Glucose feed ratio

A study carried out by Kim and co-workers [10] reported the production of copolymer poly(3HB-co-3HV) by adding propionic acid and glucose to cultures of Ralstonia eutropha during the accumulation phase. During cultivation, the dissolved oxygen concentration was kept at 20% air saturation. An increase in propionic acid to glucose feed ratio from 0.17 to 0.52 mol/mol resulted in an increase in the 3HV monomer composition from 4.3 to 14.3 mol%. However, the author reported a decrease in productivity and yield from 2.55 to 1.64 g/l/h and 0.33 to 0.28 mol/mol, respectively. 

Table 17.8 Glucose/Glutamine Ratio Experimental Data from a Chemostat Run with a Glucose to Glutamine Ratio in the Feed of 5 1...

For different feed compositions, a maximum value of PR was found for a feed ratio of 40/60. This demonstrates the existence of an optimum. The results obtained in this study were compared with the simulation of an SMB bioreactor for the inversion of sucrose to fructose and glucose and found to be consistent [160]. 

Various Japanese researchers show the possibilities of immobilising an enzyme or yeast on/in a ceramic membrane [99-101]. In the first example [99], the enzyme is boimd by Nakajima et al. to the ceramic surface of the TOTO 50 run membrane by activating it first with a silane-glutaraldehyde technique. Inver-tase is then bound to this activated surface and converts 100% of the 10-50 wt% sucrose in the feed solution. Alternatively glucose-isomerase jdelds a fructose ratio of 42% in a 45 wt% glucose feed at a residence time of 1000 s. The productivity of such systems is 10-fold higher than in conventional columns in which the enzyme is immobilised in beads. 

At the Pharmaceutical Production Research Facility of the University of Calgary experimental data have been collected (Linardos, 1991) to investigate the effect of glucose to glutamine ratio on monoclonal antibody (anti-Lewish IgM) productivity in a chemostat and they are reproduced here in Tables 17.8, 17.9 and 17.10. Data are provided for a 5 1 (standard for cell culture media), 5 2 and 5 3 glucose to glutamine ratio in the feed. The dilution rate was kept constant at 0.45 d . 

Figure 9. Effect of pressure on the (PR)/(PWP) ratio and solute separation of glucose and an imaginary solute. Membrane material, CA (E-398) membrane pore radius = 7.36 A feed flow rate = 400 cm /min feed concentration — 1 mol/m. ...

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