Degradation 1,2-dimethylbenzene by Corynebacterium strain C125

Schraa, G.; Bethe, Brigit M.; Neerven, A.R.W. van; Tweel, W.J.J. van den; Wende, E. van der; Zehnder, Alexander J. B.

doi:10.1007/bf00393844

Cited by 63 publications

(40 citation statements)

References 24 publications

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“…2) because in the recombinant system that we used the combination of the two monooxygenases converted toluene to (2,10,20,21,36), but few of these bacteria are known to grow on o-xylene; the bacteria that can grow on o-xylene include P. stutzeri OX1 (1,3,5), Corynebacterium sp. strain C125 (29), and some Rhodococcus strains (7,11,18). Catabolism of m-and p-xylenes usually occurs through the progressive oxidation of a methyl group (2, 10), whereas o-xylene catabolism occurs by direct hydroxylation of the aromatic ring (12,14), as is the case in P. stutzeri (1,5).…”

Section: Discussionmentioning

confidence: 99%

Regiospecificity of Two Multicomponent Monooxygenases from Pseudomonas stutzeri OX1: Molecular Basis for Catabolic Adaptation of This Microorganism to Methylated Aromatic Compounds

Cafaro

Notomista

Capasso

et al. 2005

Appl Environ Microbiol

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The pathways for degradation of aromatic hydrocarbons are constantly modified by a variety of genetic mechanisms. Genetic studies carried out with Pseudomonas stutzeri OX1 suggested that the tou operon coding for toluene o-xylene monooxygenase (ToMO) was recently recruited into a preexisting pathway that already possessed the ph operon coding for phenol hydroxylase (PH). This apparently resulted in a redundancy of enzymatic activities, because both enzymes are able to hydroxylate (methyl)benzenes to (methyl)catechols via the intermediate production of (methyl)phenols. We investigated the kinetics and regioselectivity of toluene and o-xylene oxidation using Escherichia coli cells expressing ToMO and PH complexes. Our data indicate that in the recombinant system the enzymes act sequentially and that their catalytic efficiency and regioselectivity optimize the degradation of toluene and o-xylene, both of which are growth substrates. The main product of toluene oxidation by ToMO is p-cresol, the best substrate for PH, which catalyzes its transformation to 4-methylcatechol. The sequential action of the two enzymes on o-xylene leads, via the intermediate 3,4-dimethylphenol, to the exclusive production of 3,4-dimethylcatechol, the only dimethylcatechol isomer that can serve as a carbon and energy source after further metabolic processing. Moreover, our data strongly support a metabolic explanation for the acquisition of the ToMO operon by P. stutzeri OX1. It is possible that using the two enzymes in a concerted fashion confers on the strain a selective advantage based on the ability of the microorganism to optimize the efficiency of the use of nonhydroxylated aromatic hydrocarbons, such as benzene, toluene, and o-xylene.

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Section: Discussionmentioning

confidence: 99%

Regiospecificity of Two Multicomponent Monooxygenases from Pseudomonas stutzeri OX1: Molecular Basis for Catabolic Adaptation of This Microorganism to Methylated Aromatic Compounds

Cafaro

Notomista

Capasso

et al. 2005

Appl Environ Microbiol

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“…Rhodococcus sp. strain C125 (25) and P. putida mt2 (33) were grown aerobically at room temperature either in nutrient broth (NB) (8 g of dry NB liter of distilled H 2 O Ϫ1 Biolife, Milan, Italy) or in a mineral medium (32) containing either 6 mM sodium benzoate or ethanol as the sole source of carbon and energy and in 20 mM phosphate buffer (2.7 g of KH 2 PO 4 liter Ϫ1 , adjusted to pH 7.2 with NaOH. The same 20 mM phosphate buffer was used for flushing steel coupons and as medium for resting cell suspensions of Rhodococcus sp.…”

Section: Methodsmentioning

confidence: 99%

Bacterial Phosphating of Mild (Unalloyed) Steel

Volkland

Harms

Müller

et al. 2000

Appl Environ Microbiol

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Mild (unalloyed) steel electrodes were incubated in phosphate-buffered cultures of aerobic, biofilm-forming Rhodococcus sp. strain C125 and Pseudomonas putida mt2. A resulting surface reaction leading to the formation of a corrosion-inhibiting vivianite layer was accompanied by a characteristic electrochemical potential (E) curve. First, E increased slightly due to the interaction of phosphate with the iron oxides covering the steel surface. Subsequently, E decreased rapidly and after 1 day reached ؊510 mV, the potential of free iron, indicating the removal of the iron oxides. At this point, only scattered patches of bacteria covered the surface. A surface reaction, in which iron was released and vivianite precipitated, started. E remained at ؊510 mV for about 2 days, during which the vivianite layer grew steadily. Thereafter, E increased markedly to the initial value, and the release of iron stopped. Changes in E and formation of vivianite were results of bacterial activity, with oxygen consumption by the biofilm being the driving force. These findings indicate that biofilms may protect steel surfaces and might be used as an alternative method to combat corrosion.Due to the poor corrosion resistance of mild (unalloyed) steel, virtually all items made of this material have to be protected against corrosion. The most common protection method is phosphating, i.e., coating the steel surface with the phosphates of zinc, iron, or manganese (34). This procedure is carried out at temperatures up to 95°C and pH values between 2 and 3.5 (21). Media used for phosphating normally contain high concentrations of zinc (in the range of several grams per liter) or manganese and also contain accelerators like nitrate, nitrite, chlorate, peroxides, and organic nitrocompounds (31). During phosphating, a considerable amount of heavy metal sludge is formed and must be removed. Several attempts have been made to develop alternative methods that are less toxic to the environment.Pedersen et al. (17) showed that Pseudomonas sp. strain S9 and Serratia marcescens sp. strain EF 190 can decrease the corrosion rate of mild steel when applied as dense suspensions (10 9 ml Ϫ1 ) or as living biofilms (17)(18)(19). A protective effect of Pseudomonas fragi and Escherichia coli DH5 was found by Jayaraman et al. (13). Here, the formation of a biofilm was crucial, as oxygen depletion under the biofilm was responsible for the corrosion protection (12). However, the mechanical instability of biofilms was seen as a drawback for their technical application.In a recent study (32), we showed that growing the aerobic biofilm-forming bacteria Rhodococcus sp. strain C125 and Pseudomonas putida mt2 in mineral medium containing more than 2 mM phosphate induced a surface reaction on mild steel coupons, resulting in the formation of vivianite. Vivianite, a barely insoluble iron(II) phosphate, is one of the compounds formed in technical acidic phosphating and is known for its corrosion protective effect. The biologically vivianite-coated steel coupons showed goo...

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“…Acinetobacter strain T5 and Arthrobacter strain T2 were isolated from the environment by selective enrichment on tetralin as described previously (30). Corynebacterium strain C125 was kindly provided by G. Schraa, Department of Microbiology, Agricultural University Wageningen, Wageningen, The Netherlands (25). Escherichia coli K-12 (ATCC 25404) and Bacillus subtilis ATCC 6633 were obtained from the American Type Culture Collection (Rockville, Md.…”

Section: Methodsmentioning

confidence: 99%

Effects of the membrane action of tetralin on the functional and structural properties of artificial and bacterial membranes

et al. 1992

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Tetralin is toxic to bacterial cells at concentrations below 100 ,mollliter. To assess the inhibitory action of tetralin on bacterial membranes, a membrane model system, consisting of proteoliposomes in which beef heart cytochrome c oxidase was reconstituted as the proton motive force-generating mechanism, and several gram-positive and gram-negative bacteria were studied. Because of its hydrophobicity, tetralin partitioned into lipid membranes preferentially (lipid/buffer partition coefficient of tetralin is approximately 1,100). The excessive accumulation of tetralin caused expansion of the membrane and impairment of different membrane functions. Studies with proteoliposomes and intact cells indicated that tetralin makes the membrane permeable for ions (protons) and inhibits the respiratory enzymes, which leads to a partial dissipation of the pH gradient and electrical potential. The effect of tetralin on the components of the proton motive force as well as disruption of protein-lipid interaction(s) could lead to impairment of various metabolic functions and to low growth rates. The data offer an explanation for the difficulty in isolating and cultivating microorganisms in media containing tetralin or other lipophilic compounds.Interest in the application of water-immiscible organic compounds in fermentations has increased in the last decade. Many lipophilic compounds are harmful to microorganisms, impair growth, and even inhibit other biological reactions. Knowledge of the toxic action of lipophilic compounds on bacterial cells is mainly restricted to the relation between the hydrophobicity (13) of a compound and its effect on a specific enzyme (19). In most studies, the cytoplasmic membrane is mentioned as a possible target, but information about the nature of the toxic action is not presented (1,19).A correlation between the hydrophobicity of a compound and its effects on cells was first observed for anesthetics (27)(28)(29), which provided a basis for calculating a dose-effect relationship. In addition, the uncoupling effects of lipophilic compounds on energy transduction have been studied in animal cells (23). For microorganisms, only a few studies on the toxic effects of lipophilic compounds on various membrane functions have been performed (3,32,33). These studies showed that hydrocarbons, e.g., 3-pinene (32) and cyclohexane (33), impaired energy transduction in both mitochondrial and plasma membranes of yeast cells. Studies on the toxic effects of ethanol on yeast cells indicated that the Ap across the plasma membrane was dissipated in the presence of ethanol (3), probably due to an increased influx of protons (3,12).In this investigation, the toxic action of the lipophilic compound tetralin on bacteria was studied. Tetralin was found to be toxic to bacterial cells at concentrations below 100 ,umol/liter (30). Tetralin, 1,2,3,4-tetrahydronaphthalene, is a bicyclic molecule that consists of an aromatic and an alicyclic moiety. The compound is widely applied as an industrial solvent and as a substitute f...

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Degradation 1,2-dimethylbenzene by Corynebacterium strain C125

Cited by 63 publications

References 24 publications

Regiospecificity of Two Multicomponent Monooxygenases from Pseudomonas stutzeri OX1: Molecular Basis for Catabolic Adaptation of This Microorganism to Methylated Aromatic Compounds

Regiospecificity of Two Multicomponent Monooxygenases from Pseudomonas stutzeri OX1: Molecular Basis for Catabolic Adaptation of This Microorganism to Methylated Aromatic Compounds

Bacterial Phosphating of Mild (Unalloyed) Steel

Effects of the membrane action of tetralin on the functional and structural properties of artificial and bacterial membranes

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