No abstract

The use of laccases applied in bioremediation processes has been increasingly studied, given the urgent need to overcome the environmental problems caused by emerging contaminants. It is known that immobilized enzymes have better operational stability under reaction conditions, allowing for greater applicability. However, given the lack of commercially available immobilized laccases, the search for immobilization materials and methods continues to gain effort. The use of polyacrylonitrile (PAN) to immobilize enzymes has been investigated since it is a low-cost material and can be modified and functionalized to well interact with the enzyme. This polymer can be used with different morphologies such as fibers, beads, and coreshell, presenting as an easily applicable alternative. This review presents the missing link between polymer and enzyme through an overview of PAN's current use as support for laccase immobilization and polymer functionalization methods, considering the importance of immobilized laccases in several industrial sectors.

This work evaluates the potential of polyacrylonitrile particles (PAN) as support for laccase from Trametes versicolor immobilization. The slurry polymerization method forms mesoporous particles with low surface area and low maximum pore volume in desorption. The particles were chemically modified by consecutive alkaline and acid hydrolysis, followed by amination and activation with glutaraldehyde to enzyme immobilization. The laccase immobilization yield was 99.48% and 14.29% using the functionalized and non-functionalized particles, respectively. The enzyme activity was measured by the oxidation of 2,2 0 -azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) at different pHs and temperatures. The PAN/laccase derivative was hyperactivated at pH 3, up to 3 times higher than the free enzyme, and performed better at 50 C after 6 h of incubation, with relative activity up to 33% higher than the free enzyme. However, both enzymes denatured when the conditions reached pH 8 and 70 C. The PAN/laccase retained 89% of the initial activity after 30 days of storage at 5 C. It was possible to reuse the enzymatic derivative for 5 cycles, with up to 50% residual activity, under 50 C and pH 3. These results show the potential of this new support for laccase immobilization and further applications of industrial interest.

The search for ideal solid support that promotes enzyme stability, easy separation and reuse cycles in different processes has grown widely. In this sense, core‐shell polymer particles draw attention because they are already widely used in adsorption, catalysis, and drug delivery, due to their remarkable advantages in surface properties adjustment, excellent mechanical stability, and high chemical resistance, as a result of the combination of the characteristics of the polymers that form the core and shell of the structure. Thus, this review article provides an overview of the synthesis processes of these particles, highlighting the characteristics that can be obtained from each synthesis technique, as well as the most recently used techniques to obtain polymeric particles with core‐shell morphology. The advantages and main challenges for the application of these structures in the immobilization of enzymes are also discussed, providing a general summary of what has been explored in the literature. Despite the potential of application, the use of these materials in the immobilization of enzymes is still little explored, with studies focused mainly on lipases and around the same classes of polymers. Therefore, there is an opportunity window regarding the investigation of the immobilization of other enzymes of commercial interest on these polymeric supports.