Penicillin G acylase from Achromobacter sp CCM 4824 An efficient biocatalyst for syntheses of beta-lactam antibiotics under conditions employed in large-scale processes
Abstrakt
Penicillin G acylase from Achromobacter sp. (NPGA) was studied in the enzymatic synthesis of β-lactam antibiotics by kinetically controlled N-acylation. When compared with penicillin acylase of Escherichia coli (PGA), the NPGA was significantly more efficient at syntheses of ampicillin and amoxicillin (higher S/H ratio and product accumulation) in the whole range of substrate concentrations.
The degree of conversion of 6-aminopenicillanic acid to amoxicillin and ampicillin (160 mM 6-APA, 350 mM acyl donor methylesterDOT OPERATOR HCl, pH 6.3, 25 oC, reaction time of 200 min) with immobilized NPGA equaled 96.9 % and 91.1 %, respectively. The enzyme was highly thermostable with maximum activity at 60 oC (pH 8.0) and 65 oC (pH 6.0).
Activity half-life at 60 oC (pH 8.0) and at 60 oC (pH 6.0) was 24 min and 6.9 h, respectively. Immobilized NPGA exhibited long operational stability with half-life of about 2,000 cycles for synthesis of amoxicillin at conversion conditions used in large-scale processes (230 mM 6-APA, 340 mM D-4-hydroxyphenylglycine methylesterDOT OPERATOR HCl, 27.5 oC, pH 6.25).We discuss our results with literature data available for related penicillin acylases in terms of their industrial potential.