Protein engineering of pencillin acyluse for improved antibiotic synthesis

PhD ceremony: S.A.W. Jager, 14.45 uur, Academiegebouw, Broerstraat 5, Groningen

Thesis: Protein engineering of pencillin acyluse for improved antibiotic synthesis

Promotor(s): prof. D.B. Janssen

Faculty: Mathematics and Natural Sciences

The production of ampicillin requires the use of chlorinated solvents and costs a lot of energy. More environmental benign alternatives, such as biocatalysis, could replace this synthesis. Simon Jager constructed mutant enzymes which could very well result in a green route for the synthesis of ampicillin.

The last century life expectancy has greatly increased. This is partly due to the discovery of antibiotics, compounds that slow down the growth of bacteria or even kill micro organisms altogether. The best known antibiotic is penicillin. Because many bacteria have become resistant to penicillin, related compounds have to be found, such as ampicillin. Penicillin acylase is an enzyme that has the potential to be used in the synthesis of ampicillin and other so called β -lactam antibiotics. However, the yield is to low for industrial application. The change of penicillin acylase by means of site-directed mutagenesis and directed evolution resulted in improved mutant enzymes. With the use of directed evolution Jager constructed hybrid enzymes and the ampicillin yield was increased by 19 % using these hybrids. Moreover, some of these hybrids were capable of catalyzing the reaction faster than the wild-type enzyme. Using site-directed mutagenesis, the yields were further improved up to 60 %. These site-directed mutants also catalyzed the reaction faster than the wild-type enzyme.