A new heterogeneous bio-catalyst was prepared by the immobilization of
pseudomonas fluorescens lipase (PFL) onto metal-organic
frameworks (MOF), NH2-MIL-53(Fe), using covalent
cross-linking. The immobilized lipase
[PEG-PFL@NH2-MIL-53(Fe)] was firstly applied for
enantioselective transesterification of (R,S)-4-fluoromandelic acid
(4-FMA) with acyl acetate. The effects of temperature, substrate ratio,
and reaction time on conversion rates and enantiomer excess were
investigated. Experimental results show that the catalytic activity,
enantioselectivity, and the thermal stability of PFL are significantly
improved by polyethylene glycol (PEG) modification and immobilization.
By optimizing the reaction conditions, the excellent results were
obtained with conversion of 49.6% and enantiomer excess of 98.0% for
the immobilized PFL catalyzed transesterification reaction. Furthermore,
the immobilized lipase possesses excellent reusability with 83% of its
initial activity after four cycles.