Influence of cadmium on growth and iron/ sulfur oxidation of Leptospirillum. ferriphilum and Acidithiobacillus. thiooxidans in pure and co-cultures

摘要

Study on the metal stress of acidophilic bacteria is important since the presence of toxic heavy metals and other toxic compounds in the acidic bioleaching environments restricts the activity of acidophilic bacteria, and the interaction between the bacteria may change its heavy metals resistance. In this study, the effect of cadmium(II)ion on the growth of Leptospirillum. ferriphilum and Acidithiobacillus. thiooxidans in pure and co-culture was investigated. After adapted by a gradually increasing concentration of cadmium, two strains, L.ferriphilum and At. thiooxidans exhibited high degree of resistance to cadmium ion, and the maximum tolerance concentration (MTC) was up to 14.4 g/L and 18 g/L, respectively. It is interesting that L. ferriphilum could grow well under 18 g/L cadmium ion in the co-culture. The result showed that the cadmium resistance of L. ferriphilum and At. thiooxidans were increased in the co-culture, in addition, the growth of L. ferriphilum and At. thiooxidans were also increased in the co-culture. It was indicated that between two cultures caused the enhanced adaptability of cadmium stress in co-culture.