Comparative metagenomics reveals microbial community differentiation in a biological heap leaching system.

The microbial community in a biological heap leaching (BHL) system is crucial for the decomposition of ores. However, the microbial community structure and functional differentiation in different parts of a biological heap leaching system are still unknown. In this study, metagenomic sequencing was used to fully illuminate the microbial community differentiation in the pregnant leach solution (PLS) and leaching heap (LH) of a BHL system. Long-read sequences (1.3 million) were obtained for the two samples, and the MG_RAST server was used to perform further analysis. The taxa analysis results indicated that the dominant genera of PLS is autotrophic bacterium Acidithiobacillus, but heterotrophic bacterium Acidiphilium is predominant in LH. Furthermore, functional annotation and hierarchical comparison with different reference samples showed that the abundant presence of genes was involved in transposition, DNA repair and heavy metal transport. The sequences related to transposase, which is important for the survival of the organism in the hostile environment, were both mainly classified into Acidiphilium for PLS and LH. These results indicated that not only autotrophic bacteria such as Acidithiobacillus, but also heterotrophic bacteria such as Acidiphilium, were essential participants in the bioleaching process. This new meta-view research will further facilitate the effective application of bioleaching.