Comparative genomics begins to unravel the ecophysiology of bioleaching

The metabolic potential of 16 bioleaching microorganisms (Eubacteria and Archaea) has been investigated, allowing the prediction of potential inter- and intra-species physiological interactions (ecophysiology) during spatial and temporal changes that are known to occur within industrial bioleaching heaps. Genome analysis has allowed preliminary models to be built for genes and pathways involved in key processes such as nitrogen and carbon cycling, sulfur and iron uptake and homeostasis, extra-cellular polysaccharide biosynthesis, heavy metal resistance and energy metabolism. This paper will focus on the diverse ways that microorganisms obtain carbon from their environment with a particular emphasis on elucidating how these processes might be expected to vary over space and time during the lifetime of a bioleaching operation. It is anticipated that this knowledge will improve our understanding of fundamental biological processes in extremely acidic environments and it is hoped that it will capture usable knowledge that can be applied to bioleaching. Comparative genomics between two strains of Acidthiobacillus ferrooxidans highlights the importance of lateral gene transfer in increasing genetic and metabolic potential and suggests that classical molecular DNA techniques, such as rDNA typing, significantly underestimate the microbial diversity of bioleaching heaps.