LAUSR

Due to the poor enzyme thermal stability, the efficient conversion of high crystallinity cellulose into glucose in aqueous phase over 50 °C with huge bottleneck. Herein, we propose an enzyme-induced MOFs encapsulation of β-glucosidase (β-G) strategy for the first time. By using various mathods, including SEM, XRD, XPS, NMR, FT-IR and BET, we confirmed the successful preparation of a porous channel-type flower-like enzyme complex (β-G@MOFs). The prepared enzyme complex (β-G@MOFs) materials showed improved thermal stability (from 50 °C to 100 °C in the aqueous phase) and excellent resistance to ionic liquids (the reaction temperature was as high as 110 °C) compared to the free enzyme (β-G). Not only realized the catalytic hydrolysis of cellulose by single enzyme (β-G) in ionic liquid, but also significantly improved the high-temperature continuous reaction performance of the enzyme. Benefiting from the significantly improved heat resistance, the β-G@MOFs exhibited 32.1 times and 34.2 times higher enzymatic hydrolysis rate compared to β-G for cellobiose and cellulose substrates, respectively. Besides, the catalytic activity of β-G@MOFs was retained up to 86% after five cycles at 110 °C. This is remarkable because the fixation of the enzyme by the MOFs ensure that the folded structure of the enzyme will not expand at high temperatures, allowing the native conformation of the encapsulated protein  well-maintained. Furthermore, we believe that this structural stability is caused by the tightness of flower-like porous MOFs.