Synthesis and characterization of mesoporous Cu-MOF for laccase immobilization

BACKGROUND Mesoporous metal–organic frameworks (MOFs) have been widely researched for enzyme immobilization, however, most are unstable in the aqueous phase. This paper reports the synthesis of a Cu–MOF for the immobilization of copper contained laccase via a surfactant-templating method with various surfactant/chelating agent mass ratios. RESULTS The Brunauer–Emmett–Teller (BET) surface area and pore diameter of the nanoscale Cu–MOF were 366–1154 m2 g−1 and 15.2–20.7 nm, respectively. The adsorption concentration and time were optimized to be 5 mg laccase mL−1 and 1 h. This immobilized system exhibited adsorption capacity up to 502 mg g−1 and activity recovery rate of 95.2%. The optimum reaction conditions for immobilizing laccase on Cu–MOF were pH 4 and 50°C. According to the Lineweaver–Burk plot, the Km of the immobilized laccase was 0.157 mmol L−1, indicating that the affinity of immobilized laccase to its substrate was higher than that of free laccase (0.290 mmol L−1). The activity of immobilized laccase after seven iterations of reuse remained approximately 50%. CONCLUSION The mesoporous Cu–MOF showed favorable adsorption capability and can be utilized in laccase immobilization. © 2017 Society of Chemical Industry