Transactions of Nonferrous Metals Society of China
JOURNAL OF RAILWAY SCIENCE AND ENGINEERING
|Vol. 17 No. 2 April 2007|
ferrooxidans and exploration of resistant mechanism
（Key Laboratory of Biometallurgy of Ministry of Education,
School of Resources Processing and Bioengineering, Central South University, Changsha 410083, China）
Abstract:The silver-resistant Acidithiobacillus ferrooxidans were isolated from 22 acid mine drainage (AMD) samples collected from Dexing Copper Mine and Chengmen Mountain Mine, Jiangxi Province, China. Isolate DX16 is obtained from the sample taken from Dexing Copper Mine and still carries out ferrous ion oxidation when incubated in 9K medium containing silver nitrate (240 mg/L). While isolate H1, a less resistant strain taken from Yin Mountain Mine, has a tolerate level of only 60 mg/L. Based on 16S ribosomal DNA sequencing, both bacterial 16SrDNA sequences are 100% similar to Acidithiobacillus ferrooxidans ATCC 23270. Through ultraviolet irradiation induced mutations, isolate mDX16 that is obtained from DX16 carries out ferrous ion oxidation when incubated in 9K medium containing higher concentration of silver nitrate (250 mg/L). When silver-resistant gene (SilC) analysis is carried out on the two isolates, it is seen that this gene was absent in both.
Key words: silver resistance; isolation and identification; UV mutation; Acidithiobacillus ferrooxidans; resistance mechanism