Enrichment and Coimmobilization of Cofactors and His-Tagged ω-Transaminase into Nanoflowers: A Facile Approach to Constructing Self-Sufficient Biocatalysts

ω-Transaminase (ω-TA), a cofactor-dependent enzyme, has been shown to be an outstanding biocatalyst for the production of chiral amines. The need for improved enzyme stability and cofactor (PLP) recyclability is an important goal in the biocatalysis process. In this study, a novel self-sufficient biocatalyst, ω-TA-PLP@Co3(PO4)2, was constructed by coimmobilizing ω-TA and PLP into Co3(PO4)2 nanoflowers for the first time. The preparation process of ω-TA-PLP@Co3(PO4)2 was investigated in detail, and the formation mechanism was clarified. The resulting ω-TA-PLP@Co3(PO4)2 was characterized by various analytical techniques, such as scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and X-ray photoelectron spectroscopy (XPS). Compared with free ω-TA, the ω-TA-PLP@Co3(PO4)2 showed improved catalytic efficiency, thermal stability, pH stability, and storage stability. Furthermore, ω-TA-PLP@Co3(PO4)2 could maintain about 72% of initial overall activity after 12 catalytic cycles. All these results confirmed the feasibility of enrichment and coimmobilization of cofactors and His-tagged ω-TA into Co3(PO4)2 nanoflowers for constructing self-sufficient biocatalysts.