Biorremediation of chemichal herbicides using fungal species or microbial consortia in soil

Abstract

Pesticides are widely used in food production worldwide. These formulations include herbicides, insecticides, fungicides and other types of pesticides. Chemical herbicides represent 47.5% of the total pesticides used worldwide. It is known that less than 10% of the applied doses of these herbicides attack the target organisms. Therefore, these compounds move on the environment by different mechanisms like rainwater, crop removal, leaching, volatilization, plant uptake, chemical degradation, adsorption, photodegradation, runoff and microbial degradation. Some herbicides are persistent and recalcitrant being a problem because their residues could be harmful for both human and/or animal health and for the environment. The excessive use and inappropriate application of chemical herbicides can cause negative effects on biodiversity. In addition, these residues could have a phytotoxic effect on the next crop and could threat the food production chain. Several processes help the dissipation of these compounds on soil, but the microbial degradation is one of the most important. Both scientific and social community have increasing interests on minimize the impact of chemical herbicides on the environment. Therefore, a lot of investigation about bioremediation strategies is performed. Although there is considerable research done on biodegradation of herbicides by bacteria, fungi are less studied in this field. Fungi are great enzyme producers and they are able to metabolize important environmental pollutants such as herbicides. They have some advantages against bacteria in bioremediation systems. They can degrade a diverse range of persistent toxic environmental pollutants and carry out a relevant role in co-metabolic degradation processes. The purpose of this chapter is to review information about studies performed in order to develop bioremediation strategies using fungi or microbial consortia to diminish chemical herbicides residues in soil.