CRISPR/dCas12a knock-down of Acidithiobacillus ferrooxidans electron transport chain bc1 complexes enables enhanced metal sulfide bioleaching

Acidithiobacillus ferrooxidans is an acidophilic chemolithoautotroph that plays an important role in biogeochemical iron and sulfur cycling and is a member of the consortia used in industrial hydrometallurgical processing of copper. Metal sulfide bioleaching is catalyzed by the regeneration of ferric iron; however, bioleaching of chalcopyrite, the dominant unmined form of copper on Earth, is inhibited by surface passivation. Here, we report the implementation of CRISPR interference (CRISPRi) using the catalytically inactive Cas12a (dCas12a) in A. ferrooxidans to knock down the expression of genes in the petI and petII operons. These operons encode bc