Optimization of environmental parameters for biodegradation of alpha and beta endosulfan in soil slurry by Pseudomonas aeruginosa

Institute of Soil & Environmental Sciences, University of Agriculture, Faisalabad, Pakistan.
Journal of Applied Microbiology (Impact Factor: 2.48). 03/2008; 104(2):364-70. DOI: 10.1111/j.1365-2672.2007.03561.x
Source: PubMed

ABSTRACT To determine optimal environmental conditions for achieving biodegradation of alpha- and beta-endosulfan in soil slurries following inoculation with an endosulfan degrading strain of Pseudomonas aeruginosa.
Parameters that were investigated included soil texture, soil slurry: water ratios, initial inoculum size, pH, incubation temperature, aeration, and the use of exogenous sources of organic and amino acids. The results showed that endosulfan degradation was most effectively achieved at an initial inoculum size of 600 microl (OD = 0 x 86), incubation temperature of 30 degrees C, in aerated slurries at pH 8, in loam soil. Under these conditions, the bacterium removed more than 85% of spiked alpha- and beta-endosulfan (100 mg l(-1)) after 16 days. Abiotic degradation in noninoculated control medium within same incubation period was about 16%. Biodegradation of endosulfan varied in different textured soils, being more rapid in course textured soil than in fine textured soil. Increasing the soil contents in the slurry above 15% resulted in less biodegradation of endosulfan. Exogenous application of organic acids (citric acid and acetic acid) and amino acids (L-methionine and L-cystein) had stimulatory and inhibitory effects, respectively, on biodegradation of endosulfan.
The results of this study demonstrated that biodegradation of endosulfan by Ps. aeruginosa in soil sediments enhanced significantly under optimized environmental conditions.
Endosulfan is a commonly used pesticide that can contaminate soil, wetlands and groundwater. Our study demonstrates that bioaugmentation of contaminated soils with an endosulfan degrading bacterium under optimized conditions provides an effective bioremediation strategy.

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Available from: Muhammad Saleem, Sep 28, 2015
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    • "For T1, 88.4 % (265.2 ± 26.7 mg/kg dry wt soil) of toluene was bioremoved within 3-day incubation, 26.4 mg/kg of toluene was further removed after 3 more days, resulting in the total removal efficiency of 97.2 %, and 5.7 mg/kg toluene was further bioremoved after another 3 more days of incubation, corresponding to 99.1 % of toluene bioremoved after 9 days. The obtained data are in accordance with the literature and indicate that the bioavailability of contaminants to the degrading bacteria could be reduced to some extent by their adsorption on clay particles (Phillips et al. 2005; Kumar and Philip 2006; Arshad et al. 2008). The soil sample used in the current study had a clay texture with clay content of 42.4 %. "
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    ABSTRACT: An indigenous Pseudomonas sp., isolated from the regional contaminated soil and identified as P. plecoglossicida, was evaluated for its aerobic cometabolic removal of cis-1,2-dichloroethylene (cis-DCE) and trichloroethylene (TCE) using toluene as growth substrate in a laboratory-scale soil slurry. The aerobic simultaneous bioremoval of the cis-DCE/TCE/toluene mixture was studied under different conditions. Results showed that an increase of toluene concentration level from 300 to 900 mg/kg prolonged the lag phase for the bacterial growth, while the bioremoval extent for cis-DCE, TCE, and toluene declined as the initial toluene concentration increased. In addition, the cometabolic bioremoval of cis-DCE and TCE was inhibited by the presence of hydrogen peroxide as the additional oxygen source, while the bioremoval of toluene (900 mg/kg) was enhanced after 9 days of incubation. The subsequent addition of toluene did not improve the cometabolic bioremoval of cis-DCE and TCE. The obtained results would help to enhance the applicability of bioremediation technology to the mixed waste contaminated sites.
    Environmental Geochemistry and Health 04/2015; DOI:10.1007/s10653-015-9707-y · 2.57 Impact Factor
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    • "Under pesticides contaminated conditions, endogenous ethylene production in soil and plants tissues may inhibit root growth of plants and ultimately rhizoremediation. The inoculation of hyperaccumulators with bacteria containing 1-aminocyclopropane-1-carboxylate (ACC) deaminase or transgenic plants expressing ACC deaminase genes possess a huge potential to overcome ethylene-induced stresses in plants and may lead to more biomass production in terms of roots and shoots, which may improve rhizoremediation (Arshad et al., 2007). "
    Biodegradation and Bioremediation, 10/2014: chapter 5; Studium Press LLC, U.S.A., ISBN: 1-62699-018-2
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    • "Chemical oxidation of endosulfan leads to the formation of endosulfan sulfate, which is more persistent than the parent isomers and equally toxic [9]. Biological treatment is considered to be a more feasible option in comparison to physicochemical methods because the latter involve high treatment costs and possibilities of causing secondary pollution problems [13] [14] [15] [16] [17]. However, high concentrations of endosulfan often inhibit biological processes. "
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    ABSTRACT: The efficiencies of reductive transformation of endosulfan by bimetallic systems consisting of zerovalent magnesium (Mg(0)) as the electron donor and three forms of palladium as the catalyst (Pd(0)-alumina, Pd(0)-carbon and Pd-K(2)PdCl(6)) were compared in this investigation. Results revealed that both Pd(0)-alumina and Pd(0)-carbon were able to remove 90 and 93% of 10mgL(-1) of endosulfan, respectively in 30min with the concomitant accumulation of trace concentrations of partially chlorinated compounds in the reaction medium. Removal of endosulfan followed first-order kinetics and the rate constant (k(obs)) value was computed to be 0.2min(-1) for both Pd(0)-alumina and Pd(0)-carbon. Pd(0)-carbon was relatively more stable and reusable in comparison to Pd(0)-alumina. More than 99% of 10mgL(-1) endosulfan was converted to hydrocarbon end product by Pd-K(2)PdCl(6) system within 6min of reaction. The formation of hydrocarbon end product suggested desulfurization and complete dechlorination of endosulfan. The efficiencies of removal of α and β endosulfan isomers were nearly the same in reaction media containing acetone or Tween 80 as the pesticide solubilizing agents. Results obtained in this study suggest the possibility of developing a reactor containing immobilized palladium for the treatment of water contaminated with endosulfan.
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