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Bull Environ Contam Toxicol (2013) 91:730733 DOI 10.1007/s00128-013-1124-2
Degradation of Clodinafop Propargyl by Pseudomonas sp. Strain B2
Baljinder Singh
Received: 18 June 2013 / Accepted: 4 October 2013 / Published online: 12 October 2013 Springer Science+Business Media New York 2013
Abstract Using clodinafop propargyl (CF) as a sole carbon, nitrogen and energy source, a CF-degrading bacterial strain was isolated from crop soil eld. This strain was identied as Pseudomonas sp. strain B2 by 16S rRNA gene sequence analysis. 87.14 % CF was degraded out of initial provided 80 mg/L CF. Degradation of CF was accompanied by release of chloride ion. The optimal pH and temperature for the growth of B2 were 7.0 and 30C, respectively in the mineral salts medium supplemented with CF. An actively growing culture of strain B2 degraded CF to clodinafop acid and 4-(4-Chloro-2-uoro-phenoxy)-phenol within 9 h, as determined by GCMS analysis. A metabolic pathway for the degradation of CF by B2 has been proposed.
Keywords Pseudomonas sp. strain B2 Clodinafop
propargyl Biodegradation GCMS
CF (prop-2-ynyl(R)-2-[4-(5-chloro-3-uoro-2 pyridyloxy) phenoxy]propionate), is an important aryloxyphenoxypropionate herbicide. CF is used for post emergence control of annual grasses in cereals, including Avena, Lolium, Setaria, Phalaris and Alopecurus spp. (Tomloin 2006). CF is absorbed by the leaves and rapidly translocated to the growing points of leaves and stems. It interferes with the production of fatty acids needed for plant growth in susceptible grassy weeds (Hammami et al. 2011). CF acts by targeting the
enzyme acetyl coenzyme-A-carboxylase, essential for lipid biosynthesis (Devine and Shimabukuro 1994). The widespread use of CF has resulted in the discharge of large amounts of the compound into the environment, which eventually reach the biosphere (Gherekhloo et al. 2010; Vazan et al. 2011). The half-lives of CF were 2.3511.20 days in soiland it rapidly degraded to the acid derivative clodinafop as major metabolite in soil (Guan et al. 2013). Several studies have demonstrated that CF and its derivatives are toxic and carcinogenic to humans and other living organisms (Kashanian et al. 2008; Gui et al. 2011). Therefore, the degradation of CF in the environment is of great concern. Only a single study concerning the biodegradation of CF can be found in the literature. This might be because of its low persistence; the half-life in...