## 5 Applications of Laccases
cerevisiae_ to eliminate phenolic compounds from lignocellulosic hydrolysates [93,94,95]. The potential of lacase applications in the field of biotechnology and the bioremediation of contaminated environments and industries is huge. Lacase oxidizes a wide range of compounds directly or indirectly in the presence of mediators, with the simultaneous reduction of molecular oxygen to water, which is the purest co-product of the reaction [95]. During the oxidation of substrates, apart from water, free radicals are formed, which furtherreact either with each other or other substances present in the reaction mixture, which is the reason for the production of various products by lacases [93], with a wide field of practical applications. Figure 2 shows the sources of lacases and their potential applications. In the paper industry, laccase is mainly used for pulp delignification and paper deinking, as well as for improving the properties of pulp fibers and the tensile strength of paper sheets [96]. The use of lacases in the bleaching of kraft pulp may result in higher yields of pulp and energy savings in addition to a significant reduction in environmental contamination with chemicals [32]. Lacases play an important role in textile processing, such as the biobleaching of fibers (cotton and wool), deinum washing, wool washing, dye synthesis and wastewater treatment. [97; 98; 99; 100; 101; 102; 103]. Laccase is an effective alternative to the most common whitening agent, hydrogen peroxide [10; 96; 104]. In the late 1990s, the first Deni-Lite laccase product from Novozymes was launched on the market for use in the textile industry for the bleaching and finishing of deinn. This commercial use of a product containing lacase initiated the further development of research and the search for new laccases that could be widely used in textile industry plants [103]. In the food industry, laccase has been used, among others, for stabilizing wine, clarifying fruit juices and baking or producing pectin from sugar beets [31; 32; 44; 96; 105; 106; 107; 108]. Laccase used in the clarification of fruit juices oxidizes most of the phenols in the juice, minimizing turbidity and increasing its stability [109; 110; 111; 112]. As the use of laccase as a food additive is still not allowed, this enzyme is used in the food industry in an immobilized form [32; 113; 114]. Figure 2: Sources of lacases and their potential applications. Lacasse participates in the formation of new bonds in homo- and heteromolecular reactions of easily oxidized substrates. The formation of new C-C, C=C, C-O and C-N or C=N and C-S bonds results in the appearance of new hybrid molecules in the reaction mixture [95; 115; 116; 117; 118], without the need to consume large amounts of energy and without highly polluting chemical compounds. These new homo- and heteromolecular molecules can be therapeutic compounds. such as antibiotics (new derivatives of \(\beta\)-lactams, sulfonamides or aminoglycos) or cytostatics (including naphthoquinone and benzofuran derivatives) [82]. In general, the formation of new compounds with the lacase department consists largely of the cross-linking of radicals generated by the enzyme with another molecule in which reactive intermediates are trapped [119]. In recent years, lacase has aroused great interest as a potential anticancer and antiviral therapeutic ingredient. The antiviral effect of lacases acquired from _Agaricus placomyces_, _Pleurotus eryngii_ and _P. ostreatus_ has been described against HIV-1 and HCV [120; 121; 122]. The antiproliferative effect of the enzyme isolated from _Abortiporus biennis_, _T. versicolor_, _Trametes mongolicum_ and _Agrocybe cylindracea_ against HepG2 hepatoma cells and MCF7 breast cancer cells was observed [123; 124; 125; 126; 127]. Recently, there has been an increase in the number of publications describing the action of lacases as biosensors for the determination of xenobiotics present in samples of various origins from the food industry to wastewater.