Effects of pH value on the expression of key iron/sulfur oxidation genes during bioleaching of chalcopyrite on thermophilic condition
Effects of pH value on the expression of key iron/sulfur oxidation genes during bioleaching of chalcopyrite on thermophilic condition
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DOI：
10.1007/s13213-019-01453-y
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发表时间：
2019-03
影响因子：
3
通讯作者：
Tangjian Peng;Dan Zhou;Yanan Liu;R. Yu;G. Qiu;W. Zeng
中科院分区：
文献类型：
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作者：
Tangjian Peng;Dan Zhou;Yanan Liu;R. Yu;G. Qiu;W. Zeng
黄铜矿细菌浸出过程中，pH值等理化因素会影响微生物的代谢。为此，pH值对生物浸出过程中的关键功能基因的表达的影响进行了评估。在初始pH值为1.0、2.0和3.0的条件下，采用中等嗜热菌的混合培养物对黄铜矿进行生物浸出，并通过测定理化参数对浸出过程进行监测。采用实时荧光定量PCR技术，对微生物群落结构的动态变化和铁硫氧化关键基因（4Fe-4S铁氧还蛋白基因和硫酸腺苷转移酶基因）的表达进行了监测。采用冗余分析和相关系数计算来揭示基因表达与各种理化因素之间的联系。在初始pH为1.0和3.0时，浸出过程比初始pH为2.0时延长。结果表明，在游离细胞和贴壁细胞中，氧化热硫杆菌（Sulfobacillusthermosulfidooxidans）和酸性热硫杆菌（Acidithiobacilluscaldus）分别是早期的优势菌群，而在后期，嗜热铁浆菌（Ferroplasmathermophilum）成为优势菌群。pH值对嗜热氧化硫化杆菌和嗜热铁浆菌的基因表达有显著影响。pH值对嗜热硫杆菌基因表达的影响不显著。该研究揭示了pH值对黄铜矿生物浸出的重要性，pH值选择性地影响某些特定物种关键功能基因的表达。
Physicochemical factors such pH value would affect the microbial metabolism during chalcopyrite bioleaching. To this end, the effects of pH on the expression of critical functional genes during bioleaching were evaluated. A mixed culture of moderate thermophiles was used for chalcopyrite bioleaching at initial pH values of 1.0, 2.0, and 3.0, and bioleaching processes were monitored via measuring the physicochemical parameters. Quantitative real-time PCR assay was used to monitor the dynamics of microbial community structures and the expression of critical iron/sulfur oxidation genes (4Fe-4S ferredoxin and sulfate adenylyltransferase genes, respectively). Redundancy analysis and calculation of correlation coefficients were used to reveal linkages between gene expression and various physicochemical factors. The leaching processes at initial pH of 1.0 and 3.0 were prolonged compared with that at initial pH of 2.0. It was shown thatSulfobacillus thermosulfidooxidansandAcidithiobacillus calduswere the dominant species during the early stage in free and attached cells, respectively, whileFerroplasma thermophilumbecame predominant in the later phase. The gene expression inSulfobacillus thermosulfidooxidansandFerroplasma thermophilumwas greatly affected by pH values. On the other hand, the relationship between pH and gene expression inAcidithiobacillus calduswas not significant. The study unraveled the importance of pH value on chalcopyrite bioleaching, and pH selectively influenced the expression of key functional genes of some specific species.