bluuebunny/crossref_metadata_2025_split huggingface dataset:
Characterization and immobilization of E. coli (ATCC‐26) β‐galactosidase
Authors: Wondolowski M. V. , Woychik J. H. 
Published: December 2004

AbstractThe β‐galactosidase from Escherichia coli ATTCC‐26 was partially purified and characterized. It was found to be comparable to galactosidases from other E. coli strains in stability, pH and temperature maxima, and activity requirements, but it had a more favorable ratio of activity toward lactose versus synthetic substrates. The galactosidase was immobilized on porous glass beads by three covalent bonding methods. Kinetic data for the free and bound enzymes were determined using natural and synthetic substrates. Activity characteristics of the free and immobilized enzymes were comparable, however, the bound forms were less stable to heat.
Transient behavior of a continuous stirred tank biological reactor utilizing phenol as an inhibitory substrate
Authors: Chi C. T. , Howell J. A. 
Published: December 2004

AbstractTransient experiments were conducted on a Pseudomomas utilizing phenol in a continuous culture by disturbing the influent substrate concentration and dilution rate. Two stable steady states existed for some ranges of the parameters. Highly damped oscillations were observed in approaching a new high conversion steady state or in returning to a new high conversion steady state following a small disturbance. When a large disturbance was applied there was a smooth (overdamped) approach to a new low conversion steady state.The observed oscillatory behavior for small disturbances was predicted by a modified Powell‐Ierusalemskii bottleneck model, but could not be predicted by a Monod‐Haldane model; neither model was accurate for predicting the effect of large disturbances.A constant wall growth factor was used to account for microbial film activity, and the existence of two stable states was directly due to the presence of the film.
Dense growth of aerobic bacteria in a bench‐scale fermentor
Authors: Bauer S. , Ziv E. 
Published: December 2004

AbstractEscherichia coli B, Escherichia coli MRE 600, Escherichia coli K 12‐3300, Pseudomonas fluorescens, and Aerobacter aerogenes were grown exponentially in a bench‐scale fermentor to cell concentrations in the range of 20 to 41 g dry cells/liter at 30°C and 30 to 55 g dry cells/liter at 25°C. The high cell concentrations were achieved in a growth system previously described for growth of Escherichia coli W (Biotechnol. Bioeng., 16, 933 (1974); ibid. 17, 227 (1975)). Various enzyme activity levels in the high‐concentration cells were compared to those in cells grown in conventional low‐density cultures. No significant differences were found. The culture supernatants were found to be essentially free of high‐molecular weight metabolic or cell lysis products. Yield constants for glucose, nitrogen, oxygen, and phosphorus were also determined in the dense cultures and some of their relations to the growth conditions are discussed.
Hydrolysis of D‐galactosides in an open tubular lactase reactor
Authors: Ngo T. T. , Narinesingh D. , Laidler K. J. 
Published: December 2004

AbstractLactose (β‐galactosidase) was attached to the inner surface of nylon tubing. Tubes of various lengths were used to bring about the hydrolysis of o‐nitrophenyl‐β‐D‐galactoside and of lactose in skim milk. The results with the former substrate were analyzed in the light of a theoretical treatment of Kobayashi and Laidler (Biotechnol. Bioeng., 16, 99, 1974), with the conclusion that the reaction is intermediate between diffusion‐free and completely diffusion‐controlled behavior. The results with skim milk show that with a single 46 m tube and continuous circulation, 90% of the lactose is removed within 20 hr. A battery of ten such tubes, with single passage, at a flow rate of 2 cm/sec, would remove more than 99% of the lactose in less than 40 min.
The application of constant recycle solids concentration in activated sludge process
Authors: Bonotan‐Dura F. M. , Yang P. Y. 
Published: December 2004

AbstractThe applicability of the model derived by Ramanathan and Gaudy (Biotechnol. Bioeng., 11, 207, (1969)) for completely mixed activated sludge treatment holding the recycle solids concentration as a system constant was investigated using an actual industrial organic wastewater. Short‐term experiments were conducted at various dilution rates (1/8, 1/6, 1/4, 1/2, 1/1.5 hr−1) for two recycle solids concentration values (5000 and 7000 mg/liter). The influent substrate concentration was maintained at 1000 mg/liter COD and the hydraulic recycle ratio, α, was kept at 0.3. It was found that for bottling plant (Pepsi Cola) waste‐waters, a steady state with respect to reactor biological solids and effluent COD, at different dilution rates, could be attained, lending experimental evidence to the assumption that a steady state could be reached in developing the model and also affecting the applicability of the model in industrial organic wastewater. The reactor biological solids and effluent COD calculated from the model closely agreed with the observed values at dilution rates lower than 0.5 hr−1. Operation at dilution rates higher than 0.5 hr−1 will washout the biological solids from the reactor and the recycle substrate concentration will be apparent if the concentration of XR were not increased.
Transient response of Enterobacter aerogenes under a dual nutrient limitation in a chemostat
Authors: Cooney Charles L. , Wang Daniel I. C. 
Published: December 2004

AbstractUtilizing a chemostat with a dual nutrient limitation of nitrogen and phosphate, we examined the transient response of the culture following a pulse of one of the limiting nutrients (ammonia). This method provided quantitative evidence that cells can be grown under dual nutrient limitation. Furthermore, the pattern of response was consistent with the hypothesis that phosphate limitation restricts nucleic acid synthesis in the cell and that nitrogen limitation restricts protein synthesis. The net result is that under a phosphate limitation there is a restricted biosynthetic capacity which we feel is closely associated with the RNA content of the cell.
Preparation and properties of soluble–insoluble nicotinamide coenzymes
Authors: Coughlin Robert W. , Aizawa Masuo , Charles Marvin 
Published: December 2004

AbstractA soluble–insoluble form of nicotinamide adenine dinucleotide (NAD+), which can be rendered either soluble or insoluble by simply adjusting the pH, has been prepared by covalently coupling NAD to alginic acid using 1,2,7,8‐diepoxyoctane. The NAD bound to the alginic acid showed the coenzymic function in the soluble state and could be collected for further use as a precipitate by lowering the pH to below 3. Coupling soluble–insoluble coenzymes with insolubilized apoenzymes is possible in fluidized and fixed‐bed reactors.
Electrolytic regeneration of the reduced from the oxidized form of immobilized NAD
Authors: Aizawa Masuo , Coughlin Robert W. , Charles Marvin 
Published: December 2004

AbstractA covalently bound adduct of nicotinamide adenine dinucleotide (NAD) with alginic acid has been found to be enzymatically active and to undergo electrochemical oxidation or reduction without significant loss of its enzymatic activity. The preparation of the adduct itself (from NAD+, alginic acid, and 1‐cyclohexyl‐3‐(2‐morpholinoethyl)‐carbodiimide metho‐p‐toluenesulfonate) is also accomplished with substantially complete retention of enzymatic activity. This adduct has been converted from the oxidized to the reduced form by controlled potential electrolysis using mercury and stainless‐steel electrodes. This electrolytically produced NADH complex could be oxidized again to the enzymatically active NAD+ complex by enzymatic reaction with the proton acceptor, 2,6‐dichlorophenol indophenol, as catalyzed by diaphorase. Using this electrolytic method with immobilized NAD, it is now possible to carry out redox reactions in which NADH is enzymatically oxidized to NAD+, with the simultaneous electrolytic regeneration of the reduced form, NADH, from the oxidized form, NAD+, produced in the enzymatic reaction.
Autoclavable low cost serum‐free cell culture media: The growth of established cell lines and production of Viruses
Authors: Keay Leonard 
Published: December 2004

AbstractFive cell lines (BSC‐1, CHO, Balb/c 3T3, HeLa, and KB) have been grown in serum‐free media for several months with regular schedules of media changing and subculturing. The medium found to be successful in all cases was MEM‐α (without the ribosides and deoxyribosides) supplemented with 1% bactopeptone, although simple MEM [minimum essential medium (Eagle)] with bactopeptone (BP) gave fairly good growth in the case of BSC‐1 and 3T3 cells. The addition of insulin was necessary for CHO, 3T3, HeLa, and KB cells. Only the BSC‐1 cells grew exclusively as a monolayer in the serum‐free systems, the CHO, HeLa, and KB cells growing as stationary suspensions and the 3T3 cells growing as a combination of monolayer and suspension depending on the age of the culture and the nature of the growth surface. SV40 was produced in BSC‐1 cells grown and infected in the MEM‐α, bactopeptone medium and adenovirus‐2 was produced in spinners of HeLa and KB cells grown in MEM‐α, bactopeptone, PVP‐360, and insulin. The yield of virus and infectivity of the viruses produced were about the same as those produced in conventional serum‐containing systems.
Glucose isomerase immobolized on porous glass
Authors: Lee Y. Y. , Fratzke A. R. , Wun K. , Tsao G. T. 
Published: December 2004

AbstractPartially purified glucose isomerase from a Streptomyces species was immobilized on porous glass particles and studied for various characteristics concerning its use as an industrial catalyst. The activities were investigated in relation to the reaction parameters and the enzyme deactivation was studied systematically under various reaction conditions. The half‐life of the immobilized enzyme was found to exceed 200 days at 50°C. The rate equation of the reversible glucose ⇄ fructose reaction was derived and the kinetic constants were determined. The rate equation was found to be in good agreement with experimental data for both forward and reverse reactions. The degree of diffusional effects was experimentally measured and theoretically analyzed.
Cell inactivation by ultrasound
Authors: Dakubu S. 
Published: December 2004

AbstractCell survival curves have been obtained for Escherichia coli B (E. coli B) after the sonication of suspensions of the bacteria with continuous wave ultrasound at a fixed frequency of 2 MHz between peak intensities of 8.7 and 2.25 W cm−2. It was found that under suitable conditions the survival curves were reproducible and it also was found that there was a clear relationship between the rate of inactivation and the peak acoustic intensity of the ultrasound. There appeared to be a lower threshold of peak intensity below which no inactivation was observed.
Kinetic analysis of Penicillin production by semicontinuous fermenters
Authors: Giona A. R. , Marrelli L. , Toro L. , De Santis R. 
Published: December 2004

AbstractThe relationships between the specific rate of nutrient consumption and biomass growth and between the specific rate of penicillin production and oxygen concentration in the broth are analyzed.The functional dependencies which have been obtained from the experimental data of industrial fermenters are used with the mass balances to develop a model of the behavior of semicontinuous operations. The proposed model allows one to study the influence of some operational parameters.The obtained results agree with the data of industrial processes.
The Influence of oxygen concentration and of specific rate of growth on the kinetics of Penicillin production
Authors: Giona A. R. , De Santis R. , Marrelli L. , Toro L. 
Published: December 2004

AbstractThe role of fundamental parameters in the conduction of penicillin semicontinuous fermentations is analyzed. Biomass concentration, penicillin production, and main nutrient consumption are particularly studied. Furthermore, the conduction of the operation is simulated with regard to conditions of constant specific rate of growth and of constant oxygen concentration in the broth. An intermediate condition is also considered.
Characterization of sand as a support for immobilized enzymes
Authors: Brotherton Jeffrey E. , Emery Alden , Rodwell Victor W. 
Published: December 2004

AbstractThe potential of sand as a support for immobilized enzymes was investigated by preparing alkylamine sand and devising methods to measure the total number of amine groups present and the fraction available for immobilization of enzymes. Alcohol dehydrogenase (alcohol:NAD oxidoreductase, EC 1.1.1.1) and lactate dehydrogenase (L‐lactate: NAD oxidoreductase, EC 1.1.1.27) were immobilized on alkylamine sand, and the stability of the immobilized protein and dehydrogenase activity was measured. Urease (urea amidohyrdrolase, EC 3.5.1.5) was also immobilized on sand to test the applicability of these methods to larger scale immobilizations. Results suggest that sand shows promise as a support for immobilized enzymes.
Immobilized enzymes on chitosan columns: α‐Chymotrypsin and acid phosphatase
Authors: Muzzarelli Riccardo A. A. , Barontini Gaetano , Rocchetti Roberto 
Published: December 2004

Abstractα‐Chymotrypsin and acid phosphatase have been immobilized on chitosan, a polyaminosaccharide, without using any intermediate reagent; the immobilized enzymes are active and their activity is much higher than for chitin‐immobilized enzymes. The best pH conditions for operating chitosan columns have been determined and columns have been used to transform substrates in large amounts, with no decrease of activity or enzyme losses. Due to the nonconvalent interaction between chitosan and enzymes, the pure and active enzymes can be eventually recovered from the columns. The effects of metal ions, aldehydes, and salts are reported and discussed. Applications are foreseen in the food and biomedical sciences and industries.
Carbon dioxide inhibition of yeast growth in biomass production
Authors: Chen S. L. , Gutmanis Feliks 
Published: December 2004

AbstractSaccharomyces cerevisiae was grown under aerobic and substrate‐limiting conditions for efficient biomass production. Under these conditions, where the sugar substrate was fed incrementally, the growth pattern of the yeast cells was found to be uniform, as indicated by a constant respiratory quotient during the entire growing period. The effect of carbon dioxide was investigated by replacing portions of the nitrogen in the air stream with carbon dioxide, while maintaining the oxygen content at the normal 20% level, so that identical oxygen transfer rate and atmospheric pressure were maintained for all experiments with different partial pressures of carbon dioxide. Inhibition of yeast growth was negligible below 20% CO2 in the aeration mixture. Slight inhibition was noted at the 40% CO2 level and significant inhibition was noted above the 50% CO2, level, corresponding to 1.6 × 10−2M of dissolved CO2 in the fermentor broth. High carbon dioxide content in the gas phase also inhibited the fermentation activity of baker's yeast.
An immobilized two‐enzyme system for the activation of the lactoperoxidase antibacterial system in milk
Authors: Björck L. , Rosén C‐G. 
Published: December 2004

AbstractLactoperoxidase catalyzes the oxidation of thiocyanate by hydrogen peroxide and an intermediary product is formed with antibacterial properties. The components of this system, with the exception of hydrogen peroxide, are present in milk. H2O2 may be introduced by means of enzymatic, generation and thus make the system complete. A two‐enzyme system consisting of β–galactosidase and glucose oxidase has been developed for this purpose. The coupled enzyme reaction is shown to work with high efficiency at the neutral pH of milk although the enzymes as such, particularly lactases suitable for immobilization, have optimal activities at much lower pH values. The results indicate that the lactoperoxidase system may in this way be employed to inactivate bacteria present in milk.
Oxygen transfer and mixing in a tower cycling fermentor
Authors: Lin C. H. , Fang B. S. , Wu C. S. , Fang H. Y. , Kuo T. F. , Hu C. Y. 
Published: December 2004

AbstractTower cycling fermentors for the production of single‐cell protein from volatile substrates were studied. The mass transfer, mixing and circulation patterns, and residence time distribution (RTD) curves were investigated in these vessels. This study suggests that the tower cycling fermentors for volatile substrates fermentation may improve product yields and at the same time reduce the power consumption, thereby resulting in a significant increase in operating cost savings and capital profits. The results of this research further indicate a future potential for commercial scale tower cycling fermentors.
Immobilization of enzymes based on hydrophobic interaction. I. Preparation and properties of a β‐amylase adsorbate
Authors: Caldwell Karin Dahlgren , Axén Rolf , Wall Margareta Berg , Porath Jerker 
Published: December 2004

AbstractSweet potato β‐amylase (α‐1,4 glucan maltohydrolase, EC 3.2.1.2) was immobilized through adsorption onto an agarose gel to which nonpolar side chains had been introduced via ether bridges.The adsorbent showed evidence of saturation at an enzyme content of 35 mg per milliliter of packed gel. The adsorption was rapid and yielded a product whose operational stability depended on the initial content of β‐amylase. Activity leakage was low. The relative activity of immobilized enzyme was inversely related to the amount of enzyme adsorbed to a given gel volume, having a maximal value of around 50% at low enzyme contents.
Bacterial yields on methanol, methylamine, formaldehyde, and formate
Authors: Goldberg I. , Rock J. S. , Ben‐Bassat A. , Mateles R. I. 
Published: December 2004

AbstractSeveral bacteria utilizing C1‐compounds as sole carbon sources were grown on these substrates in continuous culture. The molar yield values (g of cell dry wt/mol of substrate utilized) of bacteria which utilize C1‐compounds via the ribulose monophosphate pathway were between 15.7 to 17.3 when grown on methanol; while the molar yield values of bacteria which use the serine pathway for the assimilation of C1‐compounds varied between 9.8 and 13.1. The molar yield values of different bacteria which use the serine pathway decreased as the oxidation levels of the C1‐growth substrates increased. On formaldehyde the values were between 7.2 to 9.6, whereas on formate the values varied from 3.3 to 6.9.It appears that bacteria utilize Cl‐compounds more efficiently via the ribulose monophosphate pathway than via the serine pathway. The oxidation step from methanol to formaldehyde (and from methylamine to formaldehyde) in the bacteria studied may be energy yielding. A comparison has been made between the experimental yield values obtained and theoretical values.
Galactose Oxidase: Applications of the covalently immobilized enzyme in a packed Bed configuration
Authors: Dahodwala S. K. , Weibel M. K. , Humphrey A. E. 
Published: December 2004

AbstractGalactose oxidase (E.G. 1.1.3.9) was covalently immobilized to chemically modified porous silica particles by reaction of the native enzyme with pendant benzoyl azide groups on the carrier. The enzyme loading on the carrier was 100–150 units per milliliter. The immobilized enzyme was incorporated into a hardware assembly suitable for the determination of galactose or lactose concentrations in complex biological fluids. The prototype instrument as described is suitable for continuous, on‐line monitoring or discrete sample analysis. Reaction conditions can be readily provided which maintain global first order kinetics within the reactor and strict linearity of the procedure over a wide range of sample concentrations. Auto‐inactivation of the immobilized enzyme can be prevented by K3Fe(CN)6 and long‐term reactor stability can be achieved by the periodic application of the reagent to the enzyme reactor in situ.
The application of constant recycle solids concentration in completely mixed oxygen activated sludge process
Authors: Lin L. J. , Yang P. Y. 
Published: December 2004

AbstractFor better operational control of the completely mixed oxygen activated sludge process (CMOAS), a study concerning the kinetics, performance, and operational stability of the Ramanathan‐Gaudy model was conducted. Short‐term experiments were conducted at various dilution rates (1/9, 1/6, 1/3, 1/1.5, and 1/1.0 hr−1) by using two recycle solids concentration values (5000 and 10,000 mg/liter). The influent substrate was an actual industrial organic wastewater (soft drink waste) and its concentration was maintained at 1000 mg/liter COD. The hydraulic recycle ratio, α, was maintained at 0.30.It was found that for CMOAS system with constant recycle cell concentration, a “steady state” with respect to reactor biological solids and effluent COD at different dilution rates could be attained. No appreciable dilute‐out of reactor biological solids and substrate was observed up to the dilution rate of 1 hr−1 for both systems of different XR (5000 and 10,000 mg/liter). For the system of XR = 5000 mg/liter, except the dilution rate of hr−1, the effluent filtrate COD was lower than 100 mg/liter, the aerator biological solids concentration was about 1550 mg/liter, and the COD removal efficiency was higher than 90% for all dilution rates. For the system of XR = 10,000 mg/liter, the effluent filtrate COD was lower than 71 mg/liter, the aerator biological solids concentration was about 2750 mg/liter, and the COD removal efficiency was higher than 90% throughout all the dilution rates selection in the present study. The value of the Sludge Volume Index (SVI) was the range of 37.0 to 58.5 and provided good settleability of sludge. The sludge yield was 0.53 for the system of XR = 5000 mg/liter and 0.57 for the system of XR = 10,000 mg/liter. The carbohydrate and the protein content of the cells were 10.1–21.6% and 35.6–50.6%, respectively.For predicting the reactor biological solid and effluent COD of the CMOAS system by using the Ramanathan‐Gaudy model, two sets of values for the biological kinetic constants should be considered since it provided the best fit of predicted values of the observed values. In the present study, μm = 0.4 hr−1, ks = 92 mg/liter for 1/3 ⩽ D ⩽ 1, and μm = 0.05 hr−1, ks = 11.1 mg/liter for 1/9 ⩽ D < 1/3 were used to calculate the predicted values of reactor biological solid and effluent filtrate COD.
Continuous proteolysis with a stabilized protease. I. Chemical stabilization of an alkaline protease
Authors: Boudrant J. , Cuq J. L. , Cheftel C. 
Published: December 2004

AbstractDue to the loss of enzymatic activity as a function of time, an alkaline protease, selected for the continuous preparation of protein hydrolysates (J. Boudrant and C. Cheftel, Biotechnol. Bioeng., 18, 1735, 1976), was chemically stabilized by a simple treatment with glutaraldehyde. Two fractions, soluble and insoluble, were obtained. The activities of these two fractions were measured with casein and N‐benzoyl‐L‐arginine ethyl ester (BAEE) as a function of glutaraldehyde concentration used. It was noted that the insoluble fraction was practically inactive with the first substrate and that the heat stability of the soluble form was likewise enhanced. Molecular weights of these two forms were unchanged, but the uv‐spectrum of the soluble form was modified. From amino acid analysis, it appears that this treatment mainly provokes a decrease in lysine content.