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  • 1
    Electronic Resource
    Electronic Resource
    Kinetics of efrotomycin synthesis in a synthetic fermentation medium (1992)
    Springer
    Bioprocess and biosystems engineering 7 (1992), S. 257-263 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Experiments using a soluble, chemically defined fermentation medium provided important knowledge about the kinetics of efrotomycin biosynthesis. Equivalent titers were obtained in a batch process in both shaker flasks and fermentors. By extended feeding of both monosodium glutamate and glycerol at elevated temperatures, in combination with sulphuric acid pH control, the specific production rate was increased 2.8 fold and overall production rate was improved 5-fold. If the monosodium glutamate was fed too fast, then ammonium accumulated with indications of strong repression of efrotomycin biosynthesis at concentrations above 6 mM. In contrast to the complex medium used for this process, the chemically define medium was completely insensitive to changes in sterilization conditions.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00386235
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  • 2
    Electronic Resource
    Electronic Resource
    Modified microbial fermenter performance in animal cell culture and its implications for flexible fermenter design (1994)
    Springer
    Bioprocess and biosystems engineering 11 (1994), S. 57-63 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract Modified microbial fermenters were adapted for use in animal cell cultivations within an active microbial pilot plant rapidly and inexpensively. Multiple batches of Jurkat cells (human T-lymphoma) and Spodoptera frugiperda (using a baculovirus expression vector) were conducted in modified 75 L Chemap fermenters and a 280 L pilot plant seed vessel. These retrofitted reactors were evaluated for suitable temperature control, local hot spots, surface aeration capability, open-pipe sparging, impeller type and impeller speed. Influences of these operating factors on cell growth rate, cell density, glucose uptake and protein yield were quantified. Implications for the flexible design of fermenters for operation in multiuse campaign facilities are discussed. Adaption of existing microbial fermenters was found to be an attractive route for initial implementation of cell culture capacity in a research organization.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00389561
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  • 3
    Electronic Resource
    Electronic Resource
    Scale-up of the Efrotomycin fermentation using a computer-controlled pilot plant (1988)
    Springer
    Bioprocess and biosystems engineering 3 (1988), S. 31-36 
    Details
    ISSN: 1432-0797
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract A description is given of the application of computer process control and on-line data aquisition for the rapid scale-up of the Efrotomycin fermentation. This process involves the use of a pseudo-mycelial culture, solids and oil containing medium, and exhibits a high degree of sensitivity to small changes in sterilization conditions. The latter point presented the major scale-up challenge, especially when batch sterilization of medium was used. An example is given of how on-line computer-generated data were used to monitor overall metabolic changes and how this information was used to make process control decisions during the fermentation. The agitator speed was automatically controlled at the larger scale to maintain the required dissolved oxygen concentration and this enabled us to rapidly scale-up based on constant oxygen transfer coefficient. The necessary accuracy of control of sterilization conditions required at the various different scales of operation could only be met by use of continuous HTST (high temperature short time) sterilization of the medium. In addition, use of the continuous sterilizer made it much easier to specify conditions for different scales of operation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00372857
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  • 4
    Electronic Resource
    Electronic Resource
    Influence of impeller type on power input in fermentation vessels (1998)
    Springer
    Bioprocess engineering 18 (1998), S. 401-412 
    Details
    ISSN: 0178-515X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Process Engineering, Biotechnology, Nutrition Technology
    Notes: Abstract  Prior investigations comparing radial flow Rushton impellers with axial flow hydrofoil impellers (Maxflo T and A315) were extended at the pilot scale. Six types of impellers (disk-style Rushton, Prochem Maxflo T hydrofoils of three diameters pumping downwards and A315 hydrofoils pumping upwards and downwards) were compared for qualitative differences in power number behavior with Reynolds' number, single versus double impeller power draw, gassed power reduction with aeration number and gas hold-up. Power measurements were obtained using watt transducers which, although limited in accuracy and prone to interferences, were able to provide useful qualitative monitoring results. Measurements were conducted using three model liquid systems: water, glycerol and Melojel (soluble starch). Apparent viscosities for actual Streptomyces cultivations were estimated using measured gassed power values and the experimental relationships obtained for gassed/ungassed power to aeration number and power number to Reynolds' number for the glycerol model system. Results confirmed the lower power number and lower shear environment for hydrofoil impellers, yet suggested useful trends for various process parameters and process fluids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004490050463
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  • 5
    Electronic Resource
    Electronic Resource
    The Translation of Scale in Fermentation Processes: The Impact of Computer Process Control (1984)
    [s.l.] : Nature Publishing Company
    Nature biotechnology 2 (1984), S. 875-883 
    Details
    ISSN: 1546-1696
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: [Auszug] Many of the physical and chemical parameters which influence the behavior of a microorganism are changed as the scale of operation is changed. A description is given of how the most important of these effect process performance. As well as opening up new doors for novel process control techniques, ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nbt1084-875
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  • 6
    Electronic Resource
    Electronic Resource
    Process optimization for large-scale production of TGF-α-PE40 in recombinant Escherichia coli: effect of medium composition and induction timing on protein expression (1997)
    Springer
    Journal of industrial microbiology and biotechnology 18 (1997), S. 260-266 
    Details
    ISSN: 1476-5535
    Keywords: Keywords: E. coli; fermentation; induction; recombinant; expression; scale-up
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The effects of medium composition and induction timing on expression of a chimeric fusion protein TGF-α -PE40 (TP-40) in Escherichia coli strain RR1 were examined using a complex medium at several fermentor scales. Two distinctive phases in E. coli catabolism were identified during fermentation based on preferential utilization between protein hydrolysate and glycerol. Maximum specific and volumetric productivities were achieved by inducing the culture when the cells were switching substrate utilization from protein hydrolysate to glycerol. By increasing the yeast extract concentration in the production medium, initiation of the catabolic switch was delayed until high cell mass was achieved. The final titer of TP-40 at the 15-L fermentation scale was doubled from 400 mg L−1 to 850 mg L−1 by increasing the yeast extract concentration from 1% to 4% (w/v) and delaying the time of induction. This fermentation process was rapidly scaled up in 180-L and 800-L fermentors, achieving TP-40 titers of 740 and 950 mg L−1, respectively.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/sj.jim.2900382
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  • 7
    Electronic Resource
    Electronic Resource
    The enzymatic transformation of water-insoluble reactants in nonaqueous solvents. Conversion of cholesterol to cholest-4-ene-3-one by a Ncardia sp. (1975)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 17 (1975), S. 815-826 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The rapid conversion of cholesterol to cholestenone by Nocardia in the presence of high proportions of water-immiscible solvent has been demonstrated. At high agitator speeds, the reaction rate was not limited by the rates of transfer of oxygen or cholesterol to the microorganisms. Using 100 g of thawed cells in 200 ml of carbon tetrachloride containing 16% (w/v) cholesterol, at 20°C cholestenone was formed at 7 g/hr. Cells could be separated easily from the organic solvent and reused. After 7 runs (69 hr) the reaction rate had fallen only to half the value for the first run.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260170604
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  • 8
    Electronic Resource
    Electronic Resource
    The kinetics of cholesterol oxidase synthesis by Nocardia rhodocrous (1976)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 18 (1976), S. 601-621 
    Details
    ISSN: 0006-3592
    Keywords: Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The production of cholesterol oxidase by 3 liter batch cultures of Nocardia rhodocrous growing on a glycerol/yeast extract medium was investigated. Cholesterol was shown to be a good inducer of the enzyme. The optimum time for cholesterol addition and the quantity to be added were determined, resulting in a 15-fold yield increase. Cholesterol oxidase synthesis was influenced by the dissolved oxygen tension. Maximum cholesterol oxidase production was obtained at 30-40% air saturation. The effect of growth conditions on the extraction of cholesterol oxidase by Triton X-100 was investigated. The scale-up of the fermentation to 800 liters in a pilot-plant fermenter is described.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260180502
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  • 9
    Electronic Resource
    Electronic Resource
    A fluid dynamic study using a simulated viscous, shear thinning broth of the retrofitting of large agitated bioreactors (1996)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 49 (1996), S. 15-19 
    Details
    ISSN: 0006-3592
    Keywords: viscous fluid ; fluid dynamic study ; Xanthan solution ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: Studies were conducted1 in 19-m3 fermentors (14-m3 working volume) using four Rushton turbines, four Prochem Maxflo Ts, and three Lightnin' A315s and the results in water have been reported earlier. Here, a 1.7 wt/vol% Xanthan solution has been used as the working fluid, simulating viscous broths to give Reynolds numbers (Re) between 1800 and 4500. As predicted from small-scale studies, the power numbers at these values of Re were similar to those in water. The K factor (the ratio of power draw under aerated conditions compared to non-aerated) was the same as in water at the higher values of Re, but at the lower values it fell more rapidly with increasing aeration rate and to a lower value than in water. At all times, K was higher than with Rushton turbines. Vibration characteristics were also measured. Under aerated conditions, the fermentors vibrated with an amplitude 75% to 100% less than in water due to viscous damping. With increasing air flow, the amplitude increased steadily due to the presence of very large and rapidly rising bubbles in such fluids to give values 2.5 to 3 times those in water. Nevertheless, these mechanical problems can be overcome, allowing such agitators to be used successfully in high viscosity mycelial fermentations. © 1996 John Wiley & Sons, Inc.
    Additional Material: 5 Ill.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Cultivation of virus antigen in fibroblast cells using a glass fiber bed reactor (1993)
    New York, NY [u.a.] : Wiley-Blackwell
    Biotechnology and Bioengineering 42 (1993), S. 635-642 
    Details
    ISSN: 0006-3592
    Keywords: MRC-5 ; anchorage-dependent ; fibers ; cell culture ; hepatitis A ; Chemistry ; Biochemistry and Biotechnology
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Biology , Process Engineering, Biotechnology, Nutrition Technology
    Notes: The anchorage-dependent cell line, MRC-5, was cultivated successfully on glass fibers with diameters ranging from 24 to 120 μm, despite vast differences in substrate curvature. Multilayer cell growth was observed, particularly for fiber diameters 30 μm and below, which differed from the typical monolayer growth observed in T-flask cultivations. Cells were maintainable at a reduced incubation temperature and were demonstrated to support virus replication for the 21-day antigen production period. Direct microscopic observation, along with indirect calculations, indicated that only a small fraction (about 10%) of the total available fiber surface area was occupied by cells. Thus, productivity per unit surface area was replaced by productivity per unit medium volume when evaluating fiber bed performance. Antigen and protein yields, as well as nutrient uptakes, were 1.5- to 2.5-fold greater than parallel T-flask cultures when compared on this basis. Corresponding available surface area-based values were 10- to 15-fold lower for the fiber bed reactor. The multilayer cell morphology obtained in the fiber bed was attractive for antigen production when immobilized in a column reactor system. © 1993 John Wiley & Sons, Inc.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/bit.260420512
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