For bioprocess optimization, plug-flaw behaviour is an option in many
cases, However, many bioprocesses require oxygen to be supplied into t
he bioreactor. Plug-flow-like behaviour with aeration is feasible in a
series of bioreactors, This article reviews the range of aerated bior
eactors available for the approximation of plug-flow behaviour and int
roduces a new type of serial air-lift bioreactor, The optimal design o
f cascades of serial bioreactors is also discussed.