1. Department of Chemical and Biochemical Engineering, University of Western Ontario, London, Ontario N6A 5B9, Canada
2. Trojan Technologies, London, Ontario N5 V 4T7, Canada
3. USP Technologies, London, Ontario N5 V 4T7, Canada
4. Department of Microbiology and Immunology, University of Michigan, Ann Arbor, Michigan 48109, United States