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  • 1
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Recombinant fusion proteins offer important new therapeutic approaches for the future. This report describes the use of three different genetic strategies (i.e. “mono-”, “bi-” and “tri-cistronic” vectors) to achieve stable secretion from BHK cells of a glycosylated antibody-cytokine fusion protein designed for use in anti-tumour therapy. It describes selection of a robust and effective production cell line based on stability of secretion of the product, quality of mRNA and protein products and performance in in vitro bioassays for potency. The data obtained at this stage were utilised in the selection of a suitable candidate production cell line. The relative productivity and general performance of the cells in stirred tank and fixed bed culture systems indicated that a variety of cell culture technologies provided robust tools for production of a highly selected cell clone. Consistency of the product glycosylation was determined by analysis of released oligosaccharides using matrix-assisted laser desorption ionisation – time of flight mass spectrometry and high-performance anion exchange chromatography. These investigations showed consistent expression of three glycoforms of the fusion protein which varied in their relative proportions in different culture systems and at different time points in a fixed bed reactor with continuous perfusion. In conclusion, this study dealt with a range of important scientific and technical issues which are essential for regulatory approval and commercial success of a recombinant protein and elucidates some useful markers for process development for similar recombinant biologicals.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract In this work, a BHK21 clone producing a recombinant antibody/cytokine fusion protein was used to study the dependence of cell metabolism on the glucose and glutamine levels in the culture medium. Results obtained indicate that both glucose and glutamine consumptions show a Michaelis-Menten dependence on glucose and glutamine concentrations respectively. A similar dependence is also observed for lactate and ammonia productions. The estimated value of the Michaelis constant for the dependence of lactate production on glucose (K Glc Lac) was 1.4 ± 0.1 mM and for the dependence of ammonia production on glutamine (K Gln Amm) was 0.25 ± 0.11 mM and 0.10 ± 0.03 mM, at glucose concentrations of 0.28 mM and 5.6 mM respectively. At very low glucose concentrations, the glucose to lactate yield decreased markedly, showing a metabolic shift towards lower lactate production. This␣metabolic shift was also confirmed by the significant increase in the specific oxygen consumption rate also observed at low glucose concentrations. Although it was␣highly dependent on glucose concentration, the oxygen consumption also increased with the increase in␣glutamine concentration. At very low glutamine concentrations, the glutamine to ammonia yield increased, showing a more efficient glutamine metabolism.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Oxford, UK : Blackwell Publishing Ltd
    Annals of the New York Academy of Sciences 745 (1994), S. 0 
    ISSN: 1749-6632
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Natural Sciences in General
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    Journal of industrial microbiology and biotechnology 13 (1994), S. 63-69 
    ISSN: 1476-5535
    Keywords: Flocculation ; Fluidized bed reactor ; Lactic starter cultures ; Lactobacillus plantarum ; Viability ; Dilution rate ; Bleed rate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary The influence of different operational parameters, such as the dilution rate (D) and the bleeding rate (B), in the production of a flocculent strain ofLactobacillus plantarum was studied. The effect of the dilution rate was demonstrated to be related to the lactic acid concentration inside the reactor. The effect of the bleeding rate was shown to be critical in the stabilization of the operation (due to a better pH control). It also allowed a continuous recovery of cells outside the reactor. Viability testing of the lactic starter cultures showed that operation with cell purge increased the viability of the starter cultures obtained.
    Type of Medium: Electronic Resource
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  • 5
    Electronic Resource
    Electronic Resource
    Springer
    Biotechnology letters 11 (1989), S. 337-342 
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A lactic starter culture of a flocculentLactobacillus plantarum was produced in a fluidized bed reactor with higher cell volumetric productivities than in a continuous stirred tank reactor. The fluidized bed reactor was operated at optimised parameters obtained in batch reactor performed with and without pH control.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Biotechnology letters 12 (1990), S. 145-148 
    ISSN: 1573-6776
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A culture of SRB growing in lactate was incubated at different pH values in the range of 5.8 to 7.0. Highest growth rates were observed at pH 6.6. Under gás (H2S) stripping conditions the specific growth rate decreased with the undissociated acetic acid produced. An inhibition of SRB growth of 50% was observed for undissociated acetic acid concentrations of approximately 54 mg/L.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Anaerobic treatment of distillery wastewaters containing high sulfate concentrations was carried out on a two-phase process. The acidogenic phase was operated so as to produce the more favourable intermediates for methanogenic bacteria coupled with maximum sulfate removal. Sulfate removal was directly affected by pH and dilution rate (D). The maximum sulfate removal and acetic acid production was achieved at pH 6.6 and D=0.035 h−1. A linear relationship between acetic acid produced and sulfate removal was observed, indicating that acetic acid was mainly produced by sulfate reducing bacteria with important operational advantages. Higher concentrations of butyric acid were obtained at low pH values and high dilution rates.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Springer
    Applied microbiology and biotechnology 36 (1991), S. 145-147 
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Summary A sulphate-reducing culture of the genus Desulfovibrio was directly inhibited by the hydrogen sulphide (H2S) produced. Batch experiments carried out at pH 6.2 and 6.6 show that complete inhibition is achieved for almost the same H2S concentration of approximately 550 mg/l.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract The growth and productivity of an Sp2/0 cell line, F3b10, expressing a recombinant antibody (rAb) and BHK21 cells expressing either the same rAb from the same plasmids (BHK.IgG) or secreted alkaline phosphatase (SEAP) (BHK.SEAP) were investigated. The F3b10 line was grown as a single cell suspension. The BHK lines were grown either as suspended natural aggregates or on Cytodex 3 microcarriers. The data for F3b10 showed that the cell-specific rAb production rate (Qs rAb) increased in parallel with increases in the specific growth rate (μ). A similar result was obtained for suspended aggregate cultures of both recombinant BHK cell lines. In contrast, for microcarrier cultures of both BHK cell lines, Qs product increased as μ decreased. This report shows that the relationship between cell growth and Qs product for the cell lines and products studied is dependent upon the culture process. In systems where recombinant cells are growing as a single cell suspension or within a natural suspension aggregate, Qs product increased with increases in μ. In such systems, the cells have a rounded morphology. When cells were grown on microcarriers, Qs product decreased as μ increased. Cells growing attached to a surface are flat and elongated. The observed differences in the relationship of Qs product to μ are correlated with changes in cell morphology. The relationship between Qs product and μ is also affected by the choice of cell line.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 1432-0614
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract. The growth and productivity of an Sp2/0 cell line, F3b10, expressing a recombinant antibody (rAb) and BHK21 cells expressing either the same rAb from the same plasmids (BHK.IgG) or secreted alkaline phosphatase (SEAP) (BHK.SEAP) were investigated. The F3b10 line was grown as a single cell suspension. The BHK lines were grown either as suspended natural aggregates or on Cytodex 3 microcarriers. The data for F3b10 showed that the cell-specific rAb production rate (QsrAb) increased in parallel with increases in the specific growth rate (μ). A similar result was obtained for suspended aggregate cultures of both recombinant BHK cell lines. In contrast, for microcarrier cultures of both BHK cell lines, Qsproduct increased as μ decreased. This report shows that the relationship between cell growth and Qsproduct for the cell lines and products studied is dependent upon the culture process. In systems where recombinant cells are growing as a single cell suspension or within a natural suspension aggregrate, Qsproduct increased with increases in μ. In such systems, the cells have a rounded morphology. When cells were grown on microcarriers, Qsproduct decreased as μ increased. Cells growing attached to a surface are flat and elongated. The observed differences in the relationship of Qsproduct to μ are correlated with changes in cell morphology. The relationship between Qsproduct and μ is also affected by the choice of cell line.
    Type of Medium: Electronic Resource
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