LACCASES FOR SOIL BIOREMEDIATION

BUSTOS, AY; GUAUQUE TORRES, P

Microbes and Enzymes in Soil Health and Bioremediation

Springer

Año: 2019; p. 165 - 210

Bioremediation tool, by diminishing noxiousness or promoting pollutant mineralization to CO2 and water, is one of the most efficient, cost-effective and eco-friendly approaches for the rehabilitation of polluted soils. Bioremediation process is mainly based on the ability of different enzymes or complex enzymes to act on different substrates. Laccases are ligninolytic enzymes, classified as benzenediol oxygen reductase (EC 1.10.3.2) and also known as multicopper oxidases. They are widely distributed in insects, plants, archaea, fungi, and bacteria. Industrially, laccases coming from fungi are the most commonly used, however, recently bacterial laccases have attracted attention because of their versatility, which includes higher thermostability, a better tolerance to different concentrations of Cu2+ and a higher resistance to changes regarding pH and halo and high chloride. The versatility of laccases allows its use on soil to polymerize pollutants, and it also permits the bioaugmentation with immobilized laccases to degrade pollutants. Taking into account that laccase is one of the oldest enzymes ever described and it is relevant the decomposition of xenobiotics, the present chapter will be dedicated to the exploration of laccase as an invaluable tool for soil bioremediation. We will review the main aspects related to structure of laccases, substrates and mechanisms of action. Additionally, we will also focus in two main topics: the production and the immobilization techniques to enhance availability and stability of laccases. We highlighted some of the successful strategies employed to enhanced laccase production, including the screening of new promising laccase, recombinant laccases production as well as different immobilization strategies applied to increase the enzyme´s stability.