Enzymes are described as ideal green biocatalysts because they are highly specific and selective. However, their practical application is hampered because of the low stability and missing reusability of free enzymes. One method to overcome these problems is the immobilization of enzymes onto carriers. Although numerous publications discuss different immobilization strategies, optimization of these carriers for the highest enzyme activity and loading capacity, enzyme selectivity, reusability, and reactor system configuration still remains a challenging task. In this contribution, we aim to address the role of the core-shell particle design with respect to their geometry as well as the polymer shell thickness on the immobilization of biomolecules. We discovered that spherical particles with a core diameter of 200 nm and intermediate shell thickness as well as platelet-like particles exhibited excellent results with a maximum immobilization yield of laccase from Trametes versicolor of up to 92% and an activity on the carrier material of 5.722 U/(g particle). Especially, the platelet-like particles offered a scalable and convenient alternative for the immobilization of laccase. Circular dichroism measurements proved that the secondary structure of the enzyme is not impaired by immobilization onto all kinds of carrier particles. Moreover, the immobilized laccase was successfully used for the decolorization of Cibacron blue P-3R in up to 18 cycles. Finally, particle separation was achieved via citrate-induced flocculation within 10 min. This detailed study contributes to the understanding of rational design of catalytically active hybrid materials and their effective performance at interfaces for applications in textile industry and environmental technologies.
Keywords: circular dichroism; enzyme immobilization; laccase; particle size and shape; polymer interface; stimuli-responsive particles.