Last Advances in Synthesis of Added Value Compounds and Materials by Laccasemediated Biocatalysis

Laccases represent versatile catalysts being able to oxidize a wide range of aromatic substrates and are susceptible of several industrial applications based on both oxidative degradation reactions and synthetic chemistry. The range of laccase based synthetic reactions is extremely wide. Laccases are able to catalyze transformation of antibiotics based on both beta-lactams functionalization and phtalides functionalization. These enzymes can also catalyze derivatization of amino acids to obtain metabolically stable amino acid analogues, maximizing biological response while minimizing toxicity, thus representing an useful system for drug development. Biomolecules having antioxidative and anticancer activity can also be produced by laccase-mediated reactions of flavonoids oxidative coupling and phenoxazinones synthesis. Application of laccases to production of new derivatives of the hormones resveratrol, 17 beta-estradiol, totarol and isoeugenol and oligomerization products of substituted imidazoles was also reported, with applications for pharmacological purposes due to hormonal activity of the products. The enzymatic preparation of aromatic polymeric materials by the action of laccases represents a viable and non-toxic alternative to the usual formaldehyde-based chemical production of these compounds and it has been reported for several substrates such as 2,6-dimethylphenol, 4-hydroxybenzoic acid derivatives, 3,5-dimethoxy-4-hydroxybenzoic acid and 3,5-dimethyl-4-hydroxybenzoic acid, aniline and acrylamide. Moreover, laccase-mediated biografting of phenols or certain other types of low-molecular weight compounds provides a method for tailoring the surface of lignocellulosics or for adhesion enhancement in binder-less wood boards under mild conditions and usually without harmful solvents. Laccase-mediated modification of lignocellulosic materials is accomplished through two main routes: coupling of low-molecular weight compounds onto lignocellulosic materials and laccase mediated cross-linking of lignin molecules in situ. Depending on the choice of laccase substrate, properties such as improved strength properties, increased antimicrobial resistance, or hydrophilicity/hydrophobicity can be imparted to lignocellulosic materials.