Effects of Broth Components on Separation of L-glutamine by Nanofiltration
发酵液的组成对纳滤分离谷氨酰胺的影响

The effects of salt ions and other components in L-glutamine fermentation broth on the separation of L-glutamine and L-glutamic acid by nanofiltration were investigated and the effects of process operation parameters on permeation properties were studied systematically. The optimum dilution times of fermentation broth and temperature was established. The study also showed that bivalent cations could affect the permeation properties of L-glutamine and L-glutamic acid, and decreased observed rejection of glutamic acid by 8%. Higher concentration of (NH4)2SO4 in broth reduced the observed rejection of L-glutamine and L-glutamic acid and permeation flux greatly, but higher concentration of NH4Cl did not, which demonstrated different repulsion forces of membrane to different ions. When the broth was diluted to 1% for L-glutamine concentration and adjusted to pH=7, other salt ions and residual glucose in broth would not significantly influence L-glutamine separation by nanofiltration due to their low concentrations.