Abstract:
Organisms used in fermentation processes are sometimes inhibited by accumulation of products or byproducts.
One route to circumvent this is via extractive fermentation. To facilitate this, novel bioreactor
designs are required, such as the semi-partition bioreactor (SPB) which has been designed for in-situ
extractive fermentation. This study reports on the numerical investigation of an SPB, considering phase
separation, hydrodynamics and mass transfer behaviour. Key findings illustrate that a minimum agitation
speed is necessary to attain system homogeneity in the mixer section. Furthermore, the results indicate
that the working principle of the bioreactor will be effective for liquid-liquid partitioning and mass transfer
followed by flux exchange between the mixer and settler sections and subsequent phase separation in
the settler section. This mechanism has a shorter characteristic time than the replenishment of the bioreactor
with recycled (and back-extracted) extractant. The reactor thus shows promise as a route for fermentations
susceptible to product inhibition.
