A scale-down two-compartment reactor with controlled substrate oscillations: Metabolic response of Saccharomyces cerevisiae

Mixing in the Fermentation and Cell Culture Industries

“…Since an estimate of the volume of the addition zone was not available, the volume of the loop was estimated as 5% of the total fermenter volume [similar to the volume fraction used by Namdev et al (1992) and George et al (1993)] at 50 mL. Using this PFR volume, the recirculation rate was varied to obtain different residence times in the PFR.…”

“…A two-compartment scale-down model, stirred tank reactor (STR) in combination with a plug flow reactor (PFR), was also used to model the presence of glucose gradients (Figure 18-5B). The PFR was fitted with static mixers to provide high oxygen transfer rates (k L a = 600 to 1000 h −1 ) as described by George et al (1993). In this manner the cells were repeatedly exposed to high glucose levels with decreasing oxygen availability with increasing cell density.…”

Influence of scale-up on the quality of recombinant human growth hormone

“…The two-compartment system consists of one CSTR (Chemap Fermentor) in series with a PFR. The flow characteristics of the PFR have been described elsewhere (George et al, 1993). In the SDR experiments, the glucose feed was added to the PFR inlet, thus giving a zone of local high glucose concentration.…”

“…Breakthroughs have been made in hydrodynamics and mixing, modeling of two-phase gas/liquid biological processes (Guillard, 1999), large-scale microenvironment measurements (Bylund et al, 1998(Bylund et al, , 1999George, 1997;Manfredini et al, 1983;Oosterhuis and Kossen, 1984), and scale-down methodology studies (Oosterhuis et al, 1983(Oosterhuis et al, , 1985. The latter area of study includes the use of scale-down reactors (SDRs) with various biological model systems (Bylund et al, 1999;Fowler and Dunlop, 1989;George et al, 1993George et al, , 1998Larsson and Enfors, 1988;Moes et al, 1985;Neubauer et al, 1995a,b;Sweere et al, 1988a-c).…”

Scale-down and parallel operation of the riboflavin production process with Bacillus subtilis

“…Onyeka et al (2003) investigated the additional impact of the pH control via different strategies for the addition of aqueous ammonia into this system. The same two-compartment reactor was previously already described by George et al (1993) for studies of the metabolism in Saccharomyces cerevisiae. Amanullah et al (2001) used a similar scale-down approach to simulate and study spatial pH variations for cultivations of Bacillus subtilis in large-scale bioreactors.…”