Non-specific biodegradation of the organophosphorus pesticides, cadusafos and ethoprophos, by two bacterial isolates

Abstract

An enrichment culture technique was used for the isolation of microorganisms responsible for the enhanced biodegradation of the nematicide cadusafos in soils from a potato monoculture area in Northern Greece. Mineral salts medium supplemented with nitrogen (MSMN), where cadusafos (10 mg l(-1)) was the sole carbon source, and soil extract medium (SEM) were used for the isolation of cadusafos-degrading bacteria. Two pure bacterial cultures, named CadI and CadII, were isolated and subsequently characterized by sequencing of 16S rRNA genes. Isolate CadI showed 97.4% similarity to the 16S rRNA gene of a Flavobacterium strain, unlike CadII which showed 99.7% similarity to the 16S rRNA gene of a Sphingomonas paucimobilis. Both isolates rapidly metabolized cadusafos in MSMN and SEM within 48 h with concurrent population growth. This is the first report for the isolation and characterization of soil bacteria with the ability to degrade rapidly cadusafos and use it as a carbon source. Degradation of cadusafos by both isolates was accelerated when MSMN was supplemented with glucose. In contrast, addition of succinate in MSMN marginally reduced the degradation of cadusafos. Both isolates were also able to degrade completely ethoprophos, a nematicide chemical analog of cadusafos, but did not degrade the other organophosphorus nematicides tested such as isazofos and isofenphos. Inoculation of a soil freshly treated with cadusafos or ethoprophos (10 mg l(-1)) with high inoculum densities (4.3 x 10(8) cells g(-1)) of Sphingomonas paucimobilis resulted in the rapid degradation of both nematicides. These results indicate the potential of this bacterium to be used in the clean-up of contaminated pesticide waste in the environment.

Bioremediation of pendimethalin-contaminated soil

“…Our results are in agreement with previous finding reported by Kopytko et al (2002), Karpouzas et al (2005), Belal et al (2008), Derbalah and Belal (2008) and Megadi et al (2010). It was found that enrichment culture technique led to the isolation of two bacterial strains, which were able to degrade different pesticides rapidly in liquid cultures.…”

Degenotoxicity of Pendimethalin Contaminated Clay Soil by Pseudomonas resinovorans Using Anatomical, Cytogenetic and Biochemical Analysis in Vicia faba Plants

“…It showed the highest sequence similarities with P. resinovorans ATCC14235. These results are in agreement with previous finding reported by (Kopytko et al, 2002;Karpouzas et al, 2005;Belal et al, 2008;Derbalah and Belal, 2008;Megadi et al, 2010;Belal and El-Nady, 2013). It was found that enrichment culture technique led to the isolation of two bacterial strains, which were able to degrade different pesticides rapidly in liquid cultures.…”

Changes in bacterial diversity and community structure following pesticides addition to soil estimated by cultivation technique

“…Fenitrothion significantly decreased the microbial respiration, during whole experimental period, in soils treated with 10 and 200 mg/kg soil of insecticide, with the exception of the last day of experiment. It has been found that fenitrothion, like other organophosphorus pesticides, may be degraded by many soil microorganisms resulting in the increase of microbial biomass and their respiration rate (Karpouzas et al 2005;Hong et al 2007), but this phenomenon was not observed in our study. The negativ effect of used insecticide may be associated with the high toxicity of intermediate metabolites that are the products of fenitrothion biodegradation (Matsushita et al 2003).…”