根据赖氨酸的理化特性,设计采用聚乙二醇(PEG)/硫酸钠双水相体系对其进行萃取分离。以萃取率和分配系数为指标,通过单因素和正交试验探讨了双水相的物质浓度、pH值、温度以及主要因素间的交互作用对赖氨酸萃取的影响。结果表明,赖氨酸主要分配于下相盐相中,双水相的物质浓度、pH值、Na2SO4的质量分数与pH值间的交互作用对赖氨酸的萃取影响极显著。实验确定最佳萃取工艺为:20%PEG 1000、14%Na2SO4、pH 5.5、30℃,在此条件下分别萃取1.0 mg/mL赖氨酸标准液和模拟发酵液,平均萃取率分别为96.5%和94.8%,分配系数分别为0.033和0.057。

The separation of L-lysine in aqueous two-phase system containing polyethylene glycol( PEG) and sodium sulfate was carried out based on the physicochemical properties of L-lysine. According to the extraction yield and partition coefficient,the influences of mass concentration of the compositions,pH value,temperature and their interactions on L-lysine extraction were examined by single-factor and orthogonal experiments. The results showed that L-lysine preferred to partition in the bottom salt-rich phase. The content of two components,pH value,as well as the interaction of Na2SO4content and pH value had significant influence on the extraction. The optimum extraction conditions were 20%( mass) of polyethylene glycol with molecular weight 1000 and 14%( mass) of Na2SO4at pH 5. 5 and 30℃. Under the optimal conditions,the average yield and the partition coefficient of L-lysine were 96. 5% and 0. 033 respectively using 1. 0 mg / mL L-lysine solution. And a preliminary separation from simulated fermentation broth with the same concentration of L-lysine displayed a extraction yield and partition coefficient were 94. 8% and 0. 057,respectively.