bluuebunny/crossref_metadata_2025_split huggingface dataset:
Influence of manufacturing variables on the characteristics and effectiveness of chitosan products. II. Coagulation of activated sludge suspensions
Authors: Bough W. A. , Wu A. C. M. , Campbell T. E. , H0Lmes M. R. , Perkins B. E. 
Published: December 2004

AbstractChitosan samples manufactured under different conditions were compared for effectiveness of coagulating an activated sludge suspension grown on vegetable canning wastes. Computer analysis of data from Buchner funnel filterability tests resulted in quadratic polynomial equations describing the response curves for volume of filtrate versus dosage, expressed as g/liter chitosan/100 g sludge suspended solids (SSS). The quotient of the filtrate volume and dosage at the inflection points of the equations obtained for 10 test samples and 1 commercial chitosan sample were compared to evaluate the response (effectiveness) per unit amount for each chitosan product. The product made by a standard procedure (deproteinated with 3% NaOH at 100°C for 1 hr, demineralized with 1N HCL at ambient temperature for 30 min, and deacetylated with 50% NaOH at 145–150°C under N2 for 5 or 15 min) gave the best performance as a coagulating agent for this activated sludge system. Other products, including the commercial preparation, required higher dosages to achieve the same effectiveness. Products deacetylated in the presence of sir rather than nitrogen decreased waste treatment effectiveness, which approximated the trends of reduced viscosity and molecular‐weight distribution. The products containing minerals were less effective than products from which minerals had been removed prior to deacetylation, but they were more effective than the enzyme treated sample and the commercial product. In general, although chitosan products obtained after 15 min deacetylation were more effective than those receiving 5 min deacetylation, effectiveness did not correlate linearly with viscosity and molecular‐weight distribution trends. However, chitosan products deacetylated for 15 min did show that the higher‐molecular‐weight products (0.65–1.1 × 106) were more effective coagulating agents for activated sludge than the manufactured product having the lowest molecular weight (0.47 × 106) and the commercial reference sample (0.56 × 106). Thus, higher values for molecular weight were predictive of greater effectiveness for coagulation of activated sludge suspensions.
Fluidized‐bed immobilized‐enzyme reactor for the hydrolysis of cornstarch to glucose
Authors: Allen B. R. , Charles M. , Coughlin R. W. 
Published: December 2004

AbstractWe have developed an economical fluidized‐bed immobilized‐enzyme cornstarch hydrolysis reactor employing an inexpensive glucoamylase‐on‐alumina (covalently bonded) catalyst having a high initial activity (130 units/g) and excellent long term stability (t1/2 = 6450 hr at 50°C). The reactor can give higher yields of dextrose from streams containing ∼30% (wt) low dextrose equivalent (DE) cornstarch than can a comparable fixed‐bed reactor because its design exploits the fact that fluidixation permits the use of very small catalyst particles (down to 50μm in our case) which overcomes the yield‐limiting diffusion‐associated problems encountered in the use of conventional fixed‐bed cornstarch hydrolysis reactors. Furthermore, even when small catalyst particles are used the fluidized‐bed reactor does not suffer from plugging and high pressure drop problems typical of fixed‐bed reactors. The results of an initial economic analysis based on bench‐scale results indicate that the processing cost for a plant using this new technology to produce 100 × 106lb dextrose/year from low DE cornstarch would be as much as 33% lower than for a comparable plant employing conventional soluble‐enzyme technology.
Optimization of growth surface parameters in microcarrier cell culture
Authors: Levine David W. , Wang Daniel I. C. , Thilly William G. 
Published: December 2004

AbstractThe microcarrier technique for the growth of anchorage‐dependent animal cells has been studied and significantly improved. Excellent cell growth (up to 5 × 106 cells/ml) has been obtained on a newly synthesized microcarrier optimized with respect to substitution with a positively charged exchange moiety. Various parameters of microcarrier culture were examined in order to identify the source of reported “toxicities” associated with this technique. The hypothesis that bead adsorption of nutrients is responsible for such “toxicities” was found to be inconsistent with our results, which suggest that microenvironmental effects are critical for cell propagation on microcarriers.
Correlation between X‐ray diffraction measurements of cellulose crystalline structure and the susceptibility to microbial cellulase
Authors: Sasaki Takashi , Tanaka Takashi , Nanbu Noriko , Sato Yohko , Kainuma Keiji 
Published: December 2004

AbstractChemical and physical treatments of cotton cellulose have been studied in order to elucidate the relationship between the degree of crystallinity of cellulose and the susceptibility of cellulose to cellulase. Cotton cellulose powder was treated with the following solvents: 60% H2SO4, Cadoxen, and DMSO‐p ‐formaldehyde. The dissolved celluloses were recovered at high yield of over 97% by addition of nine volumes of cold acetone. X‐ray diffraction for measurements of relative crystallinity showed that the crystalline structure of cellulose declined in quantity and perfection by the dissolving treatment and changed to an amorphous form that is highly susceptible to enzymatic hydrolysis. These reprecipitated celluloses were hydrolyzed almost completely within 48 hr by Aspergillus niger cellulase containing mainly 1,4‐β‐glucan glucanohydrolase (EC 3.2.1.4), without action of 1,4‐β‐glucan cellobiohydrolase (EC 3.2.1. 91). On the other hand, cryo‐milled cellulose (below 250 mesh) still had a crystalline structure, was resistant to cellulase, and gave a low percentage of saccharification. These results indicate that in pure cellulose there are good correlations between x‐ray diffractograms and susceptibility to microbial cellulase.
Growth and composition of Escherichia coli subjected to square‐wave perturbations in nutrient supply: Effect of varying frequencies
Authors: Pickett A. M. , Bazin M. J. , Topiwala H. H. 
Published: December 2004

AbstractThe effect of regularly varying the input nutrient concentration on the growth and composition (elemental and macromolecular) of Escherichia coli ML30 grown in chemostat culture is reported. After each change in substrate concentration a lag between the stimulus and organism response occurred, the magnitude of which was dependent upon the frequency of the perturbations. Both the growth yield and macromolecular composition of the cells were found to vary with the frequency of nutrient cycling: the yield decreased by some 10% as the cycle‐times decreased from 6.0 to 0.25 hr. It is suggested that maintaining microorganisms under controlled transient conditions might be useful in increasing yields of specific microbial products (e.g., single‐cell protein).
Multilayer immobilized‐enzyme filter reactors: Urease bound to nylon fabric filters
Authors: Shemer Lev , Granot Roni , Freeman Amihay , Sokolovsky Mordechai , Goldstein Leon 
Published: December 2004

AbstractUrease was bound to commercially available nonwoven nylon fabric filters. Multilyer immoibilized‐enzyme filter reactors were constructed by packing varying numbers of urease‐nylon filters in a column. Owing to the relatively open structure and high mechanical strength of the filter fabric, compaction and pressure drop effects were minimal. The reactors could be operated in a wide range of substrate concentrations and flow rates under conditions where mass‐transfer limitations could be neglected. The kinetic behavior of the immobilized‐enzyme filter reactors could be described by a linear form of the integrated Michaelis‐Menten equation using a model based on the sequential action of the enzyme filters.
Immobilization of enzymes and microbial cells using carrageenan as matrix
Authors: Tosa Tetsuya , Sato Tadashi , Mori Takao , Yamamoto Kazo , Takata Isao , Nishida Yutaka , Chibata Ichiro 
Published: December 2004

AbstractConditions for the gelation of k ‐carrageenan, which is a new polymer for immobilization of enzymes and microbial cells, were investigated in detail. k ‐Carrageenan was easily induced to gel by contact with metal ions, amines, amino acid derivatives, and water‐miscible organic solvents. By using this property of k ‐carrageenan, the immobilization of enzymes and microbial cells was investigated. Several kinds of enzymes and microbial cells were easily immobilized with high enzyme activities. Immobilized preparations were easily tailor‐made to various shapes such as cube, bead, and membrane. The obtained immobilized preparations were stable, and columns packed with them were used for continuous enzyme reaction for a long period. Their operational stabilities were enhanced by hardening with glutaraldehyde and hexamethylenediamine.
Action of shear on enzymes: Studies with alcohol dehydrogenase
Authors: Thomas C. R. , Nienow A. W. , Dunnill P. 
Published: December 2004

AbstractYeast alcohol dehydrogenase (ADH) solutions (approximately 1 mg/ml, pH 7) were sheared in a coaxial cylindrical viscometer. This was fitted with a lid sealing the contents from the atmosphere and preventing evaporation. At 30°C after a total of 5 hr intermittent shearing at 683 sec−1 no losses of activity were observed. No losses were found after 5 hr continuous shearing and in a no‐shear control. At 40°C and 683 sec−1 there were only small activity losses in 5 hr. Shearing at 3440 sec−1 no measurable losses of activity were found with a 1.03 mg/ml solution in 5 hr at 30°C, a 1.03 mg/ml solution in 8 hr at 5°C, and with a 3.89 mg/ml solution in 3 hr at 5°C. In all these cases, however, a white precipitate formed that was not observed in zero shear control experiments. The sheared 3.89 mg/ml solution was clarified by centrifugation. It was shown that there were no ADH aggregates in the supernatant and that the precipitate was less than 2% of the original protein. At 30°C under adverse pH conditions (pH 8.8) there was no significant difference in activity losses of an approximately 1 mg/ml solution sheared at 65 and 744 sec−1. An approximately 0.5 mg/ml ADH solution, pH 7, was agitated in a small reactor with no free air–liquid interface. Peak shear rates near the impeller were estimated to be about 9000 sec−1. Only a small decrease in specific activity was observed until over 15 hr total running at 5°C.
Factors influencing fungal degradation of lignin in a representative lignocellulosic, thermomechanical pulp
Authors: Yang H. H. , Effland M. J. , Kirk T. K. 
Published: December 2004

AbstractThis research examined culture parameters influencing the rate of degradation of lignin in lignocellulosic substrates by the Basidiomycete Phanerochaete chrysosporium. Thermomechanical pulps prepared from western hemlock (Tsuga heterophylla) and red alder (Alnus rubra) were chosen as model substrates. Degradation of lignin in shallow, liquid‐phase, stationary cultures was 10 times as rapid as in agitated cultures. Lignin degradation was at least 50% more rapid in cultures under 100% O2 than in those under air. Addition of 0.12% nutrient N (dry pulp basis) increased the rate of lignin degradation two‐ to fivefold; 1.2% added N at first suppressed, then stimulated, lignin degradation. Lignin in the alder pulp was degraded over five times as rapidly as in the hemlock pulp. Addition of glucose (35% of dry pulp) to the pulps containing 0.12% added N completely suppressed polysaccharide depletion during two weeks, but did not influence lignin degradation. The maximum rate of lignin degradation was 3%/day over a two‐week incubation, or approximately 2.9 mg/mg fungal cell protein/day. The influence of the examined parameters was in complete accord with those found earlier for synthetic 14C‐lignin metabolism by P. chrysosporium.
Investigation of fermentors with various contacting devices
Authors: Viesturs U. E. , Sturmains I. A. , Krikis V. V. , Prokopenko V. D. , Erickson L. E. 
Published: December 2004

AbstractIn this work, earlier published work on the development and investigation of fermentors with various contacting arrangements is reviewed. Methods and results of investigations on optimal construction of contacting plates are presented, and mass transfer and other characteristics of the performance of the equipment are discussed. Comparative estimates of various methods of determining mass transfer coefficients are presented. The construction and basic operating characteristics of several column fermentors with various contacting arrangements are described.
Surface aeration in a small, agitated, and sparged vessel
Authors: Chapman C. M. , Nienow A. W. , Middleton J. C. 
Published: December 2004

AbstractIn a recent publication, a technique was outlined for measuring surface aeration rates in an agitated vessels while sparging, and it was shown that surface aeration rates fall rapidly with increasing sparge rates. That work was conducted in a 0.61 m diam vessels. The work reported here was done in a small vessel (0.22 m diam) where surface aeration has been reported to be of particular significance. In general, the results obtained in the small vessel confirmed those in the large one and in addition were generally in good agreement with those recently published elsewhere for an almost identical geometry. For typical practical power inputs and sparge rates, the rate of surface aeration was never more than 20% of the sparge rate and generally less than 5%. These results indicate that surface aeration is of considerably less importance than has generally been believed following the findings of workers who estimated its effect by comparing KLa values under unsparged conditions with those when sparging.
Adsorption and recovery of cellulases during hydrolysis of newspaper
Authors: Castanon Maris , Wilke Charles R. 
Published: December 2004

AbstractThe adsorption of cellulases from Trichoderma viride was studied during the hydrolysis of newspaper. By measuring individual enzyme activities it was found that in the early stage of hydrolysis enzyme components showing CxA; were adsorbed preferentially to those showing C1A; afterwards ths situation was inverted. Electrophoretic resolution of proteins in hydrolysates showed a continuous decrease of enzyme proteins in solution, and furthermore suggested that the enzymes once adsorbed remained immobilized on the substrate (even after extensive digestion). Experiments to recover the enzyme that had remained in solution after typical hydrolysis showed a potential saving of up to 40%.
Growth and composition of Escherichia coli subjected to square‐wave perturbations in nutrient supply: Effect of varying amplitudes
Authors: Pickett A. M. , Bazin M. J. , Topiwala H. H. 
Published: December 2004

AbstractThe effect of regular variations in the input limiting nutrient concentration at different cycle amplitudes on the growth and composition (elemental and macromolecular) of Escherichia coli ML30 in chemostat culture is described. The cycle time was maintained constant at 2.0 hr. The basal level of nutrient fed to cultures was also maintained constant but the concentration amplitude was varied over a range from 0.2 to 5.0 g/liter. A lag between the stimulus and organisms response was observed and found to be independent of cycle amplitude over most of the range examined. Increasing the cycle amplitude did not effect the cell yield from glucose or the elemental composition of the organisms. However, large variations in the macromolecular composition of the cells (on a dry weight basis) were found; at 4.0 g/liter amplitude the cells contained some 82% protein. The relevance of this type of reactor operation in large‐scale fermentations is discussed.
Microcalorimetry of microorganism metabolism of monosaccharides and simple aromatic compounds
Authors: Lovrien Rex , Jorgenson Gregg , Ma Maggie K. , Sund Wesley E. 
Published: December 2004

AbstractHeat conduction solution enable rapid determination of the heats of aerobic and anaerobic metabolism of substrate by microorganisms. Aliquots of 1.0 ml cell suspension, 5 × 109 cell/ml, were mixed with a few dozen nmol substrate contained in 0.5 ml, under a controlled atmosphere of air, O2, or N2. At these substrate concentration, with adapted microorganisms, metabolism and its heat generation are usually complete within 300 to 600 sec. The raw data yield ΔHapp values. The ΔHapp were determined in the range 0.001 to 0.010% substrate, and extrapolated (limit substrate concentration →0), to yield Δ0H̄, the limiting differential molar heat of metabolism. The Δ0H̄ values express the heat generated when there is rapid metabolism but little new growth, minimal contribution by H+ transfer from metabolites, and maintenance of aerobicity or anaerobicity as specified. Escherichiacoli B/5 was used for aerobic and anaerobic combustion of eight sugars. Pseudomonas multivorans, and an Acinetobacter, strain B‐1, were used for aerobic metabolism of benzene, toluene, naphthalene, and a methylnaphthalene. The larger heats of combustion of the hydrocarbons enable the use of aqueous solutions of hydrocarbons well below their solubility limits. The quotient Δ0H̄/n (n = atoms carbon/molecule substrate) varies from (‐)36 to (‐)67 kcal/mol carbon for the sugars. The most reduced sugar yields the largest exothermic heats. The quotient varies from (‐)27 to (‐)81 kcal/mol carbon for the aromatic hydrocarbons. Comparison of the calorimetric heats of metabolism of those from total aerobic combustion in aquo (where available) give measure of the efficiencies with which the heat contents of the aqueous substrate are used by the bacteria.
Bacillus sphaericus for the control of mosquitoes
Authors: Singer S. 
Published: December 2004

AbstractFrom 1972 to 1977 a large laboratory effort was devoted to determining data on efficacy, safety, environmental impact (on nontarget organisms), and some preliminary field work using several isolates of Bacillus sphaericus. The B. sphaericus strains were found to be specific in their mosquito larvicidal activity, not causing mammalian toxicity nor apparent perturbation of the environment. During this period several fermentation and industrialization problems were investigated so that by 1978, using new strains and cultures, it was possible to have prepared kilogram amounts of an active dry stable powder, of strain 1593, for field evaluation. These field evolution. These field evaluations are presently still in progress. Control has been seen particularly against Culex, Anopheles, and Psorophora species, with some what less control aganst Aedes species. Unlike the agriculturally oriented Bacillus thuringiensis candidates, B. sphaericus bacterial cell, which is digested in the larval midgut (within a peritrophic membrane), releasing a toxin as early as 15 min after ingestion. Subsequent death of the larva ensues. Recent evidence suggests that applied B. sphaericus powder will survive in aquatic situations (ditches, ponds, and tree holes) for at least nine month. Comparisons of the B. sphaeicus strains with recently isolated strains of B. thuringiensis (var. israelensis), the latter being particularly active against Aedes species, indicates that they may be useful complements of each other in overall mosquito control strategies. The recent isolation of several new strains of B. thuringiensis, from WHO‐CCBC accessions from Roumania, indicate that although the B. thuringiensis isolate is a rare event when compared to the occurrence of B. sphaericus isolates (they usually occur together in accessions from which B. thuringiensis is isolated), several new useful strains of B. thuringiensis should be anticipated. The longevity of the B. thuringiensis strains in the wild has not yet been investigated.
Application of temperature‐sensitive mutants for single‐cell protein production
Authors: Miyasaka Yuichiro , Rha Chokyun , Sinskey Anthony J. 
Published: December 2004

AbstractCell‐division‐cycle, temperature‐sensitive mutants of Saccharomyces cerevisiae were investigated as a means of altering the morphological characteristics and subsequent physical properties of single‐cell protein (SCP). Strain 4471, harboring mutation cdc 4, formed a visible complex mass at the nonpermissive temperature, after being grown at 30°C and then transferred to 37°C for 8 hr. Microscopic observation showed that the mother cell was unable to complete the budding process at the nonpermissive temperature, which caused the cells to enlarge. Viscosity measurements were used to establish and characterize optimum morphological changes in the yeast. The Maximum increase in viscosity occurred when cells were incubated at 30°C and then shifted to 37°C for 8 hr. Strain 4471 exhibited yield stress, whereas A364A did not. Maximum change in yield stress occurred when cells were shifted from 30 to 37°C for 8 hr. No significant loss of protein or RNA occurred in strain 4471, as compared to strain A364A, when incubated at the nonpermissive temperature.
Model of steady‐state‐biofilm kinetics
Authors: Rittmann Bruce E. , McCarty Perry L. 
Published: December 2004

AbstractA steady‐state biofilm is defined as one that has neither net growth nor decay over time. The model, developed for steady‐state‐biofilm kinetics with a single substrate, couples the flux of substrate into a biofilm to the mass (or thickness) of biofilm that would exist at steady‐state for a given bulk substrate concentration. Based on kinetic and energetic constraints, this model predicts for a single substrate that a steady‐state bulk concentration, Smin, exists below which a steady‐state biofilm cannot exist. Thus, in the absence of adsorption of bacteria from the bulk water and for substrate concentration below Smin, substrate flux and biofilm thickness are zero. Equations are provided for calculating the steady‐state substrate flux and biofilm thickness for S greater than Smin. An example is provided to demonstrate the use of the steadystate model.