1. Centre of Biological Engineering; University of Minho, Campus de Gualtar; Braga 4710-057, Portugal
2. Ciceco - Aveiro Institute of Materials; University of Aveiro, Campus Universitário de Santiago; Aveiro 3810-193, Portugal
3. Laboratory of Microbiology; Wageningen University; Stippeneng 4 Wageningen 6708 WE The Netherlands