Recent developments in the use of tyrosinase and laccase in environmental applications

Abstract

Our current global environmental challenges include the reduction of harmful chemicals and their derivatives. Bioremediation has been a key strategy to control the massive presence of chemicals in the environment. Enzymes including the phenoloxidases, laccases and tyrosinases, are increasingly being investigated as "green products" in the removal of many chemical contaminants in waters and soils. Both phenoloxidases are widespread in nature and attractive biocatalysts due to their ability to use readily available molecular oxygen as sole cofactor for their catalytic elimination of a large number of chemicals. Taking advantage of their catalytic potentials, remarkable advances have been made in the engineering of laccases to produce suitable biocatalysts in environmental applications. Studies about novel strategies of laccase immobilization and insolubilization for the treatment of chemical contaminants were provided. Likewise, tyrosinases are gaining increasing interest in environmental applications due to their catalytic similarities with laccases although they remain far less investigated to date. This disparity was addressed in this review along with the molecular features and catalytic mechanism of tyrosinases relevant in environmental applications. A perspective on the future use of laccases and tyrosinases in bioremediation was discussed.

Tyrosinase mediated humic substances synthesis by Bacillus aryabhattai TFG5

“…It is believed that in aqueous environment tyrosinase oxidizes low molecular weight phenols and polymerizes them to precipitate it. This enables easy removal of phenolic compounds in wastewater[38]. In the present study, it is evident from the FTIR results that the tyrosinases polymerized phenols as indicated by the presence of additional functional groups.…”

New tyrosinases with a broad spectrum of action against contaminants of emerging concern: Insights fromin silicoanalyses

“…These metalloenzymes carry a characteristic type-3 copper center formed of two copper ions (CuA and CuB), each one connected to three conserved histidine residues (Goldfeder et al, 2014), which catalyzes hydroxylation monophenols to diphenols (monophenolase reaction) and oxidation diphenols to quinones (diphenolase reaction), using molecular oxygen as electron acceptor in both reactions (Kaintz et al, 2014). This process occurs as a catalytic cycle, where the active site shifts from active oxy (Cu II -O2 -Cu II ) state to intermediate met (Cu II -OH -Cu II ) state, and then, to a resting deoxy (Cu I -Cu I ) state that requires a new dioxygen for reactivation (Ba and Vinoth Kumar, 2017). This biocatalyst have been largely used in food, cosmetic and pharmaceutical industries (Agarwal et al, 2019) and more recently, because of its low allosteric specificity and strong oxidative capacities over a diversity of phenolic and nonphenolic aromatic compounds (Asgher et al, 2014), emerged as a versatile biosensor and biocatalyst for monitoring and removing environmental contaminants, such as cresols, chlorophenols, phenylacetates, and bisphenols from natural systems (Ba and Vinoth Kumar, 2017;Harms et al, 2011).…”

Chitosan Microbeads as Supporter for Pseudomonas putida with Surface Displayed Laccases for Decolorization of Synthetic Dyes

“…In addition to biosorption, enzymatic biodegradation provides another promising approach to the decolorization of wastewater dyes [16]. Among various degrading enzymes such as phenoloxidases, laccases and tyrosinases, microbial laccases are being increasingly investigated as an effective and environmentally friendly means of treating industrial phenolic substrates [17]. Laccases (benzenediol:dioxygen oxidoreductases, EC1.10S.3.2) are a large group of multi-copper enzymes that are involved in different biological processes of organisms, such as lignifications in plants; morphogenesis, pathogenesis and detoxification in fungi; cuticle osteosis; and resistance to heave metals, chlorides, ultraviolet (UV) radiation and H 2 O 2 in bacteria, among others [16,18,19].…”

“…Laccases (benzenediol:dioxygen oxidoreductases, EC1.10S.3.2) are a large group of multi-copper enzymes that are involved in different biological processes of organisms, such as lignifications in plants; morphogenesis, pathogenesis and detoxification in fungi; cuticle osteosis; and resistance to heave metals, chlorides, ultraviolet (UV) radiation and H 2 O 2 in bacteria, among others [16,18,19]. Many previous investigations have demonstrated the ability of microbial laccases to oxidatively degrade a broad range of organic compounds, particularly aromatic substrates [20][21][22], including industrial or wastewater dyes [17,23,24]. In a similar approach, we developed a Pseudomonas cell surface display system to efficiently decolorize the anthraquinone dye Acid Green 25 and diazo dye Acid Red 18 [25] in which a mutated bacterial laccase (WlacD) [26] was projected onto the surface of target cells, enabling fast and goal-oriented decolorization on the cell surface.…”