University of Natural Resources and Life Sciences Vienna BOKU, Dept. of Agrobiotechnology, IFA-Tulln, Inst. of Environmental Biotechnology, Konrad-Lorenz-Straße 20, 3430 Tulln an der Donau, Austria.
University of Natural Resources and Life Sciences Vienna BOKU, Dept. of Agrobiotechnology, IFA-Tulln, Inst. of Environmental Biotechnology, Konrad-Lorenz-Straße 20, 3430 Tulln an der Donau, Austria.
Waste Manag. 2022 May 1;144:182-190. doi: 10.1016/j.wasman.2022.03.025. Epub 2022 Apr 1.
The biological leaching of metals from different waste streams by bacteria is intensively investigated to address metal recycling and circular economy goals. However, usually external addition of sulfuric acid is required to maintain the low pH optimum of the bacteria to ensure efficient leaching. Extremely acidophilic Acidithiobacillus spp. producing sulfuric acid and ferric iron have been investigated for several decades in the bioleaching of metal-containing ores. Their application has now been extended to the extraction of metals from artificial ores and other secondary sources. In this study, an optimized process for producing biogenic sulfuric acid from elemental sulfur by two sulfur-oxidizing species, A. thiooxidans and A. caldus and their combinations, was investigated in batch and stirred tank experiments. Using a combined culture of both species, 1.05 M and 1.4 M biogenic sulfuric acid was produced at 30 °C and 6% elemental sulfur in batch and semi continuous modes, respectively. The acid produced was then used to control the pH in a heap bioleaching system in which iron- and sulfur-oxidizing A. ferrooxidans was applied to biologically leach metals from waste incineration residuals. Metals like Cu, Ni, Al, Mn, and Zn were successfully recovered by 99, 93, 84, 77 and 68%, respectively within three weeks of heap bioleaching. Overall, a potential value recovery of incorporated metals >70% could be achieved. This highlights the potential and novelty of applying extremely acidophilic sulfur-oxidizing bacteria for cheap and efficient production of biogenic sulfuric acid and its use in pH control.
从不同废物流体中通过细菌提取金属的生物浸出，正在被深入研究，以实现金属回收和循环经济的目标。然而，通常需要外部添加硫酸来维持细菌的低 pH 最佳值，以确保高效浸出。产生硫酸和高铁的极端嗜酸嗜酸硫杆菌（Acidithiobacillus spp.）已被研究了几十年，用于含金属矿石的生物浸出。现在，它们的应用已经扩展到从人工矿石和其他二次资源中提取金属。在这项研究中，通过两种硫氧化物种——氧化硫硫杆菌（A. thiooxidans）和嗜酸氧化亚铁硫杆菌（A. caldus）及其组合，在间歇和搅拌槽实验中研究了从元素硫生产生物硫酸的优化工艺。使用两种物种的混合培养物，在 30°C 和 6%元素硫的条件下，在间歇和半连续模式下分别产生了 1.05 M 和 1.4 M 的生物硫酸。然后，所产生的酸用于控制堆生物浸出系统中的 pH 值，在该系统中，铁和硫氧化菌嗜酸氧化亚铁硫杆菌（A. ferrooxidans）被用于从垃圾焚烧残余物中生物浸出金属。在三周的堆生物浸出过程中，Cu、Ni、Al、Mn 和 Zn 等金属的回收率分别达到 99%、93%、84%、77%和 68%。总体而言，可实现约 70%以上的金属综合回收价值。这突出了应用极端嗜酸硫氧化菌生产廉价高效生物硫酸及其在 pH 控制中的应用的潜力和新颖性。
