Bio-desilication of rutile concentrate and analysis of community structure in bio-desilication reactor

The original strain HY-7 was isolated from the bauxite mine drainage (BMD) taken from a reservoir in Sanmenxia Mine, Henan Province, China. The optimum temperature and pH for the growth of strain HY-7 were 30 °C and 7.0, respectively. The optimum UV radiating time was 20 s and the positive mutation rate was 23.0%. The growth curves show that strain HY-7 needs 144 h to reach the stationary phase after its mutagenesis, which is 24 h earlier than that of the original strain. Sequence homology analysis indicated that this community consisted of mainly two branches: one sharing high homology with Paenibacillus stellifer and the other sharing high homology with Sporolactobacillus laevolacticus. The experimental results showed that the TiO2 grade of rutile concentrate increased from 78.21% to 91.80% and the recovery of TiO2 reached 95.24% after 7 d of bioleaching. The bio-desilication process can not only effectively improve the TiO2 grade of rutile concentrate but also meet the requirements of environmental protection.