NOVELTY - Enzymatic synthesis of active ingredient of amoxicillin, comprises: hydrolyzing a mother liquor; regulating a pH value of the obtained hydrolysate, separating the obtained solution, eluting the separated solution, and collecting an eluent rich in D-hydroxy phenylglycine; regulating the pH value of the eluent rich, and filtrating to obtain a filtrate A; performing nanofiltration concentration to the filtrate A; and regulating a pH value of the obtained concentrated solution to 5-6, crystallizing, filtrating, and drying the obtained solid to obtain D-hydroxy phenylglycine.    USE - The method is useful for the synthesis of active ingredient of amoxicillin (claimed).    ADVANTAGE - The energy saving method provides amoxicillin with high yield in an environment-friendly manner.    DETAILED DESCRIPTION - Enzymatic synthesis of active ingredient of amoxicillin, comprises: (a) hydrolyzing a mother liquor to obtain hydrolysate; (b) regulating a pH value of the hydrolysate to 6-7 using hydrochloric acid, separating the obtained solution through a macro porous resin column, eluting the separated solution through deionized water, and respectively collecting an eluent rich in D-hydroxy phenylglycine and an eluent rich from the eluted solution; (c) regulating the pH value of the eluent rich in D-hydroxy phenylglycine to 9.5-10, and filtrating the eluent rich in D-hydroxy phenylglycine through an ultra filtration membrane with molecular cut off of 15000-2000 Daltons to obtain a filtrate A; (d) performing nanofiltration concentration to the filtrate A through a nanofiltration membrane with molecular cut off of 150-200 Daltons to obtain a concentrated solution; and (e) regulating a pH value of the concentrated solution to 5-6 using acid, crystallizing and filtrating the concentrated solution, and drying the obtained solid to obtain D-hydroxy phenylglycine.    DESCRIPTION OF DRAWING(S) - The figure shows a flow diagram of a method for the synthesis of active ingredient of amoxicillin.