Abstract:

A new iron reduction strain, named nju-T1, was isolated from acid mine drainage (AMD) and surface tailings samples
from Yangchongshan  tailings  zone, Shizishan, Tongling, Anhui province, with FeTo  selective medium and overlay culture
technology. The morphological, physiological and biochemical research and phylogenetic analysis based on  the 16S rRNA gene
sequence showed that the strain belongs to  Acidithiobacillus. It was found that nju-T1 could reduce Fe3+ under aerobic conditions
with plate and  liquid cultural  tests. The pH range  for growth was pH 2.0-6.0, with optimum growth at pH 4.5, optimum growth
temperature at 30 ℃ and optimum ferric iron concentration at 5 mmol/L. It was inferred that the reduction sites may be located on
the cell outer membrane. AMD and tailings were controlled by the dynamic balance between the microbial functional groups and
surroundings. The nju-T1 reduced ferric to ferrous, which provided initial energy to ferrous-oxidizing bacteria and maintained the
Fe recycle and stability of acid mine environment. The research on mechanism of ferric reduction with nju-T1 not only broadens
the knowledge about  ferric  reduction bacteria mainly growing under  the anaerobic condition, but also has great significance  in understanding the formation of acid mine environment, its development mechanism and its further environmental treatment.

Key words: acid mine drainage, tailings, Acidithiobacillus sp. nju-T1；phylogenetic tree, ferric reduction