Biodegradation of dibenzo-p-dioxin, dibenzofuran, and chlorodibenzo-p-dioxins by Pseudomonas veronii PH-03.
The dioxin-degrading strain Pseudomonas veronii PH-03 was isolated from contaminated soil by selective enrichment techniques. Strain PH-03 grew on dibenzo-p-dioxin and dibenzofuran as a sole carbon source. Further, 1-chlorodibenzo-p-dioxin, 2-chlorodibenzo-p-dioxin and other dioxin metabolites, salicylic acid, and catechol were also metabolized well. Resting cells of strain PH-03 transformed dibenzo-p-dioxin, dibenzofuran, 2,2',3-trihydroxybiphenyl, and some chlorodioxins to their corresponding metabolic intermediates such as catechol, salicylic acid, 2-hydroxy-(2-hydroxyphenoxy)-6-oxo-2,4-hexadienoic acid, and chlorocatechols. The formation of these metabolites was confirmed by comparison of gas chromatography-mass spectrometry (GC-MS) data with those of authentic compounds. Although we did observe the production of 3,4,5,6-tetrachlorocatechol (3,4,5,6-TECC) from 1,2,3,4-tetrachlorodibenzo-p-dioxin (1,2,3,4-TCDD) with resting cell suspensions of PH-03, growth of strain PH-03 in the presence of 1,2,3,4-TCDD was poor. This result suggests that strain PH-03 is unable to utilize 3,4,5,6-TECC, even at very low concentration (0.01 mM) due to its toxicity. In cell-free extracts of DF-grown cells, 2,2',3-trihydroxybiphenyl dioxygenase, 2-hydroxy-6-oxo-6-phenyl-2,4-hexadienoic acid hydrolase, and catechol-2,3-dioxygense activities were detected. Moreover, the activities of meta-pyrocatechase and 2,2',3-trihydroxybiphenyl dioxygenase from the crude cell-free extracts were inhibited by 3-chlorocatechol. However, no inhibition was observed in intact cells when 3-chlorocatechol was formed as intermediate.
Hong
Hyo-Bong
HB
School of Environmental Science and Engineering, Pohang University of Science and Technology, San 31, Hyojadong, Namgu Pohang 790-784, Korea.
Nam
In-Hyun
IH
Murugesan
Kumarasamy
K
Kim
Young-Mo
YM
Chang
Yoon-Seok
YS
D001572:Benzofurans / Q000378:metabolism / Q000493:pharmacokinetics; D001673:Biodegradation, Environmental; D001711:Biotransformation; D002396:Catechols / Q000378:metabolism / Q000493:pharmacokinetics; D004147:Dioxins / Q000378:metabolism* / Q000493:pharmacokinetics; D007700:Kinetics; D010101:Oxygen Consumption; D011549:Pseudomonas / Q000254:growth & development / Q000378:metabolism*
D001572:Benzofurans; D002396:Catechols; D004147:Dioxins; C023614:dibenzofuran; C067814:3-(2-hydroxyphenyl)catechol; C020887:dibenzo(1,4)dioxin