Picture of two heads

Open Access research that challenges the mind...

The Strathprints institutional repository is a digital archive of University of Strathclyde research outputs. Strathprints provides access to thousands of Open Access research papers by University of Strathclyde researchers, including those from the School of Psychological Sciences & Health - but also papers by researchers based within the Faculties of Science, Engineering, Humanities & Social Sciences, and from the Strathclyde Business School.

Discover more...

Enzymatic synthesis of beta-lactam antibiotics via direct condensation

Ulijn, R.V. and De Martin, L. and Halling, P.J. and Moore, B.D. and Janssen, A.E.M. (2002) Enzymatic synthesis of beta-lactam antibiotics via direct condensation. Journal of Biotechnology, 99 (3). pp. 215-222. ISSN 0168-1656

Full text not available in this repository. (Request a copy from the Strathclyde author)

Abstract

In this paper, the feasibility of precipitation driven synthesis of acidic and zwitterionic beta-lactam antibiotics is studied. As an example of the first type, penicillin G was produced in good yield (160 mmol kg(-1)) directly from the free acid and an-tine aqueous substrate suspension, where the synthesis product precipitated. Such a precipitation driven synthesis via direct reversal of the hydrolytic reaction is thermodynamically unfavourable for zwitterionic beta-lactam antibiotics, such as amoxicillin. In this paper, a novel method is suggested to help favour precipitation of (poorly soluble) product salts by deliberate addition of certain counter-ions. After screening a number of different counter-ions, it was found that the amoxicillin anion forms a poorly soluble salt with Zn2+. Despite increased beta-lactam degradation due to the presence of zinc ions, in a synthetic reaction with 0.1 M ZnSO4 present the synthetic yield could be increased at least 30-fold.