Influence of Additive L-phenylalanine on Stabilization of Metastable a-Form of L-glutamic Acid in Cooling Crystallization: A Scientific Explanation

The influence of additive amino acid L-phenylalanine on stabilization of metastable -form of L-glutamic acid was investigated in cooling crystallization. Crystallization is an effective technology for purification, separation and particles that directly determines the properties of the solid product. The present study found that the additive L-phenylalanine could be used to stabilize the pure metastable -form in L-glutamic acid crystallization. Here, the additive concentration of 0.05-0.1 (g/L) was sufficient to stabilize the 100% wt metastable -form in the solid product at L-glutamic acid concentration of 30-45 (g/L). Additionally, the present results indicated that additive L-phenylalanine's adsorption on the (001) surface of -form was more favorable than that of the -form molecular, so the nucleation sites of stable -form were occupied by additive molecular, which resulted in inhibition of nucleation and growth of -form, allowing stabilization of metastable -form.