Biodegradation of phenol and cresol isomer mixtures by Arthrobacter
01 Nov 1997-World Journal of Microbiology & Biotechnology (Kluwer Academic Publishers-Plenum Publishers)-Vol. 13, Iss: 6, pp 659-663
TL;DR: The Arthrobacter species can degrade phenol, o-cresol and p-Cresol much faster than other microbes which are reported to degrade toxic compounds.
Abstract: The Arthrobacter species can degrade phenol, o-cresol and p-cresol much faster (as reflected in high specific growth rates) than other microbes which are reported to degrade toxic compounds In mixtures, phenol and p-cresol mutually inhibited each other; the inhibition constants show that phenol degradation is strongly inhibited in the presence of p-cresol rather than reverse o-Cresol enhanced phenol degradation marginally but o-cresol degradation was not affected by the presence of phenol
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01 Jan 2014
TL;DR: In this article, the effects of process parameters such as initial cresol concentration (100 - 500 ppm), pH (5-7), and temperature (30-45 O C) on Removal Efficiency (RE) of Cresol was studied and optimized using Response Surface Methodology (RSM).
Abstract: Biodegradation is widely used for removal of toxic organic contaminants from aqueous streams. Owing to the hazardous or otherwise undesirable characteristics of phenolic compounds in particular, their presence in wastewater from municipal and industrial discharge is one of the most important environmental issue. Response surface methodology is a widely used technique for modelling and optimization of the biodegradation treatment processes of water and wastewater. This methodology not only estimates linear, interaction and quadratic effects of the factors on the response, but also provides a prediction model for the response at the range of the variables studied and the optimum conditions to achieve the highest performance. In this work, statistical design was applied for the optimization of process parameters for the biodegradation of O-Cresol using Aspergillus fumigates (MTCC No.343) in a batch reactor. The effects of process parameters such as initial cresol concentration (100 - 500 ppm), pH (5-7), and temperature (30-45 O C) on Removal Efficiency (RE) of Cresol was studied and optimized using Response Surface Methodology (RSM). Using Central Composite Design (CCD), 20 experiments were carried out for the three test variables. A second order polynomial regression model has been developed using the experimental data. It was found that the degrading potential of Aspergillus fumigates was strongly affected by the variations in pH, temperature and initial cresol concentration. From the results, the optimum condition for maximum RE of O-cresol wars found to be initial Cresol concentration - 150ppm, pH - 6.6 and temperature- 31 o C. At these optimized conditions, the removal efficiency of Cresol was found to be 80.41%. A high R 2 value of greater than 0.9 indicates the fitness of the
Cites methods from "Biodegradation of phenol and cresol..."
...The effects of process parameters such as initial cresol concentration (100 – 500 ppm), pH (5-7), and temperature (30-45 O C) on Removal Efficiency (RE) of Cresol was studied and optimized using Response Surface Methodology (RSM)....
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01 Jan 2011
TL;DR: Careful selection of plant species to be used at a particular polluted sites should be cautiously approached based on the actual soil and climate conditions and other characteristics of the site, as well as the growth and/or phenol degradation by the tested bacteria.
Abstract: Tolerance of various plant seeds to different concentrations of phenol, and growth of bacteria on phenol as a sole carbon source has been investigated. Three different types of bacterial colonies have been recovered on the agar plates. Biochemical and culture morphology examination of the recovered bacteria revealed that they mainly belonged to the genus Pseudomonas, Micrococcus and Streptomyces. O.D. reading at 600 nm and UV absorbance at 273 nm determined the growth and/or phenol degradation by the tested bacteria. Incubation of 4 tested Pseudomonas spp. and 1 Streptomyces sp. in mineral salts medium (MSM) supplemented with 0.2% (w/v) of phenol for 14 days and at 28 °C indicated the removal of 124 mg/l of phenol by Streptomyces sp. (strain 3A13) as compared to 42, 84, 90 and 102 mg/l by P. putrefaciense, P. fluorescense, P. cepacia and P. acidovorans, respectively. Streptomyces sp. (strain 3A13) seems to play a significant role in decomposition of toxic compounds such as phenol. A noticeable decline in Jew's mallow (Cochorus olitorius) and Alfaalfa (Medicago sativa) seed germination of 62.5% and 86.4% was shown at 500 and 1000 mg/kg phenol or higher, respectively. Seeds of barley (Hordeum vulgare) showed more resistant to phenol with a decline of 40 and 76% at 1000 and 1500 mg/kg phenol, respectively. However, seeds of solid Horani wheat (Triticum durum) were the most resistant to phenol which showed a percentage decline of 43.5% at 1500 mg/kg phenol. The effect of different phenol concentrations was also reflected on the length of sprouts of the tested plants with severe decline (> 75%) of C. olitorius sprouts' length at 500 mg/kg phenol as compared to the most resistant plant sprouts (T. durum) that showed < 45% decline of sprouts' length. It appears that the local seed plants (T. durum and Hordeum vulgare) have the ability to germinate with 40 % or more at 1500 mg/kg phenol. Careful selection of plant species to be used at a particular polluted sites should be cautiously approached based on the actual soil and climate conditions and other characteristics of the site.
References
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TL;DR: In this paper, the degradation of benzene, toluene, and p-xylene was investigated in sandy aquifer material and by two pure cultures isolated from the same site.
Abstract: Benzene, toluene, and p-xylene (BTX) were degraded by indigenous mixed cultures in sandy aquifer material and by two pure cultures isolated from the same site. Although BTX compounds have a similar chemical structure, the fate of individual BTX compounds differed when the compounds were fed to each pure culture and mixed culture aquifer slurries. The identification of substrate interactions aided the understanding of this behavior. Beneficial substrate interactions included enhanced degradation of benzene and p-xylene by the presence of toluene in Pseudomonas sp. strain CFS-215 incubations, as well as benzene-dependent degradation of toluene and p-xylene by Arthrobacter sp. strain HCB. Detrimental substrate interactions included retardation in benzene and toluene degradation by the presence of p-xylene in both aquifer slurries and Pseudomonas incubations. The catabolic diversity of microbes in the environment precludes generalizations about the capacity of individual BTX compounds to enhance or inhibit the degradation of other BTX compounds.
350 citations
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TL;DR: Two Pseudomonas species were isolated from an aerobic pilot‐scale fluidized bed reactor treating groundwater containing benzene, toluene, and p‐xylene, and batch tests using paired substrates revealed competitive inhibition and cometabolic degradation patterns.
Abstract: Two Pseudomonas species (designated strains B1 and X1) were isolated from an aerobic pilot-scale fluidized bed reactor treating groundwater containing benzene, toluene, and p-xylene (BTX). Strain B1 grew with benzene and toluene as the sole sources of carbon and energy, and it cometabolized p-xylene in the presence of toluene. Strain X1 grew on toluene and p-xylene, but not benzene. In single substrate experiments, the appearance of biomass lagged the consumption of growth substrates, suggesting that substrate uptake may not be growth-rate limiting for these substrates. Batch tests using paired substrates (BT, TX, or BX) revealed competitive inhibition and cometabolic degradation patterns. Competitive inhibition was modeled by adding a competitive inhibition term to the Monod expression. Cometabolic transformation of nongrowth substrate (p-xylene) by strain B1 was quantified by coupling xylene transformation to consumption of growth substrate (toluene) during growth and to loss of biomass during the decay phase. Coupling was achieved by defining two transformation capacity terms for the cometabolizing culture: one that relates consumption of growth substrate to the consumption of nongrowth substrate, and second that relates consumption of biomass to the consumption of nongrowth substrate. Cometabolism increased decay rates, and the observed yield for strain B1 decreased in the presence of p-xylene.
277 citations
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TL;DR: Three previously proposed models describing the kinetics of cometabolism by resting cells are compared, and the interrelationships and underlying assumptions for these models are explored.
Abstract: Experimental observations indicate that the rates of cometabolic transformation are linked to the consumption of growth substrate during growth and to the consumption of cell mass and/or energy substrate in the absence of growth substrate. Three previously proposed models (models 1 through 3) describing the kinetics of cometabolism by resting cells are compared, and the interrelationships and underlying assumptions for these models are explored. Models 1 to 3 are shown to converge at high concentrations of the nongrowth substrate. An expression describing nongrowth substrate transformation in the presence of growth substrate is proposed, and this expression is integrated with an expression for cell growth to give a single unstructured model (model 4) that encompasses models 1 to 3 and describes cometabolism by both resting and growing cells. Model 4 couples transformation of nongrowth substrate to consumption of growth substrate and biomass, and predicts that cometabolism will result, and decreased specific growth rates for a cometabolizing population. Competitive inhibition can also be incorporated in the model. Experimental aspects of model calibration and verification are discussed. The need for models that distinguish between the exhaustion of cell activity and cell death is emphasized. © 1993 Wiley & Sons, Inc.
190 citations
"Biodegradation of phenol and cresol..." refers background in this paper
...It has been reported that if compounds involve dioxygenases and monooxygenases in their degradation, competitive inhibition is likely ( Criddle 1993 )....
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TL;DR: The evidence suggests that exposure of marine sediments to a particular PAH or benzene results in the enhanced ability of these Sediments to subsequently degrade that PAH as well as certain other PAHs.
Abstract: Rates of polycyclic aromatic hydrocarbon (PAH) degradation and mineralization were influenced by preexposure to alternate PAHs and a monoaromatic hydrocarbon at relatively high (100 ppm) concentrations in organic-rich aerobic marine sediments. Prior exposure to three PAHs and benzene resulted in enhanced [14C]naphthalene mineralization, while [14C]anthracene mineralization was stimulated only by benzene and anthracene preexposure. Preexposure of sediment slurries to phenanthrene stimulated the initial degradation of anthracene. Prior exposure to naphthalene stimulated the initial degradation of phenanthrene but had no effect on either the initial degradation or mineralization of anthracene. For those compounds which stimulated [14C]anthracene or [14C]naphthalene mineralization, longer preexposures (2 weeks) to alternative aromatic hydrocarbons resulted in an even greater stimulation response. Enrichment with individual PAHs followed by subsequent incubation with one or two PAHs showed no alteration in degradation patterns due to the simultaneous presence of PAHs. The evidence suggests that exposure of marine sediments to a particular PAH or benzene results in the enhanced ability of these sediments to subsequently degrade that PAH as well as certain other PAHs. The enhanced degradation of a particular PAH after sediments have been exposed to it may result from the selection and proliferation of specific microbial populations capable of degrading it. The enhanced degradation of other PAHs after exposure to a single PAH suggests that the populations selected have either broad specificity for PAHs, common pathways of PAH degradation, or both.
158 citations
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TL;DR: The experiments indicated that toluene- and o-xylene-degrading bacteria are also able to degrade benzene, whereas naphthalene-, 1,,4-dimethylnaphthalenes-, and phenanthrene-degarading bacteria have no or very little benzene-degRading ability.
Abstract: This study dealt with the interactions with benzene degradation of the following aromatic compounds in a mixed substrate: toluene, o-xylene, naphthalene, 1,4-dimethylnaphthalene, phenanthrene, and pyrrole. The experiment was performed as a factorial experiment with simple batch cultures. The effect of two different types of inocula was tested. One type of inoculum was grown on a mixture of aromatic hydrocarbons; the other was grown on a mixture of aromatic hydrocarbons and nitrogen-, sulfur-, and oxygen-containing aromatic compounds (NSO compounds), similar to some of the compounds identified in creosote waste. The culture grown on the aromatic hydrocarbons and NSO compounds was much less efficient in degrading benzene than the culture grown on only aromatic hydrocarbons. The experiments indicated that toluene- and o-xylene-degrading bacteria are also able to degrade benzene, whereas naphthalene-, 1,,4-dimethylnaphthalene-, and phenanthrene-degrading bacteria have no or very little benzene-degrading ability. Surprisingly, the stimulating effect of toluene and o-xylene was true only if the two compounds were present alone. In combination an antagonistic effect was observed, i.e., the combined effect was smaller than the sum from each of the compounds. The reason for this behavior has not been identified. Pyrrole strongly inhibited benzene degradation even at concentrations of about 100 to 200 micrograms/liter. Future studies will investigate the generality of these findings.
136 citations