Laccases for removal of recalcitrant and emerging pollutants

Bioremediation of wastewater can be enhanced by the use of lignolytic enzymes such as laccases. Laccases oxidize, polymerize or transform phenolic or anthropogenic compounds to less toxic derivatives. Laccase substrates are diverse, and include phenols, dyes, pesticides, endocrine disrupters and polycyclic aromatic hydrocarbons, some of which can be oxidized by extracellular fungal or bacterial laccase. Despite their enormous potential, the use of laccases for decontamination has so far usually been limited to the laboratory scale due to high enzyme production costs. The use of lignocellulosic waste material and/or wastewater as culture media for the growth of microorganisms producing laccase is gaining popularity, but is still low profile due to the ever-present challenges of this approach. The last two decades have seen the publication of numerous reviews on laccases; however, information on laccase properties and production parameters remains sketchy. Hence, a global overview of parameters affecting the biocatalysis of pollutants by laccases, particularly with regard to the economical production of these enzymes using synthetic media and waste materials, is timely.