Gibbs free energy of formation of halogenated aromatic compounds and their potential role as electron acceptors in anaerobic environments

Dolfing, Jan; Harrison, B. Keith

doi:10.1021/es00035a021

Cited by 207 publications

(133 citation statements)

References 19 publications

(27 reference statements)

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“…Acetate supported growth with 2-CP as an electron acceptor, producing CO 2 , while no growth occurred when only acetate was present. The protein yield was proportional to the amount of chlorine removed and was about twice as much on 2,6-DCP as on 2-CP, implying that, like strains DCB-1 (9,10,20) and 2CP-1 (5), strain SF3 gains energy by using the chlorinated aromatic substrate as a respiratory electron acceptor. Also, the stoichiometry of chlorine removed to acetate consumed is in agreement with the theoretical maximal value of four electron pairs produced per acetate oxidized to CO 2 , with the remaining reducing equivalents going to the biomass.…”

Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of Desulfovibrio dechloracetivorans sp. nov., a Marine Dechlorinating Bacterium Growing by Coupling the Oxidation of Acetate to the Reductive Dechlorination of 2-Chlorophenol

Sun

Cole

Sanford

et al. 2000

Appl Environ Microbiol

139

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Strain SF3, a gram-negative, anaerobic, motile, short curved rod that grows by coupling the reductive dechlorination of 2-chlorophenol (2-CP) to the oxidation of acetate, was isolated from San Francisco Bay sediment. Strain SF3 grew at concentrations of NaCl ranging from 0.16 to 2.5%, but concentrations of KCl above 0.32% inhibited growth. The isolate used acetate, fumarate, lactate, propionate, pyruvate, alanine, and ethanol as electron donors for growth coupled to reductive dechlorination. Among the halogenated aromatic compounds tested, only the ortho position of chlorophenols was reductively dechlorinated, and additional chlorines at other positions blocked ortho dechlorination. Sulfate, sulfite, thiosulfate, and nitrate were also used as electron acceptors for growth. The optimal temperature for growth was 30°C, and no growth or dechlorination activity was observed at 37°C. Growth by reductive dechlorination was revealed by a growth yield of about 1 g of protein per mol of 2-CP dechlorinated, and about 2.7 g of protein per mole of 2,6-dichlorophenol dechlorinated. The physiological features and 16S ribosomal DNA sequence suggest that the organism is a novel species of the genus Desulfovibrio and which we have designated Desulfovibrio dechloracetivorans. The unusual physiological feature of this strain is that it uses acetate as an electron donor and carbon source for growth with 2-CP but not with sulfate.Substantial amounts of halogenated aromatic compounds have been released to the environment and many of them have accumulated in groundwater and sediments (11,14,24,26). Many of these compounds are resistant to aerobic microbial metabolism often because the chlorine substitution blocks oxygenase attack. Fortunately, many halogenated compounds can be dehalogenated by anaerobic microorganisms. Several bacteria capable of dehalogenating halogenated aromatic compounds have been isolated and characterized (2,3,4,5,18,25,27,28,29). One previous isolate has been described which reductively dechlorinates 2-chlorophenol (2-CP) to phenol (5). This organism was isolated from freshwater sediment and is unique for dechlorinators in that it could also grow as a microaerophile, although it did not dechlorinate under this condition. Bacteria, such as this one, which use the dehalogenation reaction as their sole electron acceptor for energy generation and growth are termed halorespirers (25) or dehalorespirers (11).To date, much of the dehalogenation research has been directed toward understanding the fate and behavior of halogenated pollutants in freshwater sediments, soils, and sludges. Comparatively little is known about the fates of these pollutants or dehalogenating organisms from the marine environment despite the fact that marine biota produce a remarkable array of halogenated compounds (12). For example, studies by King (15) indicate that 2,4-dibromophenol occurred at concentrations of up to several hundred micromolar in hemichordate burrow walls and that this chemical was dehalogenated in these sediments under anae...

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Section: Discussionmentioning

confidence: 99%

Isolation and Characterization of Desulfovibrio dechloracetivorans sp. nov., a Marine Dechlorinating Bacterium Growing by Coupling the Oxidation of Acetate to the Reductive Dechlorination of 2-Chlorophenol

Sun

Cole

Sanford

et al. 2000

Appl Environ Microbiol

139

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“…Several dechlorinating bacteria in the delta-proteobacteria are able to utilize halogenated compounds as physiological electron acceptors for growth (1, 5, 9, 11, 14-16, 22, 29, 31, 38). Since there are many naturally occurring halogenated compounds in the environment (13) and chlororespiration releases considerable energy for growth (10), greater utilization of this lifestyle might be expected within the delta-proteobacteria.…”

mentioning

confidence: 99%

Characterization and Description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an Aryl-Halorespiring Facultative Anaerobic Myxobacterium

Sanford

Cole

Tiedje

2002

Appl Environ Microbiol

345

255

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Five strains were isolated which form a physiologically and phylogenetically coherent group of chlororespiring microorganisms and represent the first taxon in the Myxobacteria capable of anaerobic growth. The strains were enriched and isolated from various soils and sediments based on their ability to grow using acetate as an electron donor and 2-chlorophenol (2-CPh) as an electron acceptor. They are slender gram-negative rods with a bright red pigmentation that exhibit gliding motility and form spore-like structures. These unique chlororespiring myxobacteria also grow with 2,6-dichlorophenol, 2,5-dichlorophenol, 2-bromophenol, nitrate, fumarate, and oxygen as terminal electron acceptors, with optimal growth occurring at low concentrations (<1 mM) of electron acceptor. 2-CPh is reduced by all strains as an electron acceptor in preference to nitrate, which is reduced to ammonium. Acetate, H 2 , succinate, pyruvate, formate, and lactate were used as electron donors. None of the strains grew by fermentation. The 16S ribosomal DNA (rDNA) sequences of the five strains form a coherent cluster deeply branching within the family Myxococcaceae within the class Myxobacteria and are mostly closely associated with the Myxococcus subgroup. With the exception of anaerobic growth and lack of a characteristic fruiting body, these strains closely resemble previously characterized myxobacteria and therefore should be considered part of the Myxococcus subgroup. The anaerobic growth and 9.0% difference in 16S rDNA sequence from those of other myxobacterial genera are sufficient to place these strains in a new genus and species designated Anaeromyxobacter dehalogenans. The type strain is 2CP-1 (ATCC BAA-258).Myxobacteria have been considered obligately aerobic bacteria (26, 27). The phylogenic placement of this group within the delta-proteobacteria, however, would suggest the possibility of an ancestral anaerobic lifestyle for the myxobacteria (32). The delta-proteobacteria exhibit considerable anaerobic physiological diversity, including sulfate reduction, iron reduction, fermentation, and dehalogenation. Several dechlorinating bacteria in the delta-proteobacteria are able to utilize halogenated compounds as physiological electron acceptors for growth (1, 5, 9, 11, 14-16, 22, 29, 31, 38). Since there are many naturally occurring halogenated compounds in the environment (13) and chlororespiration releases considerable energy for growth (10), greater utilization of this lifestyle might be expected within the delta-proteobacteria.We used 2-chlorophenol (2-CPh) to search for chlororespiring anaerobes and found a novel group of myxobacteria, the first myxobacteria able to grow anaerobically. The new isolates grow using several ortho-substituted mono-and dichlorinated phenols, nitrate, and fumarate, as well as low concentrations of oxygen, as physiological electron acceptors. Four strains isolated from different environments in this study plus one previous isolate (5) allow a comprehensive characterization of the group. These strains ex...

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“…pentachlorobenzene), but even if the concentration of the product would be 1000 fold higher than the concentration of the substrate the adjustment would still be only 17 kJ.mol -1 . Given the fact that for example ΔG o ' for the reaction hexachlorobenzene + H 2 → pentachlorobenzene + H + + Cl -is -171.4 kJ per reaction (Dolfing and Harrison 1992) such adjustments are relatively minor, and it is safe to conclude that reductive dechlorination would remain exergonic under environmentally relevant conditions. Microorganisms in anoxic methanogenic sediments function at ΔG values of -10 to -20 kJ per reaction (Hoehler et al 2001).…”

Section: Microbiological Degradation In Sediment Conditionmentioning

confidence: 99%

“…Also, Lorah and Olsen (1999) have observed that in a freshwater tidal wetland degradation of 1,1,2,2-tetrachloroethane involved formation of 1,2-dichloroethylene rather than only classical reductive Table 5. Redox half-reactions for reductive dechlorination of hexachlorobenzene to benzene and their logK at 25 o C. Free energy (G f o ) data are from Dolfing and Harrison (1992) and Stumm and Morgan (1996), in kJmol -1 : hexachlorobenzene = 46.0 ;pentachlorobenzene = 45.7 ;1,2,3,4-tetrachlorobenzene = 55.8 ;1,2,3,5-tetrachlorobenzene = 49.2;1,2,4,5-tetrachlorobenzene = 53.5;1,2,3-trichlorobenzene = 71.7 ;1,2,4-trichlorobenzene = 60.5 ;1,3,5-trichlorobenzene = 56.8 ;1,2-dichlorobenzene = 84.3 ;1,3-dichlorobenzene = 81.8;1,4-dichlorobenzene = 78.3 ;monochlorobenzene = 102.3 ;benzene = 133.8 ;Cl -= -131.3 ;logK = -(∆G o r)/RTln(10). For sample calculation see footnote to Table 2. dechlorination to lesser chlorinated ethanes.…”

Section: Microbiological Degradation In Sediment Conditionmentioning

confidence: 99%

How Early Diagenesis Reveals in Situ Biodegradation of Herbicides in Sediment

Delmotte¹,

Macarie²,

Dolfing³

et al. 2011

Herbicides and Environment

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Gibbs free energy of formation of halogenated aromatic compounds and their potential role as electron acceptors in anaerobic environments

Cited by 207 publications

References 19 publications

Isolation and Characterization of Desulfovibrio dechloracetivorans sp. nov., a Marine Dechlorinating Bacterium Growing by Coupling the Oxidation of Acetate to the Reductive Dechlorination of 2-Chlorophenol

Isolation and Characterization of Desulfovibrio dechloracetivorans sp. nov., a Marine Dechlorinating Bacterium Growing by Coupling the Oxidation of Acetate to the Reductive Dechlorination of 2-Chlorophenol

Characterization and Description of Anaeromyxobacter dehalogenans gen. nov., sp. nov., an Aryl-Halorespiring Facultative Anaerobic Myxobacterium

How Early Diagenesis Reveals in Situ Biodegradation of Herbicides in Sediment

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