Flocculation bioreactors : engineering based problems

Abstract

The use of flocculation bioreactors is one of the most interesting ways to provide an increase of the productivity of biotechnological processes. As other high cell density systems, flocculation bioreactors allow the achievement of high biomass concentrations in each moment inside the bioreactor as well as an improvement of downstream processes. Besides these advantages, shared by all high cell density systems, flocculation bioreactors are clearly more interesting due to the absence of a support since it is well known that price is a limiting factor for the implementation of those systems. This being so, there are engineering problems that need to be addressed. In first place, the hydrodynamics of three-phase airlift bioreactors are considered, followed by the evaluation of the mass transfer properties both from gas to liquid and from liquid to solid phases. Finally, applications of flocculation bioreactors are discussed and examples are presented.