极端嗜热菌群在70℃柱浸反应器中浸出低品位硫化铜矿

Bioleaching of low-grade copper sulfide ore by extremely thermoacidophilic consortia at 70℃in column reactors

本文研究了分别引入具有不同Cu^2+抗性的M.sedula菌株对极端嗜热菌群(由A.brierleyi DSM1651和M.hakonensis HO1-1组成)在70℃柱浸反应器中浸出硫化铜矿的影响。引入Cu^2+敏感的M.sedula cop A突变菌株对硫化铜矿的浸出几乎没有影响,铜浸出率没有提高。然而,引入Cu^2+抗性M.sedula ARS50-2能显著地强化浸出过程,铜浸出率在第58天提高了27.77%。第24天后浸出液的pH表明M.sedula ARS50-2的加入能提高极端嗜热菌群的硫氧化活性。定量PCR数据表明在浸出过程中,各反应器中矿物表面与浸出液中的极端嗜热菌群群落结构不同。极端嗜热菌在浸出过程中主要吸附在矿物表面。M.hakonensis HO 1-1是浸出过程中各个反应器矿物表面的主要菌株。M.sedula ARS50-2在浸出的第34天仍然是矿物表面的主要的菌株。A.brierleyi DSM1651是浸出过程中各柱浸反应器浸出液中的主要菌株。相关数据表明加入高Cu^2+抗性菌株有利于极端嗜热菌在高浓度Cu^2+胁迫条件下对硫化铜矿的浸出。

The effects of introducing M.sedula derivatives having different Cu^2+-resistance on bioleaching capacity of a defined consortium(consisting of A.brierleyi DSM1651 and M.hakonensis HO1-1)were studied in column reactors at 70℃.Introducing M.sedula copA mutant,a copper sensitive derivative,only had negligible effects on bioleaching.While introducing M.sedula ARS50-2,a Cu^2+resistant strain,substantially consolidated bioleaching process,with 27.77%more copper recovered after 58 d of bioleaching.Addition of M.sedula ARS50-2 likely enhanced the sulfur oxidation capacity of consortium after the 24th day under the Cu^2+stress.The majority of extreme thermoacidophiles were attached on minerals surface as indicated by quantitative PCR(qPCR)data.Successions of microbial community of extremely thermoacidophilic consortia that attached on surface of minerals were different from those in leachate.M.hakonensis HO1-1 was the dominant species attached on minerals surface in each column reactor throughout bioleaching process.The sessile M.sedula ARS50-2 remained as a major species till the 34th day.A.brierleyi DSM1651 was the most abundant planktonic species in leachate of each column reactor.These results highlight that higher Cu^2+-resistance is a beneficial trait for extreme thermoacidophiles to process copper minerals.