Catalase immobilized in polypeptide/silica nanocomposites via emulsion and biomineralization with improved activities

• Published in: International journal of biological macromolecules Vol. 159; pp. 931 - 940
• Main Authors: Liou, Jhih-Han, Wang, Zih-Hua, Chen, I-Hsiu, Wang, Steven S.-S., How, Su-Chun, Jan, Jeng-Shiung
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 15.09.2020
• Subjects: Biomineralization; Catalase - chemistry; Chemistry Techniques, Synthetic; Composite; Emulsions; Enzyme Activation; Enzyme immobilization; Enzyme Stability; Enzymes, Immobilized - chemistry; Microgel; Nanocomposites - chemistry; Peptides - chemistry; Silicon Dioxide - chemistry; Star-shaped polypeptide; Biomineralization; Microgel; Enzyme immobilization; Star-shaped polypeptide; Composite
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/j.ijbiomac.2020.05.138

Polypeptide-mediated silica mineralization is an attractive approach to prepare polypeptide/silica nanocomposites for enzyme immobilization. Herein, a facile approach for in situ immobilization of catalase (CAT) in polypeptide/silica nanocomposites is developed via the preparation of cross-linked polypeptide/enzyme microgels using an emulsion process followed by silica mineralization. The efficient protein immobilization under benign condition (25–28 °C, pH 7.0, 0.05 N) was evidenced by high immobilization yield (> 99%) and no protein leakage. Our data showed that the immobilized CAT exhibited prolonged reusability and storage stability compared to free one, suggesting that the composite networks not only provide suitable microenvironments to facilitate enzymatic reactions but also confine the enzyme macromolecules to prevent subunit dissociation. Star-shaped topology exhibited better coverage onto the enzyme than linear counterpart, leading to the superior reusability (relative activity >95% for 30 cycling number) and storage stability (relative activity >95% for 60 days) of the immobilized CAT (~ 14 mg/g of support). The substrate affinity and enzymatic reaction rate for the immobilized CAT were also influenced by silica content and polypeptide topology. This strategy may provide a feasible and inexpensive approach to fabricate polypeptide/silica nanocomposites, which would be promising materials in biotechnological fields such as enzyme immobilization. [Display omitted] •A facile approach for in situ immobilization of enzyme in the polypeptide/silica nanocomposites•Preparation of polypeptide/enzyme microgels using an emulsion process followed by silica biomineralization.•Immobilized enzyme exhibiting prolonged reusability and storage stability•Substrate affinity and enzymatic reaction rate influenced by silica content and polypeptide topology.