Synthesis and characterization of mesoporous Cu-MOF for laccase immobilization

BACKGROUNDMesoporous 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. RESULTSThe 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 degrees 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%. CONCLUSIONThe mesoporous Cu-MOF showed favorable adsorption capability and can be utilized in laccase immobilization. (c) 2017 Society of Chemical Industry