1. Department of Physics, IBILCE UNESP, Universidade Estadual Paulista, R. Cristóvão Colombo 2265, 15054-000, São José do Rio Preto SP, Brazil
2. Laboratory of Physical Chemistry and Colloid Science, Wageningen University, P. O. Box 8038, 6700 EK, Wageningen, The Netherlands
3. Laboratory of Microbiology, Wageningen University, Dreijenplein 10, 6703 HB Wageningen, The Netherlands