CFD based mass transfer modeling of a single use bioreactor for production of monoclonal antibody biotherapeutics

In this study, Euler-Euler coupled computational fluid dynamics (CFD), species transport and population balance model (PBM) simulations have been used to model multiphase hydrodynamics and mass (O2) transfer in a single use bioreactor (SUB) for mAb production. In simulations, drag was estimated by Schiller-Neuman equations. O2(g) local volume fraction was estimated via species transport model (STM). The PBM equations were solved using quadrature method of moments (QMOM) to get bubble size distribution (BSD) and thereby the Sauter mean diameter,d32. Also, the mean diameter over surface (d21) and De Brouckere mean (d43) were estimated for calculation of the BSD. The mass transfer coefficient (kLa) was predicted using species transport model (STM) and Higbie?s penetration theory. The experimental estimation of kLa was performed via simplified dynamic pressure method. Total stress (?) and energy dissipation rate (?) were estimated as 34.17 Pa and 1.352 m2.s- 3, respectively. Calculations of the d32, d21 and d43 indicate that the BSD becomes more dispersed with increase in agitation speed at all aeration rates. Further, the kLa values of STM were within 0.47% to 4.21% of experimental data. In summary, with error between 4 and 10%, the proposed approach offers better visualization of O2 transport mechanism across gas?liquid interface than conventional approaches.