Lactose hydrolysis by Maxilact immobilized in an Eupergit reactor.

The work focused on the operating conditions required for the hydrolysis of lactose in whey permeate by the use of commercial lactase, immobilized on Eupergit C®. The performance of the packed-bed reactor was assessed using ultrafiltered sweet whey permeate at different lactose concentration (55g/l, 120g/l and 213 g/l). The immobilised enzyme reactor showed an efficient mass transfer reflected by the short residence time required to obtain reasonable degrees of conversion. The operational stability displayed a decrease of enzyme activity associated to a very significant increase in the stability of the already immobilized enzyme. At last, the easy and efficient use of yeasts for biomass production from spent whey, seems to be very promising in order to drastically reduce the environmental pollution from this by-product of cheese-making.