Immobilization studies of Candida Antarctica lipase B on gallic acid resin-grafted magnetic iron oxide nanoparticles

Figures & data

Figure 1 Schematic diagram for the preparation route of Cal-B enzyme immobilized polymer-grafted magnetic silica nanoparticles.

Figure 2 FTIR spectra of (a) Fe₃O₄ MNPs, (b) silica-coated MNPs, (c) amino-functionalized MNPs, (d) gallic acid-modified MNPs, (e) gallic acid−formaldehyde resin-grafted MNPs.

Figure 3 TEM images of (A) Fe₃O₄ nanoparticles and (B) Fe₃O₄@SiO₂@PGA magnetic silica nanoparticles.

Figure 4 X-ray diffraction (XRD) spectra of the polymer-grafted magnetic silica nanoparticles.

Figure 5 TGA thermograms of (a) Fe₃O₄ nanoparticles, (b) silica-coated magnetic nanoparticles, (c) amino-functionalized magnetic nanoparticles, (d) gallic acid-modified magnetic nanoparticles, (e) gallic acid−formaldehyde resin-grafted magnetic nanoparticles.

Figure 6 The magnetic hysteresis loops of (a) neat iron oxide and (b) polymer grafted iron oxide MNPs.

Figure 7 Magnetic separation of enzyme-loaded polymer-grafted nanoparticles from the reaction mixture using a magnet.

Figure 8 Optimization of immobilization time for enzyme Cal-B on polymer-grafted magnetic silica nanoparticles.

Table 1 Influence of enzyme Cal-B concentration on hydrolytic activity

S. No.	Loading^a,b (EAU/g)	Amount of enzyme taken^c (mL)	Lipase loaded (mg)	Hydrolytic activity (EAU/g)
1.	1,000	0.005	0.035	640
2.	5,000	0.025	0.175	3,920
3.	10,000	0.050	0.350	5,040
4.	15,000	0.075	0.525	8,000
5.	20,000	0.100	0.700	7,800
6.	25,000	0.125	0.875	7,640

Notes: ^aCal-B immobilized by adsorption on polymer-grafted magnetic MNPs at pH 7 and room temperature. ^b50 mg of polymer-grafted MNPs were used as enzyme support. ^cConcentration of lipase solution used is 7 mg/mL.

Figure 9 Effect of (A) pH and (B) temperature on the activity of free and immobilized Cal-B enzyme.

Figure 10 Reusability of Cal-B enzyme-loaded polymer-grafted magnetic silica nanoparticles for hydrolytic activity.