bluuebunny/crossref_metadata_2025_split huggingface dataset:
Fermentation of 1‐hexadecene by Candida lipolytica
Authors: Klug M. J. , Markovetz A. J. 
Published: December 2004

AbstractCandida lipolytica, strain Phaff, was grown on 1.0% 1‐hexadecene as sole source of carbon. Several oxidative intermediates were isolated and identified. Based on these intermediates two pathways are proposed for the degradation of the 1‐alkene via the methyl group and the double bond. Subterminal oxidation of the 1‐alkene was also indicated. Cell yield, lipid content, fatty acid profile and 1, 2‐diol concentration are given for various rates of aeration during growth in a fermentor.
Effect of alkylbenzenes on n‐alkane utilization
Authors: Traxler R. W. , Bernard J. M. 
Published: December 2004

AbstractIt has been shown that alkylbenzenes which do not support growth of Pseudomonas aeruginosa exert a stimulatory or inhibitory effect on the utilization of n‐alkanes by this organism. The effect is a function or the number of methyl substitutions to the benzene ring and the concentration of aromatic hydrocarbon. The alkylbenzenes have been shown to exert the stimulatory and inhibitory effect, on all phases of growth. The data suggests different mechanisms involved in the inhibition by benzene and p‐xylene but a similar mechanism by all of the stimulatory compounds. Warburg data demonstrates changes in the rate of oxygen uptake in the presence of trimethylbenzene at different stages of the fermentation. The release of water soluble material in the presence of trimethylbenzene suggests a permeability effect on the cells.
Growth models of cultures with two liquid phases. II. Pure substrate in dispersed phase
Authors: Erickson L. E. , Humphrey A. E. 
Published: December 2004

AbstractMathematical models which can be used to describe batch frowth in fermentations with two liquid phases are developed for systems in which the growth limiting substrate is the dispersed liquid phase. Three special cases are considered assuming pure substrate in the dispersed phase and a decreasing interfacial area due to substrate consumption. In the first, it is assumed that all growth occurs at the surface of the dispersed phase. In the second and third growth occurs at the interface and in the continuous phase. The second case assumes substrate equilibrium between the two phases while the third assumes substrate consumption in the continuous phase is limited by rate of substrate transport to that phase. Since the amount of growth at the interface and substrate transport to the continuous phase depend on the interfacial area, two limiting cases for the decrease of interfacial area with substrate consumption are also considered in this investigation. The first and third models are compared with available experimental data.
Growth models of cultures with two liquid phases. III. Continuous cultures
Authors: Erickson L. E. , Humphrey A. E. 
Published: December 2004

AbstractSome mathematical models, which have been used to describe batch growth in fermentations with two liquid phases present, are used to predict the behavior of continuous fermentations in a chemostat. Two types of dispersed systems are considered in this investigation. In the first, type, it is assumed that the composition of the dispersed phase is such that, increased substrate utilization results in a decreased substrate concentration with no change in the interfacial area. In the second type of system, the dispersed phase is assumed to be pure substrate; therefore, the substrate concentration in the dispersed phase remains constant but the interfacial area is affected by changes in dilution rate. Three special cases are examined for each type of system in order to examine the effect of the interfacial area, the phase equilibrium constant, and the mass transfer coefficient on system performance. Comparison of two of the models with available experimental data shows fair agreement, between model and data.
A laboratory‐scale press for extracting juice from leaf pulp
Authors: Davys M. N. G. , Pirie N. W. , Street G. 
Published: December 2004

AbstractA press is described with which loads of up to 1 ton can be applied quickly to 1 kg quantities of leaf pulp spread over 450 cm2. The juice extracted is similar in quantity and quality to that extracted by large‐scale equipment. Evidence is presented that the conditions of pressing are so uniform that the yields of juice are consistent.
Regulation of biosynthesis of secondary metabolites. I. Biosynthesis of chlortetracycline and tricarboxylic acid cycle activity
Authors: Hošťálek Z. , Tintérová Marta , Jechová Vendulka , Blumauerová Margita , Suchy J. , Vanék Z. 
Published: December 2004

AbstractIn the course of submerged cultivation of low‐production and industrial production strains of Streptomyces aureofaciens, the activity of enzymes of the tricurboxylic acid cycle was studied. The activities of citrate synthase (EC 4.1.3.7), aconitate hydratase (EC 4.2.1.3), isocitrate dehydrogenase (EC 1.1.1.42), fumarate hydratase (EC 4.2.1.2), and malate dehydrogenase (EC 1.1.1.37) were estimated spectrophotometrically in cell‐free preparations. In the growth phase, mainly the initial reactions of the cycle were active with both strains. In production‐phase, the activities of enzymes in the low‐production strain were 2–5 × higher than in the production strain. Benzylthioeyanate, at a concentration of 5 × l0−5M, stimulated chlortetracycline production of both strains with accompanying decrease in activity of the enzymes of the tricarboxylic acid cycle. The role of the tricarboxylic acid cycle in control of chlortetracycline biosynthesis is discussed.
A steam‐sterilizable electrode of the galvanic type for the measurement of dissolved oxygen
Authors: Van Hemert P. , Kilburn D. G. , Righelato R. C. , Van Wezel A. L. 
Published: December 2004

AbstractAn oxygen probe is developed, using the principle of the silver‐lead galvanic cell, covered with a plastic membrane. It is steam sterilizable while filled with water; after sterilization, water is easily exchanged for the electrolyte, potassium bicarbonate. Flat plastic membranes up to a thickness of about 0.1 mm can be applied. The membrane is secured and stretched in a special way, which guarantees a leakproof seal. The outer shape of the probe has a tulip‐form and consists of polished stainless steel, except for the electrode face. The electrode is suitable for laboratory and industrial use and its components are completely standardized.Almost linear response for O2‐partial pressures up to atmospheric is obtained with 0.001 in. and 0.002 in. FEP‐Teflon membranes. 90% response time is of the order of 10–15 sec for the 0.001 in. membrane, Residual current is almost negligible (< 1 μA).
The effect of Eh on regulatory processes in facultative anaerobes
Authors: Wimpenny J. W. T. 
Published: December 2004

AbstractOn increasing aeration rate in chemostat cultures of E. coli the redox potential (Eh) of the culture changes from −l50 mv to +250 mv. During this period only a slight increase in measured dissolved oxygen concentration is observed.It is suggested that Eh be used as a control variable for aeration in the oxygen limited growth condition, whilst dissolved oxygen concentration be used as control variable in the presence of excess oxygen.Change in cytochrome b1, three tricarboxylic acid cycle enzymes and hydrogenase can be related to culture Eh. These changes are discussed.
Increased oxygen mass transfer rates from single bubbles in microbial systems at low reynolds numbers
Authors: Wise D. L. , Wang D. I. C. , Matelles R. I. 
Published: December 2004

AbstractThe presence of microorganisms have been shown to increase by over 40% the mass transfer rates from small oxygen bubbles at low Reynolds number flow. This increase was found to be due only to the microbe cells as inert particles disrupting the quasi‐static liquid surface film surrounding the gas bubble and thus decreasing the gas‐liquid interfacial resistance. The observed increase in oxygen mass transfer rates was not dependent on cell viability, no effect was noted due to cell‐liquid interfacial resistance, nor was the phenomenon due to altering the physical properties of the liquid during cell propagation. These results were obtained in a unique plexiglass apparatus designed for observing under a microscope a small (0.4 mm dia.) stationary oxygen bubble collapsing into a flowing fluid. The oxygen bubble was injected by a small hypodermic needle and the fluid was suspensions of the yeast Candida intermedia, the bacterium Pseudomonas ovalis, 0.3μ alumina, as well as base points of cell free broth and pure water. Several well‐known chemical inhibitors of oxidative phosphorylation were used to limit cell oxygen uptake. Calculations of oxygen mass transfer rates were compared with the semi‐empirical model of Frössling, the circulating sphere model of Levich, and the rigid sphere concentration boundary layer model of Fried‐lander, the latter two showing strong Reynolds number dependence that may be due to radial fluid motion.
Use of pH and pE measurements during methane biosynthesis
Authors: Pohland F. G. , Mancy K. H. 
Published: December 2004

AbstractMethane biosynthesis within the anaerobic ecosystem results from the diphasic conversion of complex organic substrates through a series of biologically mediated oxidation‐reduction reactions which arc pH dependent. Routine parametric analysis of the products emanating from the corresponding acid and methane fermentation phases of the anaerobic digestion process provide a basis for determination of process condition and efficiency. Of these analyses, pH and electrode potential of pE are intensive parameters of considerable significance but for which interpretation is often difficult and misleading. Attention has been focussed on the analogy and distinction between pH and pE determinations and their application to the anaerobic ecosystem. Theoretical and practical limitations are discussed and experimental evidence presented which supports the possible use of pH and pE determinations for process evaluation and control.
An improved french pressure cell
Authors: Millbank J. W. , Neale M. J. 
Published: December 2004

AbstractA description is given of a needle valve press for disrupting cells and microorganisms. The main features of the design are reproductibility and ease of control of the needle valve settings due to absence of screw threads, case of dismantling and cleaning, and the availability of a wide range of alternative piston and cylinder sizes.
Semi‐continuous culture and monitoring system for temperature‐synchronized Euglena
Authors: Terry O. , Edmunds L. N. 
Published: December 2004

AbstractA temperature‐synchronized, semi‐continuous culture and monitoring system is described, with results from use of the system for autotrophically growing Euglena. Outflow from the culture vessel consists of measured samples taken automatically at 2‐hour intervals and fixed for later counting. Inflow is by siphon feed, which restores the culture level after each sampling. The interpretation of growth curves obtained from such cultures is discussed from the viewpoint, of division synchrony and cell cycle studies, and some general comparisons are made between batch and continuous cultures for such studies.
Continuous phased culture—A technique for growing, analyzing, and using microbial cells
Authors: Dawson P. S. S. , Kurz W. O. W. 
Published: December 2004

AbstractContinuous phased growth produces a culture in which most of the cells in the population are in the same stage of their development. The cell, thereby amplified by the size of the synchronous population, may be examined in the phased culture at any desired growth rate. Changes taking place in the cell after the cell cycle, i.e., post‐cycle changes, may be examined by a modification of the procedure. Further systematic applications of the method permit a rational approach to problems of cell growth and metabolism.The phasing technique recognizes the cells as the fundamental unit for experimental investigation, and offers a great potential in the analysis of the cell throughout its cycle, a relatively unexploited field in cell physiology and fermentation. Experiments with yeasts and bacteria illustrate some of the applications and progress made so far.
Effect of total illumination upon continuous Chlorella production in a high intensity light system
Authors: Matthern Robert O. , Kostick John A. , Okada Isao 
Published: December 2004

AbstractA high intensity light system (HILIS) was designed and constructed to define the environmental parameters affecting production of algae. The HILIS incorporates the basic concepts of an aerobic fermenter for heterotrophic cells with high intensity illumination for photosynthetic studies. Of nine parameters considered, temperature and light intensity studies using Chlorella 71105 have been completed. Total illumination was varied from 25,000 to 300,000 lumens (30 times intensity of sunlight as measured at earth's surface) in 7.7–1, culture. The effect of illumination upon growth was measured as cell concentration and total daily algal production when operating the HILIS as a continuous system at a dilution rate of 0.91 per day.Growth may be expressed as a long function of illumination. A maximum algal concentration of 25.5g/l., dry weight basis, was attained at 300,000 lumens.
Homogeneous cultivation of animal cells for the production of virus and virus products
Authors: Van Hemert P. , Kilburn D. G. , Van Wezel A. L. 
Published: December 2004

AbstractHomogeneous technique facilitates the cultivation of large quantities of cells, reduces the risk of contamination by eliminating many manipulations, and makes practical the control of conditions such as pH and oxygen tension. Although most animal cells will not multiply in free suspension, certain cell lines have lost the requirement of being attached to a solid surface. These cells can be subcultured indefinitely but have some resemblance to cancer cells such as their abnormal karyotype. Certain cell linen developed from human embryonic tissue maintain their diploid character after repeated subculture and would seem to be ideal for the production of vaccines. However, strict regulations exist for viral products for human injection in that only cells taken from normal tissue and subcultured but once may be used.A microcarrier method in which cells adhere to DEAE‐Sephadex beads permits a suspension culture which may be termed quasihomogeneous. The attached cells may be retained by sedimentation or by screening as the medium is replaced. Cell debirs from the original tissue is difficult to remove from microcarrier cultures; modifications of the trypsinization technique have alleviated but not solved this problem.Conditions for virus replication can be less critical than those for cell growth in that oxygen tension seems to have little influence on virus production. In cases where rate of virus production increases with specific growth rate of cells, homogeneous culture would have a advantage in maintaining a high cell mogeneous culture would have a valuble advantage in maintaining a high cell growth rate for a longer time. Some virus infections destroy cells, but others cause little change in cellular mteabolism except that virus is continually produced. The latter type can be conducted with a microcarrier in continuous culture with a virus titer exceeding 107 plaque forming units per milliliter for over 50 days with Rubella‐infected BHK cells.
Predator‐prey relationships in a model for the activated process
Authors: Canale Raymond P. 
Published: December 2004

AbstractThe primary objective of this paper was to develop a mathematical description for the food chain,
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Because of the interdependence of the elements in this food chain, continuous oscillations among the variables are possible. A set of three differential equations was obtained to describe the above system in a continuously fed stirred tank reactor. The differential equations obtained were examined to characterize the possible types of solutions. A limit, cycle solution was obtained for some values of the system parameters.
Recovery of biological materials through ultrafiltration
Authors: Wang Daniel I. C. , Sinskey Anthony J. , Sonoyama Takayasu 
Published: December 2004

AbstractExperiments were performed on a cellulose acetate ultrafiltration membrane (HF‐200, ABCOR Inc., Cambridge, Mass.) to test its efficacy in concentrating and purifying a crude enzyme (trypsin) preparation. Studies were also made to determine the influence of inorganic salts, pressure, and temperature on the rate of ultrafiltration for this membrane. The results showed reductions in the rates will be encountered due to the presence of inorganic salts. However, the reduced rates were still sufficiently high to make this method extremely attractive. Operating at filtration pressures above 75 psi at, 20 to 30°C for this membrane does not show any beneficial effect in terms of ultrafiltration rates. However, at 10°C there were continual increases in the filtration rates up to 100 psi. Concentration and purification studies with trypsin yielded a concentration factor of 8.35 and a purification factor 2.35. It was shown concretely that the purification of the enzyme was due to the passage of low molecular weight proteins (below 20,000) through the membrane. Enzyme activity slightly greater than 90% was obtained: 70% was found in the concentrate and 20% in the filtrate. It is concluded that membrane ultrafiltration is an ideal simple, rapid, and economical method for the recovery of biological active substances.
An improved, totally automated antibiotic bioassay machine
Authors: Burns Donald A. , Williams Paul R. , Hansen Gary D. 
Published: December 2004

AbstractA number of improvements have been made in a totally‐automated antibiotic bioassay machine previously described. The new machine accepts unmeasured, untreated, opaque suspensions of fermentation beers three times faster (120 samples per hour) and supplies printed potencies sooner (in just over two hours). Whereas the original machine employed a self‐cleaning filter and used disposable two milliliter beakers, this version involves a batch‐dialysis scheme for effecting sample purification, and provides for automated cleaning of incubation chambers.In operation, a measured, portion of thoroughly‐mixed fermentation beer is automatically diluted and transferred into one side of an incubation chamber, the two halves of which are separated by a dialysis membrane. The other half is filled with inoculated media. During the two hour incubation at 37°, dialyzable antibiotic limits growth of the inoculum in proportion to its concentration. After incubation, the turbidity of the inoculum is simultaneously read by an online computer and plotted on a strip chart recorded. The computer suplies printed potency values and sample identification on site, while the recording provides the operator with an analog record of turbidity. Fiber optics are employed in the turbidmetric readout, and an electric typewrite provides the printout.
Multiple immobilized enzyme reactors: Determination of pyruvate and phosphoenolpyruvate concentrations using immobilized lactate dehydrogenase and pyruvate kinase
Authors: Newirth T. L. , Diegelman M. A. , Pye E. K. , Kallen Roland G. 
Published: December 2004

AbstractLactate dehydrogenase (LDH) and pyruvate kinase (PK), immobilized on solid glass beads by diazotization, were used in packed bed reactors to analyze for both pyruvate (PYR) and phosphoenolpyruvate (PEP) through the disappearance of β‐nicotinamide adenine dinucleotide (NADH) monitored spectrophotometrically at 340 nm. Packed bed reactors containing PK and/or LDH were also capable of monitoring continuously varying concentrations of adenosine‐5′‐diphosphate (ADP), PEP, and PYR. The immobilized enzymes (∼40 μg/g glass) retained about 4% of the activity of the soluble enzymes. Preparations of immobilized LDH and PK exhibited enhanced stability when maintained in the presence of β‐mercaptoethanol and NADH or EDTA, respectively, and were shown to regain 75% of the original activity after four months storage at 4°C.
Fungal cultures and culture mediums for the production of cellulase
Authors: De Menezes Hilary C. , De Menezes Tobias J. B. , Boas Herval Villas 
Published: December 2004

AbstractCellulase production by strains of Myrothecium verrucaria, Stachybotrys atra and Trichoderma viride was examined. Myrothecium verrucaria was found to give the greatest yields. A variety of media were examined as potential substrates for the industrial production of cellulase. The salts content of the medium was varied and was found to affect cellulase production. Glucose, carboxymethylcellulose (CMC), filter paper and three industrial wastes were examined as possible cellulase inducers. Filter paper was found to be the most effective, followed by sugar cane bagasse and CMC.
Equations of substrate‐limited growth: The case for blackman kinetics
Authors: Dabes J. N. , Finn R. K. , Wilke C. R. 
Published: December 2004

AbstractA simplified model of cell metabolism, consisting of a series of linked reversible enzymatic reactions dependent on the concentration of a single external substrate has been developed. The general mathematical solution for this system of reactions is presented. This general solution confirms the concept of a rate‐limiting step, or “master reaction”, in biological systems as first proposed by Blackman. The maximum rate of such a process is determined by, and equal to, the maximum rate of the slowest forward reaction in the series.Of practical interest in modeling the growth rate of cells are three cases developed from the general model. The simplest special case results in the Monod equation when the maximum forward rate of one enzymatic reaction in the cell is much less than the maximum forward rate of any other enzymatic reactions.More realistic is the case where the maximum forward rates of more than one enzymatic reaction are slow. When two slow enzymatic reactions are separated from each other by any number of fast reactions that overall can be described by a large equilibrium constant, the Blackman form results:

and

A third case is that in which two slow enzymatic steps are separated by an equilibrium constant that is not large. Unlike the Monod and Blackman forms, which contain only two arbitrary constants, this model contains three arbitrary constants:

The Monod and Blackman forms are special cases of this three constant form.In comparing equations with two arbitrary constants the Monod equation gave poorer fit of the data in most cases than the Blackman form. It is concluded that workers modeling the growth of microorganisms should give a t least as much consideration to the Blackman form as is given to the Monod equation.
The effect of controlled feeding of glycerol on β‐galactosidase production byEscherichia coliin batch culture
Authors: Gray Peter P. , Dunnill Peter , Lilly Malcolm D. 
Published: December 2004

AbstractA mutant ofE. coliconstitutive for β‐galactosidase has been grown in batch culture with the carbon source, glycerol, fed at various fixed rates to the culture. High feeding rates where growth was only slightly restricted gave final enzyme levels similar to those obtained in cultures where all the glycerol was added initially. Low feeding rates resulted in breakdown of the β‐galactosidase formed and gave reduced final levels of the enzyme.