Adsorption–precipitation–cross-linking immobilization of GDSL-type esterase from Aspergillus niger GZUF36 by polydopamine-modified magnetic clarity tetroxide nanocouplings and its enzymatic characterization

• Published in: International journal of biological macromolecules 2023-08, Vol.245, p.125533-125533, Article 125533
• Main Authors: Luo, Chaocheng, Hu, Yuedan, Xing, Shuqi, Xie, Wei, Li, Cuiqin, He, Laping, Wang, Xiao, Zeng, Xuefeng
• Format: Article
• Language: English
• Subjects: Characterization; CLEA-rINANE1; Enzymatic properties; GDSL esterases; Immobilization
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2023.125533

Recombinant INANE1 (rINANE1), a recombinant intracellular GDSL-type esterase from Aspergillus niger GZUF36, has high acetate substrate specificity. Here, rINANE1 was successfully immobilized on polydopamine (PDA)-modified magnetic ferric oxide nanoparticles (Fe3O4NPs) by adsorption–precipitation–cross-linking to obtain cross-linked enzyme aggregate (CLEA)–rINANE1–Fe3O4@PDA. Fe3O4, Fe3O4@PDA, and CLEA–rINANE1–Fe3O4@PDA were characterized by scanning electron microscopy, X-ray diffraction, vibrating-sample magnetometry, Fourier transform infrared (FTIR) spectroscopy, and zeta potential analysis. Upon immobilization, CLEA–rINANE1–Fe3O4@PDA, with a protein loading of 72.72 ± 1.01 mg/g, reached optimal activity recovery of 104.40 % ± 1.14 %. FTIR analysis showed that immobilization increased the relative content of β-folding in rINANE1 by 12.25 % and reduced irregular curl by 4.16 %, rendering the structure more orderly. Specifically, under an alkaline condition (pH 10), CLEA–rINANE1–Fe3O4@PDA performed over 100 % of initial activity. The optimum temperature increased by 5 °C, and over 55 % of the initial activity was observed after 12 h at 55 °C. CLEA–rINANE1–Fe3O4@PDA showed over 40 % of its relative activity, whereas free rINANE1 showed