Abstract: A mutated expandase enzyme having higher activity on penicillin G is provided to produce 7-aminodeacetoxycephalosporanic acid (7-ADCA), which mutated expandase enzyme has one or more amino acid substitutions selected form methionine 73, glycine 79, valine 275, leucine 277, cysteine 281, glycine 300, asparagine 304, isoleucine 305, threonine 91, alanine 106, cysteine 155, tyrosine 184, methionine 188 and histidine 244, provided that the amino acid substitution at the residue position of asparagine 304 is not N304L and the amino acid substitution at the residue position of cysteine 155 is C155Y.

Abstract: Applicants have developed a process for purifying an ampicillin pro-drug ester, e.g., bacampicillin, or an acid addition salt thereof of formula I. The process comprises a step wherein a crude solution of the pro-drug ester is subjected to an evaporation which is controlled by the evaporation rate of the organic solvent such that a continuous operation is accomplished for the crystallization of the desired purified pro-drug ester or salt thereof. Said crystallization is preferably preceded by an aqueous phase extraction and/or an organic phase extraction, both preferably also being performed continuously.