bluuebunny/crossref_metadata_2025_split huggingface dataset:
Scale‐up of antibiotic fermentations by control of oxygen utilization
Authors: Jensen A. L. , Schultz J. S. , Shu P. 
Published: December 2004

AbstractOxygen Utilization as a scale‐up parameter is evaluated in two antibiotic‐producing fermentations. This method of scale‐up was used in tank‐to‐tank and in flash‐to‐flash scale‐up studies. Antibiotic yields and cell weight trends were generally duplicated in the replicate runs, with some discrepancy noted in chlortetracycline yields at high aeration levels. The apparatus for measuring oxygen consumption rates and for automatically controlling oxygen utilization, according to a predetermined pattern, is described.
Study of the dynamic behavior of the chemostat system
Authors: Koga S. , Humphrey A. E. 
Published: December 2004

AbstractThis paper deals with a theoretical study on the dynamic, character of the chemostat system. It. is primarily based on the Monod model for growth limitation, although certain more complex models are considered. Since the Monod model is described in terms of two variables, an analysis by use of a phase plane plot will show the various possible types of behavior theoretically expected for transient conditions of the system. In this paper it will be shown that the chemostat system might show an overshoot (or an underswing) with respect to changes in cell and substrate concentrations, depending on the extent to which the system might be disturbed from steady‐slate conditions. Other types of transient behavior ran also be expected when one of the system parameters such as dilution rate or input substrate concentration is disturbed in a stepwise manner. The simple Monod chemostat model was found never to oscillate in either a damped or a sustained manner as has been experimentally reported. Discussion is included about the transient behavior of other chemostat models such as that involving a variable yield coefficient, i.e., including the effect of cell maintenance requirements.
Methane as a carbon substrate for the production of microbial cells
Authors: Hamer G. , Hedén C.‐G. , Carenberg C.‐O. 
Published: December 2004

AbstractThe cultivation of aerobic, methane‐utilizing, microbial cells by submerged culture techniques, in an entirely mineral salts medium, with a view to their use as an edible protein source is discussed. Particular emphasis is placed on the potentially explosive nature of gaseous mixtures containing methane and oxygen. The experiments described investigate if fully safe operation at all times, by oxygen concentration control, is possible in agitated and sparged batch fermentors. Appreciable wastage of methane is prevented by gaseous‐phase recirculation. It is concluded that fully safe operation is possible, cultures being able to grow exponentially without substrate limitation by the gaseous‐phase nutrients.
Electronic sizing and counting of bacteria
Authors: Edwards Victo R. H. , Wilke Charles R. 
Published: December 2004

AbstractAn electronic apparatus is described that permits rapid determination of the concentration and size distribution of bacteria in electrolyte suspensions by a resistance method. The resulting size‐concentration distribution may be displayed on an oscilloscope and recorded with an X–Y plotter and an electric typewriter‐tape punch unit. The paper tape is analyzed with a computer program. Comparisons are made between electronic measurements of bacterial cell concentration and size distribution and values obtained by other methods. Effects of heat‐killing and disruption of the cell membrane on the electrical counting characteristics of the organisms are discussed.
The role of aeration and agitation in the production of glucose oxidase in submerged culture
Authors: Zetelaki Kornelia , Vas Karoly 
Published: December 2004

AbstractThe influence of agitation and aeration on growth and on production of glucose oxidase of Asp. niger has been studied. It was found that both rate of growth and glucose oxidase production was higher at an agitation speed of 700 rpm than at 460 rpm. Further increase in speed of agitation resulted in neither a higher rate of growth nor a higher glucose oxidase activity. Total glucose oxidase activity was highest in a medium containing 5% sugar (at an agitation speed of 700 rpm) and did not get higher when the sugar concentration of the medium was increased to 7%. When pure oxygen was bubbled through the culture the rate of growth of the culture (in the linear phase) was 95 mg. mycelial dry wt./100 ml./hr., and only 61 mg. when air was applied. The glucose oxidase activity of oxygenated culture was double the activity of aerated culture. Viscosity of the homogenized culture became higher with higher concentration of mycelia. The viscosity of oxygenated culture was found to be lower than that of aerated culture.
Some aspects of the metabolism of a partially colloidal substrate
Authors: Berg R. H. , Phillips D. 
Published: December 2004

AbstractThe biochemical oxygen demand (BOD) of a complex, partially colloidal substrate is divided into oxidation (fo) and synthesis (fs) fractions. The substrate being investigated is a suspension containing 10 mg./l. of dry skim milk. The oxidized and synthesized fractions of the BOD are shown to be 38.4% and 61.6%, respectively. The division of BOD is related to the time at which maximum cell growth appears. The time required to obtain maximum cell production is shown to be at least 10 hr. The relationship between the time to maximum cell production and the apparent initial activity of the seed organisms is discussed.
Transient response of continuous cultures to changes in temperature
Authors: Ryu D. Y. , Mateles R. I. 
Published: December 2004

AbstractThe purpose of this experimental study was to examine the transient response of a chemostat‐type continuous culture of Escherichia coli B to step changes in temperature by following transient limiting substrate concentration and calculating from it the transient growth rate. The transient response to step changes of temperature was tested for four different situations. In the first two cases, temperature was shifted down from 37 to 27°C., and 37 to 32°C. In the last two, it was shifted up from 32 to 37°C., and 27 to 37°C. When the temperature was shifted up, the growth rate increased rather rapidly to its transient maximum value and then decreased slowly until it, settled back into the steady‐state value. On the other hand, when the temperature was shifted down, the growth rate decreased relatively rapidly to its transient minimum and then it slowly increased and returned gradually to the steady‐state value. The magnitude of the transients was less than would be expected if the transient growth rates followed an Arrhenius function.
Toxic and inflammatory properties of two antibiotics: Muconomycin A and B
Authors: Guarino A. M. , Mendillo A. B. , DeFeo J. J. 
Published: December 2004

AbstractToxicological investigations were conducted on two new antibiotics, Muconomycin A and Muconomycin B. These non‐nitrogenous antibiotics were found to be highly toxic and capable of inducing profound inflammation in the peritoneal cavity of male albino rats. Either antibiotic produced large volumes (10–20 ml) of inflammatory exudate even when injected intraperitoneally in quantities of 1.6 × 10−10 moles. An extensive profile of the electrolytes and proteins found in inflammatory exudates was developed. Simultaneous assays of the blood serum of treated rats provided a basis for comparing the concentrations of constituents of serum with those of the exudate. The results of these assays showed that the exudate contained lower concentrations of sodium and proteins, and greater amounts of potassium, calcium, and phosphorus than the serum. Chloride ion concentrations were variable. Since previous work showed that one of the manifestations of toxicity of these substances was the production of creatinuria, further studies were carried out with ATP/Creatine Phosphotransferase. These studies show that these antibiotics are potent in vitro inhibitors of the enzyme ATP/Creatine Phosphotransferase.
Continuous cultivation of Saccharomyces cerevisiae. II. Growth on ethanol under transient‐state conditions
Authors: Mor Juan R. , Fiechter Armin 
Published: December 2004

AbstractGrowth of Saccharomyces cerevisiae LBG H 1022 on ethanol under transient‐state conditions was studied. As a cultivation device, an aerated Chemap fermentor combined with continuously working gas analyzers for oxygen and carbon dioxide was used. Yeast cell dry matter, substrate concentration, specific oxygen uptake, specific carbon dioxide release, and respiration quotient were measured during the different transient states. Depending on which range of the dilution rate the initial steady state was found, we obtain different responses to the shift experiment. For the lower range, up to D = 0.07, we deal with damped oscillations ranging above and below the steady‐state values. For the higher specific growth rates, the rate of damping is strongly enhanced and the shape of the curves becomes an asymptotic approach to the final steady states.
The influence of dissolved oxygen partial pressure on the level of various enzymes in mouse LS cells
Authors: Self Daphne A. , Kilburn D. G. , Lilly M. D. 
Published: December 2004

AbstractThe intracellular levels of seven enzymes in mouse LS cells growing in suspension culture at controlled dissolved oxygen partial pressures (pO2) have been measured. During the growth of each culture large fluctuations were observed in the levels of some enzymes, particularly aldolase and cytochrome oxidase. Mean values for the concentration of each enzyme during the growth phase have been calculated. These results are discussed in relation to previous observations made on the growth of mouse LS cells.
Cultivation of the yeast Candida lipolytica on hydrocarbons. II. One‐stage continuous cultivation on gas oil
Authors: Dostálek M. , Munk V. , Volfová Olga , Fencl Z. , Pecka K. 
Published: December 2004

AbstractContinuous cultivation of the yeast Candida lipolytica on gas oil was studied from the viewpoint of biomass production and oil deparaffination. Optimum conditions wore found at the dilution rate D = 0.16–0.19 when biomass productivity 1.7 g/l/hr and yield coefficient. y = 0.92 were achieved. At deparaffination to the same freezing point, more than double the production of biomass and deparaffined oil during a given time unit was achieved in a continuous process than in batch cultivation. Consumption of substrate was followed in both cultivation processes and it was confirmed that individual n‐alkanes of gas oil were degraded at various rates and yields. Results proved optimum cultivation conditions to depend on concentration and composition of the paraffinic fraction of gas oil used. To achieve these conditions the continuous process may be controlled by choice; of suitable dilution rate and concentration of gas oil.
Virus interactions with membrane filters
Authors: Cliver Dean O. 
Published: December 2004

AbstractA survey of interactions of membrane filters with viruses has included 28 types of membranes, 4 types of enteroviruses, and 1 reovirus. Losses of these viruses in filtration, due to adsorption to the filter membranes, appear to be governed by three factors: the chemical composition of the filter membrane, the ratio of pore diameter to the diameter of the virus particle, and the presence of substances, such as those occurring in serum, which interfere with adsorption. Membranes of cellulose triacetate and of certain other materials have a very low affinity for these viruses. Cellulose triacetate filters adsorb virtually none when the pore size exceeds the virus diameter by a factor of more than 3. At porosities nearer the virus diameter, even low‐affinity membranes adsorb large quantities of virus unless serum or some other additive interferes. Cellulose nitrate membranes, in the absence of interfering substances, adsorb enterovirus significantly at a pore size 285 times the virus diameter.
The kinetics of β‐galactosidase attached to porous cellulose sheets
Authors: Sharp A. K. , Kay G. , Lilly M. D. 
Published: December 2004

AbstractThe properties of β‐galactosidase attached to cellulose and DEAE‐cellulose sheets arc described. Those insoluble enzyme derivatives obey the Michael‐Menten relationship but, the measured kinetic parameters are very dependent on the flow conditions. The results of long‐term stability tests are given.
Prediction of product formation as an aid to decision‐making in pilot plant experiments on batch fermentations
Authors: Gyllenberg H. G. , Koskenniemi Eeva , Rauramaa V. 
Published: December 2004

AbstractA mathematical model for the prediction of product formation in batch processes is presented. The suggested procedure allows production of a prognose at any given moment of a run concerning the product concentration at any future moment of the same experiment. The series of subsequent prognoses thus produce a trend, and it is assumed that an analysis of the trend may provide information, which is useful in the evaluation of different decision alternatives in pilot plant batch experiments.
Growth of Streptococcus faecalus in dense culture
Authors: Sortland L. D. , Wilke C. R. 
Published: December 2004

AbstractA fermentation system was designed and constructed to study the growth characteristics of microorganisms at low and high cell concentrations. The technique used to develop high cell densities utilized a rotating microfiltration unit to permit the removal of cell‐free product from the fermenter. The fermenter volume and the filter were contained in a single unit composed of a series of concentric cylinders. Annuli contained the fermenter volume while the second outermost cylinder supported a microfiltration membrane. Feed to the system was pumped at constant rates, and the internal pressure built up to a value, which would effect the required filtration rate. The system was operated batchwise and continuously with and without filtration.The anaerobie growth characteristics of Streptococcus faccalus were determined at 37°C and pH 7.0 for batch, continuous, and continuous with filtration modes of operation. The growth characteristics were unchanged when the cell density was increased. Changes in cell yield peer model of glucose consumed were clearly illustrated during thee course of single run by operating the fermenter in the unsteady state with filtration. No consumption of glucose for developed was 40% packed cell volume, a value 45 times larger than could be grown in simple batch culture.
Performance of a perforated plate column as a multistage continuous fermentor
Authors: Kitai Atsuo , Tone Hiroshi , Ozaki Asaichiro 
Published: December 2004

AbstractMicroorganisms were continuously cultivated in multistage column consisting of ten perforated plate sections to which medium and air were supplied concurrently from the bottom.At steady state the cell concentration in the various stages was gradationally differentiated from the bottom to the top in the direction of medium flow. RNA content per unit cell concentration at each sage was determined. The cells in the lower stages were higher in RNA content than those from the upper stages. Wash out was observed to occur in the column at dilution rates which do not result in wash out in a single stage chemostat system.A study of the flow characteristics revealed that the overall performance of the plate column was equivalent to that of a multistage system, when hole diameter and hole area to column cross sectional area ratio were properly selected. This was true even in highly aerated conditions. These results indicated that the perforated plates in the column hindred intermixing through the plates, and that each stage functioned as an independent stirred vessel. Industrial and research application of this type fermentor was discussed.
Biopolymers in drug technology: The use of DNA in purifying Phleomycin
Authors: Pietsch Paul 
Published: December 2004

AbstractIt is sometimes easier and cheaper to extract a drug's target sites from cells than it is to purify, concentrate or manufacture the drug itself. This is especially true in the case of DNA and some of the exotic antibiotics that react with it. Phleomycin, an inhibitor of replication, was considered as a specific case in point. Biologically active components of this antibiotic mixture bind nondestructively to DNA, in vitro and in vivo, and thereafter may be processed by simple, economical methods usually reserved to macromolecules of much greater size.
The concentration of protein solutions by normal freezing
Authors: Janson Jan‐Christer , Ersson Bo , Porath Jerker 
Published: December 2004

AbstractAn apparatus is described which is designed for preparative freeze concentration experiments by the technique of normal freezing. It has a capacity of approximately 22 liters distributed over twelve vessels. The influence of various geometrical and chemical parameters such as stirring speed, crystallization rate, and sample composition on the normal freezing of protein solutions are discussed. For dilute protein solutions (<0.1%) the concentration factor generally was 8‐ to 10‐fold with recoveries of 90–100 percent. With higher protein concentrations and at ionic strengths higher than approximately 0.05, the recovery was decreased. No loss of activity was detected when concentrating enzyme solutions.
Covalent bond between the enzyme amyloglucosidase and a porous glass carrier: The effect of shearing
Authors: Weetall H. H. , Havewala N. B. , Garfinkel H. M. , Buehl W. M. , Baum G. 
Published: December 2004

AbstractThe utility of an immobilized enzyme depends not only on initial loading but also on operational half‐life. The loss of activity of an immobilized enzyme in a column reactor may occur in several ways. It is therefore of interest to determine whether the decay in activity is due to the rupture of any of the enzyme‐carrier bonds in the composite. In order to do this, it is first necessary to establish whether the enzyme on the composite is in fact covalently bound or adsorbed. In this report we have shown that there are a number of covalent links per protein molecule. We have also shown that the bond energies are sufficient to prevent shearing of the enzyme itself from the composite under any stresses which may occur in a chromatography column or packed‐bed reactor during continuous operation. The effect of the siloxane linkage on composite stability is also discussed.
Water insoluble enzyme columns: Kinetic study on steady state and transient conditions
Authors: Gellf G. , Thomas D. , Broun G. , Kernevez J. P. 
Published: December 2004

AbstractThe kinetic behavior of water insoluble enzyme columns was studied using the hydrolysis of GPNA (N‐glutaryl‐L‐phenylalanine‐p‐nitroanilide) by α‐chymotrypsin as a model. Thermal denaturation of soluble and insoluble enzyme was compared in a batch reactor and in a tubular reactor. Convection of metabolites, enzyme reaction, diffusion of metabolites across porous particles and the kinetic behavior of a water insoluble enzyme column were tested.The respective and mutual effects of the first two phenomena were comprehensively analyzed for both stationary state and transient conditions. When the ingoing substrate concentration was varying with time, convection‐reaction equations were solved by digital computation. The possible effects of diffusion limitations and unstirred layers are discussed.
Study of performance of a tubular membrane reactor for an enzyme catalyzed reaction
Authors: Closset G. P. , Cobb J. T. , Shah Y. T. 
Published: December 2004

AbstractA tubular membrane reactor offers many advantages over a solid wall reactor to carry out an enzyme catalyzed reaction. With proper membrane selectivity, the product, may be separated from the reacting stream and the enzyme recycled for continuous reuse. In most cases, enzyme reuse contributes to the economic feasibility of a continuous enzyme catalyzed process. Furthermore, the efficiency and performance of a membrane reactor is greater than that of a solid wall reactor.Continuous hydrolysis of starch by the enzyme β‐amylase, carried out in a commercially available tubular membrane unit, is studied at different starch and enzyme concentrations for a given system pressure and inlet flow rate. Results show that the performance of the membrane reactor is in all cases greater than that of the solid wall reactor. A steady state in performance of permeation rate is, however, not reached by the membrane reactor, which shows a continuous decline within the periods examined in this study. This decline is caused in part by the aging of the starch solution, but mostly by the formation of a concentrated, or gel, layer at the membrane surface. This appears to be the main limiting factor for this process since the decline in reaction and permeation rate results in a severe decrease in the amount of maltose in the permeate.
Protein modification in nonaqueous media. Preparation and properties of matrix‐supported lysozyme
Authors: Bartling Greg J. , Brown Harry D. , Chattopadhyay Swaraj K. 
Published: December 2004

AbstractHen's egg white lysozyme (EC 3.2.1.17) has been covalently attached to a polystyrene matrix via interaction of protein nucleophiles with an aromatic imidazolide function under anhydrous conditions. The polymer‐enzyme complex is prepared in a way which allows nonaqueous solubilization of the complex. The activity of the bound enzyme compares favorably with the activity of the native protein. The pH optima for the matrix‐supported protein are shifted toward the basic side. The effect of substrate concentration on rate has been determined. (A preliminary report of this work has been published: G. J. Bartling, H. D. Brown, S. K. Chattopadhyay, Nature 243, 342–344 (1973).)
An immunoadsorbent process for removing hepatitis antigen from blood and plasma
Authors: Charm Stanley E. , Wong Bing L. 
Published: December 2004

AbstractAn immunoadsorbent process has been devised for removing serum hepatitis antigen (HAA), from blood, blood plasma, and plasma products.The immunoadsorbent complexes specifically with HAA and the complex is removed from the plasma by filtration. The complex is dissociated with 0.23M NH4OH. The immunoadsorbant is regenerated for further processing, while the purified HAA by‐product my be used to produce more antibody in animals.The rate of complexing is such that HAA is reduced one log cycle each 2hr. Since available tests can only detect HAA to about 109 particles per ml, it is proposed that HAA negative plasma and plasma products can be processed to reduce HAA to a probability of less than one HAA particle per plasma pool.A gibbon injected with infectious commercial Factor IX that was subjected to the immunoadsorbent process showed no sign of infection after 8 months. However 14 weeks after injection with unprocessed Factor IX, the gibbon showed signs of infection.
Design and operational model for complete mixing activated sludge system
Authors: McKinney Ross E. 
Published: December 2004

AbstractThe complete mixing activated sludge (CMAS) system is gaining in popularity for treating both domestic and industrial wastewaters. Experience over the past 20 years has produced a simple mathematical model which can be used in both the design and the operational evaluation of CMAS systems. Laboratory pilot plants and full scale field units have furnished the basic data needed to confirm the validity of the mathematical model. The basic concepts of the model are discussed in light of field evaluations. Areas of conflict and confusion which have arisen in the past will be presented and discussed. Design examples and operational evaluations are presented for several different wastewater systems.