Isolation of Pseudomonas pickettii strains that degrade 2,4,6-trichlorophenol and their dechlorination of chlorophenols

Abstract

Three strains of Pseudomonas pickettii that can grow with 2,4,6-trichlorophenol (2,4,6-TCP) as the sole source of carbon and energy were isolated from different mixed cultures of soil bacterial populations that had been acclimatized to 2,4,6-TCP. These strains released 3 mol of chloride ion from 1 mol of 2,4,6-TCP during the complete degradation of the TCP. Of these strains, P. pickettii DTP0602 in high-cell-density suspension cultures dechlorinated various chlorophenols (CPs). Cells that were preincubated with 2,4,6-TCP converted isomers of 4-CP to the corresponding chloro-p-hydroquinones, but those preincubated with 4-CP converted CPs lacking a chlorine atom(s) at the o position to isomers of chlorocatechol. The ability of DTP0602 to dechlorinate 2,4,6-TCP was induced by 2,6-dichlorophenol, 2,3,6- and 2,4,6-TCP, and 2,3,4,6-tetrachlorophenol and was repressed in the presence of succinate or glucose.

Degradation of trichlorophenols by Alcaligenes eutrophus JMP134

“…At present, we do not know the catabolic pathways of degradation of trichlorophenols by A. eutrophus. The formation of 2,6-dichlorohydroxyquinone and 2,6-dichloro-p-benzoquinone have been reported in other bacteria [20,21]. Under our experimental conditions, we were unable to detect such intermediates.…”

“…strain GPl was found to grow only on 2,4,6-trichlorophe-no1 and degrade a few other chlorophenols [20]. On the other hand, Pseudomonas pickettii DTPO602 grows well on 2,4,6-trichlorophenol and their resting cells partially degrade 2,4,5-trichlorophenol [21]. These two strains, along with A. eutrophus JMP134, use a narrow range of chlorophenols as carbon sources.…”

EFFECT OF pH ON THE TOXICITY AND BIODEGRADATION OF PENTACHLOROPHENOL BY SPHINGOMONAS SP. STRAIN P5 IN NUTRISTAT CULTURE

“…The soil microbial community harbors numerous bacteria with different sensitivities. However, the sensititvity for chlorophenols was found to be not significantly different between chlorophenol-degrading strains and chlorophenol nondegrading strains [22]. Furthermore, we do not expect that the effect of pH on the relative toxicity of chlorophenols for strain P5 is unique because the target of toxic action is the phospholipid membrane.…”

Microbial breakdown of halogenated aromatic pesticides and related compounds

“…The mechanisms for the aerobic degradation of chlorinated phenols containing more than three chlorine substituents differ from that of monoand dichlorophenols. Several aerobic bacteria, belonging to the genera Rhodoeoccus, Mycobacterium, Arthrobacter, Flavobacterium, Pseu- 33 domonas and Azotobacter, that degrade pentachlorophenol and/or other polychlorinated phenols have been isolated [36][37][38][39][40][41][42][43][44][45]. In several of the studies, mineralization of pentachlorophenol was demonstrated by using a =4C-labelled substrate or by measuring stoichiometric release of chloride.…”

“…In these strains the initial para-hydroxylase was mem- CG-2 also degraded pentabromo-and pentafluorophenol through an identical pathway [403]. Chlorinated para-hydroquinones have also been found as intermediates in polychlorophenol degradation by several other bacteria [38,44,45,51,57,58]. A pentachlorophenol-degrading coryneform bacterium Arthrobacter sp.…”