State Key Laboratory of Biogeology and Environmental Geology & School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430074, China.
Institute of Hydrobiology, the Chinese Academy of Sciences, Wuhan 430072, China.
J Environ Sci (China). 2023 Mar;125:582-592. doi: 10.1016/j.jes.2022.03.013. Epub 2022 Mar 16.
Many investigations suggest that dissimilatory arsenate-respiring prokaryotes (DARPs) play a key role in stimulating reductive mobilization of As from solid phase into groundwater, but it is not clear how environmental Mn(II) affects the DARPs-mediated reductive mobilization of arsenic. To resolve this issue, we collected soil samples from a realgar tailings-affected area. We found that there were diverse arsenate-respiratory reductase (arr) genes in the soils. The microbial communities had high arsenate-respiring activity, and were able to efficiently stimulate the reductive mobilization of As. Compared to the microcosms without Mn(II), addition of 10 mmol/L Mn(II) to the microcosms led to 23.99%-251.79% increases in the microbial mobilization of As, and led to 133.3%-239.2% increases in the abundances of arr genes. We further isolated a new cultivable DARP, Bacillus sp. F11, from the arsenic-contaminated soils. It completely reduced 1 mmol/L As(V) in 5 days under the optimal reaction conditions. We further found that it was able to efficiently catalyze the reductive mobilization and release of As from the solid phase; the addition of 2 mmol/L Mn(II) led to 98.49%-248.78% increases in the F11 cells-mediated reductive mobilization of As, and 70.6%-104.4% increases in the arr gene abundances. These data suggest that environmental Mn(II) markedly increased the DARPs-mediated reductive mobilization of As in arsenic-contaminated soils. This work provided a new insight into the close association between the biogeochemical cycles of arsenic and manganese.
许多研究表明，异化砷酸盐呼吸原核生物（DARPs）在刺激砷从固相还原迁移到地下水中起着关键作用，但目前尚不清楚环境锰（II）如何影响 DARPs 介导的砷还原迁移。为了解决这个问题，我们从雄黄尾矿污染区采集了土壤样本。我们发现土壤中存在多种砷酸盐呼吸还原酶（arr）基因。微生物群落具有很高的砷酸盐呼吸活性，能够有效地刺激砷的还原迁移。与没有添加 Mn（II）的微宇宙相比，向微宇宙中添加 10mmol/L Mn（II）可使微生物对砷的迁移增加 23.99%-251.79%，arr 基因的丰度增加 133.3%-239.2%。我们进一步从砷污染土壤中分离出一种新的可培养 DARP，芽孢杆菌 F11。在最佳反应条件下，它可以在 5 天内完全还原 1mmol/L 的 As(V)。我们进一步发现它能够有效地催化砷从固相的还原迁移和释放；添加 2mmol/L Mn（II）可使 F11 细胞介导的砷还原迁移增加 98.49%-248.78%，arr 基因丰度增加 70.6%-104.4%。这些数据表明，环境锰（II）显著增加了砷污染土壤中 DARPs 介导的砷还原迁移。这项工作为砷和锰的生物地球化学循环之间的密切联系提供了新的认识。
