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  • 1
    ISSN: 1573-8272
    Keywords: effective diffusivities ; immunoglobulin M ; isotherms ; protein purification ; Sepharose Fast Flow
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Measurement of adsorption breakthrough curves in packed beds has shown that the amounts and rates of uptake of immunoglobulin M (IgM) onto the commonly used anionic ion-exchanger Q Sepharose Fast Flow(based on 6% agarose) are severely limited as a result of the large molecular size of this adsorbate(RMM 950000). A similar ion-exchanger based on a more porous 4% agarose, Q Sepharose 4 Fast Flow was evaluated as an alternative adsorbent for the purification of IgM. Equilibrium adsorption isotherms and the effective diffusivities of IgM within these two adsorbents were measured. Q-Sepharose 4 Fast Flow was found to have a maximum capacity for IgM 2.5 times greater than that of Q Sepharose 6 Fast Flow and the effective diffusivity of IgM was found to be between 6 and 7 times greater than with the latter material. Comparison of the breakthrough curves obtained for these adsorbents at a variety of flow velocities confirm that Q Sepharose 4 Fast Flow is a superior adsorbent for the capture and purification of large proteins.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1573-8272
    Keywords: anti-paraquat ; batch uptake ; diffusivity ; immunosorbents ; Langmuir adsorption isotherm ; paraquat ; protein conjugates ; Sepharose 4B
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A series of paraquat-protein conjugates of different molecular size has been prepared by the coupling of paraquat hexanoate to the proteins lysozyme, ovalbumin, bovine serum albumin. The characteristics of the adsorption of these conjugates to an immunosorbent consisting of monoclonal anti-paraquat antibodies covalently immobilised to Sepharose 4B have been determined. Equilibrium adsorption isotherms were found to obey the Langmuir equation and indicated that 80% or more of the antibody binding sites were accessible to the conjugates. The rates of mass transfer of the conjugates to their adsorption sites on the immobilised antibodies was well described by a model in which mass transfer is controlled by transfer across the external film and diffusion within the porous adsorbent bead. The effective diffusivities of the conjugates within the immunosorbent were measured and has allowed the effect of the size of the adsorbing molecule on the rate of adsorption to be considered. The amount of paraquat that could be adsorbed and the rates of adsorption decreased as the size of the protein to which it is conjugated increased. The diffusivity of the conjugates within the pores of the adsorbent is reduced between two and five times compared to their diffusivities in free solution. The reduction is greater for the larger proteins and the variations of the effective diffusivities and the pore diffusivities with the molecular weight of the conjugate can be well described with simple correlations.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    Biotechnology techniques 5 (1991), S. 115-120 
    ISSN: 1573-6784
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The use of Cytophaga lysing enzymes was investigated for the liberation of poly-β-hydroxybutyrate (PHB) granules from the Gram-negative bacterium Alcaligenes eutrophus. Complete cell lysis was approached within a 60 minute period. Contrary to previous findings for the lysis of Gram-negative bacteria, prior removal of the outer membrane was not essential for enzymic lysis. The destabilisation of the outer membrane by the removal of divalent cations resulted in no significant improvement in the disruption process.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Biotechnology techniques 12 (1998), S. 245-251 
    ISSN: 1573-6784
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A simple method for the selection of affinity ligands from proteolytic digests by affinity chromatography is proposed. A small proportion of the peptides in the trypsin digest of bovine serum albumin (BSA) or the pepsin digest of cytochrome are retarded on insulin-immobilised or HSA (human serum albumin)-immobilised affinity columns, respectively. The peptides in these selected fractions can be immobilised onto solid phases and used in affinity chromatography procedures for the purification of insulin or HSA. © Rapid Science Ltd. 1998
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Hoboken, NJ : Wiley-Blackwell
    AIChE Journal 35 (1989), S. 1980-1992 
    ISSN: 0001-1541
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A study was made of phenol degradation by bacteria immobilized onto particles of calcined diatomaceous earth in a draft-tube, three-phase fluidized-bed reactor.A mathematical model is used to describe simultaneous diffusion and reaction of oxygen and phenol in the reactor. Kinetic parameters for the growth of nonsupported cells were obtained in batch and chemostat experiments. Liquid-solid mass transfer coefficients were determined experimentally and showed good agreement with literature values for conventional three-phase fluidized beds. Experimental steady-state degradation data were used to calculate biofilm substrate diffusivities. These were found to decrease as the biofilm density increased.The transition from phenol to oxygen-limiting biofilm kinetics predicted by the model was shown to exist experimentally. A critical ratio of phenol/dissolved oxygen concentration was found at which this transition occurred. This provides a criterion for establishing whether increased aeration will increase the volumetric degradation rate.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0006-3592
    Keywords: malate dehydrogenase ; protein chromatography ; Saccharomyces cerevisiae ; direct extraction ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A novel technique for protein chromatography has been developed, which can be used to extract proteins from particulate-containing solutions (such as fermentation broths or preparations of disrupted cells) on a continuous basis, and delivers clarified streams of purified product. Adsorbents deployed in this type of contactor are based on PVA-coated perfluorocarbons derivitized with affinity ligands such as triazine dyes. In this article, we describe the application of this equipment for the continuous purification of malate dehydrogenase from an unclarified homogenate of Saccharomyces cerevisiae, using a Procion Red HE-7B-derivitized adsorbent. Although operating conditions were not optimized to produce a product of maximized purification factor, concentration, and yield, we have shown that MDH can be purified continuously in 78% yield at a rate of 70 U/min, with a purification factor of approximately 10. This corresponds to specific productivity of approximately 0.35 U/min per milliliter of settled adsorbent, a higher specific productivity than was feasible with the same adsorbent using expanded bed adsorption (EBA). © 1997 John Wiley & Sons, Inc. Biotechnol Bioeng 53: 427-441, 1997.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 341-354 
    ISSN: 0006-3592
    Keywords: affinity chromatography ; perfluoropolymers ; expanded bed ; dye-ligand ; dehydrogenases ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Malate dehydrogenase (MDH) and glucose 6-phosphate dehydrogenase (G6PDH) have been partially purified from preparations of homogenized yeast cells using Procion Yellow H-E3G and Procion Red H-E7B, respectively, immobilized on solid perfluoropolymer supports in an expanded bed. A series of pilot experiments were carried out in small packed beds using clarified homogenate to determine the optimal elution conditions for both MDH and G6PDH. Selective elution of MDH using NADH was effective but the yields obtained were dependent on the concentration of NADH used. Selective elution was found to be most effective when a low concentration of NaCl (0.1 M) was present. MDH could be recovered in 84% yield with a purification factor of 94 when this strategy was adopted. In the case of G6PDH, specific elution using NADP+ was successful in purifying G6PDH 178-fold in 96% yield. The dynamic capacity of both affinity supports was estimated by frontal analysis, in an expanded bed with unclarified homogenate, and corresponded to 17 U MDH/mL of settled Procion Yellow H-E3G perfluoropolymer support and 7.7 U H6PDH/mL of settled Procion Red H-E7B perfluoropolymer support. Expanded bed affinity chromatography of MDH resulted in an eluted fraction containing 89% of the applied activity with a purification factor of 113. Expanded bed affinity chromatography of G6PDH resulted in an eluted fraction containing 84% of the applied activity with a purification factor of 172. With both enzymes, the overall recovery of enzyme activity was greater than 94%, showing that the expanded bed approach to purification was nondenaturing. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Chichester : Wiley-Blackwell
    Journal of Chemical Technology AND Biotechnology 59 (1994), S. 106-106 
    ISSN: 0268-2575
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 9 (1996), S. 575-584 
    ISSN: 0952-3499
    Keywords: perfluorocarbon ; affinity chromatography ; counter-current ; lysozyme ; triazine dyes ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: In this work the development of a process capable of extracting proteins from particulate-containing solutions (such as fermentation broths) on a continuous basis, and in which adsorbent and process streams are contacted counter-currently is described. The process consists of four stages, required for the loading, washing, elution and regeneration of the adsorbent. Because of its counter-current nature, it has imporved performance over existing (though not yet commercialized) continuous processes, which have been based on CSTR-type contractors e.g. PERCAS (McCreath et al., 1993). The improved efficiency has been shown by carrying out extraction of lysozyme from a single component feed stream. The adsorbent used in this work is a Procion Red HE-7B-derivatized perfluorocarbon support, which has shown particular suitability for continuous processes due to its inherently high mechanical strength and high density. Results illustrating yields obtained using this equipment are presented and discussed.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Chicester [u.a.] : Wiley-Blackwell
    Journal of Molecular Recognition 9 (1996), S. 607-616 
    ISSN: 0952-3499
    Keywords: cell separation ; perfluorocarbon emulsion ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Medicine
    Notes: Perfluorocarbon affinity emulsions have been generated by immobilizing concanavalin A onto the surface of triazine-activated perfluorocarbon droplets. Immobilized concanavalin A densities of 0.1, 0.7 and 2.1 mg/ml were obtained by varying the concentration of cyanuric chloride used for activation. The affinity emulsions were found to adsorb Saccharomyces cerevisiae cells from solution with adsorption capacities of 1 × 109 cells, 4.6 × 109 and 6 × 109 cell/ml, respectively. Optimal conditions for the elution of bound cells were obtained by studying inhibition curves of concanavalin A-mannan precipitation using simple sugars. Methyl α-D-mannopyranoside showed the greatest inhibitory power with 50 per cent inhibition displayed at a concentration of 0.05 mM. Experiments carried out examining the concentrations of methyl α-D-mannopyranoside necessary to dissociate a concanavalin A-mannan precipitate demonstrated that at least a seven-fold higher concentration of methyl α-D-mannopyranoside was required for dissociation than that required for inhibition of its formation. The efficiency of elution of bound yeast cells was found to be dependent on the concentration of methyl α-D-mannopyranoside used, the time of elution and the immobilized ligand density. Thus, 100 per cent elution was obtained with a concanavalin A affinity emulsion (0.1 mg/ml) by incubation with 500 mM methyl α-D-mannopyranoside for 1 h.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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