bluuebunny/crossref_metadata_2025_split huggingface dataset:
Oxygen transfer in streptomyces fermentation broths
Authors: Járai M. , Gyóry E. , Tombor J. 
Published: December 2004

AbstractThe oxygen transfer coefficient has been investigated in S. noursci and S. lavendulae fermentation broths obtained from fermentors of different operating volumes (61., 30001., 20,0001.). Fermentors had KLas values ranging from 1.0 to 17.0 min−1, calculated from sulphite oxidation rates. The dynamic measurement of the volumetric oxygen transfer coefficient. (KLa) has been performed in the different fermenting systems. As the fermentation progressed, especially in the first stages, KLa values have decreased in both fermentations and in each system of fermentors. In order to characterise the whole fermenting system an average KLas was calculated from the obtained KLa values. The average KLa grew with increasing KLas values and ranged from 0.03 to 3.72 min−l. Some factors possibly having an influence on the, change of KLa have been studied.The oxygen transfer coefficients of the broths have been measured in falling films and ranged from 0.05 to 0.4 cm min−1. The flow conditions have been characterized by Reynolds numbers of broths varying between 1.0 and 60.0. The average thickness of the falling films have been measured and plotted against Reynolds number. The Re+ which is the breaking‐point of the plot increased as the fermentation proceeded. In the region of Re+ the values of the oxygen transfer coefficient increased rapidly. An approximate correlation could be established between the Re+ and the physical properties of fermentation broth.
Fluid dynamics of anaerobic fermentation
Authors: Delente Jacques , Akin Cavit , Krabbe Erik , Ladenburg Kurt 
Published: December 2004

AbstractIn beer fermentation, yeast cells are kept in suspension, despite their higher density, by natural agitation created by ascending CO2 bubbles. Yeast cells are unable to nucleate bubbles but instead release CO2 in a soluble form in such a way that the medium tends to become supersaturated.A higher concentration of yeast cells and the presence of solid particles cause the formation of bubbles at the bottom of the fermenter and practically only there. The rising bubbles grow and accelerate by sweeping the CO2 formed throughout the fermenter by the suspended yeast cells, thereby creating a fluid regime. A mathematical expression relating the bubble agitation power to the fermentation parameters was obtained and used to design more efficient fermenter shapes.
The foams of fermentation broths. I. Some parameters of the foaming of fermentation media
Authors: Szarka Laszlo , Magyar Karoly 
Published: December 2004

AbstractThe stability of foam formed during fermentation is decisively affect ed by the nature of the nutrient media used. In froth‐flotation models, (a) the foam formation time, characteristic of the tendency to foam, and (b) foam subsistence time, characteristic of the stability of foams formed, have been studied. With the utilization of these two parameters, the stability of foam from aqueous solution of several surface active components of nutrient media has been noted as a function of concentrations. Further, but, without attempting completeness, the viscosity enhancing effect of carbohydrate components, and the effect of the subsistence time of their foam, upon the stability of foam have been studied together with the correlation between “standing” time after sterilization and tendency to foam. Taking soy‐bean meal as a model, the stability of foam films in function of pi I, at constant concentration, has been studied. It seems that though a proper control of the factors mentioned, nutrient media with a low tendency of foaming can be formulated.
Microprobe techniques for determining diffusivities and respiration rates in microbial slime systems
Authors: Bungay H. R. , Whalen W. J. , Sanders W. M. 
Published: December 2004

AbstractA microprobe electrode was used to determine dissolved oxygen concentrations near the surface and within a bacterial slime mass supplied with a continuous flow of nutrient solution. With dilute medium, the oxygen profile became level at high concentrations within the film, indicating substrate‐limited respiration. More concentrated medium caused the profile to fall to low oxygen concentrations characteristic of oxygen‐limited respiration. Oxygen responses to sudden changes in concentration of nutrient medium were measured. Estimates of microbial respiration rate and of diffusivity of oxygen were based on well‐known diffusion equations.
The influence of growth conditions on the composition of some cell wall components of Aerobacter aerogenes
Authors: Tempest D. W. , Ellwood D. C. 
Published: December 2004

AbstractWith a chemostat culture, both the bacterial growth rate and the growth environment can be independently varied between wide limits. Changing the growth rate of Aerobacter aerogenes organisms (in either a glycerol‐limited medium or a Mg2+‐limited medium) affected the bacterial cell wall content; invariably slow growing organisms were smaller than faster growing ones and had a higher cell wall/biomass ratio. Changing the growth rate also influenced the composition of the walls but in this respect glycerol‐limited organisms and Mg2+‐limited organisms behaved differently. Thus, whereas increasing the growth rate of glycerol‐limited cultures caused the cell wall 2‐keto‐3‐deoxyoctonic acid (KDO) and heptose contents to increase progressively, with Mg2+‐limited cultures they decreased. Furthermore, although KDO and heptose are both components of the lipopolysaccharide layer, their ratio varied with growth rate, and with the nature of the growth‐limitation, indicating changes in the lipopolysaccharide composition. These results are discussed with particular reference to the influence of environment on cell wall content and composition, and the use of continuous culture for the production of bacterial vaccines.
Studies of fungal growth and intermediary carbon metabolism under steady and non‐steady state conditions
Authors: Carter B. L. A. , Bull Alan T. 
Published: December 2004

AbstractThe physiology of Aspergillus nidulans strain 224 has been studied under conditions of batch‐ and glucose‐limited chemostat‐culture and the effect of different steady state growth rates and dissolved oxygen tensions (DOT) examined. Measurements of the specific activities of selected glucose enzymes, the extent of oxygen uptake inhibition by glycolytic inhibitors, and radiorespirometric analyses were made in order to follow the variations in glucose catabolism, which occurred under these conditions. Greatly increased activity of the hexosemonophosphate (HMP) pathway was found during: (i) exponential growth of batch cultures; (ii) at near maximum specific growth rates (μ = 0.072 hr−1) (DOT = 156 mm Hg); and (iii) at low DOT levels (<30 mm Hg) (μ = 0.050 hr−1) in chemostat cultures. These changes in glucose eatabolism have been discussed in terms of the biosynthetic demands of the fungus under the influence of changing growth pressures. Preliminary studies also have been made of transition state behavior following stepwise alteration of the DOT. A new steady state was established after 4–5 culture doublings during which period an “overshoot” in HMP pathway activity occurred; these kinetics are indicative of a derepression of certain glucose enzymes. Low molecular weight phenols are synthesized during the exponential phase in batch cultures and these are further metabliized to a major secondary metabolite, melanin, at the onset of stationary phase conditions. The kinetics of tyrosinase production in steady state chemostats differs from those that might be predicted for an enzyme associated solely with secondary metabolism. A primary physiological role for this oxidase in Aspergillus nidulans has been postulated.
Cell growth and population activity of Saccharomyces cerevisiae in two‐stage continuous cultivation
Authors: Beran K. , Zemanová J. 
Published: December 2004

AbstractContinuous culture in a cascade of vessels with the addition of supplemental nutrients to any stage permits adjustment of the physiological state of the culture in each stage to best achieve a desired performance goal. The yeast Saccharomyces cerevisiae in two‐stage continuous cultivation was selected as a model system. With conditions in the first stage held constant‐ at a selected glucose concentration in the feed stream, dilution rate for the second stage was varied. Cell numbers, dry weight, glucose concentration, respiration coefficient, and titers of several enzymes were determined. The seed rate was defined as the ratio of glucose concentration in the feeds to stage 1 and to stage 2. At low seed rates, the calculated specific growth rate in the second stage was proportional to dilution rate. At higher seed rates, the specific growth rate based on dry weight behaved differently from that based on cell numbers, and the dependence on dilution rate was not linear.
A continuous, multistage tower fermentor. I. Design and performance tests
Authors: Falch Edvard A. , Gaden Elmer L. 
Published: December 2004

AbstractThe design of a continuous column fermentor with a multiple staging effect is described. The column is divided into four compartments by horizontal perforated plates and is provided with a central agitator shaft driving an impeller in each compartment. A tube at the center of each plate forms a liquid seal around the shaft and also acts as a “downcomer.”The fermentor is normally operated with counter‐current flow of gas and medium. Fresh medium is added to the top stage and product is withdrawn from the bottom.The effect of plate and agitator design on fermentor performance was studied in terms of factor such as oxygen transfer rate, gas holdup, and interstage mixing. By proper choice of the design parameters, the fermentor was made to approximate a perfect four‐stage cascade in terms of reactor performance.Preliminary experiments were performed with air‐water systems, but a more realistic picture of fermentor performance was obtained in experience involving propagation of Escherichia coli. Data for business and substrate concentrations in each stage confirmed the staging effect of the apparatus. The fermentor operated in a stable manner for periods of more than two weeks.
Design and physical characteristics of a multistage, continuous tower fermentor
Authors: Prokop A. , Erickson L. E. , Fernandez J. , Humphrey A. E. 
Published: December 2004

AbstractA multistage tower laboratory fermentor has been constructed consisting of eight compartments separated by sieve plates. Flow of substrate and air is concurrent from the bottom to the top of the column. It, was hoped that this system could be used to reproduce, simultaneously on a continuous basis, eight distinct phases of a batch growth curve. It was believed that the extent of batch curve simulation would depend upon the character of hydraulic mean residence time of broth in the column and in the individual compartments. The expected relationship did not occur. Rather it was found that growth in the column involved residence time characteristics not only for the fluid but also for the microorganisms, and for the growth limiting substrate. Depending upon the column operation, these could be distinct and different.The purpose of this investigation was to study the residence time distribution (RTD) of the continous (fluid) and dispersed (microorganisms) phases for model systems as well as for a yeast fermentation. Various degrees of flow nonideality, i.e., fluid blackflow and dispersed phase sedimentation, were noticed. The former seems to be due to interaction of the concurrent gas and liquid flow; it is particularly dependent upon void area of the sieve plate holes. Sedimentation is probably a function of plate design as well as cell size and density. It wa concluded that for a particular plate design the gas hold‐up wass controlled by superficial air velocity and was the main parameter governing the differences between dispersed and continous phase(Rt1). This conclusion was supported by a computeraided styudy utilizing a mathematical model of fluid flow to fit the growth kinetics and cell distribution observed experimentally throughout the fermentor.Some advantages of foam control in the tower fermentor by surface active compounds are mentioned. Also, suggestions are made for carrying out fermentations that have two liquid phases, such as a hydrocarbon fermentation. The possibility of closely approximating plug‐flow conditions in the multistage tower fermentor, a necessary condition for batch growth simulation, is discussed from a practical point of view.
The design and operation of high‐power, magnetic drives
Authors: Cameron J. , Godfrey E. I. 
Published: December 2004

AbstractA description is given of the design and operation of high‐power magnetic drives developed to enable shaft seals and glands to be dispensed within deepculture vessels, in tissue homogenizers, and in mixing and filling processes where sterility is essential. The drives operate at speeds of 300 to 2000 rpm in volumes of 300 1. to 10 ml with clearances up to 16 mm between the pole faces of the magnets.Two types of drive are described, one in which the driving and driven magnets form an integral unit on the lid of a vessel: such vessels are used for transporting material. To intiate stirring, it is only necessary to connect a motor directly, or through a cable‐drive, to the magnetic‐drive assembly. In the other type of unit the driving magnet is attached permanently to the driving motor. Locating pins on the base of the motor and corresponding sockets on the lid of the vessel ensure that when the motor is in position, the driving and driven magnets are located correctly in relation to one another.The design of these drives is based on the use of multipole, ceramic magnets. The advantages of their use in such units, compared with metal magnets, are discussed. Earlier magnetic drives are also discussed and explanations offered for the difficulties formerly met in scaling up.
Isolation and characterization of constituents in hemolymph from healthy and diseased japanese beetle larvae
Authors: Bennett Glenn A. , Shotwell Odette L. 
Published: December 2004

AbstractStudies are reviewed on the composition of hemolymph from Japanese beetle larvae, Popillia japonica. This research was conducted to determine the chemical environment required for sporulation of the milky disease organism, Bacillus popilliae. Amino acids, proteins, organic acids, lipids, carbohydrates, and oxygen content were determined in hemolymph from healthy and diseased larvae. Oxygen content of hemolymph was measured by microelectrodes implanted in the hemocoel of living larvae. Vegetative growth of the pathogen reduces the dissolved oxygen; however, as sporulation occurs, oxygen concentration approaches normal values. Trehalose, the major hemolymph sugar, is reduced by ca. 50% during the course of milky disease. Neutral lipids, phospholipids, and hydrocarbons decrease markedly with infection. Both branched‐chain and normal alkanes occur in hemolymph. Milky disease causes an increase in concentration of pyruvic, malic, glycolic, tartaric, and glyoxylic acids. The major hemolymph protein, a lipoglycoprotein, has a mol. wt. of ca. 500,000. Reduced concentration of this protein is accompanied by the appearance of a smaller protein. Amino acids that increase significantly as a result of infection are: Glutamic acid, aspartic acid, β‐alanine, phenylalanine, threonine, lysine, and serine. Hemolymph contains few peptides of low molecular weight.
Chemical and autoflocculation of microorganisms in biological wastewater treatment
Authors: Tenney Mark W. , Verhoff Francis H. 
Published: December 2004

AbstractExperimental evidence is presented which indicates that both chemical and autoflocculation of microorganisms occur by the same mechanism. Basically, long chain polymeric species attach themselves between the microbial particles and agglomerate them into flocculant particles of sufficient magnitude to subside from suspension under quiescent conditions. Properties of the polymers which are produced during autoflocculation are investigated and these polymers are shown to be capable of causing the agglutination of inorganic colloids such as alumina. It is hypothesized that these biologically generated flocculating polymers could belong to a class of compounds known as transport enzymes. The experimental data qualitatively agrees with this hypothesis.
A modified procedure for the large scale preparation of tRNA from E. coli
Authors: Bauer S. , Milner Y. , Ziv E. , Shiloach J. , De Groot N. , Lapidot Y. 
Published: December 2004

AbstractA procedure for the preparation of about 50 g batches of tRNA from 25 kg E. coli W is described. The method involves phenolic extraction of the cells, batch absorption of the tRNA on DEAE‐cellulose, washing the DEAE‐cellulose and packing it into a column, elution of the tRNA from the column and precipitation of the tRNA with ethanol. The method is less time and labor consuming than the methods described in the literature and can be carried out with relatively simple equipment.
Steady state multiplicity and stability of enzymatic reaction systems
Authors: Bruns D. D. , Bailey J. E. , Luss D. 
Published: December 2004

AbstractSeveral techniques for investigating the multiplicity and stability of open isothermal enzymatic reactors are discussed and some of the pitfalls in previous thinking pointed out. The example which is used to illustrate these methods exhibits several interesting features. Among these is the existence of a stable oscillatory state which surrounds a unique steady state which is asymptotically stable to certain finite disturbances.
Acid‐Base equilibrium in aerobic fermentations: Influence of unutilizable acids and bases on the acetic acid concentration in culture liquid
Authors: Ikeda Shigeho , Ishizaki Ayaaki , Hirose Yoshio 
Published: December 2004

AbstractAn investigation was made on the factors influencing the acetic acid concentration in the culture liquid of the aerobic fermentations where acetie acid was used as a carbon source. The acetic acid concentration in the culture liquid changed in proportion to the amount of unutilizable acid or base supplied. This was explained by the principle of conservation of electroneutrality.Another factor affecting the acetic acid concentration in the culture liquid was bicarbonate ions which were formed by the dissolution and dissociation of carbon dioxide in the gas phase of the fermentor. The increment in bicarbonate ion concentration was equal to the decrement in the acetie acid concentration in the culture liquid.
Nitrogen metabolism in extended aeration processes operated with and without hydrolytic pretreatment of portions of the sludge
Authors: Yang P. Y. , Gaudy A. F. 
Published: December 2004

AbstractNitrifying characteristics were compared for an extended aeration (total cell recycle) process and one employing an engineering modification of the process utilizing a “hydrolytic assist” to aid biological autodigestion. Laboratory pilot plants were run over a period of years, and it was found that the recently recommended “hydrolytic assist” did not militate against production of a highly nitrified effluent. Under this mode of operation, the effluent was as nitrified as the effluent from the normal extended aeration process. It was also found that the modified process rapidly recovered its nitrifying capability after a period of deprivation of excess ammonia nitrogen. Throughout the period of operation, substrate removal efficiency remained high.
Interactions in a mixed bacterial population growing on methane in continuous culture
Authors: Wilkinson T. G. , Topiwala H. H. , Hamer G. 
Published: December 2004

AbstractThe growth of a mixed methane‐utilizing culture in a continuous flow fermenter has been studied under both methane and oxygen limitation. Small additions of methanol have been shown to inhibit the methane‐utilizing moiety in the culture and it has been shown that the Hyphomicrobium sp. in the mixed culture removes any inhibitory methanol. The interaction between the methane‐utilizing Pseudomonas sp., and the Hyphomicrobium sp. has been explained and a model of the continuous mixed culture under oxygen limitation has been formulated. Qualitative predictions of transient phenomena by the model have been verified experimentally.
A study of the rheological properties of a non‐Newtonian Fermentation broth
Authors: Leduy A. , Marsan A. A. , Coupal B. 
Published: December 2004

AbstractPolysaccharide was synthesized by Aureobasidium pullulans (or Pullularia pullulans) 2552 in a sucrose medium. The field apparent viscosity of the culture medium from shake flask experiments rose to 24,500 cP and then dropped toward its initial value as the fermentation progressed. The magnitude of the maximum apparent viscosity depended on the initial pH of the fermentation broth. The inoculum age influenced the cultivation period before which the maximum viscosity was reached. Rheograms of the fermentation broths showed a change in viscosity behavior from Newtonian to pseudoplastic, and then toward Newtonian characteristics during the fermentation. The calculated non‐Newtonian index was found to be a sensitive factor for the indication of the non‐Newtonian behavior. Such behavior could not be detected from rheograms. Viscosity profiles of polysaccharide isolated from various stages of the fermentation showed a change from Newtonian to pseudoplastic behavior depending on the concentration (0–2%) of polysaccharide.
Theory of the kinetics of reactions catalyzed by enzymes attached to the interior surfaces of tubes
Authors: Koyayashi Takeshi , Laidler Keith J. 
Published: December 2004

AbstractA theoretical treatment is given of the kinetics of reactions catalyzed by enzymes attached to the inner surface of a tube, through which the substrate solution passes. A utilization factor, the ratio of the actual reaction rate to that in the absence of diffusional effects, is defined. A numerical procedure is proposed and numerical and approximate solutions for the utilization factor are given for five kinetic conditions: (a) Michaelis‐Menten behavior, (b) substrate inhibition, (c) product inhibition (competitive), (d) product, inhibition (non‐competitive), and (e) product inhibition (anticompetitive). When the enzyme chemically attached to a tube obeys a Michaelis‐Menten relationship, criteria for insignificant and significant diffusional effects are proposed.
Flow kinetics of L‐asparaginase attached to nylon tubing
Authors: Bunting Peter S. , Laidler Keith J. 
Published: December 2004

AbstractL‐Asparaginase has been attached by chemical means to the inner surface of nylon tubing. An experimental study has been carried out of the flow kinetics for such a system, asparagine solutions at various concentrations being passed through two lengths of tubing at various flow rates. Measurements were made of the concentration of the product ammonia at the tube exit, and of the rate of formation of ammonia, under the various conditions. Apparent Michaelis constants, Km(app), were some three orders of magnitude higher than the Km for the enzyme in free solution (∼13 × 10−6JM). The results were analyzed with respect to the theoretical treatment described in the preceding paper (Kobayashi and Laidler), three different methods being employed. It is concluded that at lower substrate concentrations and flow rates the reactions are largely diffusion‐controlled, the enhanced Km(app) values being largely if not entirely due to the diffusion control; ionic strength studies showed electrostatic repulsion effects to be unimportant. At high concentrations and high flow rates (when the diffusion layer is of negligible thickness) the diffusional effects are minimized, and Km(app) approaches the true Km value for the immobilized enzyme.