离子交换法吸附分离发酵液中的丙酸

比较了9种弱碱性阴离子交换树脂对费氏丙酸杆菌发酵液中丙酸的静态和动态吸附性能。结果表明：树脂ZGA330对含有12.6g/L丙酸的发酵液丙酸的静态吸附量最大，吸附量为44.9mg/g；动态吸附过程中对发酵液中主要营养成分糖、氨基酸吸附很少，而对丙酸吸附量高达205.5mg/g。成功地通过树脂吸附将发酵系统中的丙酸分离出去，实现了维生素B₁₂的高密度发酵，维生素B₁₂的产量由9.1mg/L提高到13.1mg/L，增加了0.44倍。研究结果为丙酸的发酵与吸附分离耦合过程研究提供了基础，丙酸吸附分离后的发酵液继续进行维生素B₁₂发酵生产可以解除丙酸的抑制作用，提高了维生素B₁₂的产量。

Removal of propionic acid from fermentation broth by ion-exchange resins

The adsorption abilities of nine weakly basic anion exchange resins for propionic acid(PA) in vitamin B12(VB12) fermentation broth have been evaluated.The static adsorption capacity on resin ZGA330 was found to be 44.9 mg/g dry beads at 12.6 g/L of PA.Dynamic state exchange trials,including the adsorption of glucose,amino acids and PA in the fermentation broth,were also carried out;these indicated that the adsorption of glucose and amino acids-the main nutrient components of the fermentation broth-was minimal.The dynamic adsorption capacity was 205.5 mg/g dry beads.By removal of propionic acid with ZGA330,the concentration of VB12 increased from 9.1 mg/L to 13.1 mg/L,an increase of 44%.This demonstrates that coupling of the fermentation process with separation and removal of propionic acid affords a significant improvement in the cell concentration and productivity of VB12.