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Catalysis of rice straw hydrolysis by the combination of immobilized cellulase from Aspergillus niger on β-cyclodextrin-Fe3O4 nanoparticles and ionic liquid.

Huang PJ, Chang KL, Hsieh JF, Chen ST - Biomed Res Int (2015)

Bottom Line: Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation.Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%.Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Academia Sinica, 128 Section 2, Academia Road, Nankang, Taipei 115, Taiwan.

ABSTRACT
Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase(-1) at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h(-1) L(-1). One of the advantages of immobilized cellulase is high reusability--it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L(-1)). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase.

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XPS spectra of total binding energies of immobilized cellulase from Aspergillus niger on Fe3O4 nanoparticles: (a) Fe3O4-(β-CDs); (b) Fe3O4-(β-CDs)-AP; (c) Fe3O4-(β-CDs)-AP-GE; (d) binding energy of Fe 2p; (e) binding energy of N 1s; (f) binding energy of C 1s. Dash line: Fe3O4-(β-CDs); dotted line: Fe3O4-(β-CDs)-AP; solid line: Fe3O4-(β-CDs)-AP-GE. The Fe3O4 MNPs were produced using the following ratio of ions and β-CDs: Fe2+/Fe3+/β-CDs = 0.33/1/1.
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fig4: XPS spectra of total binding energies of immobilized cellulase from Aspergillus niger on Fe3O4 nanoparticles: (a) Fe3O4-(β-CDs); (b) Fe3O4-(β-CDs)-AP; (c) Fe3O4-(β-CDs)-AP-GE; (d) binding energy of Fe 2p; (e) binding energy of N 1s; (f) binding energy of C 1s. Dash line: Fe3O4-(β-CDs); dotted line: Fe3O4-(β-CDs)-AP; solid line: Fe3O4-(β-CDs)-AP-GE. The Fe3O4 MNPs were produced using the following ratio of ions and β-CDs: Fe2+/Fe3+/β-CDs = 0.33/1/1.

Mentions: The measurement of total binding energy of Fe3O4-(β-CDs) showed characteristic peaks of Fe at 708.2 and 722 eV, which were the binding energy of Fe 2p 3/2 and Fe 2p 1/2, respectively (Figure 4(a)). When cellulase was immobilized onto Fe3O4-(β-CDs) after APTES coating, the binding energy of Fe was shifted higher by 1-2 eV (Figure 4(d)). This upward shift was due to the transfer of the Fe electron density to cellulase, thus making it more difficult to emit the Fe electrons. Moreover, compared with Fe3O4-(β-CDs)-AP and Fe3O4-(β-CDs)-APGE (Figures 4(b) and 4(c)), the characteristic peak of N was clearly detected and its intensity increased after immobilization. When APTES was conjugated onto the surface of magnetite, we detected the amine functional group at approximately 400.4 eV (Figure 4(e)). After immobilization of cellulase, two peaks were shown in the spectrum of Fe3O4-(β-CDs)-APGE, with one at 399.8 eV, which indicated the formation of Schiff base, and the other at 401.2 eV, which corresponded to the free amine of cellulase.


Catalysis of rice straw hydrolysis by the combination of immobilized cellulase from Aspergillus niger on β-cyclodextrin-Fe3O4 nanoparticles and ionic liquid.

Huang PJ, Chang KL, Hsieh JF, Chen ST - Biomed Res Int (2015)

XPS spectra of total binding energies of immobilized cellulase from Aspergillus niger on Fe3O4 nanoparticles: (a) Fe3O4-(β-CDs); (b) Fe3O4-(β-CDs)-AP; (c) Fe3O4-(β-CDs)-AP-GE; (d) binding energy of Fe 2p; (e) binding energy of N 1s; (f) binding energy of C 1s. Dash line: Fe3O4-(β-CDs); dotted line: Fe3O4-(β-CDs)-AP; solid line: Fe3O4-(β-CDs)-AP-GE. The Fe3O4 MNPs were produced using the following ratio of ions and β-CDs: Fe2+/Fe3+/β-CDs = 0.33/1/1.
© Copyright Policy
Related In: Results  -  Collection

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Show All Figures
getmorefigures.php?uid=PMC4385602&req=5

fig4: XPS spectra of total binding energies of immobilized cellulase from Aspergillus niger on Fe3O4 nanoparticles: (a) Fe3O4-(β-CDs); (b) Fe3O4-(β-CDs)-AP; (c) Fe3O4-(β-CDs)-AP-GE; (d) binding energy of Fe 2p; (e) binding energy of N 1s; (f) binding energy of C 1s. Dash line: Fe3O4-(β-CDs); dotted line: Fe3O4-(β-CDs)-AP; solid line: Fe3O4-(β-CDs)-AP-GE. The Fe3O4 MNPs were produced using the following ratio of ions and β-CDs: Fe2+/Fe3+/β-CDs = 0.33/1/1.
Mentions: The measurement of total binding energy of Fe3O4-(β-CDs) showed characteristic peaks of Fe at 708.2 and 722 eV, which were the binding energy of Fe 2p 3/2 and Fe 2p 1/2, respectively (Figure 4(a)). When cellulase was immobilized onto Fe3O4-(β-CDs) after APTES coating, the binding energy of Fe was shifted higher by 1-2 eV (Figure 4(d)). This upward shift was due to the transfer of the Fe electron density to cellulase, thus making it more difficult to emit the Fe electrons. Moreover, compared with Fe3O4-(β-CDs)-AP and Fe3O4-(β-CDs)-APGE (Figures 4(b) and 4(c)), the characteristic peak of N was clearly detected and its intensity increased after immobilization. When APTES was conjugated onto the surface of magnetite, we detected the amine functional group at approximately 400.4 eV (Figure 4(e)). After immobilization of cellulase, two peaks were shown in the spectrum of Fe3O4-(β-CDs)-APGE, with one at 399.8 eV, which indicated the formation of Schiff base, and the other at 401.2 eV, which corresponded to the free amine of cellulase.

Bottom Line: Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation.Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%.Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase.

View Article: PubMed Central - PubMed

Affiliation: Institute of Biological Chemistry, Academia Sinica, 128 Section 2, Academia Road, Nankang, Taipei 115, Taiwan.

ABSTRACT
Cellulase from Aspergillus niger was immobilized onto β-cyclodextrin-conjugated magnetic particles by silanization and reductive amidation. The immobilized cellulase gained supermagnetism due to the magnetic nanoparticles. Ninety percent of cellulase was immobilized, but the activity of immobilized cellulase decreased by 10%. In this study, ionic liquid (1-butyl-3-methylimidazolium chloride) was introduced into the hydrolytic process because the original reaction was a solid-solid reaction. The activity of immobilized cellulase was improved from 54.87 to 59.11 U g immobilized cellulase(-1) at an ionic liquid concentration of 200 mM. Using immobilized cellulase and ionic liquid in the hydrolysis of rice straw, the initial reaction rate was increased from 1.629 to 2.739 g h(-1) L(-1). One of the advantages of immobilized cellulase is high reusability--it was usable for a total of 16 times in this study. Compared with free cellulase, magnetized cellulase can be recycled by magnetic field and the activity of immobilized cellulase was shown to remain at 85% of free cellulase without denaturation under a high concentration of glucose (15 g L(-1)). Therefore, immobilized cellulase can hydrolyze rice straw continuously compared with free cellulase. The amount of harvested glucose can be up to twentyfold higher than that from the hydrolysis by free cellulase.

Show MeSH
Related in: MedlinePlus