A twostep model is developed for the aerobic biodegradation of benzene, toluene, and pxylene btx by pseudomonas putida f1. Apr 15, 2012 the major aromatic constituents of petroleum products viz. All compounds were rapidly degraded under natural aerobic conditions. Determination of the residual gamma isomer of benzene hexachloride. Monods equation adequately described aerobic biodegradation rates of benzene and toluene by the microbial population of a sandy aquifer when these compounds were initially present at concentrations lower than 100 mgl each. Phenol had little effect on the biodegradation of either toluene or benzene. Scale up to 100l of anaerobic benzene culture for field scale. A summary of field and laboratory studies prepared by. The losses due to biodegradation of benzene and naphthalene at high salinity were about 22% and 11%, while the corresponding losses at21 days with soil a3 at low salinity were 19% and 10%, respectively. Anaerobic benzene and toluene degradation was studied with different electron acceptors in batch experiments. Benzene is biodegraded in the absence of oxygen under a variety of terminal electronaccepting conditions. Microcosms were brought to room temperature prior to analysis.
Aerobic biodegradation and volatilization rates are quantified. A study of aerobic degradation of benzene by the microbial population of industrial wastewater treatment units showed only 4 mgl benzene remaining after 6 h with an initial dose of 50 mgl davis et al. Benzene, toluene and xylene were used as carbon sources. Calculating the extent of biodegradation from the isotope signatures demonstrated that at least 85% of benzene was degraded by this pathway and thus, only a small fraction was removed abiotically. Biodegradation of the gamma isomer of benzene hexachloride. Biodegradation of benzene at different temperature was evaluated by incubating bottles at temperatures ranging from 5 to 60 c. In the concentration ranges tested, toluene and benzene biodegradation kinetics were well described by the monod model.
In recent years the analysis of stable isotope fractionation has increasingly been used for characterizing and quantifying biodegradation of contaminants in aquifers. Biodegradation rates for fuel hydrocarbons and chlorinated. Kinetics of benzene biodegradation by pseudomonas aeruginosa. Benzene and toluene biodegradation with different dissolved. Biodegradation is considered to be a remedy for this issue and the usage of activated sludge is the most dominant method used among these days. Pdf kinetics of aerobic biodegradation of benzene and. Aerobic biodegradation of benzene and toluene under. Biodegradation of benzene in a batch reactor using. Howard environmental science center syracuse research corporation 6225 running ridge road north syracuse, ny 2122509 prepared for. In general, the degradation rate of benzene, toluene and phenol increased with the increase in the initial. Biodegradation of benzene, toluene, ethylbenzene and. Benzene was rapidly degraded within 7 days in microcosms containing moderately high levels of salt including 1, 2, and 2. Jan 29, 2019 to isolate bacteria responsible for the biodegradation of naphthalene, btex benzene, toluene, ethylbenzene, and o, m, and pxylene, and aliphatic hydrocarbons in petroleumcontaminated soil. Strain bda59 cells were cultured in r2a broth at 25c for.
Benzene and toluene were tested for obligate anaerobic degradation in batch reactors with sulfate as the electron acceptor. Kinetics of aerobic biodegradation of benzene and toluene in. Tex compounds degraded, but benzene generally remained persistent total duration too short. Benzene is a natural constituent of crude oil and is one of the elementary. Characterization biodegradation of benzene, toluene, ethylbenzene, and xylenes by the newly isolated bacterium pseudomonas putida ay. Initially, evidence for the degradation of benzene at the salt plains was. Postsorption contaminant biodegradation the destruction of benzene in the biotic plumestop system is further confirmed in the total system extractions figure 3, in which the full initial mass of benzene was recovered from the abiotic plumestop control, confirming non. Biodegradation rates for fuel hydrocarbons and chlorinated solvents in groundwater 337 introduction. A benchscale treatability study was thus conducted at the center for environmental microbiology cem to investigate whether benzene contained within the adsorbent pad has the potential to biodegrade within a. This study determined the model parameters describing biodegradation of benzene by conducting kinetic microcosm batch tests in both pure solution and saturated aquifer material conditions for various initial benzene 100700 mgl and microbial concentrations 10 7 10 9 colony. Biodegradability study of potassium hydrogen phthalate and.
Pdf biodegradation of benzene by halophilic and halotolerant. In this sense, the afpfc were successfully used as a support for bacterial immobilization. Both systems, immobilized and suspended cells of p. This study reports on benzene and toluene biodegradation under different dissolved oxygen conditions, and the goal of this study is to evaluate and model their removal. Both aerobic and anaerobic degradation pathways include benzene activation and channeling towards key intermediates catechol in aerobic and benzoylcoa in. Benzene has often been observed to be resistant to microbial degradation under anoxic conditions.
Effect of biofuels on biodegradation of benzene and toluene. The effect of salinity on benzene degradation was determined in microcosms using msm supplemented with 0, 0. Several aerobic metabolic pathways for the degradation of benzene, toluene, ethylbenzene and xylene btex, which are provided by two enzymic systems diox the monooxygenase attacks methyl or ethyl substituents of the aromatic ring, which are subsequently transformed by several oxidations to corresponding substituted pyrocatechols or phenylglyoxal, respectively. Recently, we have reported biodegradation of benzene, toluene. The risk that benzene and toluene from spills of gasoline will impact drinking water wells is largely controlled by the natural anaerobic biodegradation of benzene and toluene. Whilst sometimes described as oxofragmentable, and oxodegradable. The current state of practice to estimate the risk from intrusion of vapors of petroleum hydrocarbons from spills of gasoline is to measure the concentration of the chemical of concern in ground water under the spill, use henrys law to estimate a concentration of the chemical in soil gas in equilibrium with the ground water, and then assume that the chemical is transported by molecular. Anaerobic degradation of benzene, toluene, ethylbenzene, and o. Biodegradation is a very important property for toxic chemicals, because if the biodegradation rate is high, the concentration and thereby the toxic effect will be reduced rapidly, while very persistent chemicals will maintain their toxic effect for a very long time. Description, properties, and degradation of selected. The biodegradation ability of strain bda59 was evaluated with individual btex compounds benzene, toluene, ethylbenzene, or o, m, and pxylenes and a mixture in 160ml serum bottles containing 10 ml of msb medium and ye if appropriate under aerobic conditions in triplicate.
This study highlighted the role of hydrogen peroxide h2o2, nitrate, and phosphate in stimulating. Benzene is an organic chemical compound with the molecular formula c 6 h 6. The correlation of carbon and hydrogen isotope signatures of benzene in a btexcontaminated aquifer located in the area of a former hydrogenation plant gave indications that biodegradation mainly occurred under anoxic conditions. Biodegradation of benzene, toluene, and xylene btx in. Pdf substrate interactions during the biodegradation of.
Biodegradation of naphthalene, btex, and aliphatic. As it contains only carbon and hydrogen atoms, benzene is classed as a hydrocarbon. Biodegradation tests a bottom sidearm with a silicon membrane and aluminum cap was used to remove samples from the flasks, using a sterile syringe and needle. Integrated anaerobicaerobic biodegradation of multiple. A highly enriched halophilic culture was established with benzene as the sole carbon source by using a brine soil obtained from an oil production facility in oklahoma. Request pdf bacterial aerobic degradation of benzene, toluene, ethylbenzene and xylene several aerobic metabolic pathways for the. Biodegradation of benzene was evaluated at various salt concentrations ranging from 0 to 4 m. A number of recent studies, however, have demonstrated that anaerobic benzene utilization can occur. This leads to a wider application of aerobic biodegradation of benzene. The objective of this work was to evaluate microbial biodegradation kinetic of benzene and toluene by building different hypotheses on microbial degradation activity, and by validating. Pdf biodegradation of benzene, toluene, ethylbenzene.
Chiang shell development company, westhollow research center, p. The literature compilation began with an electronic search of two files in srcs efdb, datalog and biolog, as sources of extensive biodegradation information. The rate and extent of biodegradation of benzene, toluene, ethylbenzene and xylenes btex in groundwater was studied in samples from a contaminated site which contained total btex concentrations of up to 20 000. Research work with regards to the construction of bacterial. Rates were highest in the capillary zone, where 68% of the total hydrocarbon mass that volatilized from the water table was estimated to have been biodegraded. Bhc by gas chromatography showed that the insecticide persisted longer in sterilized flooded soils than in nonsterilized flooded soils. Biodegradation kinetics of benzene and naphthalene in the. When degrading two component mixtures, toluene was utilized at a rate by 73% lower in the presence of benzene and at a rate by 37% lower in the presence of xylene. Aerobic biodegradation of benzene, toluene, and xylene in. Bioremediation approaches and tools for benzene remediation under anaerobic conditions presented by. In mixture experiments, the rate of consumption of one substrate was found to be. Modeling biodegradation kinetics on benzene and toluene. The utilization of xylene also decreased by 53% in the presence of benzene and by 15% in the presence of toluene. Characterization biodegradation of benzene, toluene.
Enhanced bioremediation using sulfate andor nitrate. Applicability of stable isotope fractionation analysis for. Benzene and potassium hydrogen phthalate khp with their immeasurable applications lead to tons of generated waste. Benzene and toluene, as well as ethanol and other biofuels, are degraded under anaerobic conditions to the. Consider nitrate together with sulfate to increase the electron acceptor pool. In this study, landfill cover soil was used as an inoculum source to enrich a methane, benzene, and toluenedegrading consortium mbt14. Hypersaline water, halotolerance, biodegradation, benzene, toluene. Biodegradation of btex benzene, toluene, ethyl benzene. Biodegradation kinetics of benzene, toluene, and phenol as. Aerobic biodegradation of benzene, toluene, and xylene in a. Characterization of natural biodegradation using benzene.
Effect of biofuels on biodegradation of benzene and. The major aromatic constituents of petroleum products viz. The monooxygenase attacks methyl or ethyl substituents of the aromatic ring, which are subsequently transformed by several oxidations to corresponding substituted pyrocatechols or. Biodegradation, principally under aerobic conditions, is an important environmental fate process for water and soilassociated benzene. Benzene and toluene, as well as ethanol and other biofuels, are degraded under anaerobic conditions to the same pool of degradation products. To isolate bacteria responsible for the biodegradation of naphthalene, btex benzene, toluene, ethylbenzene, and o, m, and pxylene, and aliphatic hydrocarbons in. Some interesting phenomena were observed when both benzene and thiophene were. Also, 14c benzene was converted to 14co2, suggesting the cultures ability to mineralize benzene. Pseudomonas putida, biodegradation, btx, plasmid tol. In the present work, kinetics of the biodegradation of benzene, toluene and phenol by using a pure culture of pseudomonas putida mtcc 1194 was determined by measuring the specific growth rate and degradation rate with substrate concentration as a function of time in a batch reactor. A benchscale constructed wetland as a model to characterize.
The benzene molecule is composed of six carbon atoms joined in a ring with one hydrogen atom attached to each. A benzenedegrading nitratereducing microbial consortium. The effect of the agitation rate on the biodegradation process was also investigated at 150 and 200 rpm and at 0. The enrichment completely degraded benzene, toluene, ethylbenzene, and xylenes within 1 to 2 weeks. The median primary degradation rate of benzene, toluene, ethylbenzene, and xylene btex compounds ranges from 0. A fibrousbed bioreactor containing the coculture of pseudomonas putida and p. Oct 14, 2011 benzene degradation in laboratory microcosms electron acceptors and key players benzene. Benzene, toluene, and oxylene degradation by free and.
It has been identified in air samples of both rural and urban. Although benzene was degraded faster than naphthalene, the biodegradation of these two phcs was in general very slow with rate coefficients in the order of 10 3 to 10 2 day 1 and the applied kinetic models fitted the experimental results very well. Biodegradation of benzene by halophilic and halotolerant. Although case studies on anaerobic biodegradation are available e. Several aerobic metabolic pathways for the degradation of benzene, toluene, ethylbenzene and xylene btex, which are provided by two enzymic systems dioxygenases and monooxygenases, have been identified. Pdf kinetics modelling of the biodegradation of benzene. Benzene was biodegraded within 1 d, whereas thiophene could not be biodegraded as the sole source of carbon and energy. Monods equation adequately described aerobic biodegradation rates of benzene and toluene by the. Characterization of natural biodegradation using benzene carbon isotopes, lnapl characterization and geochemical lines of evidence background site conditions lines of evidence approach results natural attenuation and biodegradation of. Lawrence abstract this report provides abridged information describing the most salient properties and biodegradation of 27 chlori. The biodegradation of benzene, toluene and phenol in a two.
Aug 20, 2000 toluene significantly inhibited the biodegradation rate of both of the other substrates, and benzene slowed the consumption of phenol but not of toluene. Anaerobic degradation of benzene in diverse anoxic. This study shows that model wetlands can contribute to an understanding of biodegradation processes in floodplains or natural wetland systems. Therefore, btx biodegradation potential of individual as well as formulated bacterial consortium was evaluated. Pdf biodegradation of benzene, toluene, ethylbenzene, and o. Recent evidence of benzene biodegradation with nitrate. Biodegradation of petroleum hydrocarbon vapors in the.
Anaerobic degradation of benzene, toluene, ethylbenzene, and oxylene in sedimentfree ironreducing enrichment cultures. Kinetics of aerobic biodegradation of benzene and toluene in sandy aquifer material article pdf available in biodegradation 21. Oxo biodegradation is defined by cen the european standards organisation as degradation resulting from oxidative and cellmediated phenomena, either simultaneously or successively. The fate of benzene in contaminated aquifers seems to be primarily controlled by the abundance of oxygen. Benzene and lnapl in shallow groundwater mtbe in deep groundwater conclusions. Aerobic biodegradation of benzene, toluene, and xylene in a sandy aquiferdata analysis and computer modeling c. Biodegradation of petroleum hydrocarbon vapors in the vadose. Aerobic biodegradation of benzene and toluene under hypersaline. Src tr 99002 final report aerobic biodegradation of organic chemicals in environmental media. Kinetics of aerobic biodegradation of benzene and toluene. First, an initial dioxygenation step transforms btx into their catechol intermediates, but does not support biomass growth. However, the mechanism by which anaerobic benzene degradation occurs is unclear. Dallas aronson mario citra kirsten shuler heather printup philip h. Concomitant aerobic biodegradation of benzene and thiophene.
Under a single substrate, the maximum degradation rates of. The concomitant aerobic biodegradation of benzene and thiophene was investigated in microcosm experiments using a groundwater enrichment culture. The monod model was also used to characterize phenol biodegradation by p. This study extends the previous reports of anaerobic benzene degradation to sediments that varied with respect to contamination input, predominant redox condition, and salinity. Howard environmental science center syracuse research corporation 6225 running ridge road north syracuse, ny 2122509 prepared. Because of the high solubility in water relative to petroleum hydrocarbons, btex benzene, toluene, ethyl benzene and o, m and pxylene are found in the watersoluble fraction, and groundwater can transport them from tens to hundreds of meters down gradient of the contamination source 1, 2. A great deal of research has been conducted on the use of different bacteria for benzene remediation. Pdf a highly enriched halophilic culture was established with benzene as the sole carbon source by using a brine soil obtained from an oil production. The above results indicate that the coastal indigenous. Oct 20, 2011 calculating the extent of biodegradation from the isotope signatures demonstrated that at least 85% of benzene was degraded by this pathway and thus, only a small fraction was removed abiotically. Jun 16, 2000 in the concentration ranges tested, toluene and benzene biodegradation kinetics were well described by the monod model. Characterization biodegradation of benzene, toluene, ethylbenzene, and xylenes by the newly isolated bacterium pseudomonas putida ay10 in rhizosphere of wastewater treatment reed eun young lee1.
Anaerobic benzene biodegradation a new era request pdf. Biodegradation of methane, benzene, and toluene by a. Aerobic biodegradation of benzene and toluene by pseudomonas putida f1 occurred. Bacterial aerobic degradation of benzene, toluene, ethylbenzene.
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