Degradation of isoproturon in vitro by a mix of bacterial strains isolated from arable soil

Isoproturon (IPU) is widely used to control annual grasses and broad leaf weeds in cereal crops. In this study, four IPUdegrading bacterial strains, i.e., Sphingomonas sp. ISP1, Arthrobacter sp. ISP2, Acinetobacter baumannii 4IA, and Pseudomonas sp. ISP3, were isolated from agricultural soil. The mixed culture of four isolates completely degraded the herbicide at 100 mg/L within 10 days. During IPU degradation, several transient accumulations of the metabolites, including 3-(4-isopropylphenyl)1-methylurea, 3-(4-isopropylphenyl)-urea, 4-isopropylaniline, and 4-toluidine, were also identified. Moreover, the inoculation of the isolated mixed culture into the soil from a mountain with no previous herbicide application increased the degradation rate by 51% of the herbicide on average. Furthermore, bioaugmentation with isolated bacteria in the soil resulted in shortterm variations in bacterial structure compared to the unaugmented soil. The findings of this study were instrumental in understanding the mechanisms of pesticide breakdown and bioremediation in liquid media and soil.

Automated summary

In this study, four bacterial strains capable of degrading Isoproturon were isolated from agricultural soil. The mixed culture of these isolates exhibited complete degradation of the herbicide within 10 days. The inoculation of the mixed culture into soil increased the degradation rate of Isoproturon, and also caused short-term variations in bacterial structure. These findings are important for understanding the mechanisms of pesticide breakdown and bioremediation.