ALBERT

All Library Books, journals and Electronic Records Telegrafenberg

X
feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
Filter
  • Biochemistry and Biotechnology  (854)
  • 1995-1999  (854)
  • 1995  (854)
  • 1
    Electronic Resource
    Electronic Resource
    Protected amino acids as novel low-molecular-weight displacers in cation-exchange displacement chromatography (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 452-460 
    Details
    ISSN: 0006-3592
    Keywords: chromatography ; displacement ; protein purification ; cation exchange systems ; amino acid ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Although the ability to carry out simultaneous concentration and purification in a single displacement step has significant advantages for downstream processing of pharmaceuticals, a major impediment to the implementation of displacement chromatography has been the lack of suitable displacer compounds. An important recent advance in the state of the art of displacement chromatography has been the discovery that low-molecular-weight dendritic polymers can be successfully employed as displacers for protein purification in ion-exchange systems. In this article, protected amino acid esters (based on arginine and lysine) are shown to be useful displacers for protein purification in cation-exchange systems. A dynamic affinity plot is employed to evaluate the affinity of these low-molecular-weight compounds under dis-placement conditions. In contrast to large polyelectroyte displacers, the efficacy of these low-molecular-weight displacers was shown to be dependent on both the initial carrier salt concentration and the displacer concentration. In addition to the funcamental interest generated by low-molecular-weight displacers, it is likely that these displacers will have significant operatioal advantages as compared with large polyelectrolyte displacers. © 1995 John Wiley & Sons, Inc.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480507
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 2
    Electronic Resource
    Electronic Resource
    Countercurrent gradient chromatography: A continuous focusing technique (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 461-475 
    Details
    ISSN: 0006-3592
    Keywords: countercurrent gradient chromatography ; protein separation ; human serum albumin ; chromatography ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The continuous separation of proteins was performed in a countercurrent gradient chromatography (CGC) system. A magnetically stabilized fluidized bed (MSFB) was used to establish true countercurrent contact of a solid resin with a liquid buffer. STable pH gradients were formed in the system in less than 10 min and remained stable throughout the course of the separation experiment (〉2 h). The shape of the pH gradient, which ultimately controls the resolution and purity of the separation, can be controlled by making simple adjustments in the interstitial velocities of the liquid and solid phases. We have performed the separation of myoglobin and human serum albumin (HSA) using this device and achieved concentration factors of 1.75 for myoglobin and 1.2 for HSA. A mathematical model that has no adjustable parameters has been developed that predicts the focusing behaviour and capabilities of the CGC system. Using the model, we have estimated the optimum phase velocities, particle diameters, and equilibrium parameters necessary for achieving high purity and high concentrations. © 1995 John Wiley & Sons, Inc.
    Additional Material: 21 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480508
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 3
    Electronic Resource
    Electronic Resource
    Review: Protein refolding and inactivation during bioseparation: Bioprocessing implications (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 481-489 
    Details
    ISSN: 0006-3592
    Keywords: bioseparation ; protein refolding ; reverse micelles ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The recombinant production of proteins leads to inclusion bodies which contain aggregated proteins in active, partially active, and inactive conformational states. These aggregated proteins must be extracted from the inclusion bodies, unfolded, and carefully refolded to the active and the stable conformational state. Mechanistic models for protein refolding are briefly presented. Different strategies and protocols are presented that lead to the active and stable protein conformational state. The techniques presented include chaperonin-assisted refolding, amino acid substitution, polyethylene glycolassisted refolding, protein refolding in reverse micelles, and antibody-assisted refolding of proteins. The techniques presented together provide a reasonable framework of the state-of-the-art and may be carefully applied to the bioseparation of other proteins and biological macromolecules of interest. © 1995 John Wiley & Sons, Inc.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480510
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 4
    Electronic Resource
    Electronic Resource
    Purification of a pyrogen-free human growth hormone antagonist (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 520-528 
    Details
    ISSN: 0006-3592
    Keywords: human growth hormone ; animal cell culture ; purification ; serum ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Human growth hormone (hGH) is a polypeptide with 191 amino acids and a molecular mass of 22 kilodaltons. With the aid of computer molecular simulation, an hGH analog was created by altering an hGH gene to reflect the change of one amino acid (glycine [G] 120 to arginine [R]) within the third α-helix of the hGH molecule. This hGH analog, named hGHG120R, was found to be an hGH antagonist. It may have important implications in treating human conditions in which hGH levels are abnormally high, as found in type I diabetics. Several hundred milligrams of purified hGHG120R were needed to determine the biological activity of the antagonist in animal models. A multistep downstream process was developed to purify hGHG120R from cultured mouse L cells transfected with the hGHG120R gene. The process consisted of cell clarification, salt precipitation, membrane ultrafiltration, reversed phase high performance liquid chromatography, phase separation, and lyophiliation. This work discusses the rationale for the design of the process and experimental results on the purification of hGHG120R using the process. © 1995 John Wiley & Sons, Inc.
    Additional Material: 10 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480515
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 5
    Electronic Resource
    Electronic Resource
    A Time for Change (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 557-557 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480602
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 6
    Electronic Resource
    Electronic Resource
    Structured modeling and state estimation in a fermentation process: Lipase production by Candida rugosa (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 573-584 
    Details
    ISSN: 0006-3592
    Keywords: state estimation ; structured modeling ; lipase ; Candida rugosa ; fermentation ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: A simple structured mathematical model coupled with a methodology of state and parameter estimation is developed for lipase production by Candida rugosa in batch fermentation. The model describes the system according to the following qualitative observations and hypothesis: Lipase production is induced by extracellular oleic acid present in the medium. The acid is transported into the cell where it is consumed, transformed, and stored. Lipase is excreted to the medium where it is distributed between the available oil-water interphase and aqueous phase. Cell growth is modulated by the intracellular substrate concentration. Model parameters have been determined and the whole model validated against experiments not used in their determination. The estimation problem consists in the estimation of three state variables (biomass, intra- and extracellular substrate) and two kinetic parameters by using only the on-line measurement provided by exhaust gas analysis. The presented estimation strategy divides the complex problem into three subproblems that can be solved by stable algorithms. The estimation of biomass (X) and the specific growth rate (μ), is achieved by a recursive prediction error algorithm using the on-line measurement of the carbon dioxide evolution rate. μ is then used to perform an estimation of intracellular substrate and the other kinetic parameter related to substrate transport (A) by an adaptive observer. Extracellular substrate is then evaluated by means of the estimated values of intracellular substrate and biomass through the material balance of the reactor. Simulation and experimental tests showed good performance of the developed estimator, which appears suitable to be used for process control and monitoring. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480604
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 7
    Electronic Resource
    Electronic Resource
    Polyphenoloxidases immobilized in organic gels: Properties and applications in the detoxification of aromatic compounds (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 585-591 
    Details
    ISSN: 0006-3592
    Keywords: phenoloxidases ; enzyme immobilization ; reverse micelles ; organic gels ; biotic detoxification ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Gelatine gels originate from water in oil microemulsions in which the ternary system consists of isooctane/ sulfosuccinic acid bis [2-ethyl hexyl] ester/water; the solubilization of gelatin in the water pool of these microemulsions transforms them into viscous gels in which it is possible to cosolubilize various reactive molecules. These gels were used to immobilize two phenoloxidases, a laccase from Trametes versicolor and a tyrosinase from mushroom. The best balance between gel retention and catalytic activity was reached at a gelatine concentration of 2.5% (w/v) in the case of tyrosinase, while laccase immobilization was independent of gelatine concentration. Both enzymes kept the same optimum pH as the corresponding soluble controls, while a partial loss of activity was observed when they were immobilized. Immobilized enzymes showed an increased stability when incubated for several days at 4°C with a very low release from the gels in the incubation solutions. The immobilization of tyrosinase and of laccase enhanced stability to thermal inactivation. Furthermore, gel-entrapped tyrosinase was almost completely preserved from proteolysis: more than 80% of the activity was maintained, while only 25% of the soluble control activity was detected after the same proteolytic treatments. A column packed with gel-immobilized tyrosinase was used to demonstrate that enzymes immobilized with this technique may be reused several times in the same reaction without loosing their efficiency. Finally, gel-entrapped tyrosinase and laccase were capable of removing naturally occurring and xeno-biotic aromatic compounds from aqueous suspensions with different degrees of efficiency. © 1995 John Wiley & Sons, Inc.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480605
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 8
    Electronic Resource
    Electronic Resource
    Measurement of local mass transfer coefficient in biofilms (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 48 (1995), S. 737-744 
    Details
    ISSN: 0006-3592
    Keywords: biofilm ; mass transfer coefficient ; microelectrode ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Local mass transfer rates for an electrochemically formed microsink in an aerobic biofilm was measured by a mobile microelectrode using limiting current technique. Mass transfer coefficients varied both horizontally and vertically in the biofilm. The results implied the existence of an irregular biofilm structure consisting of microbial cell clusters surrounded by tortuous water channels. An unexpected increase of the local mass transfer coefficient just above the biofilm surface suggested the existence, of local flow instability in this region. As expected, the influence of bulk flow velocity on the local mass transfer rate decreased with increasing depth into the biofilm. Mass transfer coefficients fluctuated significantly inside microbial cell clusters, suggesting the existence of internal channels through which liquid could flow. A new conceptual model of biofilm microbial cluster structure is proposed to account for such biofilm microstructure irregularities. © 1995 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260480623
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 9
    Electronic Resource
    Electronic Resource
    Detachment of biomass from suspended nongrowing spherical biofilms in airlift reactors (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 46 (1995), S. 258-269 
    Details
    ISSN: 0006-3592
    Keywords: biofilm ; detachment ; abrasion ; breakage ; airlift reactor ; hydrodynamics ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: In three-phase internal loop airlift reactors, the detachment of biomass from suspended biofilm pellets in the presence of bare carrier particles was investigated under nongrowth conditions. The detachment rate was dominated by collisions between bare carrier particles and biofilm pellets. The concentration of bare carrier particles and the carrier roughness strongly influenced the detachment rate. A change in flow regime from bubbling to slug flow considerably increased the detachment rate. Otherwise, the superficial gas velocity did not directly affect the detachment rate. The influence of particle size was not clear. The bottom clearance did not affect the detachment rate within the tested range. Other aspects of reactor geometry might be important. The main detachment processes were abrasion and breakage of biofilm pellets. During the detachment process, two phases could be distinguished. In the first phase the detachment was relatively high, and both breakage and abrasion of biofilm pellets occurred. During the second phase, breakage dominated and the detachment rate was lower. The two-phase behavior is explained by differences in strength between the inner and outer biofilm layers, possibly caused by variations in local growth rates during biofilm formation. Differences in growth history might also explain the various detachment rates observed with different biofilm batches. © 1995 John Wiley & Sons, Inc.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260460309
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
  • 10
    Electronic Resource
    Electronic Resource
    A reagentless amperometric electrode based on carbon paste, chemically modified with D-lactate dehydrogenase, NAD+, and mediator containing polymer for D-lactic acid analysis. II. On-line monitoring of fermentation process (1995)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 46 (1995), S. 280-284 
    Details
    ISSN: 0006-3592
    Keywords: D-lactate ; biosensor ; on-line monitoring ; fermentation ; carbon paste electrode ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production of D-lactic acid by Lactobacillus delbrueckii (ATCC 9649) during fermentation was monitored on-line with a reagentless D-lactate dehydrogenase modified carbon paste electrode in a flow injection system integrated with a filtration sampling device. The time delay between sampling and detection was approximately 6 min. The use of an electropolymerized ortho-phenylenediamine membrane on the elctrode resulted in a very selective sensor response with acceptable stability and sensitivity. The D-lactate concentrations determined on-line agreed well with those determined by a standard method, suggesting that this sensor system is suitable for on-line monitoring of fermentation processes. © 1995 John Wiley & Sons, Inc.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260460311
    Location Call Number Expected Availability
    BibTip Others were also interested in ...
    Paper (German National Licenses)
    Fulltext
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...