Abstract: Arsenic (As) has the characteristics of highly toxic, carcinogenic and teratogenic, arsenic contaminated soil poses a great threat to the environment and human health. The oxidation of As(Ⅲ) to As(V) is a key step of arsenic pollution control. In this study, two strains A1-13 and A1-24 with arsenic oxidation ability were isolated and purified from arsenic contaminated paddy soil. The characterization and arsenic oxidation characteristics of these two strains were analyzed, and their ability to reduce arsenic pollution in rice was tested in a pot experiment. The main research results were as follows: A1-13 was identified as a strain of Achromobacte sp.. After 24 hours of cultivation at 25℃ and pH 7.0，the arsenic oxidation rate of strain A1-13 was about 95%. A1-13 had good resistance to As(Ⅲ) and could grow and reproduce under the highest As(Ⅲ) mass concentration of 1 000 mg/L. When the concentration of As(Ⅲ) exceeds 600 mg/L, the arsenic oxidation rate significantly decreases. A1-24 was identified as a strain of Sphingobium sp. The arsenic oxidation rate of strain A1-24 was about 60% at 30℃ and pH 6.4. When the mass concentration of As(Ⅲ) was greater than 400 mg/L, the growth of strain A1-24 was inhibited. When the concentration of As(Ⅲ) was greater than 200 mg/L, the arsenic oxidation rate of strain A1-24 decreased significantly. In the pot experiment, compared with the blank control without bacterial strains, the arsenic content in rice with A1-13 and A1-24 added decreased by 37.83% and 29.42%, respectively. The discovery of two functional strains in this study provided a theoretical reference for controlling arsenic pollution in rice and had certain reference value for using highly efficient functional microorganisms to treat arsenic contaminated soil.
Key words: arsenic pollution; arsenic-oxidizing bacteria; rice; arsenic oxidation rate; arsenic content in rice
（Acta Laser Biology Sinica, 2025, 34(2): 184-192）