dc.description.abstract | Modern industry recognizes enzymes as important catalysts for batch production of food,
drugs and cosmetics. Because of their price and poor technical characteristics in free form,
enzymes are mostly used as immobilized derivative. Therefore, there is a constant need
for new and improved supports, possessing sufficient amount of active groups on it's
surface to interact with enzyme, but on the other side chemically inert to the reaction
media. Mechanical stability and price range are as much important as chemical stability.
The aim of this study was to investigate properties of modified ionic resin Purolite A109
for lipase immobilization. Purolite A109 is polystyrenic (styrene-divinylbenzene
copolymer), macro porous anion exchange resin with primary amine weak base functional
groups. It's advantages could be low price, and excellent mechanical and chemical
characteristics. Modification of this resin was performed using cyanuric chloride (CTC) and
epychlorhydrine. In both cases FTIR spectroscopy confirmed that modification process was
successful. Lipase from Candida rugosa was immobilized on both modified supports.
Approximately 30% of proteins was bound to both carrier. Hydrolytic activity of both, free
and immobilized lipase was determined, and based on these results activity retention
after immobilization process was calculated. Results showed that significantly higher
activity retention was obtained in case of CTC-Purolite – 67 %. Thermal stabilities of these
two immobilized enzymes on 65 °C were compared to thermal stability of free enzyme.
Relative activity of free enzyme decreased below 50% of initial activity within 30 min. On
the other hand, both immobilized enzymes showed significant thermal stability. Relative
activity of epoxy-Purolite dropped below 50 % of initial activity within 3 hours, while CTCPurolite
dropped below 50 % of initial activity within 5 hours. | sr |