State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430070, People's Republic of China.
State Key Laboratory of Biogeology and Environmental Geology, School of Environmental Studies, China University of Geosciences (Wuhan), Wuhan 430070, People's Republic of China.
Ecotoxicol Environ Saf. 2018 Dec 15;165:1-10. doi: 10.1016/j.ecoenv.2018.08.079. Epub 2018 Aug 30.
Arsenite-oxidizing bacteria (AOB) play a key role in the biogeochemical cycle of arsenic in the environment, and are used for the bioremediation of As contaminated groundwater; however, it is not yet known about how arsenic affects biofilm formations of AOB, and how biofilm formations affect bacterial arsenite-oxidizing activities. To address these issues, we isolated seven novel AOB strains from the arsenic-contaminated soils. They can completely oxidize 1.0 mM As(III) in 22-60 h. Their arsenite oxidase sequences show 43-99% identities to those of other known AOB. Strains Cug1, Cug2, Cug3, Cug4, and Cug6 are able to form biofilms with thickness of 15-95 µm, whereas Cug8 and Cug9 cannot form biofilms. It is interesting to see that arsenite inhibited the biofilm formations of heterotrophic AOB strains, but promoted the biofilm formations of autotrophic strains in a concentration-dependent manner. The arsenite-oxidizing rates of Cug1 and Cug4 biofilms are 31.6% and 27.6% lower than those of their suspension cultures, whereas the biofilm activities of other strains are similar to those of their suspension cultures. The biofilm formation significantly promoted the bacterial resistance to arsenic. This work is the first report on the complex correlations among environmental arsenic, bacterial biofilm formations and bacterial arsenite-oxidizing activities. The data highlight the diverse lifestyle of different AOB under arsenic stress, and provide essential knowledge for the screening of efficient AOB strains used for constructions of bioreactors.
砷氧化细菌（AOB）在环境砷的生物地球化学循环中发挥着关键作用，并被用于受砷污染地下水的生物修复；然而，目前尚不清楚砷如何影响 AOB 的生物膜形成，以及生物膜形成如何影响细菌的亚砷酸盐氧化活性。为了解决这些问题，我们从砷污染土壤中分离出了 7 株新型 AOB 菌株。它们可以在 22-60 小时内完全氧化 1.0mM 的 As(III)。它们的亚砷酸盐氧化酶序列与其他已知的 AOB 具有 43-99%的同源性。菌株 Cug1、Cug2、Cug3、Cug4 和 Cug6 能够形成厚度为 15-95µm 的生物膜，而 Cug8 和 Cug9 不能形成生物膜。有趣的是，亚砷酸盐抑制了异养 AOB 菌株的生物膜形成，但以浓度依赖的方式促进了自养菌株的生物膜形成。Cug1 和 Cug4 生物膜的亚砷酸盐氧化速率比悬浮培养物低 31.6%和 27.6%，而其他菌株的生物膜活性与悬浮培养物相似。生物膜形成显著提高了细菌对砷的抗性。这项工作首次报道了环境砷、细菌生物膜形成和细菌亚砷酸盐氧化活性之间的复杂相关性。这些数据突出了不同 AOB 在砷胁迫下的多样生活方式，为筛选用于构建生物反应器的高效 AOB 菌株提供了必要的知识。
