• amino esters;
  • antibiotics;
  • enzyme catalysis;
  • hydrolases;
  • lactams


The current enzymatic production of semisynthetic β-lactam antibiotics requires isolation and purification of the intermediate 6-aminopenicillanic acid which adds cost and complexity to the manufacturing process. In this work, we took advantage of the unique substrate specificity of α-amino ester hydrolases to perform a purely aqueous one-pot production of ampicillin from penicillin G and D-phenylglycine methyl ester, catalyzed by α-amino ester hydrolase and penicillin G acylase. The synthesis was performed in both a one-pot, one-step synthesis resulting in a maximum conversion of 39 %, and a one-pot, two-step process resulting in a maximum conversion of 47 %. The two-enzyme cascade reported in this paper is a promising alternative to the current enzymatic two-step, two-pot manufacturing process for semisynthetic β-lactam antibiotics which requires intermittent isolation of 6-aminopenicillanic acid.