Bioremediation of soil contaminated by propachlor using native bacteria

Soil from a herbicide disposal site was used to enrich for microorganisms that degraded 2-Chloro-N-isopropylacetanilide (propachlor). A bacterium, PEM1, able to mineralize the herbicide was isolated. A product of the microbial metabolism of propachlor was identified as N-isopropylacetanilide, suggesting that the first step in the mineralization process is dehalogenation. Strain PEM1 could grow on N-substituted acylanilides, but was incapable of growth on aniline and phenol. Rates of degradation of propachlor were monitored in low-organic-matter soil at field capacity, amended with 0•1–100 μg of herbicide per g of soil and inoculated with two different amounts of strain PEM1. Rates of degradation were comparable, and removal of propachlor close to 90% by 8 days.