Fluoride tolerance of co-culture of bioleaching microorganisms and community dynamics under fluoride stress

In order to explore the fluoride tolerance and the community dynamics of mixed bioleaching microorganisms,a co-culture including five typical bioleaching strains(Acidithiobacillus ferrooxidans ATCC 23270,Leptospirillum ferriphilum YSK,Sulfobacillus thermosulfidooxidans ST,Acidithiobacills thiooxidans A01,Acidithiobacills caldus S1)was constructed.The results show that the growth of the co-culture is inhibited by fluoride stress,and the co-culture keeps the stable cell density at high fluoride stress.The sulfur activity of the co-culture is not affected by fluoride stress.Microbial community dynamics of the co-culture was analyzed by real-time fluorescent quantitative PCR technology.The results show that L.ferriphilum YSK and A.caldus S1 are always the dominant species at fluoride stress or non-stress,while the minor is A.ferrooxidans ATCC 23270,5.thermosulfidooxidans ST and A.thiooxidans A01.Besides,S.thermosulfidooxidans ST is inhibited most obviously in the co-culture at fluoride stress,secondly A.caldus S1,A.thiooxidans A01 and A.ferrooxidans ATCC 23270,while the L.ferriphilum YSK still maintains a very stable growth.