bluuebunny/crossref_metadata_2025_split huggingface dataset:
Use of the upflow sludge blanket (USB) reactor concept for biological wastewater treatment, especially for anaerobic treatment
Authors: Lettinga G. , van Velsen A. F. M. , Hobma S. W. , de Zeeuw W. , Klapwijk A. 
Published: December 2004

AbstractIn recent years considerable effort has been made in the Netherlands toward the development of a more sophisticated anaerobic treatment process, suitable for treating low a strength wastes and for applications at liquid detention times of 3–4 hr. The efforts have resulted in new type of upflow anaerobic sludge blanket (UASB) process, which in recent 6 m3 pilot‐plant experiments has shown to be capable of handling organic space loads of 15–40 kg chemical oxygen demand (COD)·m−3/day at 3–8 hr liquid detention times. In the first 200 m3 full‐scale plant of the UASB concept, organic space loadings of up to 16 kg COD·m−3/day could be treated satisfactorily at a detention times of 4 hr, using sugar beet waste as feed. The main results obtained with the process in the laboratory as well as in 6 m3 pilot plant and 200 m3 full‐scale experiments are presented and evaluated in this paper. Special attention is given to the main operating characteristics of the UASB reactor concept. Moreover, some preliminary results are presented of laboratory experiments concerning the use of the USB reactor concept for denitrification as well as for the acid formation step in anaerobic treatment. For both purposes the process looks feasible because very satisfactory results with respect to denitrification and acid formation can be achieved at very high hydraulic loads (12 day−1) and high organic loading rates, i.e., 20 kg COD·m−3/day in the denitrification and 60–80 kg COD·m−3/day in the acid formation experiments.
Kinetic behavior of immobilized Penicillin acylase
Authors: Carleysmith S. W. , Dunnill P. , Lilly M. D. 
Published: December 2004

AbstractPenicillin acylase has been immobilized to carboxymethylcellulose and to the resin Amberlite XAD7. The reaction kinetics of the enzyme were affected by both intrinsic (molecular) and microenvironmental effects. The Michaelis constant for the enzyme increased after immobilization as a result of an intrinsic effect of the reagent, glutaraldehyde, used for enzyme immobilization. Microenvironmental effects were of two types: diffusional limitation of access of substrate and a reaction‐generated pH depression in the support particles. This depression of internal pH was observed in all the preparations and could be reduced by addition of pH buffering salts to reactor. An adsorbed pH‐indicating dyc was used to determine the surface and internal pH of particles of XAD7–penicillin acylase under various reaction conditions. The extent of diffusional rate limitation in XAD7–penicillin acylase was related to the penetration depth of protein into the porous support particles. The penetration depth of protein and thus the diffusional limitation of the reaction rate could be controlled by the conditions of preparation of the immobilized enzyme. A staining technique was used to observe the location of the protein.
Extracellular microbial polysaccharides. II. Evolution of broth Power‐law parameters for xanthan and pullulan batch fermentation
Authors: Thomson Norman , Ollis David F. 
Published: December 2004

AbstractThe shear viscosities of xanthan batch fermentation broths obey a power‐law relation τ = K (P)[ẏ]N(P), where the power‐law parameters are functions of xanthan concentration P. within the shear rate range of 1.15 to 384.0 sec−1. Cell‐free solutions prepared from these samples exhibit the same values of K and N as the corresponding cell‐bearing broth. Further, in the course of the fermentation time, t, it was found that K(P) and N(P) were related by an equation of the form ln K[P(t)] = ln τ0 – N[P(t)]·ln ẏ0, leading to a dimensionless power‐law equation valid over the entire fermentation: (τ/τ0) = (ẏ/ẏ0)N[P(t)]. The resulting power‐low from[(τ/τ0) = [ẏ/ẏ0]N(t)] indicates that all related samples will exhibit power‐low plots passing through the common point, (τ0γ0). These equations have previously been observed with other polysaccharide solution. They are also shown here to be applicable to the pullulan fermentation data of Leduy et at. The parameter K is related to polymer concentration (P) with the correlation K = A PB, where B = 1.75 ± 0.25 for xanthan solutions. With X(t), S(t), and P(t) available from paper I, the correlations of this paper (hereafter referred to as II) [K(t) = f(P)(t) and N(t) = g(K(t))] provide a predictive description of the shear viscosity evolution of polysaccharide‐producing fermentation broths.
Yield regulation of lysine biosynthesis in Brevibacterium flavum
Authors: Shvinka J. , Viesturs U. , Ruklisha M. 
Published: December 2004

AbstractA scheme for lysine biosynthesis using variants of the Brevibacterium flavum intermediary metabolite synthesis is discussed. The main precursor of lysine that we are concerned with here is oxalacetate, which can be synthesized through the TCA or glyoxylate cycles or by carboxylation of PEP. Material energy balances for the main pathways of lysine biosynthesis from glucose and acetate have been formulated. Energy consumption, in the from of ATP – PATP (number of mol ATP consumed/1 mol lysine synthesized), was calculated for the main pathways of lysine biosynthesis. Theoretical conversion yields Ypmax (g product/g substrate) were estimated. Experimental data were presented concerning the increase of Yp by means of metabolism regulation: (a) by TCA‐and glyoxylate‐cycle enzyme induction; (b) by maintaining PEP carboxylase activity; (c) by eliminating by‐product synthesis.
Distributed parameter model of an airlift fermentor
Authors: Merchuk Jose C. , Stein Y. , Mateles R. I. 
Published: December 2004

AbstractA distributed parameter model for an airlift fermentor is presented. A riser represents the airlift fermentor, with plug flow in both gas and liquid phases, a well‐mixed section that acts as gas separator, and a downcomer with plug flow. The set of equations proposed makes possible both the understanding and design of the system. Macroscopic balances shows a behavior that is very close to conventional continuous stirred tank fermentor from the viewpoint of biomass production. In addition, the model predicts concentration profiles of biomass, substrate and oxygen in the liquid, and oxygen in the gas phase. This allows estimation of optimal gas flow rate for sufficient oxygen transfer with minimum energy input.
Partial acid hydrolysis of cellulosic materials as a pretreatment for enzymatic hydrolysis
Authors: Knappert Diane , Grethlein Hans , Converse Alvin 
Published: December 2004

AbstractPartial acid hydrolysis was studied as a per treatment to enhance enzymatic hydrolysis, such a pretreatment was carried out in a continuous flow reactor on oak corn Stover, newsprint, and Solka Floc at temperatures ranging from 160 to 220°C, acid concentration ranging from 0 to 1.2%, and a fixed treatment time of 0.22 min. The resulting slurries and solids were than hydrolyzed with Trichoderma ressei QM 9414 cellulase at 50°C for 48 hr. For all substrates except Solka Floc, increased glucose yields were achieved during enzymatic hydrolysis of the pretreated materials as compared to hydrolysis of the original substrate. In several cases, after pretreatment, 100° of the potential glucose content of the substrate was converted to glucose after 24hr of enzymatic hydrolysis. It is felt that the increased glucose yields achieved after this pretreatment are due to acid's removal of hemicellulose, reduced degree of polymerization, and possibly due to a change in the crystal structure of the cellulose.
Analysis of fermentation processes using flow microfluorometry: Amylase and protease activities in Bacillis subtilis batch cultures
Authors: Fazel‐Madjlessi Jila , Bailey James E. 
Published: December 2004

AbstractFlow microfluorometry, which provides detailed information on the state of a microbial population, has been employed to characterize the Bacillus subtilis population during time intervals in which significant changes in the culture amylase activity occur. Four different batch experiments have been conducted, and the influences of inoculum age, fermentation temperature, and aeration rate on microbial population dynamics and amylase activity have been examined. Relatively high rates of amylase activity increase are observed twice during the batch, first as double cells initiate sporulation and later during germination. Rapid decreases in amylase activity are observed in highly (25–50%) sporulated populations, and in at least one experiment, during a transition from large, rounded protoplast forms to normal rod morphology. Amylase and protease activities do not follow parallel nor proportional trajectories in these 72 hr batch fermentations.
Efficiency of bovine liver catalase as a catalyst to cleave H2O2 added continually to buffer solutions
Authors: Ibrahim M. , Schlegel H. G. 
Published: December 2004

AbstractEmpirical estimations of H2O2 concentration in a system containing bovine liver catalase and continually supplied with H2O2 were done to evaluate the efficiency of the enzyme to cleave H2O2. It was found that the continuous addition of H2O2 leads to the formation of steady‐state concentrations of H2O2 in the medium. At a constant catalase concentration both the level and the duration of the steady state are dependent on the flow rate of H2O2. The increase of the catalase concentration in the medium does not change the steady‐state level, it merely leads to the maintenance of the steady state for longer durations. At higher flow rates of H2O2, no steady state could be maintained, even when catalase was present in high excess. The incomplete cleavage of H2O2 by catalase under these conditions is due to the low affinity of catalase toward H2O2 (high Km value, apparent Km = 0.1M H2O2) and to the rapid inactivation of the enzyme during the continuous addition of H2O2.
Kinetic study on thermal stability of immobilized invertase
Authors: Ooshima Hiroshi , Sakimoto Masuo , Harano Yoshio 
Published: December 2004

AbstractThe kinetic study of the thermal stability of three kinds of invertases: native, immobilized on porous glass covalently, and on ion‐exchange resin ionically, has been carried out, measuring their enzymatic activity for sucrose hydrolysis. Thermal deactivations of all invertases obeyed first‐order kinetics, being independent of substrate concentration, with kd and ΔEd, ΔSd* as shown in Tables I and II, respectively. Based on these parameter values, the effects of immobilization and pH at deactivation on the stability have been considered, and it was suggested that the ionic bond gives a more loosely deformed enzyme than the covalent bond.
Evaluation of steady‐state‐biofilm kinetics
Authors: Rittmann Bruce E. , McCarty Perry L. 
Published: December 2004

AbstractLaboratory‐scale biofilm reactors were used to evaluate a model of the kinetics of steady‐state biofilm and the concept that there is a minimum concentration, Smin, below which no steady‐state activity can occur. With acetate as the ratelimiting substrate, the steady‐state concept of Smin was verified for naturally grown biofilms. Substrate removal and biofilm thickness declined rapidly as the substrate concentration approached Smin, which was 0.66 mg/liter for acetate. Using independently derived kinetic parameters, the model of steady‐state‐biofilm kinetics successfully predicted substrate utilization and biofilm thickness without the need for fitting factors. The results imply that organic materials may persist in water and wastewater, in part, because they are too low in concentration to supply sufficient energy to sustain the microorganisms.
Protease production by immobilized mycelia of Streptomyces fradiae
Authors: Kokubu Toshinori , Karube Isao , Suzuki Shuichi 
Published: December 2004

AbstractStreptomyces fradiaewas immobilized in polyacrylamide gel prepared from 5% total acrylamide (90% acrylamide and 10%N,N′‐methylenebisacrylamide). Production of protease by the immobilized mycelia was attempted in a batch system. A dilute medium containing 0.5% starch, 0.5% meat extract, and 0.05% yeast extract was employed. The reusability of the immobilized and washed mycelia was examined. The activity of protease production by washed mycelia was rapidly decreased with increasing use cycles. The activity of the immobilized mycelia increased gradually, and reached a maximum after ten use cycles. Then, the activity gradually decreased with increasing reaction cycles. This might be caused by destruction of the gels. On the other hand, the sterilization of the surface of the immobilized mycelia was effective for elongation of the lifetime. As a result, the half‐life of protease production by the sterilized immobilized mycelia was about 30 days. The rate of protease production by immobilized mycelia was 12,000 U/ml/hr. This value was four times higher than that by submerged culture.
Acidogenic fermentation of corn stover
Authors: Datta Rathin 
Published: December 2004

AbstractCorn stover was fermented by anaerobic acidogenic bacteria to produce volatile (C2–C6) organic acids. Mild pretreatment with dilute alkali solutions produced a two‐fold increase in fermentability. A mixture of lime and sodium carbonate was found to be a better pretreatment agent than sodium hydroxide. Methane generation was inhibited by low temperature (⩽ 25°C) and high solids [≥ 2.5% (w/v)] fermentation. Volatile acid yields of 0.5–0.55 g acetic acid equiv/g dry ash‐free (DAF) stover could be obtained in batch fermentations. Several extractants and extraction solvents for organic acids were found to be nontoxic to acidogenic fermentation. The data show that acidogenic fermentation can produce useful volatile fatty acids in high yields from a complex lignocellulosic feedstock. These fermentations are nonsterile, need no stirring, and are easy to run. Moreover, cellulose, pentosans, and other carbohydrates are directly utilized by acidogenic bacteria. Hence, acidogenic fermentation could be useful in converting biomass to chemical feedstocks and fuel.
Development of a hollow‐fiber system for large‐scale culture of mammalian cells
Authors: Ku K. , Kuo M. J. , Delente J. , Wildi B. S. , Feder J. 
Published: December 2004

AbstractA flat‐bed hollow‐fiber cell culture system has been developed which maximizes the utilization of the large fiber surface while diminishing significantly the problems inherent in a cartridge‐type reactor. The reactor core consists of a shallow bed of hollow fibers sandwiched between two stainless‐steel microporous filter plates through which the media flow is directed normal to the plane of the fiber bed. Reactors with both 930 and 9300 cm2 of fiber surface have been successfully constructed and operated. A variety of cells has been grown in these reactors including SV3T3 cells, baby hamster kidney cells, Vero cells, and rhesus money kidney cells, and cell products such as plasminogen activator and migration inhibition factor (MIF) were produced. This system offers an excellent prototype for scaleup design.
An outdoor biophotolytic system using the cyanobacterium Anabaena cylindrica B629
Authors: Smith Geoffrey D. , Lambert Grant R. 
Published: December 2004

AbstractThe cyanobacterium Anabaena cylindrica B629 was suspended in small glass beds and incubated in a gas‐tight glass vessel outdoors under a gas atmosphere comprising carbon monoxide (0.2%), acetylene (5%), oxygen (6.5%), and nitrogen. The solution phase initially contained sodium bicarbonate (10mM) at pH 7. Under these conditions the organism continuously produced hydrogen gas for over three weeks. The temperature of the culture was maintained below 30°C and minimum night temperatures were recorded. The vessel was covered by a shadecloth, which reduced the natural illumination by approximately 70%. The system is an alternative to those requiring the strict absence of oxygen and little nitrogen, and requires virtually no attention during the incubation period.
The scale‐up from 0.1 to 100 liter of a unit process system based on 3‐mm‐diameter glass spheres for the production of four strains of FMDV from BHK monolayer cells
Authors: Whiteside J. P. , Spier R. E. 
Published: December 2004

AbstractThis paper describes the scale‐up from 0.1 to 100 liter of the unit process based on 3‐mm‐diameter glass spheres for the growth of BHK monolayer cells. The production of four strains of FMD virus at the 0.1‐, 10‐, and 100‐liter scales was examined. Cell growth was estimated from measurements of the concentration of glucose in the growth medium, while the release of virus was inferred from measuring the concentration of LDH in the culture supernatant fluid. The yields of virus at 0.1‐, 1‐, and 10‐liter scales were similar but that from the 100‐liter version was somewhat lower. The reason for this lower yield and the method used to overcome it over outlined.
Photometabolic production of hydrogen from organic substrates by free and immobilized mixed cultures of Rhodospirillum rubrum and Klebsiella pneumoniae*
Authors: Weetall Howard H. , Sharma Bhavender P. , Detar Clarence C. 
Published: December 2004

AbstractA culture of R. rubrum cells apparently contaminated with K. pneumoniae were immobilized by entrapment in agar. This system was used as model for hydrogen production by photometabolic means. Observed results indicated that the contaminant exerted a major influence on the observed results. This preparation, when immobilized and used in a specifically designed reactor with glucose substrate, showed operational half‐lives of approximately 1000 hr. The feasibility of using this “mixed” culture for producing hydrogen from acid hydrolyzed cellulose and wood sawdust was also examined.
Energetic yields associated with hydrocarbon fermentations
Authors: Erickson L. E. 
Published: December 2004

AbstractEnergetic yields associated with microbial growth on hydrocarbons are investigated and compared with values for other organic substrates. Both cell growth and extracellular product formation are investigated. Both carbon and energy limitations are considered in estimating theoretical yields. Carbon, available electron, and ATP balances are used in the theoretical analysis. The results indicate that the availability of carbon may limit growth and product formation.
Inorganic carbon sources and biomass regulation in intensive microalgal cultures
Authors: Goldman Joel C. , Dennett Mark R. , Riley Carol B. 
Published: December 2004

AbstractThree freshwater and one marine algal species were grown under inorganic carbon limitation in laboratory continuous cultures. Comparisons were made between HCO3− alkalinity and bubbled CO2 as carbon sources. HCO3− alkalinity was an excellent source of inorganic carbon below specific pH levels, but chemical precipitation at high pH placed an upper limit on productivity that was far lower than potential light‐limiting levels. With bubbled CO2 it was possible to achieve light limitation. The main factor controlling productivity was the mass flux of inorganic carbon added to the culture, which is the product of gas flow rate and influent P level. Small bubbles were more efficient than large bubbles at low gas flow rates and P levels, but led to froth flotation of algal cells and concomitant reductions in productivity at high bubble rates. At 1% CO2 productivity was still dependent on mass fluxes of added carbon, but was independent of bubble size. At high bubble rates with 1% CO2 narcosis was evident. Maximum yields occurred at intermediate dilution rates when inorganic carbon was supplied via bubbled gas.
Separation of meso and racemic 2,3‐butanediol by aqueous liquid chromatography
Authors: Voloch Marcio , Ladisch Michael R. , Rodwell Victor W. , Tsao George T. 
Published: December 2004

AbstractFermentation of xylose by Klebsiella pneumoniae (ATCC 8724) producers meso and nonmeso 2,3‐butaneodiol. The enzyme Kinetic of 2,3‐butanediol stereoisomer formation from acetone is currently under study in our laboratory. Modeling of these kinetics requires resolution of meso and racemic 2,3‐butanediol and positive identification of these resolved components. We report their resolution by aqueous liquid chromatography on both an analytical and a preparative scale. The resolved stereoisomer were identified by a combination of gas chromatography, gas chromatography/mass spectroscopy, 13C‐NMR spectroscopy, optical activity, and, melting points of the m‐dinitrobenzoyl eaters of meso and racemic 2,3‐butanediol. An aqueous liquid chromatographic technique for resolving and qualifying major components of a butanediol fermentation mixture in 40 min is presented.
A distributed parameter model for an airlift fermentor. Effects of pressure
Authors: Merchuk José C. , Stein Yehuda 
Published: December 2004

AbstractA previously presented model for an airlift fermentor is extended by considering the variations of pressure along the tubes. The fluid dynamics of the system is represented with the acid of correlations obtained from experiments. Only oxygen concentrations are considerations are considered. The influences of the various parameters affecting the system are analyzed. The model allows prediction of oxygen concentrations in the different points of an airlift fermentor and calculation of the best values of the gas flow rate.
A unified partition coefficient theory for chromatography, immobilized enzyme kinetics, and affinity chromatography
Authors: Taylor James B. , Swaisgood Harold E. 
Published: December 2004

AbstractA unified treatment of systems containing immobilized biochemical and chromatographic systems was developed from basic thermodynamic considerations of partitioning in biphasic systems. Division of the overall partitions coefficient into electrostatic and nonelectrostatic interactions provided an effective stratagem for analysis of these systems. The properties of both strong and weak ionogenic matrices were explored. It was Found that the matrix charge concentration and the bulk solutions pH and ionic strength completely determine the electrostatic partition coefficient. Hence, the relationships developed allow prediction of partition coefficients from readily obtainable experimental parameters. It was also shown that even at low concentrations, the presence of immobilized protein can alter the properties of the matrix phase. However, a weak ionogenic matrix has an unusual property which allows for a biological switching device. Ina characteristics pH range, such matrices will maintain a constant micro environmental pH while the partitioning of a substrate ion is greatly variable. Finally, the theoretical treatment suggests simple procedures for determination of binding constants from affinity or adsorption chromatography.
Combined product and substrate inhibition equation for cellobiase
Authors: Hong Juan , Ladisch Michael R. , Gong Chen‐shung , Wankat Phillip C. , Tsao George T. 
Published: December 2004

AbstractCellobiase (CE 3.2.1.21) is a β‐glucosidase which hydrolyzes cellobiose to glucose and is known to be subject to both product and substrate inhibition. This work report a model which combines both product and substrate inhibition effects for cellobiase isolated from a commercial preparation of Trichoderma viride from Miles Laboratories (Elkhart, IN). An integrated rate equation is presented which predicts the trends of time courses for hydrolyses of cellobiose a t concentrations ranging from 14.6–1416mM cellobiose. The constants used in the model (determined from initial rate data) are compared to those reported for cellobiase obtained from other sources of T. Viride. Most notable in this comparison is the apparently higher activity and reduced inhibition of this enzyme compared to other sources of cellobiase.