State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
School of Metallurgy and Environment, Central South University, Changsha 410083, Hunan, China; Zijin Mining Group Company Limited, Shanghang 364200, Fujian, China.
Sci Total Environ. 2023 Apr 15;869:161752. doi: 10.1016/j.scitotenv.2023.161752. Epub 2023 Jan 21.
Monitoring of the microbial community in bioleaching system is essential for control process parameters and enhance the leaching efficiency. Due to the difficulty of sampling, microbial distribution, community succession and bioleaching activity along the vertical depth of bioleaching heaps remain unresolved. This study investigated the geochemical parameters and microbial community structure along a depth profile in a bioleaching heap and leachate. 80 ore samples at different heap depths and 9 leaching solution samples from three bioheaps of Zijin Copper Mine were collected. Microbial composition, mineral types and geochemical parameters of these samples were analyzed by 16S rRNA high-throughput sequencing and a series of chemical measurement technologies. The results revealed that the pH, Cu, Fe and the total sulfur contents were the major factors shaping the composition of the microbial communities in the bioleaching system. The extent of mineral oxidation increased as the sample depth increases, followed by the increasing of sulfur oxidizers. The abundance of sulfur and iron oxidizers including members of Acidithiobacillus, Sulfobacillus and Acidiferrobacter were significantly higher in the leaching heap than in the leaching solution, meanwhile, they showed strong positive interactions with other members within the same genera and iron oxidizer Leptospirillum and Ferroplasma. Besides, Acidithiobacillus negatively interacted with heterotrophs such as Sphingobium, Exiguobacterium, Brevundimonas and so on. On the contrast, members of Leptospirillum and unclassified Archaea were significantly abundant in the leaching solution and revealed strong interactions with members of Thermoplasmatales. The main conclusion of this study, especially the leaching potential of microorganisms prevailing in bioheaps and their relationships with geochemical factors, provides theoretical guidance for future process design such as the control of processing parameters and microbial community in heap leaching.
监测生物浸出系统中的微生物群落对于控制过程参数和提高浸出效率至关重要。由于采样困难，微生物分布、群落演替和生物浸出堆沿垂直深度的生物浸出活性仍然没有得到解决。本研究调查了生物浸出堆和浸出液中沿深度剖面的地球化学参数和微生物群落结构。从紫金铜矿的三个生物堆中采集了 80 个不同堆深的矿石样本和 9 个浸出液样本。通过 16S rRNA 高通量测序和一系列化学测量技术分析了这些样本的微生物组成、矿物类型和地球化学参数。结果表明，pH 值、Cu、Fe 和总硫含量是塑造生物浸出系统中微生物群落组成的主要因素。随着样品深度的增加，矿物氧化程度增加，随后硫氧化菌的数量增加。硫和铁氧化菌（包括嗜酸菌、硫杆菌和嗜酸铁杆菌的成员）的丰度在浸出堆中明显高于浸出液中，同时，它们与同一属内的其他成员以及铁氧化菌 Leptospirillum 和 Ferroplasma 表现出强烈的正相互作用。此外，嗜酸菌与异养菌（如 Sphingobium、Exiguobacterium、Brevundimonas 等）呈负相互作用。相比之下，Leptospirillum 和未分类古菌的成员在浸出液中丰度较高，与 Thermoplasmatales 的成员表现出强烈的相互作用。本研究的主要结论，特别是生物堆中占优势的微生物的浸出潜力及其与地球化学因素的关系，为未来的工艺设计提供了理论指导，例如堆浸过程中处理参数和微生物群落的控制。
