Facile fabrication of a recyclable nanobiocatalyst: immobilization of Burkholderia cepacia lipase on carbon nanofibers for the kinetic resolution of a racemic atenolol intermediate

摘要

Immobilization of surfactant treated Burkholderia cepacia lipase on the surface of carbon nanofibers was performed via two different methods: adsorption and covalent attachment. Simple adsorption of lipase on carbon nanofibers turned out to be a poor strategy, exhibiting an immobilization efficiency of 36%, while covalent coupling using 1-ethyl-3-[3-dimethylaminopropyl] carbodiimide (EDC)/ N -hydroxysuccinimide (NHS) showed better immobilization efficiency (56%). The nanobioconjugate fabricated using the latter method showed an eleven-fold increase in enzyme activity towards the hydrolysis of p -nitrophenyl palmitate and enhanced dispersion in organic solvents. At 80?°C, the half-life of lipase in the nanobioconjugate was almost 20 fold higher than that of free lipase, demonstrating its thermal stability. The as-prepared nanobioconjugate was reused for nine consecutive reaction cycles achieving 100% yield in the hydrolysis of p -nitrophenol palmitate but losing almost 50% of the initial activity after seven operational cycles. Finally, this heterogeneous nanobioconjugate was more active and enantioselective [ C = 47.8, ee _(p) = 97.0 and E = 194] than free lipase [ C = 35.4, ee _(p) = 97.1 and E = 88] towards the kinetic resolution of a racemic intermediate of atenolol yielding the S enantiomer, which signifies its importance as a nanobiocatalyst.