【作者】 吴昊；

【导师】 张赣道；

【作者基本信息】 南京工业大学 ， 生物化工， 2005， 硕士

【摘要】 L-苯丙氨酸(L-Phenylalanine，简称L-Phe)是人体八种必需的氨基酸之一，是低糖甜味剂阿斯巴甜的主要原料，市场需求量很大。目前我国L-苯丙氨酸生产规模小、成本高，而降低L-苯丙氨酸生产中的成品分离纯化成本是当前的重要课题。本文选择WH6强酸性阳离子树脂，采用模拟移动床技术，建立了小试规模的模拟移动床，用驻波设计法优化设计了L-苯丙氨酸分离工艺，实现了连续、高效分离纯化L-苯丙氨酸过程，并将研究成果成功地应用到实际生产中。 WH6铵型阳离子树脂在经过离心、膜过滤等预处理的酶转化液中对L-苯丙氨酸有较高的吸附容量及良好的吸附选择性。静态条件下，转化液pH1.5，常温(10-25℃)下吸附6h，单位质量的树脂对L-Phe的吸附容量达0.083g/g。动态条件下，对离子交换柱A(φ40×227)最佳吸附工艺为：离交柱在常温下以5.5mL／min的流速进料吸附2.5L的转化液，树脂吸附L-Phe接近饱和，树脂对L-Phe吸附容量提高到0.12g/g。采用纯水洗杂，纯水流速5.5mL／min、用量750mL，洗杂中L-Phe损失为0.96％。对经过纯水洗杂的离子交换柱A采用的氨水浓度梯度动态解吸的工艺为：柱温50℃，先用0.2mol／L的低浓度氨水解吸L-天冬氨酸(L-Asp)、蛋白等杂质，再用0.5mol／L浓氨水集中解吸L-Phe，氨水流速为15mL／min；pH≤3.3的解吸液为解吸初流被废弃排放，几乎可完全除去L-Asp、蛋白等杂质；收集pH3.3～10.7范围内的L-Phe解吸主流，其L-Phe解吸收率达到95.37％，解吸液中L-Phe浓度高达30g/L；pH≥10.7为解吸尾流含有少量L-Phe，可回收利用。 本文考虑了树脂床层轴向扩散及树脂内外扩散等传质阻力的影响，成功地采用驻波法最优设计了实验室及工业生产规模的模拟移动床系统分离L-苯丙氨酸。实验室经连续运行4天分离110L转化液表明，模拟移动床系统中各组分在相应的各功能区中形成稳定的吸附、解吸驻波，L-Phe的解吸收率高达97.6％，解吸液中L-Phe浓度高达35.28g/L，单位质量L-Phe的氨水(0.5mol／L)消耗率仅为38.37L／kg，实现了L-苯丙氨酸与L-天冬氨酸等杂质的完全、高效的分离及连续、稳定的分离过程操作。工业生产的模拟移动床分离系统连续稳定运行30天，L-Phe的解吸收率达96.5％，解吸液中L-Phe浓度高达30g/L，单位质量L-Phe更多还原

【Abstract】 L-phenylalanine(L-Phe) is a kind of essential amino acids, it is a essential raw material of edulcorant: Aspartame and other intermediates, there are many demands of this amino acid. There are some flaw in L-Phe production inland, such as underproduction and in miniature. So it is an main research subject to reduce the cost of L-Phe separation. In this disquisition, the way of L- L-Phe separation by Simulated Moving Bed based on strong acid type ion exchange resin is studied. The Simulated Moving Bed separation technology is optimized by Standing Wave Design and applied to L-Phe production.The ammonia type resin WH6 has high adsorption capacity and favorable preferential adsorption to L-Phe in liquid of transformation after pretreatment. In static test, Optimized adsorption condition is adsorbed in normal temperature(10-25℃) for 6h, pH is 1.5. Adsorption capacity is 0.083g/g. In dynamic test, Optimized adsorption condition for column A(Φ40×227) is adsorbed in 5.5mL/min and fed 2.5L. Adsorption capacity is raised to 0.12g/g. Aqua pura washing condition is optimized, washing rate is 5.5mL/min, 750mL, the lost is about 0.96%. Desorption by ammonia concentration gradient to column A is optimized. Desorption temperature is 50℃, L-aspartic acid(L-Asp) and protein are first extracted from resin by aqua ammonia(0.2mol/L), then most L-Phe is extracted by stronger ammonia(0.5mol/L). When pH≤3.3 , L-Asp and protein are separated; the range of collection for L-Phe in extract is from pH3.3 to pH10.7, the recovery of L-Phe desorption is 95% , concentration is 30g/L in extract; when pH≥10.7, some residual L-Phe in extract is recovered.In Standing Wave Design of SMB, axial dispersion coefficient, film mass-transfer coefficient, internal and external diffusion are not negligible, process parameters are calculated and applied to SMB experiment and production. SMB experiment steady running for 4 days separated 110L transformation, adsorption and desorption waves of L-Phe or L-Asp are stable in relevant zones in continuous更多还原