| Autor: |
Leung, Kam T, Tresse, Odile, Errampalli, Deena, Lee, Hung, Trevors, Jack T |
| Zdroj: |
FEMS Microbiology Letters; October 1997, Vol. 155 Issue: 1 p107-114, 8p |
| Abstrakt: |
Pentachlorophenol‐degrading Sphingomonassp. UG30 and Sphingomonas chlorophenolicastrains RA2 and ATCC 39723 can transform p‐nitrophenol in either mineral salts‐glutamate or mineral salts‐glucose medium after an initial lag period. However, mineralization of p‐nitrophenol by these bacterial strains was observed only in mineral salts‐glucose medium. When p‐nitrophenol was the sole nitrogen source in the growth medium, UG30 mineralized 32% of 140 mM [14C]p‐nitrophenol which was 10% higher than the amount of [14C]p‐nitrophenol mineralized in mineral salts‐glucose medium. UG30 did not transform or mineralize p‐nitrophenol (in a growth medium) in the absence of glucose or glutamate. All three strains released nitrite during p‐nitrophenol degradation in mineral salts‐glucose medium and mineral salts‐glutamate medium. The transformation rate of p‐nitrophenol by UG30 was dependent on the initial p‐nitrophenol concentration, with the optimal rate being found at 310 μM of p‐nitrophenol and inhibition observed at ≥1100 μM of p‐nitrophenol. Pre‐exposure of UG30 cells to p‐nitrophenol eliminated the initial lag phase of p‐nitrophenol transformation. However, pre‐growth of UG30 cells on pentachlorophenol did not reduce the lag period for p‐nitrophenol transformation. Both p‐nitrophenol‐ and pentachlorophenol‐induced UG30 cells degraded pentachlorophenol without any lag phase. Thin layer chromatographic analysis of the reaction mixture suggested 4‐nitrocatechol was an intermediate of p‐nitrophenol transformation by UG30. |
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