卷式膜超滤L-乳酸发酵液过程研究

比较截留分子量(MWCO)为1000D 和3000D 的卷式超滤膜在去除L- 乳酸发酵液中蛋白质等杂质过程中对蛋白质截留率和乳酸透过率的影响，研究超滤时间、操作压力、蛋白质质量浓度及操作温度等操作工艺参数对膜通量的影响，分析膜通量随时间的变化规律，建立描述膜通量与操作压力、蛋白质浓度关系的数学模型。结果表明：MWCO 为3000D 的膜更适合用于超滤L- 乳酸发酵液，其膜通量随着超滤时间的延长衰减；随着操作压力和温度的增加而升高，随着蛋白质质量浓度的增加而降低，所建立的数学模型与实验结果吻合良好。

Spiral-wound Membrane Ultrafiltration of L-lactic Acid containing Fermentation Supernatant

The clarification of L-lactic acid containing fermentation supernatant by ultrafiltration is an important pretreatment step for the separation of L-lactic acid. In this study, spiral-wound membrane modules with molecular weight cut-offs (MWCO) of 1000 D and 3000 D were used to filtrate the L-lactic acid containing supernatant derived from Rhizopus oryzae AS3.819 fermentation, and the one with 3000 D MWCO was selected for the subsequent investigations due to larger membrane flux, in which, 4 process conditions (i.e., ultrafiltration time, operation pressure and temperature and protein concentration) affecting the membrane flux of the selected module were explored and a mathematical model was developed describing the relationship of the function with operation pressure and protein concentration. The membrane flux of the spiral-wound membrane module with 3000 D MWCO attenuated with prolonged ultrafiltration time and increasing protein concentration, but elevated with increasing operation pressure and temperature. The developed model revealed good reliability in predicting the membrane flux of the spiralwound membrane module with 3000 D MWCO.