Functionalized corn stalk carboxymethyl cellulose and mesoporous silica SBA-15 composite hydrogel-immobilized lipase for the resolution of racemic ibuprofen ethyl ester

Figures & data

Figure 1. Schematic illustration of CMC-g-PAA/SBA-15 composite hydrogels formation and immobilization PSL enantioselective hydrolysis racemic ibuprofen ethyl ester mechanism.

Figure 2. The FT-IR spectra of (a) SBA-15, (b) Cellulose extracted from corn stalks, (c) CMC, (d) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.6 wt% MBA), (e) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.5 wt% MBA) and (f) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.4 wt% MBA)

Figure 3. SEM images of (a) SBA-15, (b) Cellulose extracted from corn stalks, (c) Carboxymethyl cellulose, (d) CMC-g-PAA, (e) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.5 wt% MBA), (f) CMC-g-PAA/SBA-15 (12 wt% CMC, 0.6 wt% SBA-15, and 0.6 wt% MBA) and (g) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.4 wt% MBA).

Figure 4. X-ray diffraction patterns of (a) Cellulose extracted from corn stalks, (b) CMC, (c) SBA-15, (d) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.6 wt% MBA), (e) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.5 wt% MBA) and (f) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.4 wt% MBA)

Figure 5. Thermal characteristics of (a) Cellulose extracted from corn stalks, (b) CMC, (c) CMC-g-PAA/SBA-15(12 wt% CMC, 0.6 wt% SBA-15, and 0.6 wt% MBA) and (d) CMC-g-PAA/SBA-15(10 wt% CMC, 0.6 wt% SBA-15, and 0.4 wt% MBA)

Figure 6. FTIR spectra of PSL and PSL-CMC-g-PAA/SBA-15.

Table 1. Comparison of the catalytic properties of free and immobilized PSL.

Samples	Bound protein (mg/g)	Activity (μmol/g·min)	E value
Free PSL	—	216.5	38.1
PSL-CMC-g-PAA/SBA-15	320.0	316.8	88.2

Figure 7. Effect of temperature on free (a) and immobilized (b) the enzymatic hydrolysis of ibuprofen ethyl ester. The standard reaction was carried out in a 20 ml round-bottom flask containing free PSL 13 mg or immobilized PSL 40 mg (protein content: 13 mg), 1 mmol racemic ibuprofen ethyl ester, and 5 mL of 50 mM sodium acetate buffer (pH 7.0). The resulting mixture was shaken at different temperature (20-60°C) (180 rpm).

Figure 8. Effects of pH on the free (a) and immobilized (b) enzymatic hydrolysis of ibuprofen ethyl ester. The standard reaction was carried out in a 20 ml round-bottom flask containing free PSL 13 mg or immobilized PSL 40 mg (protein content: 13 mg), 1 mmol racemic ibuprofen ethyl ester, and 5 mL of 50 mM sodium acetate buffer (pH 5.0-8.0). The resulting mixture was shaken at 40°C (180 rpm).

Figure 9. Effect of time on the free (a) and immobilized (b) enzymatic hydrolysis of ibuprofen ethyl ester. The standard reaction was carried out in a 20 ml round-bottom flask containing free PSL 13 mg or immobilized PSL 40 mg (protein content: 13 mg), 1 mmol racemic ibuprofen ethyl ester, and 5 mL of 50 mM sodium acetate buffer (pH 7.0). The resulting mixture was shaken at 40°C (180 rpm) for (0-4 h).

Figure 10. Reusability of immobilized PSL on the enzymatic hydrolysis of ibuprofen ethyl ester. The standard reaction was carried out in a 20 ml round-bottom flask containing 40 mg immobilized PSL, 1 mmol racemic ibuprofen ethyl ester, and 5 mL of 50 mM sodium acetate buffer (pH 7.0). The resulting mixture was shaken at 40°C (180 rpm).

Figure 11. The ¹H NMR spectra of (S)-ibuprofen.

Figure 12. Lineweaver- burk polt of (a) free PSL and (b) PSL-CMC-g-PAA/SBA-15.

Table 2. Parameters obtained from fitting the Lineweaver- burk polt.

Samples	R^2	Km (μmol/L)
Free PSL	0.9697	28.7852
PSL-CMC-g-PAA/SBA-15	0.9642	23.5294