School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, PR China.
School of Environmental Science and Engineering, Changzhou University, Changzhou 213164, PR China.
Sci Total Environ. 2024 Oct 15;947:174711. doi: 10.1016/j.scitotenv.2024.174711. Epub 2024 Jul 10.
Numerous studies have demonstrated that the co-leaching of ores by different silicate bacteria significantly improves the performance of bioleaching systems. Nevertheless, the mechanism of different silicate bacteria synergistically or complementarily enhanced the leaching process of lithium-containing silicate remains unclear. This study discussed the leaching impact of the combined presence of two metabolically distinct silicate bacteria on lepidolite, with the aim of comprehending the synergistic effect resulting from the presence of Bacillus mucilaginosus and Bacillus circulans in the leaching process. The results indicated that the polysaccharides and proteins secreted by bacteria-containing functional groups such as -OH and -COOH, which played an important role in the complex decomposition of ores. Organic acids played the role of acid etching and complexation. Bacillus mucilaginosus and Bacillus circulans exhibited low individual leaching efficiency, primarily due to their weak organic acid secretion. Moreover, the prolific polysaccharide production by Bacillus mucilaginosus led to bacterial aggregation, diminishing contact capability with minerals. Bacillus circulans decomposed the excessive polysaccharides produced by Bacillus mucilaginosus through enzymatic hydrolysis in the co-bioleaching process, providing later nutrient supply for both strains. The symbiosis of the two strains enhanced the synthesis and metabolic capabilities of both strains, resulting in increased organic acid secretion. In addition, protein and humic acid production by Bacillus mucilaginosus intensified, collectively enhancing the leaching efficiency. These findings suggested that the primary metabolic products secreted by different bacterial strains in the leaching process differ. The improvement in bioleaching efficiency during co-leaching was attributed to their effective synergistic metabolism. This work contributes to the construction of an efficient engineering microbial community to improve the efficiency of silicate mineral leaching, and reveals the feasibility of microbial co-culture to improve bioleaching.
大量研究表明，不同硅酸盐细菌协同浸出矿石可显著提高生物浸出系统的性能。然而，不同硅酸盐细菌协同或互补增强含锂硅酸盐浸出过程的机制尚不清楚。本研究讨论了两种代谢不同的硅酸盐细菌同时存在对锂云母的浸出影响，旨在理解 Bacillus mucilaginosus 和 Bacillus circulans 在浸出过程中协同作用的效果。结果表明，细菌分泌的多糖和蛋白质含有-OH 和-COOH 等功能基团，在矿石的复杂分解中起着重要作用。有机酸起到酸刻蚀和络合的作用。Bacillus mucilaginosus 和 Bacillus circulans 的单独浸出效率较低，主要是因为它们分泌的有机酸较弱。此外，Bacillus mucilaginosus 产生的大量多糖导致细菌聚集，降低了与矿物的接触能力。Bacillus circulans 在共生物浸出过程中通过酶解分解了 Bacillus mucilaginosus 产生的过量多糖，为两株菌提供了后续的营养供应。两株菌的共生增强了两株菌的合成和代谢能力，导致有机酸分泌增加。此外，Bacillus mucilaginosus 产生的蛋白质和腐殖酸增加，共同提高了浸出效率。这些发现表明，不同细菌菌株在浸出过程中分泌的主要代谢产物不同。共浸出过程中生物浸出效率的提高归因于它们有效的协同代谢。这项工作有助于构建高效的工程微生物群落，以提高硅酸盐矿物浸出效率，并揭示了微生物共培养提高生物浸出的可行性。
