Isolation and characterization of a bacterial strain of the genus Ochrobactrum with methyl parathion mineralizing activity

Abstract

Aims: To isolate and characterize a methyl parathion (MP)‐mineralizing bacterium, and to elucidate the degradative pathway of MP and localize the responsible degrading genes. Methods and Results: A bacterial strain, designated B2, capable of mineralizing MP was isolated from the MP‐polluted soil. Analysis of the 16S rRNA gene sequence and phenotypic analysis suggested that strain B2 had a close relationship with Ochrobactrum anthropi. B2 could totally degrade MP and four metabolites [p‐nitrophenol (PNP), 4‐nitrocatechol (4‐NC), 1,2,4‐benzenetriol (BT) and hydroquinone (HQ)] were identified by HPLC and gas chromatography‐mass spectrometry analyses. Plasmid curing of strain B2 resulted in the loss of ability of B2 to degrade PNP, but not the ability to hydrolyse MP. Conclusions: Ochrobactrum sp. B2 can mineralize MP rapidly via PNP, 4‐NC, BT and HQ pathway. B2 harbours a plasmid encoding the ability to degrade PNP, while MP‐hydrolysing activity is encoded on the bacterial chromosome. Significance and Impact of the Study: This new bacterial strain (B2) capable of mineralizing MP will be useful in a pure‐culture remediation process of organophosphate pesticides and their metabolites such as nitroaromatics.

Microbial Survey of a Full-Scale, Biologically Active Filter for Treatment of Drinking Water

“…Studies on pure cultures of Rhizobiales have shown that they may also be capable of degrading methyl parathion, metolachlor, polyacrylamides, and quaternary ammonium alcohols, all potential source water contaminants (14,23,27,39).…”

Functional Assembly of a Microbial Consortium with Autofluorescent and Mineralizing Activity for the Biodegradation of Organophosphates

“…All cultures were grown with shaking at 30°C. At each time point, a 1 mL aliquot was withdrawn and centrifuged, and the supernatant was stored at -20°C for PNP analysis by HPLC (28). (Figure 1).…”

Removal of Methyl Parathion from Artificial Off-Gas Using a Bioreactor Containing a Constructed Microbial Consortium

“…PNP and its metabolites were determined using an Agilent 1100 series HPLC equipped with a diode array detector (DAD) and a Zorbax 300SB-C18 column. Details for GC and HPLC analyses are described by Qiu et al (27). The pH was determined using a digital pH meter (PH-3C, Shanghai, China).…”

“…Nitrite ion was quantitatively determined by the method of Montgomery and Dymock (26). PNP was quantified by HPLC (Agilent 1100), and its metabolites were identified by GC-MS (6890N GC-5973N MSD, Agilent Technologies, Palo Alto, CA) (27). Hydroquinone oxidation was monitored spectrophotometrically by measuring the increase at 320 nm (28).…”

“…All cultures were grown with shaking at 30°C. At each time point, a 1 mL aliquot was withdrawn, centrifuged, and the supernatant was used for PNP analysis by HPLC (27).…”