Immobilization of Mucor miehei Lipase onto Macroporous Aminated Polyethersulfone Membrane for Enzymatic Reactions

Abstract

Immobilization of enzymes is one of the most promising methods in enzyme performance enhancement, including stability, recovery, and reusability. However, investigation of suitable solid support in enzyme immobilization is still a scientific challenge. Polyethersulfone (PES) and aminated PES (PES–NH2) were successfully synthesized as novel materials for immobilization. Membranes with various pore sizes (from 10–600 nm) based on synthesized PES and PES–NH2 polymers were successfully fabricated to be applied as bioreactors to increase the immobilized lipase performances. The influence of pore sizes, concentration of additives, and the functional groups that are attached on the PES backbone on enzyme loading and enzyme activity was studied. The largest enzyme loading was obtained by Mucor miehei lipase immobilized onto a PES–NH2 membrane composed of 10% of PES–NH2, 8% of dibutyl phthalate (DBP), and 5% of polyethylene glycol (PEG) (872.62 µg/cm2). Hydrolytic activity of the immobilized lipases indicated that the activities of biocatalysts are not significantly decreased by immobilization. From the reusability test, the lipase immobilized onto PES–NH2 showed a better constancy than the lipase immobilized onto PES (the percent recovery of the activity of the lipases immobilized onto PES–NH2 and PES are 97.16% and 95.37%, respectively), which indicates that this novel material has the potential to be developed as a bioreactor for enzymatic reactions.

The synthesis of biodiesel catalyzed by Mucor miehei lipase immobilized onto aminated polyethersulfone membranes

“…The membranes were selected to check the effect of additives and amination process toward the membrane's properties. Moreover, according to the previous report, PESNH 2 -10 D2 P5 has a high enzyme loading value (Handayani et al 2012). Based on the results, it can be inferred that the amount of monolayer adsorbed gas onto PESNH 2 -10 D2 P5 membrane after immobilization was the largest.…”

“…The synthesized PES-NH 2 membranes were prepared as described in the previous study (Handayani et al 2012). N-methyl pyrrolidone (NMP) was supplied by Across Organics.…”

“…PES was synthesized by condensation polymerization which followed Keitoku's procedure with several modifications as described in the previous work (Keitoku et al 1994;Handayani 2010;Handayani et al 2012). Aminated PES (PES-NH 2 ) was obtained by a nitration reaction of synthesized PES and followed by a reduction reaction using SnCl 2 · 2H 2 O. PES and PES-NH 2 membranes with certain composition of additives were obtained by inversion phase technique.…”

“…The selection was performed based on the enzyme loading value in the previous investigation (the amount of lipase immobilized onto PESNH 2 -10 D8 P5 was the largest) (Handayani et al 2012). After incubation in a rotary shaker at room temperature for 3 h, the membrane was dried and applied as solid support for lipase.…”

“…By some methods of characterization, the properties of biodiesel produced by the immobilized enzyme are also investigated. The support material used in this study is aminated polyethersulfone (PES-NH 2 ) which had been previously synthesized and reported by the authors (Handayani et al 2012). From the previous work, although the enzyme interacted with PES-NH 2 membranes through physical interaction, the enzyme activity was not decreased during the immobilization.…”