1. Department of Food Chemistry, Faculty of Mathematics and Natural Sciences, University Wuppertal, Gauss-Str. 20, 42119 Wuppertal, Germany.
2. Department Chemistry and Pharmacy, University Erlangen–Nuernberg, Schuhstrasse 19, 91052 Erlangen, Germany
3. Institute of Microbiology, University Erlangen–Nuernberg, Staudtstr. 5, 91058 Erlangen, Germany