Serratia marcescens AB1: A rhizosphere bacterium mitigating the acetochlor stress on the soil environment

Microbial remediation, a significant research focus in bioremediation, shows promise in addressing pollution. In this study, the optimal medium for acetochlor-degrading bacteria AB1 was determined by the response surface method as 29.94 g L⁻¹ sucrose, 10.06 g L⁻¹ yeast extract, and 20.32 g L⁻¹ NaCl. The single-factor method identified optimum degradation conditions, including a temperature of 30 °C, pH of 7.0, inoculation with 3% AB1, and an initial acetochlor concentration of 10 mg L⁻¹. The strain reached a maximum degradation rate of 79.87% within 5 days. AB1 performed nitrogen fixation, phosphorus dissolution, potassium hydrolysis, siderophore production, and biofilm formation. In the presence of acetochlor, it also induced the upregulation of genes, wza and luxS. Utilizing a green fluorescent protein and rifampicin-resistant strain LAB1-gfp, it demonstrated stable colonization in maize rhizospheres and soils, enhancing growth and degradation. This reduced the acetochlor half-life to 12.77 days and increased soil enzyme activity, providing a theoretical foundation for acetochlor bioremediation.