Study on arsenic tolerance of moderately thermophilic bacteria Leptospirillum ferrooxidans and Acidithiobacillus caldus
In this study,two moderately thermophilic bacteria,including L.ferrooxidans(Leptospirillum ferrooxidans)and A.caldus(Acidithiobacillus caldus),used in bioleaching processes of refractory gold ores were taken as the main research objects.The effects of valence of arsenic(As(Ⅲ)and As(Ⅴ))on the bio-oxidation of two moderately thermophilic bacteria were investigated through studied by shake flask experiment.The results were compared with two mesophilic bacteria,A.ferrooxidans(Acidithiobacillus ferrooxidans)and T.thiooxidans(Thiobacillus thiooxidans).The results showed that the tolerance to As(Ⅲ)of moderately thermophilic bacteria was sig-nificantly weaker than that of mesophilic bacteria,but both of thermophilic and mesophilic bacteria showed similar tolerance to As(Ⅴ).At the same time,the effect of As(Ⅲ)on iron-oxidizing bacteria in growth was greater than that on sulfur-oxidizing bacteria.It was found that increasing the bacteria inoculation amount and domesticating bacteria was conducive to the adaptation of moderately ther-mophilic bacteria to arsenic toxicity.In the actual ore pulp system,increasing the inoculation amount could make moderately thermoph-ilic bacteria finally to adapt to the high arsenic environment and obtain better ore bioleaching effect.The highest mass concentration can reach about 1.54 g/L,and the arsenic leaching rate can be up to 70%in only 10 days.
bio-oxidationmoderately thermophilic bacteriavalence of arsenicdomesticationbacteria inoculation amount
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维普
