中国有色金属学报(英文版)
Transactions of Nonferrous Metals Society of China
Vol. 22 No. 12 December 2012 |
(1. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, China;
2. Key Laboratory of Biometallurgy of Ministry of Education of China,
Central South University, Changsha 410083, China)
Abstract: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.
Key words: Acidithiobacillus ferrooxidans; sulfur metabolism; surfactant Tween-80; RT-qPCR