Isolation and identification of native sulfuroxidizing bacterium capable of uranium extraction

Abstract

Bioleaching is the extraction of metals from their ores through the use of microorganisms. In<br />this process, the use of native bacteria leads to achieve more yields of metals. So, in the present<br />study, native sulfur-oxidizing bacterium in potentiality of uranium extraction was isolated from<br />Ghachin mine in Iran and identified by partial gene sequencing. For this purpose, the water<br />samples were collected from Ghachin mine and cultivated in Starkey medium. In following, the<br />isolate was inoculated into individual Starkey plates and incubated until the colonies indicating<br />the purified bacterium appeared. Then, the identification was carried out based on phenotypic<br />characteristics and 16s rDNA sequencing. After that, bioleaching of uranium experiments<br />carried out using uranium ore at 2.5 and 5% pulp densities. The result showed that after 15 days<br />of incubation, the bacteria in the fresh samples was grown. Following 5-7 days of the plate's<br />incubation, we obtained the single purified colonies of the bacteria. On the basis of 16s rDNA<br />nucleotide sequencing, the bacteria showed 99.71% similarity to A. thiooxidans ATCC 19377.<br />Besides, the bioleaching experiments indicated that the bacterium is capable of uranium<br />extraction in 2.5 and 5% pulp densities during 3 and 5 days. In conclusion, in this study, for the<br />first time, we isolated the native sulfur-oxidizing bacterium capable of uranium extraction, from<br />uranium mine of Gachin in Bandar Abbas, Iran.