Preparation of Metal-Hybridized Magnetic Nanocellulose for ω-Transaminase Immobilization

The enzyme ω-transaminase (ω-TA) has garnered significant attention due to its capacity to catalyze the synthesis of chiral amines with high efficiency. Nevertheless, the lack of stability of ω-TA and the difficulty of recycling and reuse are still challenges that limit its application. This study developed a novel magnetic nanocellulose composite carrier (NNC@Fe3O4@Ni), synthesized from microcrystalline cellulose via low-eutectic solvent treatment, amine modification, and metal hybridization. The NNC@Fe3O4@Ni was characterized by FTIR, XPS, XRD, BET, and VSM. Additionally, the performance and catalytic behavior of the immobilized enzyme were investigated. The results revealed that NNC@Fe3O4@Ni exhibited a high specific surface area, superparamagnetism, and dual-site functionality (amine/Ni2⁺). Response Surface Methodology (RSM) optimized the carrier-enzyme interaction parameters, yielding optimal immobilization conditions: a mass ratio of 50.8 mg g−1, temperature of 12.5 °C, and duration of 58.6 min, achieving 82.91% enzyme activity recovery. Compared to free enzymes, the immobilized variant demonstrated enhanced catalytic stability, with expanded optimal pH (9.0) and temperature (30 °C). Thermal stability assessments showed 84.39% activity retention after 5 h at 30 °C and 90.30% residual activity post-120 h storage. The catalyst maintained >80% efficiency over 10 reuse cycles. These findings confirm the efficacy of magnetic nanocellulose carriers in enhancing ω-TA stability, reusability, and catalytic performance, offering a viable strategy for industrial biocatalytic processes.