Isolation and characterization of a phorate degrading bacterium

Abstract

Aims: To study the degradation of phorate by a bacterium isolated from phorate‐contaminated sites. Methods and Results: Ralstonia eutropha strain AAJ1 isolated from soil was found to degrade phorate (supplied as sole carbon source) upto 85% in 10 days in liquid medium. Half‐life (t½) of phorate in the liquid medium in control (uninoculated) and in experimental (inoculated with R. eutropha, strain AAJ1) samples was recorded as 36·49 and 6·29 days, respectively. Kinetics revealed that phorate degradation depends on time and the reaction follows the first order kinetics. Diethyl dithiophosphate was one of the degradation products, which is markedly less toxic than the parent compound; other degradation products included phorate sulfoxide and phorate sulfone. Release of inorganic phosphates and sulfates indicated the potential of the isolate to further degrade the above‐mentioned metabolites to simpler forms. The strain was also found to posses phosphomonoesterase and phosphodiesterase enzymatic activity, which are involved in biodegradation of organophosphorus compounds. Conclusions: Ralstonia eutropha AAJ1 could degrade and detoxify phorate upto 85% in 10 days in laboratory conditions. Significance and Impact of the Study: The isolate has the potential to be utilized for remediation of phorate‐contaminated water and soil.

Screening for Lactobacillus plantarum Strains That Possess Organophosphorus Pesticide-Degrading Activity and Metabolomic Analysis of Phorate Degradation

“…The phosphoric acid group metabolic compounds are similar to the diethyl phosphoric acid in chemical structure, which have been reported as phorate degradation products released by Azotobacter ( Kadam and Gangawane, 2005 ). Among the metabolites identified in our study, O,O,O -Tris(2-methylphenyl) thiophosphate with P = S bond is similar to diethyl dithiophosphate, which has been reported as a phorate degradation metabolite produced by Ralstonia eutropha ( Rani et al, 2009 ). The decomposed metabolites of phorate seem to be derived from the oxidizing attack of hydroxyl radical and the substitution of sulfur by oxygen in the P-S bond ( Wu et al, 2010 ).…”

“…Phorate is thioester of phosphoric acid with a central phosphorus atom. The potential metabolites released upon microbial phorate hydrolysis include diethyl dithiophosphate, triethyl dithio-phosphate, diethyl disulfide, formaldehyde, and hydrogen sulfide ( Singh et al, 2003 ; Rani et al, 2009 ; Jariyal et al, 2014 ). Our work identified a number of potential phorate-derived metabolites released by cultivation of L. plantarum in phorate-containing MRS.…”

Isolation and evaluation of potent Pseudomonas species for bioremediation of phorate in amended soil

“…During this period, the rate of phorate degradation was not compensated by a parallel increase in contents of its metabolites-phorate sulfone and phorate sulfoxide, the final levels of which varied from 1.70 to 17.90, and 0.62 to 5.92 mg kg À 1 , respectively the values being higher during initial periods of growth. Both sulfone and sulfoxide are known to be main metabolites of phorate degradation (Rani et al, 2009). However, no phoratoxon has been detected in any of the samples, reported to be third major metabolite of phorate degradation (Henderson et al, 2004) establishing its complete absence during phorate metabolization by Pseudomonas sp.…”

“…A number of bacterial species isolated from soils are known to grow on phorate and cause active phorate degradation but to different extents in liquid media (Serdar et al, 1982;Venkatramesh et al, 1987;Bano and Musarrat, 2003;OrtizHernandez et al, 2003;Rani et al, 2009). In soil containing 200 mg mg À 1 phorate, Rhizobium sp., Proteus sp.…”

Phytotransformation of Phorate by Brassica juncea (Indian Mustard)

“…Gas chromatography and gas chromatography-mass spectrometry analyses were performed according to Rani et al (2009). The retention times of phorate on GC and GC-MS were 8.2 and 18.4 min, respectively.…”