Biodegradation of epoxyconazole and piraclostrobin fungicides by Klebsiella sp from soil

Three bacterial strains have been isolated from soil in which soybean had been continuously cropped and treated with Opera (R), a fungicide containing epoxyconazole and pyraclostrobin. The three strains (1,805, 2,801 and 3,803), obtained from soil at 80-100 cm depth, were selected on medium containing 0.03% Opera (R). Morphological examination revealed that the strains were Gram-negative, and two of them (1,805 and 2,801) exhibited polymorphism. The growth profiles demonstrated that 1,805 and 3,803 were more efficient growing in the presence of Opera (R) than 2,801. Maximum growth was reached between 24 and 48 h, however, 2,801 was not able to survive after this period. The total protein content produced by 1,805, 2,801 and 3,803 in liquid selective medium containing Opera (R) were 111.0 +/- 0.02, 80.0 +/- 0.05 and 130.5 +/- 0.07 mu g/ml, respectively. According to its biochemical and molecular features, strain 1,805 was identified as Klebsiella sp. On the basis of the characteristics presented (facultative anaerobic nature, polymorphic character and capacity of growing in the presence of Opera (R)) strain 1,805 seems to be able to degrade the epoxyconazole and pyraclostrobin.