1. Department of Chemistry University of Copenhagen Thorvaldsensvej 40 1871 Frederiksberg Denmark
2. Present address: Frick Chemistry Laboratories Princeton University 08544 New Jersey USA
3. National Biologics Facility Department of Biotechnology and Biomedicine Technical University of Denmark Building 220, Kemitorvet 2800 Kgs. Lyngby Denmark
4. The Novo Nordisk Foundation Center for Biosustainability Technical University of Denmark Building 220, Kemitorvet 2800 Kgs. Lyngby Denmark