Design and engineering characterization of a horizontal tubular bioreactor with spiral impeller for cell cultivation

Abstract

Aerated stirred tank bioreactors (STRs) are the norm for commercial production of biologicals but tend to exert high shear forces from high impeller tip speeds, direct sparging, bubble disruption at the surface and foam formation. In this work, a novel 5 liter horizontal tubular bioreactor (HTB) fitted with a spiral impeller was designed for cell cultures. The abiotic and engineering characterization of the HTB was undertaken in terms of fluid flow pattern, mixing time (θm), minimum agitation speed Njs, volumetric oxygen mass transfer coefficient (kLa), and power consumption (P). The bioreactor showed optimum operability between 2 and 3 litre, and comparable mixing time ranges, power consumption and volumetric oxygen mass transfer coefficients (kLa) between 5 and 16 h−1 to a STR and other conventional systems. An ANOVA analysis disseminated that impeller immersion and mixing speeds had significant effects on mixing times, while aeration rates and mixing speeds significantly impacted kLa. The abiotic and engineering characterization investigations revealed that the bioreactor design supported good surface aeration with bubble entrainment for oxygen mass transfer while imparting low energy into the system, which are key attributes in promoting a low shear environment for cell culturing.