Production of functionally active Penicillium chrysogenum isopenicillin N synthase in the yeast Hansenula polymorpha
1 Molecular Cell Biology, Groningen Biomolecular Sciences and Biotechnology Institute (GBB), University of Groningen, P.O. Box 14, 9750 AA Haren, The Netherlands
2 DSM Anti-Infectives, DSM Gist (624-0270), P.O. Box 425, 2600 AK, Delft, The Netherlands
3 Kluyver Centre for Genomics of Industrial Fermentation, Julianalaan 67, 2628 BC Delft, The Netherlands
BMC Biotechnology 2008, 8:29 doi:10.1186/1472-6750-8-29Published: 19 March 2008
β-Lactams like penicillin and cephalosporin are among the oldest known antibiotics used against bacterial infections. Industrially, penicillin is produced by the filamentous fungus Penicillium chrysogenum. Our goal is to introduce the entire penicillin biosynthesis pathway into the methylotrophic yeast Hansenula polymorpha. Yeast species have the advantage of being versatile, easy to handle and cultivate, and possess superior fermentation properties relative to filamentous fungi. One of the fundamental challenges is to produce functionally active enzyme in H. polymorpha.
The P. chrysogenum pcbC gene encoding isopenicillin N synthase (IPNS) was successfully expressed in H. polymorpha, but the protein produced was unstable and inactive when the host was grown at its optimal growth temperature (37°C). Heterologously produced IPNS protein levels were enhanced when the cultivation temperature was lowered to either 25°C or 30°C. Furthermore, IPNS produced at these lower cultivation temperatures was functionally active. Localization experiments demonstrated that, like in P. chrysogenum, in H. polymorpha IPNS is located in the cytosol.
In P. chrysogenum, the enzymes involved in penicillin production are compartmentalized in the cytosol and in microbodies. In this study, we focus on the cytosolic enzyme IPNS. Our data show that high amounts of functionally active IPNS enzyme can be produced in the heterologous host during cultivation at 25°C, the optimal growth temperature for P. chrysogenum. This is a new step forward in the metabolic reprogramming of H. polymorpha to produce penicillin.