The capacity of Actinobacteria isolated from arid ecosystems in the bioremediation of soils polluted by λ-cyhalothrin-pesticide

The insecticide lambda cyhalothrin has been used in many crops for many years in the arid soils of the Algerian Sahara and in other countries. The urgency of the use of different biological techniques is necessary for depollution, to compensate the devastating effects of this insecticide. Actinobacteria have very large capacities of degradation because of their very important metabolic potential. The exploration of extreme ecosystems such as chotts and saline soils which has not been studied sufficiently is a promising approach to give native Actinobacteria with a high adaptive capacity to hot climates and high levels of arid soil salinity. In this work, several Actinobacteria were isolated on three selective media from the soils of Chott Melghir and El-Oued, in the northeast of the Algerian Sahara. The study of their growth capacities on lambda-cyhalothrin taken as the sole source of carbon and nitrogen is tested on minimum media. The isolate S1 and SO11 are the most effective in the biodegradation of the insecticide. They can live at temperatures ranging from (15 °C to 55 °C) and in neutral to alkaline pH. The lambda-cyhalothrin degradation tests showed that the selected isolates could grow on this insecticide as a sole source of carbon and nitrogen at maximum concentrations of 3 to 4 g/L. These two bacteria are assigned to Streptomyces genus. This study shows that Streptomyces are excellent agents for the bioremediation of arid soils contaminated by this insecticide.