Abstract:Two acidicbacillus strains were isolated from samples of uranium biological heap leaching ore in Jiangxi and Guangdong province by successive diluting method. 16s rRNA gene sequence analysis confirms that one bacteria is Acidimicrobium ferrooxidans and the other is Leptospirillum ferriphilum. Concentration of chlorine ion of 1 g/L below has no effect on ferroxidase activity. Activity weakens with concentration of chloride ion in 1~2 g/L, but proper adjustment can enable bacterium to adapt and maintain acceptable activity. However, when chloride ion concentration is 2 g/L above, ferroxidase activity weakens rapidly and growth of bacteria is even inhibited with lower ferroxidase activity when concentration of chloride ion is 3 g/L above.