MgO anchored N-doping biochar enhances the bensulfuron-methyl biodegradation by Acinetobacter YH0317: Higher reactive oxygen species level and bacterial viability.

ABSTRACT

Bensulfuron-methyl (BSM) is a typical broad-spectrum sulfonylurea herbicide and the runoff of BSM residues from agricultural regions poses a significant threat to the ecosystem. Here we develop a bacteria-material hybrid system constructed by Acinetobacter YH0317 and Mg(NO3)2 modified biochar (MBC) for efficiently degrading BSM under various conditions including pH and temperature. Results showed that BSM biodegradation efficiency by YH0317&MBC (96.7 %) was significantly higher than YH0317&BC (79.5 %) and YH0317 (43.9 %) at 15 °C after 7 d of incubation. The addition of MBC significantly increased the reactive oxygen species (ROS) level, which was significantly higher than group YH0317. Moreover, the bacterial viability, extracellular polymeric substances (EPS) production, and membrane permeability of YH0317 were also enhanced with the addition of MBC. The electron paramagnetic resonance (EPR) and quenching experiments revealed that singlet oxygen (1O2) was the dominant active substance produced by MBC. The YH0317&MBC could effectively remove the BSM, and reduce the oxidative stress to soybean, which was beneficial to the growth of soybean through hydroponic experiment. This study establishes a microorganism-material system that efficiently removes BSM in aquatic environments and emphasizes the importance of ROS in pollution removal by the hybrid system.