ISSN print edition: 0366-6352 ISSN electronic edition: 1336-9075 Registr. No.: MK SR 9/7 Published monthly

Cellulase immobilized onto amino-functionalized magnetic Fe₃O₄@SiO₂ nanoparticle for poplar deconstruction

Yan-Yan Huang, Peng Zhan, Fen Wang, Li-Shu Shao, Lin Zhang, Yan Qing, and Jie-Nan Chen

School of Materials Science and Engineering Central South University of Forestry and Technology, Changsha, China

E-mail: pzhan1982@csuft.edu.cn

Received: 20 March 2022  Accepted: 15 May 2022

Abstract:

A two-step synthesis method was successfully applied to covalently immobilize cellulase Cellic CTec2 onto silicon dioxide-coated functionalized magnetic nano-Fe₃O₄ particle (Fe₃O₄@SiO₂). The optimized immobilization parameters were as follows: 2% glutaraldehyde, 100 U CMCase activity of Cellic CTec2, pH 4.5, 20 °C for 4 h, holding a corresponding CMCase activity of 3341 U/g and protein loading of 50 mg/g, respectively. The morphology and composition of nanoparticles were characterized by transmission electron microscope (TEM), vibrating sample magnetometer (VSM), Fourier transform infrared (FTIR), and X-ray diffraction (XRD). The TEM images showed that Fe₃O₄ and Fe₃O₄@SiO₂ particles are spherical with non-uniform size (10–20 nm) and typical core–shell shaped (20–40 nm), respectively. The VSM value of Fe₃O₄, Fe₃O₄@SiO₂, and immobilized cellulase was 91 emu/g, 64 emu/g, and 59 emu/g, respectively, along with notable superparamagnetism. The FTIR and XRD spectra confirmed that cellulase has been successfully immobilized onto the amino-functionalized Fe₃O₄@SiO₂ particles. The polyacrylamide gel electrophoresis analysis showed that there was no significant difference between free and immobilized cellulase. The immobilized cellulase showed good thermal, pH, and storage stability. In addition, the immobilized cellulase was employed for enzymatic saccharification of poplar wood, holding a maximum enzymatic saccharification rate of 38.4% at 72 h, indicating potential for lignocellulosic biomass deconstruction.

Keywords: Cellulase; Immobilization; Fe3O4@SiO2; Poplar; Bioethanol

Full paper is available at www.springerlink.com.

DOI: 10.1007/s11696-022-02292-z

Chemical Papers 76 (9) 5807–5817 (2022)