1. Laboratory of Microbiology, Wageningen University, Stippeneng 4, 6708 WE Wageningen, The Netherlands
2. CEB-Centre of Biological Engineering, University of Minho, Campus de Gualtar, 4710-057 Braga, Portugal
3. Environmental Microbiology Laboratory, École Polytechnique Fédérale de Lausanne, CH A1 375 Station 6, Lausanne CH-1015, Switzerland