Increased chalcopyrite bioleaching capabilities of extremely thermoacidophilic Metallosphaera sedula inocula by mixotrophic propagation
Increased chalcopyrite bioleaching capabilities of extremely thermoacidophilic Metallosphaera sedula inocula by mixotrophic propagation
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DOI：
10.1007/s10295-019-02193-3
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发表时间：
2019-08-01
影响因子：
3.4
通讯作者：
Zeng, Weimin
中科院分区：
文献类型：
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作者：
Ai, Chenbing;Yan, Zhang;Zeng, Weimin
属于硫化叶菌目的极度嗜酸的Crenarchaeota，例如景天金属球菌（Metallosphaera sedula），具有代谢多样性，并且与生物浸出具有很大的相关性。然而，用不同能量底物繁殖的极端嗜热菌对难熔黄铜矿随后生物浸出的影响仍然未知。其不同生物浸出潜力背后的转录反应仍然难以捉摸。在此，首次表明用典型能量基质繁殖的景天接种物具有不同的黄铜矿生物浸出能力。用酵母提取物进行异养繁殖的接种物在生物浸出方面存在缺陷；然而，用黄铜矿、黄铁矿或硫进行混合营养繁殖的接种物在 12 天内分别回收了 79%、78% 和 62% 的铜。与异养繁殖的接种物相比，在黄铜矿、黄铁矿或硫培养的接种物中分别鉴定出 937、859 和 683 个差异表达基因（DEG），包括与生物浸出相关代谢相关的基因上调，例如 Fe2+ 和硫氧化、CO2 固定。用黄铁矿或硫磺繁殖的接种物分别与黄铜矿培养的接种物共享480和411°。接种物中参与 Fe2+ 和硫氧化的 DEG 库的差异极大地影响了随后的黄铜矿生物浸出率。首次鉴定出可能与硫氧化有关的新基因（例如 Msed_1156、Msed_0549）。这项研究强调，混合营养繁殖的极端嗜热菌，尤其是黄铜矿，应该以工业规模接种到黄铜矿堆中。
Extremely thermoacidophilic Crenarchaeota belonging to the order Sulfolobales, such as Metallosphaera sedula, are metabolically versatile and of great relevance in bioleaching. However, the impacts of extreme thermoacidophiles propagated with different energy substrates on subsequent bioleaching of refractory chalcopyrite remain unknown. Transcriptional responses underlying their different bioleaching potentials are still elusive. Here, it was first showed that M. sedula inocula propagated with typical energy substrates have different chalcopyrite bioleaching capabilities. Inoculum propagated heterotrophically with yeast extract was deficient in bioleaching; however, inoculum propagated mixotrophically with chalcopyrite, pyrite or sulfur recovered 79%, 78% and 62% copper, respectively, in 12 days. Compared with heterotrophically propagated inoculum, 937, 859 and 683 differentially expressed genes (DEGs) were identified in inoculum cultured with chalcopyrite, pyrite or sulfur, respectively, including upregulation of genes involved in bioleaching-associated metabolism, e.g., Fe2+ and sulfur oxidation, CO2 fixation. Inoculum propagated with pyrite or sulfur, respectively, shared 480 and 411 DEGs with chalcopyrite-cultured inoculum. Discrepancies on repertories of DEGs that involved in Fe2+ and sulfur oxidation in inocula greatly affected subsequent chalcopyrite bioleaching rates. Novel genes (e.g., Msed_1156, Msed_0549) probably involved in sulfur oxidation were first identified. This study highlights that mixotrophically propagated extreme thermoacidophiles especially with chalcopyrite should be inoculated into chalcopyrite heaps at industrial scale.