to improve phase separation (Schmid et al., 1998a) and may be applicable where the
products are sufficiently stable.
As an alternative to the use of microporous membranes, dense phase membranes have
also been investigated for the direct recovery of product from a two-phase, stirred-tank
bioreactor by pervaporation (Mathys et al., 1997). Data obtained from a wide range of
polymeric membranes makes it clear that the design and operation of such units will
involve a trade off between flux and selectivity. Following the phase separation step very
Figure 5.7 Process flowsheets for (a)
conversion of a poorly water-soluble
substrate into a poorly water-soluble
product, and (b) conversion of a poorly
water-soluble substrate into a water-
soluble product. Dashed lines represent
options for organic phase recycle while
dotted lines represent options for
biocatalyst recyle.
Multiphase bioreactor design 136