Purification of L-theanine from enzymatic catalyzed reaction solution by ion-exchange resins

L-theanine was isolation and purification from enzymatic catalyzed reaction solution by 717 anion-exchange resins.Through static and dynamic experiments, different operating conditions in the fixed bed to separate L-theanine were investigated.The results showed that the optimal conditions were pH8.5, adsorption balance time was 16min and exchange capacity was 0.083mmol/g in static experiment.The optimal flow rate was 0.5BV/h in dynamic experiment.Under these conditions, the reaction solution was diluted with water, added into the ion exchange column and eluted by 0.5mol/L hydrochloric acids.White crystal of L-theanine was obtained after concentrated, crystallized and dryied.