Enrichment and isolation of a mixed bacterial culture for complete mineralization of endosulfan.
01 Jan 2006-Journal of Environmental Science and Health Part B-pesticides Food Contaminants and Agricultural Wastes (Taylor & Francis Group)-Vol. 41, Iss: 1, pp 81-96
TL;DR: Three novel bacterial species are isolated from contaminated soil collected from the premises of a pesticide manufacturing industry using both mixed and pure cultures to assess their potential for the degradation of aqueous endosulfan in aerobic and facultative anaerobic condition.
Abstract: In the present study, we isolated three novel bacterial species, namely, Staphylococcus sp., Bacillus circulans–I, and Bacillus circulans–II, from contaminated soil collected from the premises of a pesticide manufacturing industry. Batch experiments were conducted using both mixed and pure cultures to assess their potential for the degradation of aqueous endosulfan in aerobic and facultative anaerobic condition. The influence of supplementary carbon (dextrose) source on endosulfan degradation was also examined. After four weeks of incubation, mixed bacterial culture was able to degrade 71.82 ± 0.2% and 76.04 ± 0.2% of endosulfan in aerobic and facultative anaerobic conditions, respectively, with an initial endosulfan concentration of 50 mg l−1. Addition of dextrose to the system amplified the endosulfan degradation efficiency by 13.36 ± 0.6% in aerobic system and 12.33 ± 0.6% in facultative anaerobic system. Pure culture studies were carried out to quantify the degradation potential of these individual sp...
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TL;DR: This chapter attempts to analyze the impacts of pesticides on soil microbial communities, soil biochemical reactions, and soil enzymes, and a few reports reveal some positive effects of applied pesticide on soil health.
Abstract: Pesticides are extensively used in agriculture as a part of pest control strategies. Owing to their xenobiotics characteristics, pesticides may adversely affect the proliferation of beneficial soil microorganisms and their associated biotransformation in the soil. Inactivation of nitrogen‐fixing and phosphorus‐solubilizing microorganisms is observed in pesticide‐contaminated soils. Recent studies show that some pesticides disturb molecular interactions between plants and N‐fixing rhizobacteria and consequently inhibit the vital process of biological nitrogen fixation. Similarly, many studies show that pesticides reduce activities of soil enzymes that are key indicators of soil health. The applied pesticides may also influence many biochemical reactions such as mineralization of organic matter, nitrification, denitrification, ammonification, redox reactions, methanogenesis, etc. However, a few reports reveal some positive effects of applied pesticides on soil health. In this chapter, we attempt to analyze the impacts of pesticides on soil microbial communities, soil biochemical reactions, and soil enzymes.
326 citations
TL;DR: Gene encoding for enzyme has been identified for several pesticides, which will provide a new inputs in understanding the microbial capability to degrade a pesticide and develop a super strain to achieve the desired result of bioremediation in a short time.
Abstract: Biodegradation is a natural process, where the degradation of a xenobiotic chemical or pesticide by an organism is primarily a strategy for their own survival. Most of these microbes work in natural environment but some modifications can be brought about to encourage the organisms to degrade the pesticide at a faster rate in a limited time frame. This capability of microbe is some times utilized as technology for removal of contaminant from actual site. Knowledge of physiology, biochemistry and genetics of the desired microbe may further enhance the microbial process to achieve bioremediation with precision and with limited or no scope for uncertainty and variability in microbe functioning. Gene encoding for enzyme has been identified for several pesticides, which will provide a new inputs in understanding the microbial capability to degrade a pesticide and develop a super strain to achieve the desired result of bioremediation in a short time.
164 citations
Cites background from "Enrichment and isolation of a mixed..."
...Kumar and Philip [6] studied the degradation of endo-...
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...Kumar and Philip [6] studied the degradation of endosulfan by three bacterial species namely Staphylococcus sp., Bacillus circulans-I, and Bacillus circulans-II, both in mixed culture and pure culture....
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TL;DR: This review describes the most recent progress in biotechnological approaches for enhancing the capability of microorganisms and plants through the characterization and transfer of pesticide-degrading genes, induction of catabolic pathways, and display of cell surface enzymes.
Abstract: The use of genetically modified or native microorganisms and plants to degrade or remove pollutants has emerged as a powerful technology for in situ remediation. An understanding of the genetic basis of the mechanisms of how microorganisms and plants biodegrade pollutants and how they interact with the environment is important for successful implementation of this technology. Recent studies have demonstrated that microbes and transgenic plants produce pesticide-degradaing enzymes that can mineralize different groups of pesticides and their metabolites with greater efficiency. This review describes the most recent progress in biotechnological approaches for enhancing the capability of microorganisms and plants through the characterization and transfer of pesticide-degrading genes, induction of catabolic pathways, and display of cell surface enzymes.
159 citations
Cites background or methods from "Enrichment and isolation of a mixed..."
...…isolated from contaminated soil collected from the premises of a pesticide manufacturing industry were able to degrade 72 to 76% of endosulfan (initial endosulfan concentration: 50 mg L−1) in aerobic and facultative anaerobic conditions in four weeks of incubation (Kumar & Philip, 2006b)....
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...Indigenous microorganisms (natural attenuation) can be used for detoxification of contaminants in the environment (Karpouzas et al., 2005; Kumar & Philip, 2006a; Siddique et al., 2003a)....
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TL;DR: Three bacterial strains, Pseudomonas spinosa, P. aeruginosa, and Burkholderia cepacia, were the most efficient degraders of both α- and β-endosulfan as they consumed more than 90% of the spiked amount in the broth within 14 days of incubation, which may imply that these bacterial strains could be employed for bioremediation of endOSulfan polluted soil and water environments.
Abstract: Extensive applications of persistent organochlorine pesticides like endosulfan on cotton have led to the contamination of soil and water environments at several sites in Pakistan. Microbial degradation offers an effective approach to remove such toxicants from the environment. This study reports the isolation of highly efficient endosulfan degrading bacterial strains from soil. A total of 29 bacterial strains were isolated through enrichment technique from 15 specific sites using endosulfan as sole sulfur source. The strains differed substantially in their potential to degrade endosulfan in vitro ranging from 40 to 93% of the spiked amount (100 mg l−1). During the initial 3 days of incubation, there was very little degradation but it got accelerated as the incubation period proceeded. Biodegradation of endosulfan by these bacteria also resulted in substantial decrease in pH of the broth from 8.2 to 3.7 within 14 days of incubation. The utilization of endosulfan was accompanied by increased optical densities (OD595) of the broth ranging from 0.511 to 0.890. High performance liquid chromatography analyses revealed that endosulfan diol and endosulfan ether were among the products of endosulfan metabolism by these bacterial strains while endosulfan sulfate, a persistent and toxic metabolite of endosulfan, was not detected in any case. The presence of endosulfan diol and endosulfan ether in the bacterial metabolites was further confirmed by GC-MS. Abiotic degradation contributed up to 21% of the spiked amount. The three bacterial strains, Pseudomonas spinosa, P. aeruginosa, and Burkholderia cepacia, were the most efficient degraders of both α- and β-endosulfan as they consumed more than 90% of the spiked amount (100 mg l−1) in the broth within 14 days of incubation. Maximum biodegradation by these three selected efficient bacterial strains was observed at an initial pH of 8.0 and at an incubation temperature of 30°C. The results of this study may imply that these bacterial strains could be employed for bioremediation of endosulfan polluted soil and water environments.
140 citations
Cites background from "Enrichment and isolation of a mixed..."
...The biodegradation rates observed in the case of these strains were much higher than of previously documented bacterial strains utilizing endosulfan either as sulfur or carbon source (Awasthi et al. 1997, 2003; Sutherland et al. 2002; Kumar and Philip 2006)....
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TL;DR: In the treatment in which glucose was used, degradation percentages of methyl parathion and chlorpyrifos of 98% and 97% respectively were obtained in 120 h, which is the highest percentage of reduction in toxicity.
Abstract: The simultaneous degradation of the pesticide methyl parathion and chlorpyrifos was tested using a bacterial consortium obtained by selective enrichment from highly contaminated soils in Moravia (Medellin, Colombia). Microorganisms identified in the consortium were Acinetobacter sp, Pseudomonas putida, Bacillus sp, Pseudomonas aeruginosa, Citrobacter freundii, Stenotrophomonas sp, Flavobacterium sp, Proteus vulgaris, Pseudomonas sp, Acinetobacter sp, Klebsiella sp and Proteus sp. In culture medium enriched with each of the pesticides, the consortium was able to degrade 150 mg l−1 of methyl parathion and chlorpyrifos in 120 h. When a mixture of 150 mg l−1 of both pesticides was used the percentage decreased to 72% for methyl parathion and 39% for chlorpyrifos. With the addition of glucose to the culture medium, the consortium simultaneously degraded 150 mg l−1 of the pesticides in the mixture. 4 treatments were carried out in soil that included the addition of glucose with microorganisms, the addition of sugar cane with microorganisms, microorganisms without nutrient addition and without the addition of any item. In the treatment in which glucose was used, degradation percentages of methyl parathion and chlorpyrifos of 98% and 97% respectively were obtained in 120 h. This treatment also achieved the highest percentage of reduction in toxicity, monitored with Vibrio fischeri.
127 citations
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TL;DR: It is concluded that metabolism of this compound does not involve the action of extracellular peroxidases, and it is suggested that the metabolism of endosulfan is mediated by two divergent pathways, one hydrolytic and the other oxidative.
Abstract: Recent studies have shown that cultures of white rot fungi not favoring the production of lignin and manganese peroxidases are effective in degrading certain xenobiotics In this study we have used endosulfan as a model xenobiotic to assess the enzymatic mechanisms of pesticide metabolism under ligninolytic (nutrient-deficient) and nonligninolytic (nutrient-rich) culture conditions Rapid metabolism of this chlorinated pesticide occurred under each nutrient condition tested However, the extent of degradation and the nature of the metabolic products differed for nutrient-deficient and nutrient-rich media The pathways for endosulfan metabolism were characterized by analysis of the fungal metabolites produced The major endosulfan metabolites were identified by gas chromatography-electron capture detection and gas chromatography-mass spectrometry as endosulfan sulfate, endosulfan diol, endosulfan hydroxyether, and a unknown metabolite tentatively identified as endosulfan dialdehyde The nature of the metabolites formed indicates that this organism utilizes both oxidative and hydrolytic pathways for metabolism of this pesticide Piperonyl butoxide, a known cytochrome P-450 inhibitor, significantly inhibited the oxidation of endosulfan to endosulfan sulfate and enhanced hydrolysis of endosulfan to endosulfan diol We suggest that the metabolism of endosulfan is mediated by two divergent pathways, one hydrolytic and the other oxidative Judging by the inactivity of extracellular fluid and partially purified lignin peroxidase in metabolizing endosulfan, we conclude that metabolism of this compound does not involve the action of extracellular peroxidases
236 citations
TL;DR: The results suggest that this mixed culture is worth investigating as a source of endosulfan-hydrolyzing enzymes for use in enzymatic bioremediation of endOSulfan residues.
Abstract: An endosulfan-degrading mixed bacterial culture was enriched from soil with a history of endosulfan exposure. Enrichment was obtained by using the insecticide as the sole source of sulfur. Chemical hydrolysis was minimized by using strongly buffered culture medium (pH 6.6), and the detergent Tween 80 was included to emulsify the insecticide, thereby increasing the amount of endosulfan in contact with the bacteria. No growth occurred in control cultures in the absence of endosulfan. Degradation of the insecticide occurred concomitant with bacterial growth. The compound was both oxidized and hydrolyzed. The oxidation reaction favored the alpha isomer and produced endosulfate, a terminal pathway product. Hydrolysis involved a novel intermediate, tentatively identified as endosulfan monoaldehyde on the basis of gas chromatography-mass spectrometry and chemical derivatization results. The accumulation and decline of metabolites suggest that the parent compound was hydrolyzed to the putative monoaldehyde, thereby releasing the sulfite moiety required for growth. The monoaldehyde was then oxidized to endosulfan hydroxyether and further metabolized to (a) polar product(s). The cytochrome P450 inhibitor, piperonyl butoxide, did not prevent endosulfan oxidation or the formation of other metabolites. These results suggest that this mixed culture is worth investigating as a source of endosulfan-hydrolyzing enzymes for use in enzymatic bioremediation of endosulfan residues.
177 citations
"Enrichment and isolation of a mixed..." refers background or result in this paper
...But throughout the present study, the intermediate metabolites (endosulfan sulfate, endosulfan lactone, endosulfan diol, endosulfan ether, endosulfan hydroxy ether, and endosulfan monoaldehyde) reported by previous researchers [11,15,16,18,19] were not observed....
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...Endosulfan can be degraded by attacking the sulfide group by oxidation and/or hydrolysis to form the toxic metabolite endosulfan sulfate and less toxic endosulfan diol, respectively.[15] But the formation of intermediate compounds (metabolites) is mainly based on the metabolic activity of the specific culture and the environmental conditions....
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...Sutherland et al.[15] reported that degradation of endosulfan can be achieved via oxidation and hydrolysis pathways, but it leads to the formation of toxic endosulfan sulfate and less toxic endosulfan diol, respectively....
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TL;DR: The results of this study suggest that these novel strains are a valuable source of potent endosulfan-degrading enzymes for use in enzymatic bioremediation.
Abstract: Endosulfan (6,7,8,9,10,10-hexachloro-1,5,5a,6,9,9a-hexahydro-6,9-methano-2,3,4-benzo-dioxathiepin-3-oxide) is a cyclodiene organochlorine currently used as an insecticide all over the world and its residues are posing a serious environmental threat. This study reports the isolation and identification of enriched microorganisms, capable of degrading endosulfan. Enrichment was achieved by using the insecticide as either the sole source of carbon or sulfur in parallel studies. Two strains each of fungi (F1 and F4) and bacteria (BF2 and B4) were selected using endosulfan as a sole carbon source. A Pandoraea species (Lin-3) previously isolated in our laboratory using lindane (gamma-HCH) as a carbon source was also screened for endosulfan degradation. F1 and F4 (Fusarium ventricosum) degraded alpha-endosulfan by as much as 82.2 and 91.1% and beta-endosulfan by 78.5 and 89.9%, respectively, within 15 d of incubation. Bacterial strains B4 and Lin-3 degraded alpha-endosulfan up to 79.6 and 81.8% and beta-endosulfan up to 83.9 and 86.8%, respectively, in 15 d. Among the bacterial strains isolated by providing endosulfan as a sulfur source, B4s and F4t degraded alpha-endosulfan by as much as 70.4 and 68.5% and beta-endosulfan by 70.4 and 70.8%, respectively, after 15 d. Degradation of the insecticide occurred concomitant with bacterial growth reaching an optical density (OD600) of 0.366 and 0.322 for B4 and Lin-3, respectively. High OD600 was also noted with the other bacterial strains utilizing endosulfan as a sulfur source. Fungal and bacterial strains significantly decreased the pH of the nutrient culture media while growing on endosulfan. The results of this study suggest that these novel strains are a valuable source of potent endosulfan-degrading enzymes for use in enzymatic bioremediation.
159 citations
"Enrichment and isolation of a mixed..." refers background in this paper
...Detoxification of endosulfan through biological means is receiving serious attention as an alternative to existing methods, such as incineration and landfill.[8] Numerous studies have been reported regarding the isolation of pure and mixed cultures of bacteria and fungi [9–15] capable of degrading endosulfan....
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...While studying endosulfan degradation by various microbes, it is reported that fungal cultures removed more alpha endosulfan compared to beta endosulfan, while bacteria degraded more beta endosulfan compared to alpha endosulfan.[8] But Awasthi, Manickam, and Kumar[12]...
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TL;DR: Using a cell-free preparation from Trichoderma harzianum, it is demonstrated that endosulfan metabolism in vitro was stimulated by exogenously added NADPH, and the evidence that the initial metabolic product of endOSulfan was endos sulfuran sulfate is concluded.
Abstract: A fungus, Trichoderma harzianum, was found to degrade DDT, dieldrin, endosulfan, pentachloronitrobenzene, and pentachlorophenol but not hexachlorocyclohexane. The fungus degraded endosulfan under various nutritional conditions throughout its growth stages. Endosulfan sulfate and endosulfan diol were detected as the major fungal metabolites of endosulfan. Piperonyl butoxide, when added to the growth medium, completely inhibited the endosulfan degradation. Di-n-propyl malaoxon also inhibited the overall endosulfan degradation, but under such an inhibitory condition the formation of endosulfan sulfate was still observed. Using a cell-free preparation from Trichoderma harzianum, we could demonstrate that endosulfan metabolism in vitro was stimulated by exogenously added NADPH. Together with the evidence that the initial metabolic product of endosulfan was endosulfan sulfate, we concluded that the major enzyme system responsible in Trichoderma harzianum responsible for degradation of endosulfan is an oxidative system.
151 citations
"Enrichment and isolation of a mixed..." refers result in this paper
...But throughout the present study, the intermediate metabolites (endosulfan sulfate, endosulfan lactone, endosulfan diol, endosulfan ether, endosulfan hydroxy ether, and endosulfan monoaldehyde) reported by previous researchers [11,15,16,18,19] were not observed....
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TL;DR: Among the isomers and metabolites of HCH and DDT, beta-HCH, pp'-DDT and pp'-DDE were found to be dominant and will serve as a baseline against which future anthropogenic effects may be assessed.
Abstract: The paper examines the concentrations of isomers of hexachlorocyclohexane (HCHs), dichlorodiphenyl trichloroethane and its metabolites (DDTs), α-endosulfan and endosulfan sulfate in surface sediment samples collected from the mouth of Hugli estuary in the vicinity of Sundarban mangrove environment, eastern part of India. An overall pattern of accumulation of these pesticides was in the order of: ΣHCH>endosulfan sulfate>ΣDDT>α-endosulfan. The concentration of these compounds was quite low. An elevated level of ΣHCH, ΣDDT and endosulfan sulfate were marked during premonsoon months, a period characterized by high salinity and pH values. Among the isomers and metabolites of HCH and DDT, β-HCH, pp′-DDT and pp′-DDE were found to be dominant. The sources of contamination are closely related to human activities, such as domestic and industrial discharges, agricultural chemical applications and soil erosion due to deforestation. The study is compared to other estuarine environment in India and abroad. The present data will serve as a baseline against which future anthropogenic effects may be assessed.
147 citations