Isolation and characterization of (RS)-2-(4-Chloro-2-methylphenoxy)propionic acid-degrading bacteria from soils

Abstract

Fifteen numerically dominant (RS)-2-(4-Chloro-2-methylphenoxy)propionic acid ( MCPP, mecoprop ) degrading bacteria were isolated from soils, and their genetic and phenotypic characteristics were investigated. The mecoprop-degrading microorganisms were ubiquitous in golf course soils, while no positive degradation was observed from agricultural soils. The isolate were able to utilize the herbicide MCPP as a sole source of carbon and energy. Nine out of the fifteen isolates were able to degrade both (R)-mecoprop and (S)-mecoprop, five strains ( MP1, 4, 9, 18, 24 ) could degrade only (S)-mecoprop and one strain exhibited enantioselective degradation of (R)-mecoprop. The isolates also vigorously utilized other phenoxyacid herbidides, including 2,4-D, 2,4-DP, and MCPA, as sole carbon sources. Analysis of 16S rDNA sequences indicated that the all isolates were related to members of the genus, Sphingomonas. The REP-PCR analysis of the isolates revealed that some strains isolated from different soils exhibited identical REP-PCR patterns. All of the isolates were observed to have plasmid DNAs. Isolates, MP4, MP17, and MP24 identified as the same strains by 16s rDNA sequence and REP-PCR analyses exhibited different plasmid profile and degradation properties to each other.