Abstract:

Mine tailing pollution is an environmental problem that has attracted worldwide attention. Its large output and high pollution risks were serious threats to the environment. Sulfur oxidation processes under the mine tailing conditions can produce hydrogen ions, leading to the acidification of mine tailing, which will activate and migrate metal pollutants and further cause harmful effects to the surrounding environment. As important participants in the biogeochemical cycle of sulfur, sulfur oxidizing microorganisms are the main components of sulfur oxidation under the mine tailing condition. Therefore, it is particularly important to strengthen the understanding of in situ microbe-driven sulfur oxidation processes in mine tailings. Till now, however, isolation and identification of sulfur oxidizing microorganisms in mine tailing and their impacts on in-situ environment still need to be further explored. Thus, this study collected the mine tailing samples from the "world antimony capital" tin mine as the research object. The plate scribing method was used to isolate and purify the in-situ microbial population of mine tailing under the conditions of sulfur oxidation, and identify its species by using the 16S rRNA and sulfur oxidation gene (soxB) sequence analysis. Then, the microcosm experimental system of sulfur oxidation condition was constructed to verify the functions of two pure bacteria with sulfur oxidation genes. In addition, the relationship between mine tailing acidification and sulfur oxidizing microorganisms was explored by constructing the simulation experimental system of mine tailing in-situ conditions. The results showed that two pure strains involving sulfur oxidation genes were successfully obtained, which were named as Methyloversatilis sp. LJY-1 and Limnobacter sp. LJY-2. We found that LJY-1 was the first discovered Methyloversatilis species with sulfur oxidation function, and its sulfur oxidation ability was significantly stronger than that of LJY-2. Based on the simulation experiments of mine tailing in situ conditions, it was proved that the microbe-driven sulfur oxidation process significantly aggravated the acidification of mine tailing (P<0.05). According to the differences in the water content of mine tailings, this study also revealed that the acidification process of mine tailing under flooding condition was significantly faster than that under the wet condition (P<0.05). The study is of great significance to the management and restoration of mine tailing sites.

Key words: mine tailing, sulfur oxidation microorganisms, sulfur oxidation gene, tailing acidification

摘要：

尾矿污染是全球备受关注的环境问题之一,其产量大、污染风险高,对环境造成了严重的威胁。尾矿条件下的硫氧化过程会产生氢离子,导致尾矿酸化,进而使得金属污染物活化和迁移,对周边环境造成危害。硫氧化微生物作为硫元素生物地球化学循环的重要参与者,其硫氧化代谢途径是尾矿中硫氧化的主要组成部分。因此,加强对尾矿原位条件下微生物驱动的硫氧化过程的理解尤为重要。然而,目前对尾矿中硫氧化微生物的分离鉴定及其对原位环境的影响仍需进一步探讨和解析。针对这一问题,该文以“世界锑都”锡矿山的尾矿为研究对象,采用平板划线法,在硫氧化条件下对尾矿原位微生物种群进行分离纯化,并结合16S rRNA和硫氧化基因（soxB）序列分析对其进行物种鉴定。同时,构建硫氧化条件微宇宙实验体系,对两株具有硫氧化基因的纯菌进行功能验证。除此以外,通过构建尾矿原位条件模拟实验体系,探究尾矿酸化与硫氧化微生物之间的联系。结果显示,该研究成功得到了两株具有硫氧化基因的纯菌,分别为Methyloversatilis sp. LJY-1和Limnobacter sp. LJY-2。硫氧化实验进一步表明,LJY-1是首次被发现的具有硫氧化功能的Methyloversatilis属类,并且LJY-1的硫氧化能力明显强于LJY-2。基于尾矿原位条件模拟实验,证明在尾矿原位条件下,微生物驱动的硫氧化过程显著加剧了尾矿酸化（P<0.05）。针对尾矿不同阶段中含水率的差异,该研究进一步揭示了淹水条件下尾矿酸化过程显著快于湿润条件（P<0.05）。研究结果对尾矿场地的管理和修复具有重要意义。

关键词: 尾矿, 硫氧化微生物, 硫氧化基因, 土壤酸化