Design of Raspberry-Shaped Microcarriers with Adjustable Protrusions and Functional Groups for the Improvement of Lipase Immobilization and Biocatalysis: Environmentally Friendly Esterification of Oleic Acid for Biodiesel

Raspberry-shaped microparticles with adjustable protrusions and functional groups were synthesized and applied as carriers for the immobilization of lipase. The structural advantages of the raspberry-shaped microcarriers with immobilized lipase (RM-IL) are not only that the protrusions are constructed to play the role of a spacer arm, but the block structure enhances the bioactivity of lipase at the oil–water interface. The activation method used for the carrier has a significant effect on the performance of immobilized lipase. RM-IL prepared by carboxylic acid activation has a 3.5-fold increase of activity compared with that from amine activation and generates a fourfold increase of protein bound to 164 mg g⁻¹ of carrier. Finally, RM-IL is used as an environmentally friendly and high-efficiency biocatalyst to catalyze the esterification of oleic acid for biodiesel under mild conditions, and the conversion can reach up to 82.1 %. Above all, raspberry-shaped microcarriers prepared by an improved seed emulsion polymerization have prospects for industrialization.