bluuebunny/crossref_metadata_2025_split huggingface dataset:
Hydrolysis of raffinose in a hollow‐fiber reactor using an unrefined mixture of α‐galactosidase and invertase
Authors: Silman R. W. , Black L. T. , McGhee J. E. , Bangley E. B. 
Published: December 2004

AbstractRaffinose was converted enzymatically in a hollow‐fiber reactor to melibiose, sucrose, galactose, glucose and fructose. The enzymes were a crude extract of α‐galactosidase and invertase produced by Aspergillus awamori NRRL 4869 on a solid substrate, Wheat bran. With a concentration of raffinose, C0, entering the reactor at a flow rate Q, and with C being the concentration of raffinose exiting the reactor, the conversion (C/C0), was studied as a function of Q at two level of C0. The data could be fairly well fitted using the analysis of Waterland et al. even though a mixed crude enzyme system was being investigated. It was found empirically that In (C/C0) was linear in Q−1, with the absolute value of the slope decreasing with increasing C0. The linearity of such plots were predicted by Lewis and Middleman from Waterland et al. for a single enzyme system obeying first‐order kinetics, the slope being independent of C0. Although the assumptions involved in this approximate analytical solution are not valid, the observed linearity of the In (C/C0) vs. Q−1 plots is excellent and should prove useful in reactor design considerations.
Effect of external mass transfer of activation energy of hydrolysis of BAEE and casein by trypsin immobilized on molecular sieve type 4A
Authors: Mukherjea R. N. , Bhattacharya P. , Gangopadhay T. , Ghosh B. K. 
Published: December 2004

AbstractIn this investigation, the activation energies of the hydrolysis of N‐(α)‐benzol‐L‐arginine ethyl ester (BAEE) and casein have been determined using trypsin immobilized on molecular sieve type 4A. There is a complete absence of intraparticle diffusion in the system, and the temperature dependence of the reaction has been studied only under external diffusional limitation. While the hydrolysis of BAEE by bound trypsin in found to be controlled by external diffusion, that of casein is kinetically controlled.
Pulse response in an immobilized‐enzyme column: Theoretical method for predicting elution curves
Authors: Adachi S. , Hashimoto K. , Matsuno R. , Nakanishi K. , Kamikubo T. 
Published: December 2004

AbstractA theoretical method for predicting the elution profile of a pulse response in an immobilized‐enzyme column is proposed. The method is based on a mass balance model, which is extensively used in gel chromatography. To test the method, a pulse of sucrose solution was applied to a column of spherical acrylamide gel in which was entrapped invertase from yeast, and it was eluted with 0.05M acetate buffer at pH 5.0. The elution curves of the substrate and the product were in fairly good agreement with the theoretically calculated ones. The method was extended to the system of reversible as well consecutive reactions.
Estimation of Trichoderma QM 9414 biomass and growth rate by indirect means
Authors: Harima Takeshi , Humphrey Arthur E. 
Published: December 2004

AbstractTrichoderma QM 9414 was aerobically grown on glucose as the sole carbon and energy sources in a chemostat culture. The specific rates of glucose consumption (QG), oxygen consumption (Q), and carbon dioxide production (Q) at the steady state were measured to estimate the growth and maintenance requirements. From the results it was estimated that 2 mol adenosine triphosphate (ATP) were produced when1 mol NADH was oxidized through the respiratory chain of this microorganism. The true growth yield for ATP (YATP) and specific ATP consumption rate for maintenance (Q) calculated with this value were 0.0106 g dry cell/mmol ATP and 5.2 mmol ATP/g dry cell/hr, respectively. Using the relationships between specific growth rate (μ) and (Q) and between μ and QG obtained from chemostat‐culture data, cell and glucose concentration histories were estimated from the carbon dioxide production rate during the batch culture. The estimated cell concentrations agreed with the experimentally measured values. Glucose concentration were slightly overestimated.
Methane production from wastewaters by immobilized methanogenic bacteria
Authors: Karube Isao , Kuriyama Shinichi , Matsunaga Tadashi , Suzuki Shuichi 
Published: December 2004

AbstractA methanogenic population was immobilized onto agar gel, polyacrylamide gel, and collagen membrane. Agar‐gel‐entrapped methanogenic microorganisms gave the highest activity. The optimum agar concentration was between 1.5 and 3% (w/v), and the optimum microbial content was 20 mg wet cells/g gel. The optimum conditions for methane production by immobilized whole cells were pH 7.0–7.5 and 37–45°C. The rate of methane production was initially 1.8 μmol/g gel/hr. Methane productivity was gradually increased and reached a steady state (4.5μmol/g gel/hr) after 25 days of incubation. The immobilized methanogenic microbial population continuously evolved methane over a 90 day period. No difference in methane productivity was observed after three months of storage at 5°C. Methane was also produced by immobilized whole cells under aerobic conditions. Furthermore, carbohydrates, such as glucose, in wastewater completely decomposed by immobilized whole cells.
Studies on the immobilization of trypsin on sand
Authors: Puvanakrishnan R. , Bose S. M. 
Published: December 2004

AbstractTrypsin was immobilized on sand using five different methods. Attempts were made to attach amino‐functional groups onto sand using 3‐aminopropyltriethoxysilane, hexamethylenetetramine, hexamethylenediamine, and melamine. Glutaraldehyde was used as a bifunctional agent in all the methods. Methods for the estimation of the proteolytic 1activity and protein content of immobilized trypsin were standardized. The maximum retained activity was observed for trypsin immobilized on sand via 3‐aminopropytriethoxysilane and glutaraldehyde. Immobilized trypsin showed a shift in the pH optimum toward the acidic side over that of soluble trypsin in all five cases. The optimum temperature for both native and immobilized trypsin prepared by the silane‐glutaraldehyde method was found to be 45°C. However, the pH and thermal stabilities of immobilized trypsin were observed to be better than that of the native enzyme.
Stability analysis of commensal and mutual relations with competitive assimilation in continuous mixed culture
Authors: Miura Yoshiharu , Tanaka Hiroki , Okazaki Mitsuo 
Published: December 2004

AbstractThe population dynamics of continuous mixed cultures with pure commensalism, commensalism plus competitive assimilation, pure mutualism, and mutualism plus competitive assimilation was disused. The population does not display oscillatory phenomena where there is a single interaction of commensalism or mutualism. Damped oscillations take place when two interactions (such commensalism and competitive assimilation or mutualism and competitive assimilation) coexist in the continuous mixed culture. The stability of these systems was discussed in detail.
Estimation of diffusion coefficients of proteins
Authors: Young M. E. , Carroad P. A. , Bell R. L. 
Published: December 2004

AbstractA correlation for estimating the diffusion coefficients of protein molecules is presented. The correlation is based upon literature values of the protein diffusion coefficients and molal volumes for 143 proteins. The correlation can be used for the estimation of diffusion coefficients using only molecular weight. Accuracy is such that a linear regression on 301 proteins showed 75% of the diffusion coefficients estimated fell within 20% of the experimental values. The relationship between this correlation, the Stokes–Einstein equation, and the Wilke–Chang correlation is discussed.
Relationship between bulking and physicochemical–biological properties of activated sludges
Authors: Beccari M. , Mappelli P. , Tandoi V. 
Published: December 2004

AbstractResearch into bulking in laboratory‐scale activated‐sludge plants are reported upon. A correlation between sludge volume index (SVI) and biopolymer content (exocellular polymer, ECP) has been determined or sludge obtained under various operating conditions and with different chemical and physical characteristics. This paper interprets that correlation. A method for ECP determination that is quicker and just as precise as the gravimetric one and which enables this parameter to be used not only to interpret bioflocculation mechanisms but also as a parameter for evaluating optimal plant operation is reported.
Problems concerning the operation of high productivity biomass fermentations using volatile liquid hydrocarbon feedstocks
Authors: Hamer G. , Hamdan I. Y. , Khamis Alisar S. , Baroon Zainab H. 
Published: December 2004

AbstractThe possibilities of using liquefied petroleum gas (LPG) heavy ends, predominantly volatile liquid n‐alkanes (a location‐specific hydrocarbon feedstock) for single‐cell protein (SCP) production are examined against criteria established to define potentially attractive SCP production processes. The factors discussed include the use of the heat of vaporization for fermentor cooling, the efficiency of conversion of nalkane vapors, problems of maintaining constant composition substrates when feeding volatile liquid n‐alkane vapors to laboratory fermentors, the possible solvent effect of liquid n‐alkanes, and the possibilities of competitive inhibition. The study confirms that mixed volatile n‐alkane feedstocks will introduce major physical and biological problems for both product and process research and development. Even when the technical problems are solved, the economic question of whether a direct production route using the feedstock as the fermentation substrate or an indirect route involving the conversion of the feedstock, by chemical means, into methanol, which can then be used as the fermentation substrate, needs careful examination.
Immobilized yeast cells with methanol oxidase activity: Preparation and enzymatic properties
Authors: Couderc R. , Baratti J. 
Published: December 2004

AbstractCells form the yeast Hansenula polymorpha (ATCC 26012) were successfully immobilized by entrapment in a polyacrylamide gel. The resulting gel showed high methanol oxidase activity especially after treatment with a detergent (CTAB). The enzymatic properties of the gel‐entrapped cell were not very different from that of the soluble enzyme except that no inhibition was observed at high methanol concentration. In continuous reactors, the gel‐entrapped cells showed a much higher stability than other enzyme preparations. The inactivation mechanism was investigated and proved to be the oxidation of essential SH group(s) of the methanol oxidase molecule by hydrogen peroxide. Treatment with β‐mercaptoethanol prevented inactivation or regenerated activity.
Continuous production ofL‐isoleucine using immobilized growing Serratia marcescens cells
Authors: Wada Mitsuru , Uchida Tomofumi , Kato Jyoji , Chibata Ichiro 
Published: December 2004

AbstractAn immobilized growing cell system was applied to the continuous L‐isoleucine production by Serratia marcescens. In the new immobilized‐cell systems using the carrageenan gel method. S. marcescens cells in the gel required nutrients and oxygen for growth, and the numbers of living cells per milliliter of gel increased to the levels of that of free cells in the liquid medium. This immobilized growing cell system exhibited high and stable activity for isoleucine production under steady‐state conditions. Continuous isoleucine production was carried out by feeding the nutrient medium under aeration into a fluidized bed reactor containing the immobilized cells. In the continuous operation, an efficient production was maintained by automatically controlling the pH of the reaction mixture at 7.5. The productivity of isoleucine increased using multibed reactors. In a two‐bed reactor system, the effluent L‐isoleucine concentration reached 4.5 mg/ml at a retention time of 10 hr, and a steady state was maintained for longer than 30 days.
Polymethylglutamate as a new matrix for covalently immobilized enzymes: Preparation and properties of urease and uricase
Authors: Minamoto Yoshiki , Yugari Yasumi 
Published: December 2004

AbstractPolymethylglutamate (PMG), a synthetic polypeptide, was used as a new carrier to immobilize urease (EC 3.5.1.5) and uricase (EC 1.7.3.3) by the azide method. The enzymes could be immobilized onto PMG in various forms, such as film, fiber, coating on various beads, and a silicon tube. The retained activities of the immobilized enzymes were excellent (more than 95%), therefore it was possible to immobilized almost all activities of the enzymes added in the coupling mixtures. Heat stabilities of the resulting immobilized enzymes were markedly improved, while the optimal pH and Km values remained almost unchanged. The urease immobilized on the PMG‐coated glass beads packed in a column, was found to retain its activity more than 80% of the initial value, even after the occasional use for a year. In view of the improved retained activities and stabilities of the immobilized enzymes, PMG may therefore be a very versatile matrix for the immobilized enzymes.
Enzymatic biosynthesis of cephalexin
Authors: Rhee D. K. , Lee S. B. , Rhee J. S. , Ryu Dewey D. Y. , Hospodka J. 
Published: December 2004

AbstractThe reaction kinetics of the enzymatic of cephalexin from 7‐aminodea‐cetoxy cephalosporanic acid and phenylglycine methylester was studied using the synthesizing enzyme obtained from Xanthomonas citri. The activation energy, Km value for 7‐aminodeacetoxy cephalosporanic acid and phenylglycine methylester, and Ki value for phenylglycine methylester were determined as 8.63 kcal/mol, 3.7mM, 14.5mM, and 70mM, respectively. The enzyme was found to be constitutive and susceptible to deactivation.
Structure and function of the Bacillus thuringiensis protein crystal
Authors: Nickerson Kenneth W. 
Published: December 2004

AbstractThe structural chemistry of the Bacillus thuringiensis parasporal protein crystal is discussed in terms of purification techniques, removal of contaminating proteases, crystal subunit size, crystal shape, interchain crosslinks, the ultimate toxin, and lysinoalanine. The alkaline pH cleavage of disulfide bonds is stressed in relationship to this role in crystal solubilization and toxin formation. The future implication s of plasmid‐coded crystal formation and B. thuringiensis var. israelensis (effective against mosquitoes and black flies) are also discussed.
Production and efficacy of baculviruses
Authors: Shieh T. R. , Bohmfalk G. T. 
Published: December 2004

AbstractSeveral baculvirusus of nuclear polyhedrosis virus (NPV) have been produced and tested for microbial control of various Lepidoptera spp. To date, there are three registered preparations of NPV that are exempt from the requirement of tolerance by the Environmental Protection Agency (EPA) in the United States (US). The first and only commercially available viral preparation used in agriculture was developed by Sandoz, Inc. under the name of Elcar® for control of Heliothis spp. on cotton. The other two baculovirus preparations were developed and registered by the US Department of Agriculture (USDA) for control of Douglas‐fir tussock moth and gypsy moth on forests. Several methods are being used for production of NPV viruses: (1) field collection of diseased larvae, (2) laboratory rearing of insects followed by infection with viral inoculum, (3) tissue culture. and (4) tissue culture and mass rearing larvae. Recent progress in mass production of insect virus points toward the adoption of tissue culture with the whole organism technology for production of a standardized viral product. The practical usefulness of various baculovirus preparations has been demonstrated for protection of forests from defoliation by various lepidopterous species. In agriculture, Elcar® has been successfully marketed and has been very well received for use in integrated pest management on cotton. Recent development also demonstrated that use of adjuvants further increase the efficacy of Elcar® against Heliothis spp. on cotton.
Production and efficiency of protozoa
Authors: Brooks Wayne M. 
Published: December 2004

AbstractDespite the chronic and debilitative nature of the infection they cause, several species of microsporidia and neogregarines offer a good potential as microbial control agents, particularly against insect pests of high economic thresholds. Techniques for mass production of protozoa have usually involved per os, inoculation or injection of the protozoa into their usual or alternate hosts. The spores are harvested subsequently from heavily infected host tissues by grinding, filtration, and differential centrifugation. Although fresh spores are used in most field tests, the spores of many species can be stored with high survival either frozen or in water at low temperatures (0–4°C) for up to several months. Sunlight or ultraviolet (UV) radiation is a serious factor limiting spore persistence. However, the protozoa do not appear to be significantly limiting spore persistence. However, the protozoa do not appears to be significantly more susceptible to UV radiation than other insect pathogens and persistence can be prolonged with UV protectants. Most field tests with protozoa have involved the application of spores in sprays and have usually resulted in a high degree of infection in the target host species. The potential for control of few species has been improved by formulation of spores in to baits, and the potential of other species will likely increase if suitable bait formulation can be devised in the future. One species, Nosema locustae, formulated as a bait, has been successfully used to control grasshoppers on rangelands. Limited laboratory and field studies have also suggested that increased short‐term control might be obtained if candidate protozoan species can be combined with certain insecticides. While recent and increased efforts have been devoted to assess the potential of protozoa as microbial control agents, potential hazards to nontarget organism have been investigated for only three species. Their close relation taxonomically to protozoa pathogenic for mammals will necessitate careful evaluation of the safety of candidate control species for nontarget organisms.
Mechanistic model of the growth of Streptococcus cremoris HP at super optimal temperatures
Authors: Franks P. A. , Hall R. J. , Linklater P. M. 
Published: December 2004

AbstractThe kinetic response of Streptococcus cremoris HP to growth at super optimal temperatures is reported. The response to a step increase in temperature was shown to be transient and to result from an increased metabolic rate caused by the raised temperature combined with thermal deactivation of the cell mass present. The catabolic and anabolic activities of the cell were shown to decay at different rates resulting in an accumulation of cells capable of catabolism (energy production) but unable to reproduce. The proposed mechanism was confirmed by independent estimates of the catabolic and anabolic activities of the culture. A mathematical model based on the proposed mechanism and incorporating simultaneous exponential growth, thermal death, and catabolic uncoupling of anabolically inactive cells was developed. Experimental evaluation of the model indicated the presence of a delay in deactivation of metabolic activity in response to a temperature transient. After the inclusion of this delay in death, it was confirmed that the model was capable of prediction of the balanced growth and transient response of this organism to changes in growth temperature. The delay in death was shown to be of major significance to the control of a simulated cheddar cheese fermentation.
Conversion of cellulose to glucose with cellulase of Trichoderma viride ITCC‐1433
Authors: Herr Dieter 
Published: December 2004

AbstractTrichoderma viride ITCC‐1433 secretes a cellulase complex that is rich in β‐glucosidase and therefore well suited for the saccharification of cellulosic materials. The cellulase was investigated with respect to optimum conditions of reaction and enzyme stability. Avicelase, CMCase, and β‐glucosidase differed considerably in their physicochemical properties. At temperatures above 50°C, β‐glucosidase is not very stable. Therefore, as a compromise the conditions of hydrolysis were chosen to be 50°C and pH 4.5. With the crude culture filtrate of T. viride ITCC‐1433 a nearly pure glucose solution of 4% is reached from a 10% cellulose suspension. Wood pulp and newsprint are hydrolyzed to a much smaller extent. With an enzyme concentrate up to 8% glucose accumulated in the reaction fluid within 48 hr. At this time the glucose‐cellobiose ratio was 75:1. Glucose was demonstrated to be the most potent inhibitor of total hydrolysis. The addition of glucose to the enzyme‐substrate solution at zero time completely stopped its own formation and cellobiose and reducing groups (oligosaccharides) accumulated. By removing glucose through an ultrafilter device about 90% saccharification of cellulose to glucose was achieved in 48 hr without any accumulation of cellobiose.
Oxygen transfer and mycelial growth in a tubular loop fermentor
Authors: Ziegler H. , Dunn I. J. , Bourne J. R. 
Published: December 2004

AbstractA 22 m long. 20 liter tubular loop fermentor (TLF) has been tested for oxygen transfer characteristics and as a reactor for mycelial growth. Model calculations show that the flow pressure drop has an important influence on the axial oxygen profiles. A design model that accounts for this influence is presented. Using the model, KLa values are calculated from the results of sulfite oxidation experiments. These are correlated with power consumption and aeration rates. The KLa dependence on aeration rate was found to be less than found with tank reactors. The growth kinetics of three metabolite‐producing mycelial organisms in the TLF are presented: a Streptomyces, a Fusarium, and a Acrophialophora. In order to determine the influence of reactor type on the growth and product formation, these cultures have been grown in tanks and shake flasks. The antibiotic, product spectrum of Streptomyces is compared on the basis of inhibition tests and it is shown that the distribution of products is reactor dependent. The Fusarium culture produced a previously unknown metabolite, whose concentration in the loop fermentor was four times higher than in a shake flask. The Acrophialophora culture grew twice as fast in the loop fermentor, but produced essentially none of the specific product. Power Consumptions of up to 8 kW/m3 in the tubular fermentor did not appear to harm the mycelia.
Study of a “bloom” of the oil‐rich alga Botryococcus braunii in the Darwin River Reservoir
Authors: Wake L. V. , Hillen L. W. 
Published: December 2004

AbstractA “bloom” of the freshwater alga Botryococcus braunii Kützing appeared in the Darwin River Reservoir in 1976. At the time of algal sampling, the "bloom" was estimated at 1500 ton and possibly double this mass at a maximum cell concentration. The alga is characterized by a high liquid hydrocarbon content, sufficient to cause flotation of the algal colonies. This report is an examination of the waters of the reservoir and of the characteristics of the alga. Observations are included on the formation of a material known as Coorongite, a rubbery complex produced by the drying of colony aggregates at the shoreline. Earlier reports of “blooms” of B. braunii are reviewed in relation to this study.
Ultraviolet‐sensitive photographic process using enzymes
Authors: Kuan K. N. , Lee Y. Y. , Melius P. 
Published: December 2004

AbstractA unique silver‐free and ultraviolet (UV)‐sensitive photographic process using enzymes has been developed. It utilizes α‐chymotrypsin acylated to a light‐sensitive stereoisomeric ester as the basic photographic material. When UV light is exposed to the file, the signal is registered by the appearance of melanin pigment through the chymotrypsin‐mediated activation of pre‐tyrosinase.