Proline-Activated Lipase was In Situ Encapsulated by MOF to Prepare a High-Activity Temperature-Tolerant Enzyme Catalyst

In situ encapsulation of lipase within MOFs can enhance its stability and enable its reuse, which improves lipase’s greenness and economy. However, the compact MOFs framework can hinder the opening of the lipase’s active site “lid”, limiting the catalytic process. This study employs a strategy where amino acids are used to preopen the “lid” before in situ encapsulation of lipase to improve its activity. The experiment reveals that proline can increase the lipase’s activity by 1.2 times. Additionally, proline can coordinate with Cu2+ to form clusters that promote MOFs encapsulation process, increasing the enzyme loading to 139 mg/g, a 41% improvement. Comparison of the secondary structure of lipase before and after encapsulation demonstrated that proline can induce the unfolding of the “α-helix lid”, exposing the active site and enhancing catalytic efficiency. The resulting proline30-CRL@CuBDC exhibited activity 2.5 times higher than the directly encapsulated CRL@CuBDC, with its activity at 90 °C being 7.7 times that of lipase, and its conversion rate of substrate acetic acid to isoamyl acetate at 80 °C being 6.3 times that of lipase. The use of proline to preopen the “lid” followed by in situ encapsulation offers a novel approach for regulating enzyme activity during the encapsulation process.