Batch cell 7.4 data

The most important effect of concentration polarization is to reduce the membrane flux, but it also affects the retention of macromolecules. Retention data obtained with dextran polysaccharides at various pressures are shown in Figure 6.12 [17]. Because these are stirred batch cell data, the effect of increased concentration polarization with increased applied pressure is particularly marked. A similar drop of retention with pressure is observed with flow-through cells, but the effect is less because concentration polarization is better controlled in such cells. With macromolecular solutions, the concentration of retained macromolecules at the membrane surface increases with increased pressure, so permeation of the macromolecules also increases, lowering rejection. The effect is particularly noticeable at low pressures, under which conditions increasing the applied pressure produces the largest increase in flux, and hence concentration polarization, at the membrane surface. At high pressure, the change in flux with... 

In macromolecular ultrafiltration, 2is pressure is increased, permeate flux first Increases and then In a large number of cases levels out and remains more or less pressure Independent. This could be due to the increase In solute concentration at the membrane surface such that either gel formation occurs or the corresponding osmotic pressure approaches the applied pressure. Limiting flux for the gel polarized case was recently analyzed for cross flow and unstirred batch cell systems by Trettln and Doshi (1980,a, b). In this paper we have analyzed the osmotic pressure limited ultrafiltration for the two systems. Our unstirred batch cell data and the literature cross flow data agree quite well with the theory. We have further shown that an unstirred batch cell system can be used to determine whether pressure Independent ultrafiltration of macromolecular solution is gel or osmotic pressure limited. Other causes for the observed pressure Independence may be present but are not considered in this paper. 

Fig.l Batch culture data showing (a) viable cell (Xy) and antibody (MAb) concentration and (b) cell cycle distribution for normal(n)/arrested(ar) cultures. Simulation results are shown by lines. 

Goldsmith (1971) pointed out that developed osmotic pressures for macromolecular solutions were not necessarily negligible. The ultrafiltration of Carbowax 20M (polyethylene oxide) and various Dextrans was studied in thin channel and tube flow as well as stirred batch cell. Both turbulent and laminar flow regimes were considered. Data were analyzed with the use of Eq. (2) and the phenomenological relationship of Eq. (1) with Rg = 0. From Eq. (1) it was possible to calculate an average... 

In all batch cell experiments, data acceptability limits were... 

When the assumption of constant wall concentration is justified, data for the unstirred batch cell and thin channel systems may be interpreted using models presented in Trettln and Doshi (1980a, 1980b). Such an analysis is performed where agreement is shown to be very good between theory and osmotic pressure limited ultrafiltration experiments. 

Myers and Graham (Ml6) studied the growth of Chlorella ellipsoidea in continuous culture. Their results are not given in such a way that direct comparison with the batch growth data of Tamiya et al. (Tl) is possible however, Myers and Graham found that the productivity at low cell concentrations seemed to be predictable from batch data which they obtained. 

In the following discussion, we will focus on reactive vapor liquid equilibria. Measurements of reactive liquid—liquid equilibria can be done in standard batch cells operated as mixer-setders using appropriate analytical methods, as long as only data on the fully established equilibrium is needed. Practically no data seems to be available in the literature on liquid-liquid equilibria in mixtures that have not reached chemical equilibrium. 

Chen, S.J., et al.. Mass-spectrometer composition probe for batch cell studies of supercritical fluid phase-equilibria. Journal of Chemical and Engineering Data, 1993. 38(2) p. 211-216. 

A variety of UF membranes are commercially available. Table 6.3.8 provides an illustration of the properties and performance characteristics of a series of polymeric flat membranes that are used in a batch cell. The data on solute rejection were acquired in a stirred batch UF cell of the type to be considered in Section 6.4. 

Burkholderia cepacia (formerly Pseudomonas cepacia), a Gram-negative bacterium, is able to utilize a wide variety of carbon sources and accumulate PHAs under nutrient-limiting conditions and excess carbon (Young et al. 1994 Ramsay et al. 1995). Ramsay et al. (1995) have shown its ability to utilize xylose on an ammonium-limited medium and produce P(3HB). Batch fermentation data showed that when xylose was the single substrate, the maximum specific P(3HB) production rate, the yield of P(3HB) produced from substrate consumed (Yphb/s). and the percentage of P(3HB) accumulated in the cells were 0.072 g/(g h), 0.11 g g and 45 % (w/w), respectively. These results were very similar to the ones published for this strain on fmctose. 

Six test batches were conducted of which consisted of 1 control sample and 5 testing samples in each test batch. The counted cell number after 48h was taken mean value and compared with the cell number of control sample in its test batch. The data are figured in the Table 4. 

Figure 3.7 shows the growth of R. rubrum in a batch fermentation process using a gaseous carbon source (CO). The data shown follow the logistic model as fitted by (3.14.2.11) with the solid lines, which also represent an unstructured rate model without any lag phase. The software Sigma Plot was used to fit model (3.14.2.11) to the experimental data. An increase in concentration of acetate in the prepared culture media did not improve the cell dry weight at values of 2.5 and 3 gT-1 acetate, as shown in Figure 3.7. However, the exponential growth rates were clearly observed with acetate concentrations of 0.5-2 g-F1 hi the culture media.

In the dialyzed batch start-up phase and the subsequent continuous operation a substantial increase in viable cell density and monoclonal antibody (MAb) titer was observed compared to a conventional suspension culture. The raw data, profiles of the viable cell density, viability and monoclonal antibody titer during the batch start-up and the continuous operation with a dialysis flow rate of 5 L/d are shown in Figures 17.6 and 17.7. The raw data are also available in tabular form in the corresponding input file for the FORTRAN program on data smoothing for short cut methods provided with the enclosed CD. 

Despite the differences between the estimated derivatives values, the computed profiles of the specific MAb production rate are quite similar. Upon inspection of the data, it is seen that during the batch period (up to t=2I2 h), qM is decreasing almost monotonically. It has a mean value of about 0.5 /ug/(l(f cells-h). Throughout the dialyzed continuous operation of the bioreactor, the average qM is about 0.6 fxg/(l(f cells-h) and it stays constant during the steady state around time... 

Andersen et al. (1996) and Andersen (1995) have studied the effect of temperature on the recombinant protein production using a baulovinis/insect cell expression system. In Tables 17.15, 17.16, 17.17, 17.18 and 17.19 we reproduce the growth data obtained in spinner flasks (batch cultures) using Bombyx mori (Bm5) cells adapted to serum-free media (Ex-Cell 400). The working volume was 125 ml and samples were taken twice daily. The cultures were carried out at six different incubation temperatures (22, 26,28, 30 and 32 TT). 

Table 17.15 Growth of Bm5 Cells Growth Data taken from a Batch Culture of Bm5 Cells Incubated at 22 TT...

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