"Also, it’s mildly radioactive since it contains low deposits of uranium and thorium."
Hmmm. In principle then we could also be using bioleaching to separate out uranium and thorium?
I'm scratching my head. The bacteria produce gluconic acid, is that the whole business of making them available to chemical separation, or is there a biological component too?
Chemical reactions conducted by biology tend to be different to those conducted by geology or chemists. Enzymes tend to be very efficient catalysts. Biological reactions tend to proceed via a much larger number of transition (intermediate) states than abiological ones, and this sometimes shows up in the isotopic distributions of elements in reaction products -- reactions with lighter isotopes go faster.
Could we then use biotechnology both for refining uranium ore, and isotope separation? Enrichment? That'd be good for a laugh.
[Yes I reread the article, no biotechnological step in the chemical separation. But I can dream can't I?]