扩张床吸附分离丙酸耦合维生素B_(12)发酵

Separation of Propionic Acid by Expanded Bed Adsorption Coupled with Vitamin B_(12) Fermentation

采用扩张床吸附丙酸与维生素B12发酵相耦合以解除丙酸对维生素B_(12)发酵的抑制.选用弱碱性阴离子交换树脂330对发酵液中的丙酸进行了扩张床吸附和解吸工艺研究,丙酸浓度10g/L(pH5.0)、树脂量为发酵液体积的1/10、上料流速710mL/min时,湿树脂动态吸附量为57.73mg/g;解吸剂NaOH3mol/L、流速1.32mL/min时,解吸率为93.2%.将此工艺用于发酵过程中丙酸的原位吸附分离,构建了一种新型原位分离发酵系统.通过降低发酵液中丙酸的浓度,有效缓解了丙酸对细胞生长的抑制作用,提高了细胞发酵密度,维生素B_(12)及丙酸产量相对于补料分批发酵分别提高了26.6%和39.4%.

Using alkalescence anion exchange resin 330 to adsorb propionic acid from fermentation broth,the expanded bed adsorption and desorption process of propionic acid were investigated systematically with the selected resin,and the optimized operation conditions were obtained as follows：pH 5.0,concentration of propionic acid 10 g/L,resin humid volume 1/10 of the fermentation broth volume,20 min and flow velocity 710 mL/min.Under above conditions,the dynamic adsorption capacity reached 57.73 mg/g.When the concentration of NaOH was 3 mol/L and flow velocity 1.32 mL/min,the desorption rate reached 93.2%,an coupled bioprocess for in situ recovery of propionic acid coupled with fermentation of vitamin B_（12） was established based on this technology.By decreasing the concentration of propionic acid,the inhibition of propionic acid to Propionibacterium freudenreichii was lightened dramatically.High density of cell and vitamin B_（12） were obtained compared with the Fed-batch fermentation,the yields of vitamin B_（12） and propionic acid increased 26.6% and 39.4%,respectively.