超滤法预处理L-乳酸发酵液

以白酒酒糟乳酸发酵液为研究对象,采用截留分子量为100 kDa的中空纤维超滤膜（聚偏氟乙烯PVDF膜）去除其中的蛋白质等杂质,为后续电渗析分离提纯L-乳酸提供合格的料液。研究表明,操作压力、温度、pH值和进料速度对蛋白质截留率、乳酸回收率和发酵液的膜通量均有影响;乳酸回收率与蛋白质截留率基本呈负相关关系,是因为被截留的蛋白质等在膜面形成滤饼层,有吸附并截留乳酸的作用。通过单因素实验,确定了在操作压力为20 kPa,温度为27℃,pH为3.9,进料速度为280 mL/min的情况下处理效果最好,蛋白质截留率可达到98.01%,乳酸回收率可达到97.78%,发酵液的膜通量为7.26 L/（m2·h）。

Pretreatment of L-lactic acid fermentation broth by ultrafiltration

Ultrafiltration with a hollow fiber membrane（PVDF,100 kDa） was utilized to remove protein in lactic acid fermentation broth from vinasse,thus the broth could be suitable for subsequent electrodialysis.The impacts of pressure,temperature,pH and feed velocity on protein removal,lactic acid recovery and membrane flux were investigated.The result demonstrated that lactic acid recovery was negatively correlated to protein removal rate,it was because the filter cake formed on the membrane surface could adsorb the lactic acid in the broth.The optimal conditions in case of pressure,temperature,pH and feed velocity were determind to be 20 kPa,27 ℃,3.9,and 280 mL / min,respectively.Under such conditions,the protein removal rate,lactic acid recovery rate,and membrane flux were 98.01 %,97.78 %,and 7.26 L /（m2· h）,respectively.