Bioremediation of lindane-contaminated soil by Streptomyces sp. M7 and its effects on Zea mays growth

Abstract

The objective of the present study was to study the lindane bioremediation abilities of Streptomyces sp. M7 in soil samples and to know the pesticide effects on maize plants seeded in lindane-contaminated soil previously inoculated with Streptomyces sp. M7. When different initial pesticide concentrations (100, 150, 200, and 300 μg kg −1) were added to sterile soil, the microbial growth observed was similar to the control without lindane. A decrease of the residual lindane concentration was detected in soils samples in relation to the abiotic controls (29.1%, 78.03%, 38.81%, and 14.42%, respectively). The optimum Streptomyces sp M7 inoculum was selected in sterile soil spiked with lindane 100 μg kg −1soil; it was 2 g kg −1 soil for obtaining the most efficient bioremediation process (56% removal). Lindane concentrations of 100, 200, and 400 μg kg −1 soil did not affect the germination and vigor index of maize plants seeded in contaminated soils without Streptomyces sp. M7. When this microorganism was inoculated at the same conditions a better vigor index was observed and 68% of lindane removal. These results confirm the lindane-contaminated soil bioremediation potential of Streptomyces sp. M7.