Metabolic Potential of Serratia sp. 22S for Chlorphenoxyacetic Acids Conversion

A bacterial strain 22S belonging to the genus Serratia was isolated from soil samples contaminated with chemical production wastes. The strain was found to be nonpathogenic based on the study of its virulence, toxicity, infectivity, and invasiveness. In batch culture, Serratia sp. 22S was able to separately utilize chlorophenoxyacetic acids (100 mg/L) as the sole source of carbon and energy. The catabolism pathway for chlorophenoxyacetic acids was suggested through complete reductive dechlorination of the substrate followed by meta -cleavage of the aromatic ring of catechol based on the compounds found in the culture medium (2,4-dichloro-6-methylphenoxyacetic, phenoxyacetic, and 2-hydroxy-2-hexenedionic acids). Intact cells experiments confirmed this assumption. In model systems, good adaptability and survival of the 22S strain in the soil was revealed, and the content of chlorophenoxyacetic acids up to a certain concentrations had a positive effect on the growth of the strain, most likely due to its selective effect.