Isolation of acephate-degrading bacteria and phytoremediation–microbial remediation from soil for the project of water diversion from the Yangtze River to Chaohu Lake

Huili WangJielun ChangChang Pan^*Dongsheng JiangYemei WangQin YinXi ChenXi LiaoManman LiXiaoke Zhang

• Anqing Normal University, Anqing, China

This study focuses on soils from typical riparian zones along the project of water diversion from the Yangtze River to Chaohu Lake, aiming to screen acephate-degrading microorganisms and to systematically evaluate their degradation efficiency. Through pot experiments, we investigated the synergistic effects of plants and selected functional microorganisms on acephate removal from soil, providing a scientific basis and technical reference for remediating acephate-contaminated soils. Five acephate-degrading strains were isolated and identified via 16S rDNA sequencing as Enterobacter cloacae, Enterobacter hormaechei, Bacillus badius, Sphingobacterium spiritivorum, and Serratia nematodiphila. Although all strains degraded acephate, their efficiencies differed significantly. Except for the 50 mg L-1 acephate condition with added glucose, Bacillus badius consistently exhibited higher degradation efficiency across all tested conditions. Furthermore, increasing acephate concentration in the culture medium from 10 mg L-1 to 50 mg L-1 reduced degradation efficiency across strains. However, adding 0.1 g L-1 glucose enhanced degradation rates for all strains, with Bacillus badius achieving the highest degradation efficiency (76.17% at 10 mg L-1 acephate). For combined experiments, we paired Bacillus badius (with superior in vitro degradation performance) with Persicaria hydropiper, and Sphingobacterium spiritivorum with Carex dimorpholepis. At both 200 μg kg-1 and 1000 μg kg-1 soil acephate concentrations, combined remediation efficiencies exceeded those of microbes or plants alone. The combination of Bacillus badius and Persicaria hydropiper achieved the highest removal rate of 91.27% at the 1000 μg kg-1 acephate concentration. These findings significantly enrich the repository of acephate-degrading bacteria and demonstrate that combined remediation with Bacillus badius and Persicaria hydropiper is an effective strategy for the bioremediation of acephate-contaminated soils within the project of water diversion from the Yangtze River to Chaohu Lake.