1. Karlsruhe Institute of Technology, Institut für Ingenieurbiologie und Biotechnologie des Abwassers; Am Fasanengarten Geb. 50.31 76131 Karlsruhe Germany
2. University of Tübingen; Department of Geosciences; Hölderlinstraße 12 72074 Tübingen Germany
3. also University of Applied Science Hochschule Emden/Leer; Faculty of Technology, Microbiology-Biotechnology; Constantiaplatz 4 26723 Emden Germany