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Factors influencing the ability of Pseudomonas putida strains epI and II to degrade the organophosphate ethoprophos
Author(s) -
Karpouzas D.G.,
Walker A.
Publication year - 2000
Publication title -
journal of applied microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.889
H-Index - 156
eISSN - 1365-2672
pISSN - 1364-5072
DOI - 10.1046/j.1365-2672.2000.01080.x
Subject(s) - pseudomonas putida , biology , pseudomonadales , pseudomonas , microbiology and biotechnology , population , pseudomonadaceae , bacteria , carbamate , biodegradation , pesticide , food science , chemistry , biochemistry , agronomy , ecology , genetics , demography , sociology
Two strains of Pseudomonas putida (epI and epII), isolated previously from ethoprophos‐treated soil, were able to degrade ethoprophos (10 mg l −1 ) in a mineral salts medium plus nitrogen (MSMN) in less than 50 h with a concurrent population growth. Addition of glucose or succinate to MSMN did not influence the degrading ability of Ps. putida epI, but increased the lag phase before rapid degradation commenced with Ps. putida epII. The degrading ability of the two isolates was lost when the pesticide provided the sole source of phosphorus. Degradation of ethoprophos was most rapid when bacterial cultures were incubated at 25 and 37 °C. Pseudomonas putida epI was capable of completely degrading ethoprophos at a slow rate at 5 °C, compared with Ps. putida epII which could not completely degrade ethoprophos at the same time. Pseudomonas putida epI was capable of degrading ethoprophos when only 60 cells ml −1 were used as initial inoculum. In contrast, Ps. putida epII was able to totally degrade ethoprophos when inoculum densities of 600 cells ml −1 or higher were used. In general, longer lag phases accompanied the lower inoculum levels. Both isolates rapidly degraded ethoprophos in MSMN at pHs ranging from 5·5 to 7·6, but not at pH 5 or below.