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目的:用膜分离和离子交换技术分离纯化转化液中的L-丝氨酸。方法:以膜过滤去除菌体、蛋白质和色素,离子交换获得纯L-丝氨酸溶液,经反渗透膜浓缩制备L-丝氨酸。结果:用陶瓷膜去除菌体,氨基酸损失率为0.84%。除菌体后的转化液经超滤-纳滤输出的清液,加入碱或乙醇无蛋白质析出,透光率达90%以上,是活性炭脱色处理后滤液的2.5倍,氨基酸损失率为7%。L-丝氨酸与甘氨酸的离交分离条件为上柱流速55mL·min-1,解吸剂浓度0.08mol.L-1,解吸流速30mL·min-1。用反渗透膜浓缩解吸液,L-丝氨酸损失量仅为真空减压浓缩的40%。结论:用膜分离和离子交换技术分离纯化L-丝氨酸,优于传统的絮凝剂沉淀蛋白质、活性炭脱除色素和真空减压浓缩,可明显提高L-丝氨酸收率和产品质量。
OBJECTIVE: To separate and purify L-serine in the conversion solution by membrane separation and ion exchange technology. Methods: Mycelia, proteins and pigments were removed by membrane filtration, pure L-serine solution was obtained by ion exchange and concentrated by reverse osmosis membrane to prepare L-serine. Results: The cell membrane was removed with ceramic membrane, the loss rate of amino acid was 0.84%. After removal of the bacterial body transformation liquid by ultrafiltration - nanofiltration output of the supernatant, adding alkali or ethanol without protein precipitation, the light transmittance of more than 90%, activated carbon is 2.5 times the filtrate after discoloration, the loss rate of amino acid is 7% . L-serine and glycine separation conditions for the column on the flow rate of 55mL · min-1, desorbent concentration of 0.08mol.L-1, desorption flow rate of 30mL · min-1. Concentration of the desorption solution with a reverse osmosis membrane, loss of L-serine only vacuum concentrated vacuum 40%. CONCLUSION: Separation and purification of L-serine by membrane separation and ion-exchange technology is superior to the traditional flocculant-precipitated protein, activated carbon removal of pigment and vacuum decompression concentration, which can significantly improve the L-serine yield and product quality.