Study on the Process Optimization of Extracting α-Aminoadipic Acid From 7-Aminocephalosporanic Acid Crystallization Mother Liquor

7-aminocephalosporanic acid (7-ACA) is an important intermediate for the synthesis of cephalosporin antibiotics. At present, most domestic manufacturers use a one-step enzymatic process for its production. While 7-ACA is generated during the reaction, α-aminoadipic acid (α-AAA) is produced as a by-product, which eventually enters the crystallization mother liquor of the 7-ACA product. The residual α-AAA in the mother liquor has high recovery value. In this study, an efficient process route for extracting α-AAA from 7-ACA crystallization mother liquor was established through steps including dissolution, concentration, macroporous adsorption resin adsorption, elution, reconcentration, and isoelectric point crystallization. The experimental results showed that LXT-036 macroporous adsorption resin could effectively separate α-AAA from 7-ACA. The α-AAA in the adsorption residual liquid was then crystallized using the isoelectric point method at a pH of 3.50~4.00. When the processing volume of the crystallization mother liquor reached 3.5~4.0 BV, the yield of α-AAA was approximately 37.5 g/L. This process provides feasible solution for the rational utilization of resources in antibiotic industrial waste liquor.