Degradation of MCPA, 2,4-D, and Other Phenoxyalkanoic Acid Herbicides Using an Isolated Soil Bacterium

A soil bacterium was isolated capable of metabolizing the five phenoxyalkanoic acid herbicides 2,4-D, 2,4-DB, MCPA, MCPB, and 2,4,5-T in mineral solution with the individual herbicides as sole carbon source. The optimum temperature for breakdown was in the range 20-30 degrees. In a 500-L aerated tank, the organism metabolized kilogram quantities of both 2,4-D and MCPA dimethylamine formulations to inorganic chloride. This bacterium retained activity for at least 18 months after storage in a frozen state at -70 degrees C. When applied to field plots, the organism is able to survive in the soil for at least 615 days and degrade both 2,4-D and MCPA significantly more rapidly than in soil from an untreated control lot