Anaerobic degradation of toluene in denitrifying Pseudomonas sp.: indication for toluene methylhydroxylation and benzoyl-CoA as central aromatic intermediate

Abstract

The anaerobic degradation of toluene has been studied with whole cells and by measuring enzyme activities. Cultures of Pseudomonas strain K 172 were grown in mineral medium up to a cell density of 0.5 g of dry cells per liter in fed-batch culture with toluene and nitrate as the sole carbon and energy sources. A molar growth yield of 57 g of cell dry matter formed per mol toluene totally consumed was determined. The mean generation time was 24 h. The redox balance between toluene consumed (oxidation and cell material synthesis) and nitrate consumed (reduction to nitrogen gas and assimilation as NH3) was 77% of expectation if toluene was completely oxidized; this indicated that the major amount of toluene was mineralized to CO2. It was tested whether the initial reaction in anaerobic toluene degradation was a carboxylation or a dehydrogenation (anaerobic hydroxylation); the hypothetical carboxylated or hydroxylated intermediates were tested with whole cells applying the method of simultaneous adaptation; cells pregrown on toluene degraded benzyl alcohol, benzaldehyde, and benzoic acid without lag, 4-hydroxybenzoate and p-cresol with a 90 min lag phase, and phenylacetate after a 200 min lag phase. The cells were not at all adapted to degrade 2-methylbenzoate, 4-methylbenzoate, o-cresol, and m-cresol, nor did these compounds support growth within a few days after inoculation with cells grown on toluene. In extracts of cells anaerobically grown on toluene, benzyl alcohol dehydrogenase, benzaldehyde dehydrogenase, and benzoyl-CoA synthetase (AMP forming) activities were present. The data (1) conclusively show anaerobic growth of a pure culture on toluene; (2) suggest that toluene is anaerobically degraded via benzoyl-CoA; (3) imply that water functions as the source of the hydroxyl group in a toluene methylhydroxylase reaction.

Corrective Action Study to Evaluate Intrinsic Remediation for the POL Bulk Fuel Storage Area, Myrtle Beach Air Force Base, Myrtle Beach, South Carolina

“…Numerous laboratory and field studies have shown that hydrocarbon-degrading bacteria can participate in the degradation of many of the chemical components of jet fuel and gasoline, including the BTEX compounds (e.g., Jamison et al, 1975;Atlas, 1981Atlas, , 1984Atlas, , 1988Gibson and Subramanian, 1984;Reinhard et al, 1984;Young, 1984;Bartha, 1986;Wilson et al, 1986Wilson et al, , 1987Wilson et al, , and 1990Barker et al, 1987;Baedecker et al, 1988;Lee, 1988;Chiang et al, 1989;Grbic-Galic, 1989 andCozzarelli et al, 1990;Leahy and Colewell, 1990;Altenschmidt and Fuchs, 1991;4-35 Alvarez and Vogel, 1991;Baedecker and Cozzarelli, 1991;Ball et al, 1991;Bauman, 1991;Borden, 1991;Brown et al, 1991;Edwards et al, 1991 and1992;Evans et al, 1991a and1991b;Haag et al, 1991;Hutchins and Wilson, 1991;Hutchins et al, 1991a and1991b;Beller et al, 1992;Bouwer, 1992;Edwards and Grbic-Galic, 1992;Thierrin et al, 1992;Malone et al, 1993;Davis et al, 1994). Biodegradation of fuel hydrocarbons can occur when an indigenous population of hydrocarbon-degrading microorganisms is present in the aquifer and sufficient concentrations of electron acceptors and nutrients, including fuel hydrocarbons, are available to these organisms.…”

Draft Treatability Study in Support of Remediation by Natural Attenuation Building 1212 at Fairchild Air Force Base, Spokane, Washington

“…Numerous laboratory and field studies have shown that hydrocarbon-degrading bacteria can participate in the degradation of many of the chemical components of jet fuel and gasoline, including the BTEX compounds (e.g., Jamison et al, 1975;Atlas, 1981Atlas, , 1984Atlas, , and 1988Gibson and Subramanian, 1984;Reinhard et al, 1984;Young, 1984;Bartha, 1986;Wilson et al, 1986Wilson et al, , 1987Wilson et al, , and 1990Barker et al, 1987;Baedecker et al, 1988;Lee, 1988;Chiang et al, 1989;Grbic-Galic, 1989 andCozzarelli et al, 1990;Leahy and Colewell, 1990;Altenschmidt and Fuchs, 1991;Alvarez and Vogel, 1991;Baedecker and Cozzarelli, 1991;Ball et al, 1991;Bauman, 1991;Borden, 1991;Brown et al, 1991;Edwards et al, 1991 andEvans et al, 1991a andHaag et al, 1991;Hutchins and Wilson, 1991;Hutchins et al, 1991a andBeller et al, 4-26 Bouwer, 1992;Thierrin et al, 1992;Malone et al, 1993;Davis et al, 1994). Biodegradation of fuel hydrocarbons can occur when an indigenous population of hydrocarbon-degrading microorganisms is present in the aquifer and sufficient concentrations of electron acceptors, nutrients, and electron donors such as fuel hydrocarbons, are available to these organisms.…”

Remediation by Natural Attenuation Treatability Study for Operable Unit 1, Hill Air Force Base, Ogden, Utah

“…Numerous laboratory and field studies have shown that hydrocarbon-degrading bacteria can participate in the degradation of many of the chemical components of fuel hydrocarbons, including the BTEX compounds (e.g., Jamison et al, 1975;Atlas, 1981Atlas, 1984Atlas, , 1988Gibson and Subramanian, 1984;Reinhard et al, 1984;Young, 1984;Bartha 1986;Wilson et al, 1986Wilson et al, , 1987Wilson et al, , and 1990Barker et al, 1987;Baedecker et al, 1988Lee, 1988Chiang et al, 1989;Grbic-Galic, 1989 and1990;Cozzarelli et al, 1990 Leahy andColewell, 1990;Altenschmidt and Fuchs, 1991;Vogel, 1991 Baedecker andCozzarelli, 1991;Ball et al, 1991;Bauman, 1991;Borden, 1991;Brown et al, 1991;Edwards et al, 1991 andEvans et al, 1991a andHaag et al, 1991;Hutchins et al, 1991a andBeller et al, 1992;Bouwer, 1992;Edwards and Grbic-Galic, 1992;Thierrin et al, 1992;Malone et al, 1993;Davis et al, 1994). Fuel hydrocarbons biodegrade naturally when an indigenous population of hydrocarbon-degrading microorganisms is present in the aquifer and sufficient concentrations of electron acceptors and nutrients are available to these organisms.…”