Instantaneous synthesis of organic-inorganic laccase-cobalt phosphate hybrid nanoflowers: Structural and biocatalytic characterization

Abstract

Organic-inorganic hybrid nanoflowers (HNFs) have been synthesized by soft biomineralization procedures and are mainly used in biocatalysis and biosensing. Previously-reported methods for the synthesis of HNFs have so far required a 3-day incubation, bath sonication, or shear stress tension, which possibly introduces damage to the organic component. In this study, a novel method for instant fabrication of laccase@Co3(PO4)2•HNFs was developed without using harsh conditions. The prepared HNFs were assembled instantly by the “concentrated method,” which resulted in the fast growth of the flower-shaped nanostructures by a higher collision rate of the primary nucleation sites. The obtained results indicated that catalytic efficiency and enzymatic activity of laccase@Co3(PO4)2•HNFs were 113% and 110%, respectively, compared to the free enzyme. Also, the stability of the immobilized enzyme was enhanced by 400% in basic pH values. The activity of laccase@Co3(PO4)2•HNFs declined to 50% of the initial value after 10 reusability cycles, indicating successful immobilization of the enzyme. Structural studies revealed a 32% increase in the α-helix content after hybridization with cobalt phosphate, which improved the activity and stability of the immobilized laccase. Furthermore, the fabricated HNFs exhibited a considerable ability to remove moxifloxacin as an emerging pollutant. The antibiotic (10 mg/L) was removed by 24% and 75% after 24 h through adsorption and biodegradation mechanisms, respectively. This study introduces a new method for synthesizing HNFs, which could be used for the instant fabrication of efficient biocatalysts, biosensors, and adsorbents to be potentially employed in industrial, biomedical, and environmental applications.