Enhanced performance of lipase immobilized onto Co2+-chelated magnetic nanoparticles and its application in biodiesel production

There is an urgent need to exploit new strategies for lipase immobilization to prepare biodiesel. In this study, 5-Aminoisophthalic acid, as a novel metal-chelating ligand, was successfully grafted onto magnetic nanoparticles (MNP) decorated with 3-Glycidoxypropyltrimethoxysilane for Co2+-chelated affinity immobilization of Pseudomonas fluorescens lipase (PFL). The results revealed that the maximum PFL immobilization capacity of Co2+-chelated MNP was 136.9 mg/g at pH 8.0, and 2125% of activity recovery of the immobilized PFL was tested in esterification of lauric acid with 1-dodecanol. Then, the immobilized PFL was applied to prepare biodiesel from waste cooking oil, and 95% of conversion rate was achieved under the optimum conditions. The immobilized PFL could retain 83% biodiesel yield after 10 cycles of repeated use, demonstrating a satisfactory operational stability. Moreover, the support could be easily regenerated when the inactivated enzyme was desorbed and it could be effectively re-chelated with the Co(II) ions. Therefore, the newly designed strategy for PFL immobilization displays great potential in biotechnological applications.