Immobilization of enzymes is one of promising methods in enzymes performances enhancement, such as stability, recovery, and reusability. However, investigation of suitable solid support in enzyme immobilization is still the one of problems to prevent the reduction of enzymes activity. Polyethersulfone (PES) and aminated PES (PES-NH2) as novel materials for the immobilization were successfully synthesized. Structure of synthesized polymers were characterized by NMR, FTIR, and MALDI-TOF. The membranes based on PES and PES-NH2 with various pore sizes (from 10 to 600 nm) was fabricated to be applied as bioreactor to increase the immobilized lipase performances. The influences of pore sizes, concentration of additives, and the presence of functional groups on PES backbone toward enzyme loading and enzyme activities were studied. The largest enzyme loading was obtained by the immobilization of Mucor miehei onto PES-NH2 membrane composed of 10% of PES-NH2, 8% of DBP, and 5% of PEG (872.62 g/cm2). Activity of immobilized lipase was determined by hydrolysis reaction of pNPA and methanol to produce pNP which showed the hydrolysis reaction catalyzed by immobilized lipase onto synthesized PES (10%) membrane represented the highest enzyme activity value (568.48 mmol pNP min-1 cm-2). From the reusability test, the immobilized lipase onto PES-NH2 showed better constancy than the immobilized lipase onto PES by four times of reactions which indicated that this novel material is potential to be developed as bioreactor on enzymatic reaction.
Keywords: Aminated PES, solid support, Mucor miehei, enzymatic reaction, lipase immobilization
Lipase, also known as triacylglycerol ester hydrolase (EC22.214.171.124), is one of interesting biocatalysts with widely biotechnological applications. Lipase plays attractive roles in various reactions because of its beneficial properties, such as displays great regio-selectivity and stereo-selectivity, easily produced in a high yield from microbial organisms (i.e. fungi and bacteria), may facilitate considerably the design of rational engineering strategies because of the unique molecular crystal structure, and does not require the cofactor like the other enzymes .
Immobilized enzyme becoming important in the catalyzed reactions because it shows high reusability, reduce the operational and production costs, and displays high efficiency on catalytic activity controlling [2,3]. Therefore, numerous efforts have been devoted for insoluble immobilized enzyme development in various applications such as heterogeneous biocatalyst application, selective adsorbents investigation, releasing protein drugs control, analytical devices application, and solid phase protein development [4-14]. In addition to its attractive properties, the commonly major problem in immobilization of enzyme is enzyme active sites blocking because of interaction between enzyme and its solid support [15,16,17]. Therefore, the selection...