Enhancement of deltamethrin degradation by soil bioaugmentation with two different strains of Serratia marcescens

M Cycoń,A Żmijowska,Z Piotrowska-Seget

doi:10.1007/s13762-013-0322-0

Abstract

Deltamethrin is one of the most commonly used pyrethroid in agricultural practice in different geo- graphic regions of the world. It is detected in many envi- ronments, especially in soil and water, and can exhibit toxic effect to human and other organisms. In this study, we describe two bacterial strains DeI-1 and DeI-2, isolated from soil, and both identified as Serratia marcescens based on profile of the fatty acid methyl esters, biochemical test, and 16S RNA gene analysis, which were shown to effi- ciently degrade deltamethrin. Degradation of deltamethrin in mineral salt medium (50 mg l -1 ) proceeded by strains DeI-1 or DeI-2 reached the values of 88.3 or 82.8 % after 10 days, and DT50 was 2.8 or 4.0 days, respectively. Bioaugmentation of deltamethrin-contaminated non-sterile soils (100 mg kg -1 ) with strains DeI-1 or DeI-2 (3 9 10 6 cells g -1 of soil) enhanced the disappearance rate of pyrethroid, and its DT50 was reduced by 44.9, 33.1, 44.4, and 58.2 days or 39.1, 25.8, 35.6, and 46.0 days in sandy, sandy loam, silty loam, and silty soils, respectively, in comparison with non-sterile soils with only indigenous microflora. The three-way ANOVA indicated that DT50 of deltamethrin was significantly (P 0.01) affected by soil type, microflora presence, and inoculum, and the interaction between these factors. Generally, the lower content of clay and organic carbon in soil, the higher degradation rate of deltamethrin was observed. Obtained results show that both strains of S. marcescens may possess potential to be used in bioremediation of deltamethrin- contaminated soils.

Highlights

Deltamethrin ((S)-a-cyano-3-phenoxybenzyl (1R,3R)-3(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate) (Fig. 1) is a broad-spectrum insecticide belonging to pyrethroids
Two beta-cypermethrin-degrading strains JC1 and JCN13 belonging to genus Serratia that differed in their capability of the red pigment production and urea hydrolysis were screened by Zhang et al (2010)
Bacteria from genus Serratia, known as very metabolically active bacteria, were isolated from various environments contaminated with synthetic pyrethroids (Grant et al 2002; Zhang et al 2010)

Summary

Introduction

Deltamethrin ((S)-a-cyano-3-phenoxybenzyl (1R,3R)-3(2,2-dibromovinyl)-2,2-dimethylcyclopropane carboxylate) (Fig. 1) is a broad-spectrum insecticide belonging to pyrethroids. They are synthetic compounds that made to mimic the pyrethrins produced by chrysanthemum flowers. Deltamethrin penetrates the cuticles of insects and acarines, as well as kills insects through ingestion. It acts as neurotoxin, and a-cyano group induces the inhibition of the sodium channel activation gate. A-cyano group induces the inhibition of the sodium channel activation gate This results in prolonged permeability of the nerve to sodium leading to blockage of nerve conduction. Deltamethrin can affect activity of the chloride and calcium channels, possibly due to their phosphorylation (Burr and Ray 2004)

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