“…The introduction of convective transport is crucial in overcoming diffusive mass transport limitation of nutrients (Nakajima and Cardoso, 1989) especially of the sparingly soluble oxygen. Several investigators modeled the mass transport through this biocatalyst layer, through enzyme membrane layer (Ferreira et al, 2001;Long et al, 2003;Belfort, 1989;Hossain and Do, 1989;Calabro et al, 2002;Waterland et al, 1975; www.intechopen.com Salzman et al, 1999;Carvalho et al, 2000) or cell culture membrane layer (Melo and Oliveira, 2001;Chau, 1990, 1996;Piret and Cooney, 1991;Sardonini and Dibiasio, 1992;Lu et al, 2001;Schonberg and Belfort, 1987). These studies analyze both the mass transport through the membrane and the bulk phase concentration change.…”