Open AccessMineralization of p ‐nitrophenol by pentachlorophenol‐degrading Sphingomonas spp.
Author(s) -
Leung Kam T,
Tresse Odile,
Errampalli Deena,
Lee Hung,
Trevors Jack T
Publication year - 1997
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1997.tb12693.x
Subject(s) - pentachlorophenol , nitrophenol , chemistry , mineralization (soil science) , nitrite , 4 nitrophenol , sphingomonas paucimobilis , biodegradation , sphingomonas , nuclear chemistry , food science , chromatography , environmental chemistry , biochemistry , bacteria , nitrogen , biology , organic chemistry , catalysis , 16s ribosomal rna , gene , nitrate , genetics
Pentachlorophenol‐degrading Sphingomonas sp. UG30 and Sphingomonas chlorophenolica strains 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 [ 14 C] p ‐nitrophenol which was 10% higher than the amount of [ 14 C] 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.