1. Department of Chemical Engineering, Groupe de Recherche en Sciences et Technologies Biomédicales, Bio-P2 Research Unit, École Polytechnique de Montréal, P.O. Box 6079, succ. Centre-Ville, Montréal (Qc), Canada H3C 3A7, and Animal Cell Technology Group, Bioprocess Sector, Biotechnology Research Institute, National Research Council Canada, Montréal (Qc), Canada H4P 2R2