This study aims to develop an innovative immobilization strategy for penicillin G acylase (PGA) through microenvironment optimization of a composite carrier matrix, with the goal of enhancing catalytic performance, operational stability and reusability of the immobilized enzyme for industrial biocatalytic applications.
A hierarchical assembly approach was used to fabricate Mn²+-(Fe3O4/manganese-substituted hydroxyapatite (Mn-HA))@ß-CD nanoparticles (NPs) as the composite carrier. The design incorporated Fe3O4 NPs as the magnetic core, while Mn²+ ions coordinated with ß-cyclodextrin (ß-CD) and Mn-HA complexes to form a structurally reinforced core-shell coating layer. Systematic investigations were conducted to optimize critical parameters, including immobilization methodologies, carrier microenvironment characteristics and organic linker arm dimensions. The effects of these parameters on catalytic efficiency, storage stability and operational reusability were comprehensively evaluated.
The optimized Mn²+-(Fe3O4/Mn-HA)@ß-CD-g-KH560-PGA nanoparticles demonstrated exceptional biocatalytic performance, achieving an enzyme activity (EA) of 31,414 U/g with an EA recovery rate of 93.8% and enzyme loading capacity of 138 mg/g. The immobilized PGA exhibited remarkable operational stability, maintaining 70.0% of its initial activity after 12 consecutive catalytic cycles, with a recovery ratio of 89.5%. These superior properties were attributed to the Mn²+-rich composition, polyhydroxy functionality and optimized linker arm architecture of the composite carrier.
The unique integration of magnetic Fe3O4 core, Mn²+-coordinated ß-CD/Mn-HA complex and optimized linker arm architecture represents a significant advancement in enzyme immobilization technology. The demonstrated improvements in catalytic performance and operational stability offer substantial potential for industrial biocatalytic applications.
