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

omega-Transaminase (omega-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, omega-TA-PLP@Co-3(PO4)(2), was constructed by coimmobilizing omega-TA and PLP into Co-3(PO4)(2) nanoflowers for the first time. The preparation process of omega-TA-PLP@ Co-3(PO4)(2) was investigated in detail, and the formation mechanism was clarified. The resulting omega-TA-PLP@Co-3(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 omega-TA, the omega-TA-PLP@Co-3(PO4)(2) showed improved catalytic efficiency, thermal stability, pH stability, and storage stability. Furthermore, omega-TA-PLP@Co-3(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 omega-TA into Co-3(PO4)(2) nanoflowers for constructing self-sufficient biocatalysts.