Synthesis and characterization of mesoporous Cu–<scp>MOF</scp> for laccase immobilization

Abstract

Abstract 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 m 2 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 K m 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