bluuebunny/crossref_metadata_2025_split huggingface dataset:
Comparison of measured and calculated oxygen solubilities in fermentation media
Authors: Quicker G. , Schumpe A. , König B. , Deckwer W.‐D. 
Published: December 2004

AbstractA fast physical method is used to measure oxygen solubilities in various solutions of sugars and salts, in nutrition media, and in fermentation broths of Penicillium chrysogenum. The findings were compared with the predictions of a solubility model which assumes that the solubility reduction is log‐additive with respect to various compounds (mainly sugars and electrolytes). A striking agreement between experimental results and predictions was found.
Alcohol fermentation of sweet potato. I. Acid hydrolysis and factors involved
Authors: Azhar A. , Hamdy M. K. 
Published: December 2004

AbstractFactors affecting acid hydrolysis of sweet potato powder (SSP) to fermentable sugars were examined. These include HCl concentration, temperature, time, and levels of SPP. Maximum reducing sugar, reported as dextrose equivalent (DE), was detected after 24 min hydrolysis (1% SPP) in 0.034N HCl heated at 154°C. These samples also had 3.43% droxymethylfurfural (HMF) based on dry weight. A high level of HMF (9.2%) was detected in 1% SPP heated at 154° in 0.10N HCl for 18 min. The lowest concentration of HMF formed (1.8%), at maximal DE of 61%, was established in samples containing 5% SPP and heated at 154° in 0.034N HCl for 48 min. Aqueous extracts of uncured SPP, examined by HPLC, contained glucose, fructose and sucrose, but degraded SPP had only glucose and fructose. Products of degraded SPP, under appropriate conditions, could be used for alcohol fermentation.
Immobilization of Brevibacterium flavum cells on collagen for the production of glutamic acid in a recycle reactor
Authors: Constantinides Alkis , Bhatia Daleep , Vieth Wolf R. 
Published: December 2004

AbstractIn this study, live cells of Brevibacterium flavum were immobilized for the production of glutamic acid. The reason for such a choice was that glutamic acid fermentation is an extensively studied fermentation and one which requires the viability of entire cellular faculties for the acid production. Brevibacterium flavum was chosen because it is an industrially used bacterium, and is very potent via a vis glutamic acid production. Studies were performed to find aeration and agitation conditions for optimal growth and glutamic acid productivity. Experiments were also done to find the optimum harvesting time. The cell activity peaks during the run of fermentation, and the time at which the peak occurs, was found. Conventional methods for immobilizing the cells on collagen were found to be lacking. The pH and drying were the two main reasons for loss of viability of the cells; the latter being more important. A modified immobilization procedure has been devised, which can immobilize live cells at any given pH and ionic strength, in contrast to the conventional method which requires the pH to be above 11 or below 3. This new method involves dialysis of collagen in suitable dialysis bags against water at pH7 (or buffer at any desired pH). The dialysed collagen blended at 20,000 rpm, resulted in a very smooth dispersion, unnoticeably different from collagen dispersion prepared at pH 11. The dispersed collagen was then cast and dried at an elevated temperature, and high air flow rate over the cast membrane, decreasing the time of drying from 6–8 hr ( in the conventional method) to 1.5–2 hr. The membrane has been tested for glutamic acid producing capabilities in a column reactor with the membrane spirally wound. The reactor has been operated under continuous conditions for 5–10 days with stable activities.
Ribonuclease isolated from yeast (Saccharomyces carlsbergensis): Characterization and properties
Authors: Shetty J. K. , Weaver R. C. , Kinsella J. E. 
Published: December 2004

AbstractThe homogeneity of a purified ribonuclease from brewers' yeast was determined by velocity sedimentation and polyacrylamide gel electrophoresis techniques. The velocity sedimentation pattern gave a single peak with a Sapp 3.46 and polyacrylamide gel electrophoresis showed one major band. The absorption spectrum of the enzyme showed maximum absorption at 277–278 nm and minimum at 252 nm. The enzyme was relatively stable to extreme pH values and high temperature. Both NaCl and KCl increased the enzyme activity whereas enzyme was inhibited by divalent metal ions. The inhibition of the enzyme was increased in the order of Ca2+ > Mg2+ > Fe2+Cu2+. Chemical modification studies of the enzyme showed that tryptophan residues and disulfide bonds were required for enzyme activity.
Conversion of the enzymatic hydrolysate of shellfish waste chitin to single‐cell protein
Authors: Revah‐Moiseev Sergio , Carroad Paul A. 
Published: December 2004

AbstractThe conversion of the enzymatic hydrolysate of shellfish chitin waste to single‐cell protein was investigated as part of a comprehensive waste treatment program. Forty‐two yeasts were screened for ability to assimilate the monomer of chitin, N‐acetylglucosamine, which has been shown to be the sole product of enzymatic hydrolysis of chitin. The Yeast Pichia Kudriavzevii was selected for study, based on ability to grow at high temperature (37°C and above), low pH (4.0 ± 0.5), and in a nutritionally simple medium. Growth rates of P. kudriavzevii were similar on N‐acetylglucosamine and on the chitin hydrolysate. Dependencies of specific growth rate on temperature, pH, medium composition, and oxygen tension were studied. The variations of yield, protein content, and total nucleic acid content with the specific growth rate were evaluated. The amino acid distribution of the protein of P. kudriavzevii was obtained.
Enzymes in preparative organic synthesis: Coincidence of the pH optimum for catalyst effectiveness with the pH optimum for the catalyzed reaction equilibrium
Authors: Martinek Karel , Semenov Anatole N. , Berezin Ilya V. 
Published: December 2004

AbstractThe study concerned the pH profile of the apparent equilibrium constant for synthesis of N‐benzoyl‐L‐phenylalanine ethyl ester from the respective acid and ethanol in the biphasic system chloroform + 5% (v/v) water. The substitution of water (as a reaction medium) for the biphasic aqueous–organic system shifted the pH profile toward neutral pH values. As a result the pH range thermodynamically conducive to synthesis of the final product in the biphasic system coincided with the pH optimum of the catalytic activity of the enzyme used (α‐chymotrypsin). This approach should, in principle, be considered as general: first, per se it is independent of a catalyst (enzyme) nature; second, the biphasic method helps the shift ionic equilibria involving not only organic acids, but also bases. A physical mechanism of the ionic equilibrium shift is the same is both cases, namely, a preferable extraction from water into an organic phase of one generally nonionic (more hydrophobic) form of the reagent.
Utilization of carbohydrates by Thermomonospora sp. Grown on glucose, cellobiose, and cellulose
Authors: Moreira A. R. , Phillips J. A. , Humphrey A. E. 
Published: December 2004

AbstractThermomonospora sp. was grown on glucose, cellobiose, and in order to study its growth characteristics with different carbohydrate substrates and to assess the validity of some of the assumptions made in a previously proposed model for the cellulose fermentation with this microorganism. It was observed that the nitrogen and protein contents of the cells are essentially constant during the fermentation and independent of the carbon source when glucose or cellobiose are utilized. Under oxygen starvation conditions it was shown that unidentification organic compound(s) accumulate(s) in the culture broth. Culture fluorescence was shown to be an excellent variable for monitoring and control of the fermentation process. This microorganism showed a preference for crystalline cellulose (Avicel) as substrate although it grows readily on a more amorphous cellulose (Solka Floc). The production of extra cellular protein is shown to be growth related. Data were obtained confirming the decrease in the number of active adsorption sites as the cause for the decrease in the cellulose digestion rate. It is suggested that a future model should account for the time change of surface characteristics of the cellulose particles.
Production of cellulases by Thermomonospora sp.
Authors: Moreira A. R. , Phillips J. A. , Humphrey A. E. 
Published: December 2004

AbstractGlucose, cellulose, Avicel, and Solka Floc were utilized as substrates for growth of Thermomonospora sp in order to study the induction–repression characteristics of its associated cellulase system. While glucose proved to be an effective repressor of the cellulase enzymes, the other three substrates induced relatively high levels of enzyme activity as measured by the filter paper assay. On a unit cell mass basis the highest values of cellulase activity were obtained when Avicel was utilized as the carbon and energy source. The nature of the cellulosic material and its initial concentration were identified as two very important parameters of the induction process.
A novel method for determining the parameters of microbial kinetics
Authors: Szetela Ryszard W. , Winnicki Tomasz Z. 
Published: December 2004

AbstractIt is conventional to describe the relationship between the specific rate of microbial growth and the concentration of the inhibitory substrate in terms of the Andrews–Edwards equation. A novel method for establishing the constants of this equation is presented. The equation is transformed to a polynomial and the empirical data are approximated by a quadratic polynomial. The results obtained for the biodegradation of phenol in a mixed culture (activated sludge) are discussed.
Eeffect of pH on growth in a respiration‐deficient mutant of Saccharomyces cerevisiae
Authors: Sawada Tatsuro 
Published: December 2004

AbstractThe effects of pH on the budding cycle of a respiration‐deficient mutant of Saccharomyces cerevisiae were investigation by monitoring the time course of bud development on single cells. The volume of each bud was measured at various time intervals between the inception of its development and inception of development of the next bud on the mother cell. A previous report that the budding cycle consisted of two phases (a rapid‐growth phase and a slow‐growth phase) was confirmed. With increase in pH from 3.8 to 6.0 the budding cycle shortened as a result of both increase in rate of the rapid‐growth phase and decrease in the duration of the slow‐growth phase. Although further increase in pH to 7.4 further increased the rate of the rapid‐growth phase, the budding cycle lengthened as a result of an increase in time lag and increase in duration of the slow‐growth phase. The growth rate, in terms of bud volume, conformed with the expression: (1/V)(dV/dτ) = ξ exp(–V/η), where the values of ξ and η were dependent on pH. The cell volume distribution in a batch culture was compared with the cell volume distribution calculated from the growth curve of a single bud. Similarities in the curves suggested that the growth pattern of a whole culture reflected the growth pattern of a single cell.
Mixed cultures: Commensalism and competition with Proteus vulgaris and Saccharomyces cerevisiae
Authors: Tseng Murray M‐C. , Phillips Colin R. 
Published: December 2004

AbstractSeveral modes of interaction are demonstrated and modeled in the Proteus vulgaris–Saccharomyces cerevisiae system, in particular, commensalism (citrate present. glucose limiting, the nicotinic acid required by the bacterium supplied by the yeast), and commensalism and competition [citrate absent, both organisms compete for the same limiting carbon source (glucose) and the yeast supplies the nicotinic acid for the bacterium]. By varying the medium component concentrations, competition (citrate absent, glucose limiting, nicotinic acid not limiting), mutualism (citrate excess, glucose limiting, nicotinic acid absent), and neutralism (citrate limiting, glucose limiting, and nicotinic acid excess) could also be created. Kinetic models for commensalism and commensalism plus competition were developed to describe cell growth, substrate utilization, and nicotinic acid production. Good agreement with experiment was obtained for the commensalism case.
Production of earthworms as a potentially economical source of protein
Authors: Hartenstein Roy 
Published: December 2004

AbstractThe main objectives of this study were (1) to determine the optimum frequency for transferring a fixed population of Eisenia foetida into fresh surroundings to effect maximum production of earthworm biomass, (2) to determine carrying capacity and maximum production of E. foetida biomass per unit area–volume–time at 24°C, and (3) to measure the nucleic acid concentration of this earthworm. Population were rapidly decimated in limed peat moss with horse manure as food when transferred weekly or when held for ten weeks in the same substrate; no significant differences and high survival obtained at intermediate intervals. Significantly more cocoons were produced when transfers were made every two weeks, and a trend was seen toward a lower level of cocoon production with length of detention in substrate. The growth rate of adults was approximately similar in relation to the frequency of transfer, as was biomass, at transfer frequencies of every 2 to 9 weeks. One interpretation of the data is that a detention interval of 6 to 8 weeks is optimum for maximizing production of biomass; eight weeks is the interval commonly selected in commercial practices. Carrying was 9.5 g live weight on a surface area–volume of 24 cm2–110 cm3 with horse manure as food on 20 g of soil as substrate; maximum production in this space was 2 g live weight in 7 weeks, which extrapolates to 6685 kg protein/ha yr. Nucleic acid concentration was 2.9%, which falls below values of about 6–28% obtained for microbes, and may exceed values for mammalian muscle by about twofold.
Single‐cell protein production from spent sulfite liquor utilizing cell‐recycle and computer monitoring
Authors: Gold Daniel , Mohagheghi Ali , Cooney Charles L. , Wang Daniel I. C. 
Published: December 2004

AbstractSpent sulfite liquor (SSL), a waste product of the paper pulping industry, is produced at a rate of 1 ton (dry basis) per ton of pulp. The sugar content of SSL is about 30 g/L. To reduce the biological oxygen demand (BOD) of SSL before disposal, torula yeast (Candida utilis) is produced by a continuous culture process, the productivity of which is limited by sugar concentration and cell growth rate. To increase productivity, a recycle system has been designed and tested. Cells were sedimented continuously with a flocculating agent (bentonite) before being recycled to the fermentor. A bentonite concentration of 0.02 g/g cell was required. A computer monitoring system based on material balancing techniques was developed to monitor and control the recycle system. With this computer system, productivity was raised to 6.1 g/L h, with cell concentration up to 65 g/L in the recycle stream and 24 g/L in the fermentor. This represents a productivity increase of 150% over continuous culture with no recycle.
Kinetic modeling of a multiple immobilized enzyme system. II. Application of the model
Authors: Mercer D. G. , O'Driscoll K. F. 
Published: December 2004

AbstractThe mathematical model for the reaction sequence catalyzed by immobilized invertase and glucose oxidase discussed in the preceding article has been used successfully to duplicate experimental findings. In addition, it has been used as a tool for the simulation and prediction of effects derived from alterations to system‐related and gel‐related parameters. The effects of gel diffusivity on the overall conversion of sucrose substrate to reaction products was investigated through use of this model. Changes in the enzyme loading within a gel and the results of varying the ration of invertase activity to glucose activity were also evaluated. Through use of concentrations of the molecular species determined at the collocation points within a gel particle and in the bulk liquid phase, an estimate of the thickness of the diffusion boundary layer around the gel particle was determined which was in close agreement with values obtained from classical mass transfer relationships. For most of this study, the enzymes were coimmobilized within the same polymeric matrix. However, a number of tests were run with the enzymes immobilized individually and placed in separate reactors in a sequential reactor system. The experimental results from these tests were duplicated successfully by means of the model with little modification to the basic computer program. Such an example illustrates the potential flexibility of the model and its overall versatility.
Five‐year perspective of the large‐scale growth of mammalian cells in suspension culture
Authors: Zwerner R. K. , Cox R. M. , Lynn J. D. , Acton R. T. 
Published: December 2004

AbstractThe Cell Culture Center at the University of Alabama in Birmingham was set up to produce large quantities of cells and their products from suspension cultured cell lines. This system has now been in operation for over five years and has been effective in producing large quantities of mammalian cells of murine and human origin. This article describes the system and some growth parameters which have been of importance for large‐scale mammalian cell growth.
Inhibitory effects of particulate materials in growing cultures of Thiobacillus ferrooxidans
Authors: Dispirito Alan A. , Dugan Patrick R. , Tuovinen Olli H. 
Published: December 2004

AbstractParticulate materials (flowers of sulfur, fluorapatite, glass beads, and pyrite) inhibited the growth of Thiobacillus ferrooxidans on ferrous iron at pH 1.5. The degree of inhabitation varied with the type of the particulate and culture conditions. The inhibition caused by pyrite involved a soluble toxic component. The inhibition caused by sulfur particles and glass beads was alleviated by incubation under static culture conditions (i.e., no shaking) but oxidation rates declined because of lack of aeration an increase in the pH above 2 also relieved the inhibition. The nature of inhibition. The nature of inhibition by different particles varied from declined iron oxidation rates to prolonged lag periods depending on the concentration of the test material. Thus, the results indicate that the bacterial activity at the liquid‐solid interface is different from that in the bulk liquid phase and is influenced by the proton concentration and by the physiochemical properties of the solids.
Effect of chemical treatments on the degradability of cotton straw by rumen microorganisms and by fungal cellulase
Authors: Miron Josual , Ben‐Ghedalia Daniel 
Published: December 2004

AbstractThree different chemical treatments—sulfur dioxide, ozone, and sodium hydroxide—were applied on cotton straw, and the effect on cell‐wall degradability was assessed by using rumen microorganism and Trichoderma reesei cellulase. Sulfur dioxide (applied at 70°C for 72 h) did not change the lignin content of cotton straw but reduced the concentration of hemicellulose by 48%. Ozone exerted a dual effect, both on lignin (a 40% reduction) and hemicellulose (a 54% decrease). The treatment with NaOH did not solublize cell‐wall components. The in vitro organic matter digestibility with rumen fluid of cotton straw was increased significantly by ozone and SO2 treatments, by 120% and 50%, respectively, but not by NaOH. T. reesei cellulase was applied on the chemically pretreated cotton straw at a low level (6 filter paper U/g straw, organic matter), and the release of reducing sugars was determined. The highest level of reducing sugars (30.6 g/100 g organic matter) was obtained with the O3‐cellulase combination, which solubilized 64% of the cellulose and 88% of the hemicellulose. the SO2‐ and the NaOH‐pretreated cotton straw were hydrolyzed by T. reesei cellulase to the same extent (21 g reducing sugars/100 g organic matter). The rumen fluid digestibility of the enzymatic ally hydrolyzed straw was not increased further over the effect already obtained with the chemical pretreatments. However, the fermentability of the combined treatments was increased markedly. In the O3‐cellulase‐treated cotton straw, 83% of the rumen fluid digestible material consisted of highly fermentable components. Although ozone proved to be the most potent pretreatment for enzymic saccharification in this study, the absolute result was modest. The limited effect of the combined O3‐cellulase treatment was probably associated with the pretreatment limitations, but not with the enzyme level. Based on the differential response of the chemically treated cotton straw to attack by rumen microorganisms on the one hand, and by T. reesei cellulase on the other hand, a hypothesis has been suggested as to the location of lignin and hemicellulose in the cellwall unit of cotton straw.
The effect of Hofmeister anions and protein concentration on the activity and stability of some immobilized NAD‐dependent dehydrogenases
Authors: Carrea G. , Bovara R. , Pasta P. , Cremonesi P. 
Published: December 2004

AbstractThe effect of several factors on the activity and stability of alcohol dehydrogenase, glyceraldehyde‐3‐phosphate dehydrogenase, and 20β‐hydroxysteroid dehydrogenase, both free and immobilized on CNBr‐activated Sepharose 4B, was investigated. Enzymes were im‐ mobilized under different conditions including various degrees of matrix activation, variable amounts of protein, in the presence, or in the absence of, additives (coenzymes, dithioth‐ reitol, salts). Activity recovery was in general satisfactorily high with 20β‐hydroxysteroid dehydrogenase, low with glyceraldehyde‐3‐phosphatedehydrogenase, and markedly linked to the concentration of immobilized protein with alcohol dehydrogenase. In the latter case the advantageous stabilizing effect of high enzyme concentrations was notably diminished by the parallel decrease of the effectiveness factor. The effect of high concentrations of anions of the Hofmeister series was examined. It was found that 1M phosphate and 0.5M sulfate dramatically stabilize both free and immobilized enzymes against inactivation by temperature and urea. Km, values of apolar substrates were considerably lowered by the two anions while Km values of polar substrates were not affected. In some cases Vmax values also were influenced by high concentrations of these anions. The present results appear of interest particularly in view of enzyme utilization for analytical as well as for preparative purposes.
Enzymatic synthesis of formic acid from H2 and CO2 and production of hydrogen from formic acid
Authors: Klibanov Alexander M. , Alberti Barbara N. , Zale Stephen E. 
Published: December 2004

AbstractWhole cells of Alcaligenes eutrophus (as well as isolated P. oxalaticus formate dehydrogenase and A. eutrophus hydrogenase coupled via NAD+ or methyl viologen) have been shown to produce H2 from formic acid. Immobilization of the cells in kappacarrageenan gel greatly enhances their stability at room temperature. The rate of hydrogen production catalyzed by immobilized A. eutrophus has been studied as a function of the concentrations of the cells and formate and also pH. An inhibition by high concentrations of formate has been found. Immobilized cells were also capable of synthesizingformate from H2 and bicarbonate. Yields of formate up to 30% have been obtained. The catalytic efficiency of immobilized A. eutrophus cells was compared with that of palladium adsorbed on activated carbon.