摘要
The effects of surfactant Tween-80 on the growth, sulfur oxidation, and expression of selected typical sulfur metabolism relevant genes of Acidithiobacillus ferrooxidans ATCC 23270 were investigated. The results showed that in the presence of 10-2 g/L Tween-80, the growth of A. ferrooxidans and its metabolism on the insoluble substrate S0 and CuFeS2 were promoted. After 24 d of bioleaching, the copper extraction yield of chalcopyrite at 10-2 g/L Tween-80 increased by 16% compared with the bioleaching experiment without Tween-80. FT-IR spectra analysis revealed that the result was probably caused by the extracellular polymeric substances whose composition could be changed by the surfactant addition. RT-qPCR was used to analyze the differential expressions of 17 selected sulfur metabolism relevant genes in response to the addition of Tween-80. Down-regulation of the extracellular protein genes indicated the influence of Tween-80 on bacteria-sulfur adsorption. Variation of the expression level of the enzymes provided a supplement to sulfur metabolism investigation.
研究了表面活性剂 Tween-80 对 Acidithiobacillus ferrooxidans ATCC 23270 生长、硫氧化和硫代谢相关典型基因表达的影响。结果表明,当培养基中含有 10 2g/L Tween-80 时,A. ferrooxidans 的生长以及其对不溶性底物(S0和 CuFeS2)的代谢得到了促进。在该条件下,经过 24 d 的生物浸出,黄铜矿的铜离子浸出率比对照组(不含 Tween-80)高 16%。FT-IR 光谱分析表明,这可能是由于 Tween-80 的存在而导致胞外多聚物成分发生变化而引起的。用 RT-qPCR 来分析 17 个硫代谢相关基因在 Tween-80 存在时的表达差异。胞外蛋白质基因表达下调表明了Tween-80 对细菌硫吸附作用的影响。硫代谢相关酶基因表达水平的变化为硫代谢的研究提供了参考。
基金
Projects (50974140, 51274257) supported by the National Natural Science Foundation of China
Project (20090162110054) supported by the PhD Programs Foundation of Ministry of Education of China
