黃銅礦的浸出及其基因Afe0022的差異表達(dá)
(1. 中南大學(xué) 資源加工與生物工程學(xué)院，長沙 410083；
2. 中南大學(xué) 教育部生物冶金重點實驗室，長沙 410083)
摘 要: 通過搖瓶浸礦比較研究3株Acidithiobacillus ferrooxidans (At. ferrooxidans)菌DY15、DY26和DC的耐受Cu2+能力的差異以及在不同的初始Cu2+濃度影響下菌對黃銅礦浸出能力的不同。采用Real time RT(Reverse transcriptase) PCR檢測這些菌株的陽離子通道蛋白基因Afe0022在不同Cu2+環(huán)境下的差異表達(dá)，進(jìn)行相對表達(dá)量分析。結(jié)果表明：DY15、DY26和DC菌的最高Cu2+抗性分別是0.40、0.22和0.04 mol/L，且在以元素硫為能源的9K培養(yǎng)基中，3株菌DY15，DY26和DC對應(yīng)的培養(yǎng)體系pH值在7 d內(nèi)由1.8分別降到0.8、1.2和1.3，說明DY15的硫氧化能力最強(qiáng)；3株菌都具有較好的亞鐵氧化能力，在40 h內(nèi)，DY15、DY26和DC的Fe2+氧化率分別是80%、100%、100%。黃銅礦精礦浸礦實驗表明，DY15對黃銅礦精礦的浸出效率最高，DY26的其次，DC的最低，但DY15的單菌浸出效率略低于3株菌的混合浸出效率。對Cu2+抗性越強(qiáng)的菌株，其基因Afe0022表達(dá)量越高，這對菌株的Cu2+抗性能力有一定的理論解釋作用，在分子層面上為研究At. ferrooxidans菌抗銅機(jī)理提供一定的理論依據(jù)。
關(guān)鍵字: 嗜酸氧化亞鐵硫桿菌；黃銅礦精礦浸出；元素硫氧化；Cu2+抗性；差異表達(dá)
（1. School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Biometallurgy, Ministry of Education, Central South University, Changsha 410083, China）
Abstract:The effects of different initial concentrations of Cu2+ on chalcopyrite concentrate bioleaching and the difference of ability in response to copper ion (Cu2+) were investigated with three strains of Acidithiobacillus ferrooxidans (At. ferrooxidans) DY15, DY26 and DC. The real time reverse transcriptase (RT) PCR was used to analyze the difference expression of gene Afe0022 cation channel protein in copper ion with different concentrations. The results show that strain DY15, DY26 and DC have the copper ion tolerance level of 0.40, 0.22 and 0.04 mol/L, respectively. When the elemental sulfur acts as the energy resource in 9K medium, the oxidation capacity of elemental sulfur of strain DY15 is better than that of elemental sulfur of DY26 and DC, and after 7 d, the pH values of DY15, DY26 and DC decline from 1.8 to 0.8, 1.2 and 1.3, respectively. All three strains can oxidize ferrous ions well, and after 40 h, the oxidation capacities of ferrous ions of three strains are 80% (DY15), 100% (DY26), and 100% (DC), respectively. In the leaching experiment, strain DY15 has the highest bioleaching efficiency on chalcopyrite concentrate while strain DC has the least bioleaching efficiency in the three strains, but the mixed cultures containing 3 strains exhibit the highest bioleaching efficiency than the pure cultures of DY15. The stronger the capacity of strain resistance to Cu2+ is, the more the expression of gene Afe0022 is. This result assists interpretation of bacterium resistance to Cu2+, and provides theoretical basis to study the mechanism of bacterium resistance to Cu2+ in molecular level.
Key words: Acidithiobacillus ferrooxidans; chalcopyrite concentrate bioleaching; sulfur oxidation; Cu2+ resistance; difference expression
