Highly efficient synthesis of ampicillin in an "aqueous solution-precipitate" system: repetitive addition of substrates in a semicontinuous process |
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Authors: | Youshko M I van Langen L M de Vroom E van Rantwijk F Sheldon R A Svedas V K |
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Institution: | Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, 119899 Moscow, Russia. |
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Abstract: | The synthesis of ampicillin catalyzed by Escherichia coli penicillin acylase was optimized in an aqueous system with partially dissolved antibiotic nucleus 6-aminopenicillanic acid (6-APA). The yields of both 6-APA and acyl donor could be improved by repetitively adding substrates to the reaction, allowing the concentration of 6-APA to remain saturated throughout. In this reaction concept, with four subsequent additions of substrates, 97% conversion of 6-APA and 72% of D-(-)-phenylglycine methyl ester (D-PGM) to ampicillin was achieved. The synthetic potential of this concept was estimated using a mathematical model which showed that by increasing the amount of added substrates a nearly quantitative conversion of 6-APA and 85% conversion of acyl donor into ampicillin could be achieved. |
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Keywords: | ampicillin synthesis penicillin acylase aqueous solution‐precipitate system aqueous biocatalytic process |
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