Figure 6.17 Membrane reactor as an
extracorporeal device for the treatment
of hypercholesterolemia (adapted from
Shefer et al., 1993).
Enzymatic membrane reactors have also been used in the chemotherapy of cancer by
exploiting the fact that malignant cells are more sensitive to some amino acids
concentration (e.g. arginine, asparagine, phenylalanine) than normal cells. This suggested
that the corresponding enzymes (arginase, asparaginase, phenylalanine ammonia-lyase)
could be used for the depletion of those amino acids in the plasma with the consequent
inhibition of the growth of malignant cells (Pedersen et al., 1978; Rossi et al., 1981;
Mazzola & Vecchio, 1980; Jackson et al., 1979). For instance, a hollow fibre module
with covalently attached asparaginase to the outside of the fibres was successfully used as
an extracorporeal device to reduce the level of asparagine in healthy dogs (Jackson et al.,
1979). This could contribute to the treatment of some acute lymphocytic leukaemias.
Conversion of OligosaccharidesA number of the applications of membrane reactors found in the literature deal with the
transformation of oligosaccharides such as lactose, maltose, saccharose, cellobiose or
cyclodextrins (Table 6.9). The products obtained via these reactions, whether being
mono-or oligosaccharides, are usually sweet and may therefore find application in the
food industry as sweeteners or dietary products (Belitz & Grosch, 1987). A number of
references describes the continuous hydrolysis of lactose, an abundant disaccharide
which is found in milk, whey and other dairy products (Jones et al., 1984; Park et al.,
1985; Peterson et al., 1989a, 1989b; Czermark & Bauer, 1991; Bakken et al., 1992). In
thèse applications α-galactosidase was used to split lactose into its two component
monosaccharides, glucose and galactose. The lactose-hydrolysed products thus obtained
can be consumed in different forms (syrups, milk powders) by people that suffer from
lactose intolerance with a concomitant decrease in symptoms (Bakken et al., 1992).
Enzymatic membrane reactors 175