bluuebunny/crossref_metadata_2025_split huggingface dataset:
Biological particles of given size, shape, and density for use in biological reactors
Authors: Atkinson B. , Black G. M. , Lewis P. J. S. , Pinches A. 
Published: December 2004

AbstractNovel biomass support particles containing growing cells have been developed for use in large‐scale fermentation processes. The characteristic size of the entrapped biomass is identical to that of the physical structure of the support particle, and particles can be produced of any size, shape, and density with a wide variety of microorganisms. Use of the particles in fermentors leads to high biomass concentration independent of throughput, predetermined biomass concentrations, the use of novel types of fermentor with advantageous performance characteristics, possibilities for the optimization of advantageous diffusion effects, and new procedures for biomass recovery.
Production of citric acid in continuous culture
Authors: Kristiansen B. , Sinclair C. G. 
Published: December 2004

AbstractWork has been carried out on the production of citric acid by Aspergillus foetidus in single‐stage continuous culture, operated under nitrogen‐limiting conditions at dilution rates between 0.04 to 0.21 hr−1. Citric acid concentration increased rapidly as the dilution rate decreased and appears to be critically dependent on the pH in the culture vessel and the nitrogen concentration in the feed. A mathematical model based on a distinction between basic cells, which require nitrogen but do not produce citric acid, and stroage cells, which accumulate carbon and simultaneously produce citric acid, is proposed.
Design of scraped tubular fermentors
Authors: Moo‐Young M. , Van Dedem G. , Binder A. 
Published: December 2004

AbstractConventional stirred‐tank fermentors are inefficient in carrying out certain fermentation processes because of one or more of the following constraints: media backmix–flow, solids wall–deposits, microbial growth–disruption. Two series of novel design of aerated scraped tubular fermentors have been developed to over come the deleterious effects of these constraints. One design is based on a horizontal tube fitted with an internal mechanical wall‐scraper that also promotes media segregation; the other design is based on a vertical array of vessels interconnected by small gas‐jetting orifices that promote media segregation and clean‐surface operation. Tests with cultures of Trichdorma viride (for single‐cell protein production) and Candida lipolytica (for lipase production) have been carried out. It is shown that these novel fermentors can minimize the effects of catabolite repression inherent in both cultures and of wall growth in the former.
Investigation of the significance of a carbon and redox balanced to the measurement of gaseous metabolism of Saccharomyces cerevisiae
Authors: Barford J. P. , Hall R. J. 
Published: December 2004

AbstractA complete carbon and redox balance for Saccharomyces cerevisiae grown in batch culture with ethanol as the limiting carbon and energy source is reported. A novel method, which allowed the determination of carbon dioxide contained in the culture medium and biomass, is described and revealed amounts considerably in excess of what was expected from equilibrium data. Furthermore, elemental composition of the biomass was used to calculate the amount of oxygen required for biosynthetic reactions. When these corrections are applied to experimentally measured gas metabolism data, apparently anomalous results are shown to be consistent with the overall metabolism of bakers' yeast. These findings have wide implications to the quantitative study of the metabolism and energetics of facultative aerobes.
Effect of growth rate on the amino acid composition of Fusarium moniliforme cultivated continuously for fungal protein production
Authors: Macris B. J. , Kokke R. 
Published: December 2004

AbstractFusarium moniliforme was shown to be a promising fungus for microbial protein production. 1−3The fungus grows well on the aqueous extracts of carob pods, a low value agricultural product well known in the Mediterranean areas. In a previous paper2quantitative data were presented on the production of fungal protein by growing F. moniliforme on a carob aqueous extract in a continuous culture. In the present paper the amino acid profile of the biomass was determined and the resulting essential amino acid index was calculated.
Reactor properties of a high‐speed bead mill for microbial cell rupture
Authors: Limon‐Lason J. , Hoare M. , Orsborn C. B. , Doyle D. J. , Dunnill P. 
Published: December 2004

AbstractLaboratory and pilot‐plant high‐speed bead mills of 0.6 and 5 liter capacity and consisting of four and five impellers in series, respectively, were used to follow the batch and continuous disruption of bakers' yeast (Saccharomyces cerevisiae). The mills are not scaled equivalents. Throughputs ranging from 1 × 10−6m3/sec to 12 × 10−6m3/sec for the 0.6 liter mill and from 16 × 10−6m3/sec to 100 × 10−6m3/sec for the 5 liter mill were used for continuous disruption studies. Variables studied included the effect of impeller tip speed, temperature, and packed yeast concentration (ranging from 15 to75% by weight packed yeast). Disruption kinetics, as measured by the release of soluble protein, followed a first‐order rate equation, the rate constant being a function of impeller tip speed and yeast concentration. For continuous disruption studies the bead mills behaved as a series of continuous stirred‐tank reactors, each impeller forming a reactor. In the smaller mill a considerable degree of backflow between the reactors was evident. For certain mixing conditions the maximum amount of releasable protein was dependent on the impeller geometry, construction material, and also the concentration of packed yeast. The relative power efficiencies of the two mills are discussed along with possible criteria for scaling of bead mills.
Preparation and properties of an immobilized derivative of penicillinase
Authors: Klemes Yoel , Citri Nathan 
Published: December 2004

AbstractPenicillinase (β‐lactamase I, EC 3.5.2.6)secreted by Bacilluus cereus, strain 569/H, was covalently attached to aminoethyl cellulose via glutaraldehyde. The immobilized derivative shows increased thermostability and decreased susceptibility to conformational changes induced by certain substrates of penicillinase. The decline in the rate of such substrates was consequently suppressed by immobilization. A marked increase in Km was observed with all substrates except for the unsubstituted 6‐aminopenicillanic acid. The altered properties of the new derivative are attributed to the constraint imposed by immobilization on the conformational flexibility of the enzyme molecule. Thus, apart from obvious technological interest, immobilized penicillinase provides a useful model for the study of the role of flexibility in the function of an enxyme.
Biological production of methane from energy crops
Authors: Clausen E. C. , Sitton O. C. , Gaddy J. L. 
Published: December 2004

AbstractLaboratory studies at the University of Missouri‐Rolla have demonstrated the feasibility of producing methane by anaerobic digestion of various of crop materials, such as grasses and corn stalks. These studies indicate that up to 6.0 f3methane are produced/b crop material destroyed. Preliminary design and economic studies of a large methane plant show that the reactors represent the largest cost item and that efforts should be concentrated on defining reaction kinetics and reactor design. A process to produce 50 M̄ f3methane/day is described, and the preliminary design and economics are analyzed.
Production of single cell protein from ethanol by fed‐batch process
Authors: Watteeuw C. M. , Armiger W. B. , Ristroph D. L. , Humphrey A. E. 
Published: December 2004

AbstractThe production of single cell protein (SCP) form ethanol is an interesting process to study from a biochemical engineering viewpoint. The cellular yield mainly depends upon the metabolic activity of the cells and the amount of substrate available. Fedbatch fermentations Were run in a 70 liter highly instrumented computer‐coupled fermentor using Candida utilis. Respiratory quotient and culture fluorescence, measuring NADH, indicate by which pathway ethanol is utilized. By monitoring these parameters it is possible to control the ethanol concentration so that accumulation of acetate is minimized and the conversion of ethanol to cell mass is maximized.
On‐line identification of parameters in a fermentation process
Authors: Bravard J. P. , Cordonnier M. , Kernevez J. P. , Lebeault J. M. 
Published: December 2004

AbstractIn a fermentation process, the establishment of gas mass balances provides valuable information and allows both measurements concerning the characteristics of the biomass itself and the monitoring of a cultivation process. If the quantity and oxidation level of substances excreted into the fermentation broth are known or constant, the yield factor and the dry cell‐weight production are stoichiometrically related to the quantity of CO2 evolved and to the quantity of O2 consumed. Where frequent measurements of both yield factor and dry cell‐weight production are desirable or where rapid adjustment of the parameters is necessary, on‐line identification of these parameters is required, An algorithm allowing the identification of the specific growth rate is presented. Moreover, this technique allows one to estimate the percent protein in the biomass during continuous culture.
Secretion of cellulase and β‐glucosidase by Trichoderma viride ITCC‐1433 in submerged culture on different substrates
Authors: Herr Dieter 
Published: December 2004

AbstractTrichoderma viride ITCC‐1433 produces high yields of cellulase and especially β‐glucosidase when grown in submerged culture on different carbon sources. Cellulase synthesis was strongly repressed in the presence of glucose and only a low constitutive activity of β‐glucosidase and carboxymethylcellulase, but no Avicelase, could be demonstrated when culturing T. viride on glucose. With carboxymethylcellulose (CMC) as a substrate the secretion of enzyme as well as growth depended on the degree of substitution, but in general CMC cannot be regarded either as a powerful inducer or as a carbon source. With insoluble cellulose, maximum enzyme production and activities were obtained using an alkali‐treated cellulose powder. On this substrate the excretion of soluble protein into the culture broth increased and the protein concentration corresponded to cellulolytic activities.
Role of agitation conditions in nitrification
Authors: Novak Lawrence T. 
Published: December 2004

AbstractThe objective of this study was to determine the role of agitation conditions in the oxidation of nitrite ions by Nitrobacter. Batch reaction kinetic experiments were conducted in baffled stirred tanks. The range of agitation conditions studied was 6200 ↔ 95700 ergs/cm3 sec. This power input corresponds to 3.2 ↔ 45.6 hp/ 1000 gal, or a “hem Scale” of 3 ↔ 9. After a lag phase, the reaction kinetics were found to be zero order with respect to nitrite over a concentration range of 590 to 10 mg/liter nitrite nitrogen (NO2−‐N). The zero‐order rate constants were found to significantly decrease with increasing impeller power input per volume of liquid (P / V).
Cost‐effective dissolved oxygen monitor–controller for continuous culture
Authors: Archibald Frederick 
Published: December 2004

AbstractA number of devices for the control of the dissolved oxygen (DO) tension in small continuous cultures are now in use, but because of the sophisticated proportional control employed, are prohibitively expensive for many applications. This report describes a flexible cost‐efficient DO monitor and controller which, including DO probe, valves, and gas solenoid, can be constructed for 400 dollars. The device employs two‐position control of gas flow and agitation speed and is readily adaptable to a variety of application; Construction, operation, and performance in conjunction with a small fermentor are briefly discussed.
Preparation and properties of immobilized flavokinase
Authors: Merrill Alfred H. , McCormick Donald B. 
Published: December 2004

AbstractFlavokinase (ATP: riboflavin 5'‐phosphotransferase, EC 2.7.1.26) purified from rat liver by affinity chromatography, has been immobilized by amide linkage to aminoalkyl‐agarose beads. The immobilized enzyme differs from the soluble enzyme in having greater stability slightly higher Km for the substrates, riboflavin and ATP, a broader pH optimum, and a lower energy of activation. These results suggest that the immobilized enzyme is influenced by the microenvironment of the bead and is subject to some degree of internal diffusional limitation. A Small (3ml), continuous, plug‐flow reactor prepared with immobilized flavokinase effects 5% conversion of riboflavin to riboflavin 5′‐phosphate (FMN) with a flow rate of 0.16 ml/min, which corresponds to an output of 5 nmol FMN/min. Immobilized flavokinase is effective for phosphorylating riboflavin and numerous riboflavin analogs and provides a facile methods for preparing exclusively, unlike other synthetic methods, the 5′‐phosphates.
Degradation of ribonucleic acid by immobilized ribonuclease
Authors: Dale Bruce E. , White Don H. 
Published: December 2004

AbstractAn immobilized enzyme (pancreatic ribonuclease bound to porous titania) was investigated for the degradation of purified yeast ribonucleic acid as a substrate. The immobilized enzyme is active and stable in the pH range 4–8. Dependence of enzymatic activity on ionic strength, pH, temperature, fluid flow rate, and substrate concentration were investigated. A cummulative fluid residence time of 6 sec is sufficient for 5% substrate conversion at 25°C and pH 7.0. The critical flow rate (i.e., the fluid flow rate necessary to remove film diffusion resistance) approximately doubles with each 10°C rise in reaction temperature. The critical flow rates obtained in this study are about 40 times greater than those obtained for a similar study on immobilized glucose oxidase. Arrhenius plots gave activation energies of −9.6 and −7.1 kcal/g mol at pH 4.6 and 7.0, respectively. The work reported herein is a bench‐scale investigation of an immobilized enzyme with primary emphasis on the mass transfer and kinetic characteristics of the system. The rapid reaction rates obtainable at relatively low temperatures offfer a potential alternative method of purifying yeast single cell protein (SCP) with minimum loss of desired protein. The key questions are how such a system would react in a yeast homogenate, what conditions in such a system must be controlled, and what type of immobilized reactor should be utilized, if such further work continued to show promise.
Effect of PO2 on growth and physiological characteristics of Candida utilis in a multistage tower fermentor
Authors: Páca Jan , Grégr Vratislav 
Published: December 2004

AbstractThe effect of increasing the partial pressure of oxygen in the aeration gas on growth and physiological activity of the yeast Candida utilis in a multistage tower fermentor was studied. The measurements were made at steady states of continuous culture for single values of dilution rate, temperature, and pH in all stages of the fermentor and with one given ethanol concentration in the growth medium feed. The partial pressure of oxygen in the gas phase was changed in the range from 165 to 310 torr. The results revealed the existence of the upper critical value of the partial oxygen pressure in the gas phase. It was demonstrated that the upper critical value of PO2 influences not only the growth rate, biomass yield, and productivity but also the cell physiology resulting in changes of respiration activity and activity of alcohol and aldehyde dehydrogenases.
Evaluation of data consistency and estimation of yield parameters in hydrocarbon fermentations
Authors: Ferrer Alexis , Erickson L. E. 
Published: December 2004

AbstractThe consistency of experimental data for hydrocarbon fermentations is reviewed using carbon and available electron balances and the mean values of the regularities for carbon weight fraction in biomass and biomass reductance degree. True growth yields and maintenance coefficients are estimated from both batch and continuousculture data and the results are compared.
Hydrolysis of organophosphate insecticides by an immobilized‐enzyme system
Authors: Munnecke D. M. 
Published: December 2004

AbstractAn enzyme preparation that could detoxify parathion and eight other organophosphate pesticides was covalently bound to either porous glass or porous silica beads. This immobilized‐enzyme system was examined for its use in detoxification of pesticides in production wastewaters. The kinetics of parathion hydrolysis were examined at flow rates up to 96 liter/hr and at influent substrate concentrations ranging from 10–250 mg/liter. The enzyme reactor was able to hydrolyze 95% o1r more of the parathion added to industrial wastewaters generated during its production, thus reducing the effluent parathion concentration to below 500 ppb. Laboratory continuous‐flow experiments were conducted for 70 days with industrial wastewater and indicated no loss in immobilized‐enzyme activity. The influence of pH, temperature, solvents, and detergents on enzyme stability and activity and enzyme reactor kinetics will be discussed.
On‐line estimation of kLa by an analog computer
Authors: Yoshida Toshiomi , Ohasa Sugayuki , Taguchi Hisaharu 
Published: December 2004

AbstractA new method was developed for estimating the volumetric oxygen transfer coefficient, kLa, in a fermentor. Various methods were investigated for the on‐line estimation of kLa with an analog computer employing a steepest‐descent calculation technique. The method by which kLa is estimated (by minimizing the error residue of the model) was found to be very applicable. A method for the simultaneous estimation of the volumetric oxygen transfer coefficient and respiration rate in biological systems is also presented.
Quantitative physiology of Penicillium chrysogenum in penicillin fermentation
Authors: Ryu Dewey D. Y. , Hospodka J. 
Published: December 2004

AbstractUsing continuous and fed‐batch penicillin fermentation systems some important metabolic parameters have been determined for the purpose of achieving process improvement and better process control. The specific uptake rates determined under the optimal conditions are: 0.33 mmol hexose/g cell/hr, 1.6 mmol oxygen/g cell/hr, 2mg NH3‐nitrogen/g cell/hr, 0.6 mg PO4‐phosphorus/g cell/hr, 2.8 mg SO4‐sulfur/g cell/hr, 1.8 mg phenyl acetic acid/g cell/hr. It was also found that during the production phase, or idiophase, the specific growth rate should be maintained at about 0.015 hr−1 in order to support the maximum penicillin productivity of the given strain. Based on the results of this study a significant process improvement has been achieved through proper control of the supply and demand of the important nutrients and oxygen.
Studies of growth conditions in wood for three white‐rot fungi and their cellulaseless mutants
Authors: Eriksson Karl‐Erik , Grünewald Annette , Vallander Lars 
Published: December 2004

AbstractWhite‐rot fungi, which have the ability to degrade all the wood components including lignin, are of great interest in biotechnological processes based on wood and other lignocellulosic materials. It was demonstrated earlier that enough lignin can be degraded to cause a decrease in the energy demand for production of thermomechanical pulp if wood chips are pretreated by cellulaseless mutants of white‐rot fungi. This paper concerns the growth conditions in wood for three white‐rot fungi and their cellulaseless mutants in order to determine optimal conditions for such pretreatment processes. The pH and temperature optima have been determined as well as the growth rate in wood. The results show that the growth rate in wood. at least for Cel 44 (a cellulaseless mutant of Sporotrichum pulverulentum), is not the rate‐limiting step in delignification. From different mixtures of urea and NH4H2PO4 the optimal nitrogen source was determined for the mutants. The optimal C/N ratio was found to vary between 160/1 and 400/1. It is suggested that the lower the C/N ratio, the faster the growth. It was also demonstrated that both water‐ and acetone‐extractable substances in wood supported the growth of cellulaseless mutants. When some glucose was added to the wood, the weight loss caused by Cel 44 increased. All these observations support earlier findings that lignin in wood cannot be degraded by white‐rot fungi unless a more easily metabolizable carbon source is used simultaneously.
Lactic acid fermentation of crude sorghum extract
Authors: Samuel William A. , Lee Y. Y. , Anthony W. B. 
Published: December 2004

AbstractCrude extract from sweet sorghum supplemented with vetch juice was utilized as the carbohydrate source for fermentative production of lactic acid. Fermentation of media containing 7%(w/v) total sugar was complex completed in 60–80 hr by Lactobacillus plantarum, product yield averaging 85%. Maximum acid production rates were dependent on pH, initial substrate distribution, and concentration, the rates varying from 2 to 5 g(liter·hr.) The lactic acid yield was lowered to 67% under limited medium supplementation. The fermented ammoniated product contained over eight times as much equivalent crude protein (N × 6.25) as the original medium. Unstructured kinetic models were developed for cell growth, lactic acid formation, and substrate consumption in batch fermentation. With the provision of experimentally determined kinetic parameters, the proposed models accurately the fermentation process.
Extracellular microbial polysaccharides. I. Substrate, biomass, and product kinetic equations for batch xanthan gum fermentation
Authors: Weiss Rebecca M. , Ollis David F. 
Published: December 2004

AbstractVarious biomass (X), product (P), and substrate (S) rate equations are considered in order to synthesize a general xanthan fermentation model from literature data. Analytical forms that provide reasonable descriptions for the X, P, and S behaviors reported by Moraine and Rogovin are shown to be the logistic equation, the Luedeking–Piret equation a modified Luedeking‐Piret equation, respectively. The autonomous logistic equation allows the serial evaluation of parameters for all thee equations, rather than a simultaneous determination required by nonautonomous models.
Possible commercial formulations of insect‐parasitic nematodes
Authors: Nickle W. R. 
Published: December 2004

AbstractAt least two experimental nematode biological insecticide formulations are currently being produced in small quantities around the world, These formulations are efficacious and people are willing to pay money for them. Advantages for the use of these parasites can be: nonpolluting, self‐perpetuating, safe, and not harmful to beneficial organisms. The disadvantages are: relatively short shelf‐life, acceptability, moisture, price, and dispersal techniques. One of the preparations is a nematode that vectors a bacterium. It can be produced at the rate of 100 × 106 infective nematodes/2 liter container at a cost of 2 cents/106. It can kill over 1000 species of insects. The other product kills over 60 species of mosquitoes and has been sold as mermithid nematode eggs in moist sand. This mosquito parasite can be established in the new site and self‐perpetuate to suppress mosquito parasite can be established in the new site and self‐perpetuate to suppress mosquito populations. It kills the mosquito before pupating. Increased research activity, using these parasites in the last ten years, has stimulated interest in these organisms for pest insect control.