Use of sugarcane bagasse for the bioremediation of lindane contaminated soil by a defined consortium of actinobacteria

Abstract

The indiscriminate use of lindane led adverse effects on human health and the environment. Bioremediation is a tool that allows removing this contaminant by using biological activity. The use of actinobacteria consortia is an attractive approach because of their ability to degrade lindane and to increase the metabolic pathways to remove it. On the other hand, several studies have reported bioremediation of contaminated soils by adding agro-industrial wastes. The aim of this work was to study the ability of an actinobacteria consortium to remove lindane in soil using sugarcane bagasse as amendment and bulking agent. Bioremediation assays were performed on non-sterile silty loam soil microcosms, artificially contaminated with lindane (2 mg kg-1). Different ratios of soil: residue and nutrients (carbon, nitrogen and phosphorous) were used. Furthermore, particulate size of sugarcane bagasse (0.5 mm and 5.0 mm) and moisture content (20% and 30%) were evaluated. The soil microcosms were inoculated with a defined consortium formed by the Streptomyces sp. A2, A5, A11 and M7 strains and incubated for 14 days under aerobic conditions. Residual lindane concentrations were measured by gas chromatography. Statistical analysis indicated that there were significant differences in the removal of lindane among the treatments with different ratios of soil:residue. The best lindane removal (47.3 %) after 14 days was obtained with a particulate size of 0.5 mm with 30% moisture content and soil:bagasse ratio of 98:2. The actinobacteria consortium has the ability to remove lindane in non-sterile silty loam soil. Sugarcane bagasse enhanced the rate of biodegradation of lindane with respect to soils without bagasse addition amendment, so this residue can be a promising tool to restore pesticides contaminated soils.