Overexpression of quorum sensing genes in enhances cell attachment and covellite bioleaching.

Cell adhesion is generally a prerequisite to the microbial bioleaching of sulfide minerals, and surface biofilm formation is modulated via quorum sensing (QS) communication. We explored the impact of the overexpression of endogenous QS machinery on the covellite bioleaching capabilities of , a representative acidophilic chemolithoautotrophic bacterium. Cells were engineered to overexpress the endogenous qs-I operon or just the gene under control of the promoter. Both strains exhibited increased transcriptional gene expression of and improved cell adhesion to covellite, including increased production of extracellular polymeric substances and increased biofilm formation. Under low iron conditions, the improved bioleaching of covellite was more evident when was overexpressed alone as compared to the native operon. These observations demonstrate the potential for the genetic modulation of QS as a mechanism for increasing the bioleaching efficiency of covellite, and potentially other copper sulfide minerals.