Demineralization of glutamine fermentation broth by electrodialysis

The application of electrodialysis technology in demineralization of glutamine fermentation broth was studied. We used the one-dimension Nernst–Planck equation to describe the process of demineralization of the glutamine fermentation broth system, did the theoretical calculation on the demineralization ratio and the loss rate of glutamine, and made a comparison with the experimental results. The results show: the one-dimension Nernst–Planck equation can describe the process of electrodialysis demineralization of the fermentation broth system, there is a little deviation between the result of the theoretical calculation and the experimental result, and the loss rate of glutamine in the experimental data is a little higher than that in the theoretical calculation. Moreover, we also investigated the change of the current efficiency of the simulation feed solution and fermentation broth in the electrodialysis along with the process of demineralization. The current efficiency decreases a little along with the process of demineralization, and the current efficiency in the fermentation broth is lower than that in the simulation feed solution.

We used the one-dimension Nernst–Planck equation to carry out numerical calculation for the demineralization ratio of the Gln fermentation broth system and compare it with the experimental results. The results proved the following: 1. The equation can describe the ED demineralization process of the fermentation broth accurately. The theoretical calculation is a little different from the experimental result in that the Gln loss rate in the experimental data is higher than the value in the theoretical calculation because the theoretical calculation only considers electromigration but neglects the other secondary mass transfer processes, but the two have the same changing trend. 2. The theoretical calculation has proved that, when we control the pH value of the feed solution at the isoelectric point of the Gln, the effect of the ED demineralization is the best. Hence, in the ED demineralization process, we should control the pH value near the isoelectric point. 3. In the comparison of the variation of the current efficiency between the simulation feed solution and the fermentation broth along with the demineralization process, we found that the current efficiency will lower with the demineralization process, and the overall current efficiency of the fermentation broth is lower than that of the simulation feed solution. Thist is caused by the residual biomass and polysaccharides in the fermentation broth.