stability of the process is extended into higher dilution rates, as well as into higher influent concentrations. Finally, the presence of the mixed substrate changes dramatically the “washout” conditions for both substrates. All these facts point out that the biodegradation of chlorinated organics is more efficient in a mixed substrate environment.
Fluorescence and photoacoustic spectroscopy of immobilized thylakoids
Authors: Thomasset Brigitte , Barbotin Jean‐Noël , Thomas Daniel , Thomasset Thierry , Vejux Alain , Jeanfils Joseph 
Published: December 2004

AbstractThe O2 evolution activity of immobilized chloroplast membranes in different environments (albumin‐glutaraldehyde matrix, urethane polymer and alginate beads) is presented. As previously shown, the stability of photosystem II (PS II) of lettuce thylakoids appears to be increased by the immobilization process. For understanding such stability, some spectral investigations have been made about the energy distribution between the immobilized photosystems. The low‐temperature (77 K) fluorescence emission and photoacoustic spectroscopy are well adapted to solid particle studies. Especially, it has been shown that the fluorescence ratio (F735/F695) and photoacoustic ratio (PA676/PA440) are good indicators of the functional level of native and immobilized thylakoids. Such ratios are also given after storage and after continuous illumination conditions. Some results about the role played by glutaraldehyde (in the case of albumin‐glutar‐aldehyde matrix) in the stabilization process are also reported.
Two‐stage continuous fermentation of Saccharomycopsis fibuligeria and Candida utilis
Authors: Admassu Wudneh , Korus Roger A. , Heimsch Richard C. 
Published: December 2004

AbstractBiomass production and carbohydrate reduction were determined for a two‐stage continuous fermentation process with a simulated potato processing waste feed. The amylolytic yeast Saccharomycopsis fibuligera was grown in the first stage and a mixed culture of S. fibuligera and Candida utilis was maintained in the second stage. All conditions for the first and second stages were fixed except the flow of medium to the second stage was varied. Maximum biomass production occurred at a second stage dilution rate, D2, of 0.27 h −1. Carbohydrate reduction was inversely proportional to D2, between 0.10 and 0.35 h −1.
Hollow‐fiber membrane bioreactors using immobilized E. coli for protein synthesis
Authors: Inloes Douglas S. , Smith William J. , Taylor Dean P. , Cohen Stanley N. , Michaels Alan S. , Robertson Channing R. 
Published: December 2004

AbstractActively growing Escherichia coli C600(pBR322), immobilized within the macroporous matrix of asymmetric‐wall hollow‐fiber membranes, has been propagated to extremely high densities, typically more than 1012 cells/mL of accessible void volume, in some regions cells accounting for nearly 100% of the available macrovoid volume forming a tissue‐like mass. Production rates of β‐lactamase, an enzyme used as an indicator of the culture's biosynthetic potential, remained at high and relatively stable levels for more than three weeks of continuous operation, and effluent supernatant enzyme activities attained 25% of the accumulated level measured in a 24‐h shaker‐flask culture. Based on the accessible void volume within the fiber wall, the β‐lactamase productivity was independent of the specific asymmetric membrane used. On a per cell basis, however, cells cultured using hollow‐fiber membranes were only 10% as productive as those in the shaker‐flask culture, possibly due to the high packing density or culture aging. By contrast, the hollow‐fiber bioreactor was 100 times more productive than the shaker‐flask culture on a reactor‐volume basis, primarily as a consequence of the high cell densities. Reactor productivity was dependent on the number of cells in the reactor, suggesting that reactor performance was kinetically controlled and not mass transport limited.
Cultural properties and mass–energy balances in methanol fermentation by Methylomonas methanolovorans
Authors: Amano Yoshifumi , Takada Nobuo , Sawada Hidekazu , Sakuma Hideo , Terui Gyozo 
Published: December 2004

AbstractThe cultural properties of an obligate methanol utilizer, Methylomonas methanolovorans, were investigated in batch and continuous cultures, and the problems of mass‐energy balances were examined. Among the culture data, an exponential increase of growth lag with increased methanol concentration, as well as the inhibition kinetics in the relation between attainable maximum specific growth rate (μm ≦ 0.52) and methanol concentration are of interest. In the latter case, the inhibition constant (Ki) and the index number were 40 g/L, and 3 (dimensionless), respectively. The maximum yield coefficient (Y) in both batch and chemostat cultures was around 0.52. An analysis of the behavior of respiratory activity (Qo2) in response to the dissolved oxygen concentration (DO) indicated that the oxygen‐terminal entity should be regarded as a single one with a saturation constant for DO of 32 μg/L (1.1 × 10−6M). Chemostat data showed that the saturation constant for methanol is as low as 2.2 mg/L or 7 × 10minus;5M. A linear relationship was observed between the respiratory activity (mol O2g−1h−1) and the specific growth rate (μ i h−1), with the relationship Qo2 = 0.0504μ + 0.00112. The theory of mass and energy balances used by Roels has been reformed to give useful relationships between RQ or the cell yield and μ. In the case of M. methanolovorans, the relations can be greatly simplified since the influence of metabolic by‐product formation was negligible. Experimental RQ values (theoretical values for Y = 0.52 and 0.445) at varying μ‐values were compared with theoretical ones; despite considerable fluctuations, the results were regarded to conform with theory. By use of mass balance equations and enthalpy data of known compounds, the heat evolution in methanol fermentation was estimated indirectly to be 612 kcal/100 g biomass formed. The YATP problems are also discussed.
Mode of uptake of insoluble solid substrates by microorganisms. I: Sterol uptake by an arthrobacter species
Authors: Goswami P. C. , Singh H. D. , Bhagat S. D. , Baruah J. N. 
Published: December 2004

AbstractThe mode of uptake of sterols, which are nearly insoluble in water by an Arthrobacter species, was studied on the basis of substrate transfer via the aqueous phase (solubilization/pseudosolubilization) and through direct contact with sterol particles. Growth of the organism, on stero powder was predominantly in nonlogarithmic in character, indicating a possible limitation of substrate transfer. Soluble sterol was shown to be the preferential form of the substrate for assimilation by the organism. Evidence was obtained for increased solubilizition of β‐sitosterol and cholesterol during microbial growth on these substrates. But the rate of solubilization of β‐sitosterol (3.06 mg L−1 h−1) was too inadequate to account for the observed substrate uptake rare (107 mg L−1 h−1) during growth. A cholesterol solubilization rate of 44 mg L−1 h−1 could, however, account to an appreciable extent for the observed cholesterol uptake rate of 140 mg L−1 h−1 during growth. Increasing attachement of cells to sterol particles during growth was observed by microscopic examination, indicating that growth may take place over the surface of sterol particles. By using the synthetic surfactant HYOXYD AAO (alkyl aryl polyglycol ether), which prevented attachment of cells to sterol particles without affecting the metabolic integrity of the cells, it was shown that growth indeed took place predominantly on the surface of the sterol particles. Increased generation of finer particles of sterol, which provides increased substrate surface area during growth, was demonstrated. It was concluded that with β‐sitosterol, growth takes place almost entirely by attachement, whereas with cholesterol, about 30% of the growth take place on solubilized substrate and the rest through attachament.
Mode of uptake of insoluble solid substrates by microorganisms. II: Uptake of solid n‐alkanes by yeast and bacterial species
Authors: Cameotra Swaranjit S. , Singh H. D. , Hazarika A. K. , Baruah J. N. 
Published: December 2004

AbstractUsing two species of yeast and one of bacterium, evidence has ben obtained which indicates that the microbial uptake of solid alkane powders occurs primarily through a substrate solubilization mechanism. EDTA, a strong inhibitor of hydrocarbon solubilization by the cells, inhibited the growth of these organisms on alkane powder; the inhibition could be removed vai a supply of artificially solubilized alkane. One of the yeast strians, which was a mutant incapable of growing on solid alkane powder and liquid alkane, could grow very well on artifically solubilized alkanes. It was demonstrated that the solid alkane solubilization rate during microbial growth could satisfactorily account for the maximal alkane uptake rate actully observed during growth. The specificity of solubilization for the solid alkane used as the growth substrate was demonstrated.
Effects of temperature shift on growth rate of Escherichia coli BB at lower glucose concentration
Authors: Chohji Tetsuji , Sawada Tatsuro , Kuno Sigeru 
Published: December 2004

AbstractAlthough a shift in nutritinal conditins brings about transient unbalanced growth in normally grown Escherichia coli, a shift in temperature without changing the nutritional conditions results in immediate adaptation to the new conditions. However, when a medium contained an insufficient amount of nutrient, such as glucose, a temperature shift caused a lag time in temperature shiftup was primarily determined by the postshift temperature. These situatins were quite similar to those observed in nutrient shiftup, but a growth profile during the lag time was more distorted than that found in the nutrient shiftup. The transient unbalanced growth appeared to be caused by a difference in physiological states of bacteria, as expressed by macromolecule content per cell characterized by the pre and postshift environments, and was capable of expressing theoretically its profile and duration according to the model of Cooper and Helmstetter. On the other hand, the shiftdown in temperature in the presence of a limiting concentration of glucose caused extraordinarily long lag time, and transient cessation of cell division during that period. This response was unable to explain by the Cooper and Helmstetter model. In contrast to the temperature shiftup, the duration of lag time in the shiftdown was expresed as functions of the poshift temperature and the difference in physiological states of the pre‐ and postshift environments.