## 7 Methods of Increasing the Productivity and Activity of Laccases
### Improvement of Catalytic Activity of Lacases  
In recent years, researchers have used methods such as the optimization of reaction conditions, including the search for reaction mediators or inducers, the use of surfactants, the immobilization of enzymes on matrices with various properties, and modifications of catalytic activity and substrate specificity using molecular biology and engineering techniques to increase enzyme activity [315; 316]. In the work of [PERSON] et al. (2019), it was proposed to optimize the lacase-mediator system (LMS) to reduce pesticide levels in the aquatic environment [183]. Among all the tested mediators, the best degradation efficiency was achieved for the lacase-vanillin system at 30 \({}^{\circ}\)C after 5 h incubation. The lacase-mediator system (LMS) can overcome obstacles such as steric hindrance (for macromolecular compounds), very low affinity between the compound and the active site of the enzyme and high redox potential of putative substrates. ABTS is the first synthetic molecule to act as a lacase mediator [106]. To improve the stability of enzymes and increase their activity in a wide range of pH and temperatures, immobilization is being used. This process also allows the enzyme to be used multiple times and facilitates its storage, which reduces the cost of the reaction. Methods such as adsorption, entrapment, encapsulation, covalent bonding, and self-immobilization have been used to immobilize lacase [89; 292; 293; 294; 296; 317; 318]. In the [PERSON] et al. (2013) study, _C. gallica_ lacase immobilized on mesoporous silica spheres by adsorption cross-linking has been used to eliminate endocrine-disrupting compounds (EDCs) from wastewater [319]. Compared to the free enzyme, the immobilized enzyme had significantly higher thermostability, with half-lives of 31.5 h and 3.9 h, respectively, compared to 6.1 h and 0.6 h at 55 \({}^{\circ}\)C and 75 \({}^{\circ}\)C. The improvement in temperature resistance in the biocatalyst was probably due to the reduction of molecular mobility and the improvement in conformational stabilization due to the high degree of multipoint attachment to the substrate. Immobilized lacase used in a continuously stirred membrane reactor eliminated more than 95% of 10 mM BPA and 10 mM EE2 and 70% of 10 mM diclofenac when treated individually and more than 90% when treated as a mixture in a pH 5 aqueous buffer solution for more than a 60 reactor volume. After more than 80 h of real wastewater treatment, over 85% of BPA and EE2 and 30% of diclofenac were degraded. Much attention is paid to nanomaterials and nanobiocatalysts. The nanomaterial particles form a complex with the enzyme through a covalent bond [320]. Nanomaterials provide a larger immobilization surface, which increases the enzyme load per unit mass of particles and, thus, increases the efficiency of the immobilized enzymes [321; 322]. The reuse of immobilized laccases improves the efficiency and durability of the process by reducing the costs associated with the loss of enzymes and materials [159; 323]. To improve the decolorization performance of HR dyes, [PERSON] et al. (2019) developed a method of laccase immobilization on a nanoporous Zeolite-X carrier [324] chemically belonging to hydrated aluminosilicates forming a three-dimensional network skeleton with the same size of interconnected pores and channels. Covalent immobilization on the nanomaterial improved enzyme properties such as resistance to pH and temperature changes lowered the activation energy and increased the catalytic efficiency. Complete discoloration of AB 225 occurred after 15 min of incubation and RB 19 after 45 min. In addition, the immobilized formulation retained 100% of its original activity after seven consecutive decolorization cycles. The laccase of _Nigroporus durus_ ATCC 26726 immobilized on nanoporous Zeolite-X (ZX) can be successfully used in the textile industry for water treatment.