1. Department of Biosystems Science and Engineering, Eidgenössische Technische Hochschule (ETH) Zurich, Mattenstrasse 26, CH-4058 Basel, Switzerland.
2. Département Génie Biologique, Institut Universitaire de Technologie (IUT), F-69622 Villeurbanne Cedex, France.
3. Faculty of Science, University of Basel, Mattenstrasse 26, CH-4058 Basel, Switzerland.