behaviour of micellar systems and how dissimilar the substrates concentrations accessed
by microencapsulated enzymes are. Therefore, reversed micellar systems should be
regarded as complex systems instead of being classified as homogeneous systems since
this definition causes detrimental effects to several aspects of their interpretation.
Table 7.2 Concentration of hexanol in the micellar
sub-phases (integrated model)
ST sw Saot,f Saot,ads Sorg Sef SefMM
100 0.077 8.01 79.8 12.1 8.01 8.60
200 0.370 38.3 103.6 57.8 38.6 34.1
250 0.551 57.0 106.4 86.1 57.6 52.5
350 0.925 95.7 108.8 144.5 96.7 201.2
400 1.114 115.3 109.4 174.1 116.5 376.5
450 1.304 135.0 109.8 203.8 136.3 273.2
550 1.686 174.5 110.4 263.4 176.1 516
650 2.068 214.0 110.8 323.0 216.1 650
1000 3.407 352.7 111.5 532.4 356.1 1000REVERSED MICELLAR BIOREACTORS
State-of-the-ArtReversed micelles have also been referred to as nanoreactors or microreactors due to their
constitutional properties. Nevertheless, this does not ensure self-sufficiency to perform a
continuous process. There are only very few examples of reactors applied to reversed
micellar systems and all of them involve the use of membranes, usually membrane
modules encompassing ceramic membranes.
Ultrafiltration membrane reactors are one of the most appropriate type of reactors to
achieve the confinement of microencapsulated enzymes, whilst simultaneously obtaining
product separation, as they are based on a size exclusion pressure-driven process. One
exception was the stirred tank reactor (STR)-plug flow reactor (PFR) used by Doddema
et al. (1987). This reactor constituted of a STR made of glass and a stainless steel tube
acting as a PFR, although this reactor also included an hollow fibre unit (Amicon
polysulfonate) to separate the product in a counter-current mode. The STR-PFR reactor
was designed to perform the enzymatic oxidation of steroids using isolated cholesterol-
oxidase or Nocardia rhodochrous cells, both entrapped in reversed micelles.
The hydrolysis of olive oil (Hakoda et al., 1996; Prazeres et al., 1993, 1994a), peptide
synthesis (Luisi and Laane, 1986; Serralheiro et al., 1994, 1999), hydrolysis of lecithin
(Morgado et al., 1996), L-tryptophan production (Blanch, 1990; Eggers and Blanch,
1988) and degradation of pesticides (Komives et al., 1994) are among the applications of
the membrane bioreactors (MBR). Chang and Rhee (1991) also performed the continuous
Multiphase bioreactor design 208