Biodegradation of Diazinon by Serratia marcescens DI101 and its Use in Bioremediation of Contaminated Environment

Abstract

Four diazinon-degrading bacteria were isolated from agricultural soil by using an enrichment technique. The biochemical analysis and molecular method including RFLP indicated that these isolates were identical, and one strain designated DI101 was selected for further study. Phylogenetic analysis based on 16S rDNA sequencing indicated that the strain DI101 clearly belongs to the Serratia marcescens group. The ability of the strain to utilize diazinon as a source of carbon and phosphorus was investigated under different culture conditions. The DI101 strain was able to completely degrade 50 mg/l diazinon in MSM within 11 days with a degradation rate of 0.226 day-1. The inoculation of sterilized soil treated with 100 mg/kg of diazinon with 10 6 CFU/g DI101 resulted in a faster degradation rate than was recorded in non-sterilized soil. The diazinon degradation rate by DI101 was efficient at temperatures from 25 to 30 o C and at pHs from 7.0 to 8.0. The degradation rate of diazinon was not affected by the absence of a phosphorus supplement, and addition of other carbon sources (glucose or succinate) resulted in the slowing down of the degradation rate. The maximum degradation rate (V max) of diazinon was 0.292 day-1 and its saturation constant (K s) was 11 mg/l, as determined by a Michaelis-Menten curve. The strain was able to degrade diethylthiophosphate-containing organophosphates such as chlorpyrifos, coumaphos, parathion, and isazofos when provided as a source of carbon and phosphorus, but not ethoprophos, cadusafos, and fenamiphos. These results propose useful information for the potential application of the DI101 strain in bioremediation of pesticide-contaminated environments.

Biodegradation of Paraoxan as an Organophosphate Pesticide with Pseudomonas plecoglocissida Transfected by opd Gene

“…These chromatograms showed a reverse relationship between incubation time and concentration of paraoxon in the culture tubes (Figure 3). Organophosphate pesticides are directly applied to the agricultural farms and can be washed off into the nearby sewerage and gullies, which are consequently carried by water to rivers and lakes and when spread in the environment they become polluted and require remediation (12)(13)(14).…”

“…Exposure to organophosphate pesticides results in millions of poisoning (8)(9)(10)(11). Organophosphate pesticides are utilized directly to the soil and can be washed off into the nearby sewerage and gullies, and consequently carry water to rivers and lakes and when these substances distributed in the environment they become polluted and require remediation (12)(13)(14). Degradation of organophosphate compounds by microbial enzymes is the focus of biodegradation researches.…”

Biodegradation and Bioremediation of Organic Pesticides

“…From soil, Singh et al have isolated a strain related to Enterobacter which can mineralize chlorpyrifos, parathion, diazinon, coumaphos and isazofos (49). Similarly, it has been found that a bacterial biodegrader related to Serratia can degrade diazinon (50). The A-esterase, can be encoded on genome or plasmid.…”

Native mycota in agricultural soils exposed to pesticides and Aspergillus oryzae tolerance to chlorpyrifos in microcosms assays

“…Many studies have found that the inoculation of adapted microorganisms on pesticide contaminated soils is a good option to decontaminate them (Diez 2010, Abo-Amer 2011, Massiha et al 2011. Soil fungi have been described as the main degraders' microorganisms of complex organic matter from xenobiotics contaminated environments.…”