This study evaluated the effect of three sulfate salt-based culture media on the reprecipitation of sulfur under the action of two types of bacterial inoculum, a pure strain of Acidithiobacillus ferrooxidans (ATCC 23270) and a consortium of this strain and Acidithiobacillus thiooxidans (ATCC 15494), in a biodesulfurization process for coal (particle size < 0.25 mm) from the 'La Guacamaya' mine (Puerto Libertador, Cordoba, Colombia). All of the experiments were periodically monitored, with measurements taken of pH, cell concentration, iron concentration, and pyrite oxidation. Additionally, mineralogical analyses were conducted on the initial and final coal samples, through scanning electron microscopy with an energy-dispersive X-ray spectrometer. The results showed that sulfate reprecipitation occurred primarily, and nearly entirely, during the first 3 days of the process. While all the treatments obtained high levels of mineral oxidation, the reprecipitation processes decreased in media with low concentrations of sulfate, leading to the higher final removal of inorganic sulfur. The bioassays revealed that after 15 days, the maximum pyrite oxidation (86%) and inorganic sulfur removal (53%) was obtained with the treatments using the Kos and McCready culture media. The bacteria evaluated were found to have a great ability to adapt to very simple culture media with minimal nutrient concentrations, and even with some nutrients absent (as in the case of magnesium).

中文翻译：

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煤生物脱硫过程中硫酸盐的早期再沉淀使用嗜酸化学无机营养细菌

本研究评估了三种基于硫酸盐的培养基在两种细菌接种物、一种纯菌株氧化亚铁硫杆菌 (ATCC 23270) 以及该菌株与氧化硫硫杆菌 (ATCC 15494) 的联合作用下对硫再沉淀的影响），在来自“La Guacamaya”矿（解放者港，科尔多瓦，哥伦比亚）的煤（粒径 < 0.25 毫米）的生物脱硫过程中。定期监测所有实验，测量 pH、细胞浓度、铁浓度和黄铁矿氧化。此外，通过带有能量色散 X 射线光谱仪的扫描电子显微镜，对初始和最终煤样进行了矿物学分析。结果表明，硫酸盐再沉淀主要发生，几乎全部发生，在该过程的前 3 天。虽然所有处理都获得了高水平的矿物氧化，但在硫酸盐浓度低的介质中再沉淀过程减少，导致无机硫的最终去除率更高。生物测定表明，在 15 天后，使用 Kos 和 McCready 培养基处理获得了最大的黄铁矿氧化 (86%) 和无机硫去除 (53%)。发现所评估的细菌具有很强的适应非常简单的培养基的能力，该培养基具有最低的营养浓度，甚至缺乏某些营养（如镁的情况）。导致更高的无机硫最终去除率。生物测定表明，在 15 天后，使用 Kos 和 McCready 培养基处理获得了最大的黄铁矿氧化 (86%) 和无机硫去除 (53%)。发现所评估的细菌具有很强的适应非常简单的培养基的能力，该培养基具有最低的营养浓度，甚至在缺乏某些营养的情况下（如镁的情况）。导致更高的无机硫最终去除率。生物测定表明，在 15 天后，使用 Kos 和 McCready 培养基处理获得了最大的黄铁矿氧化 (86%) 和无机硫去除 (53%)。发现所评估的细菌具有很强的适应非常简单的培养基的能力，该培养基具有最低的营养浓度，甚至在缺乏某些营养的情况下（如镁的情况）。