2017 Theses Doctoral

Tools and Methods to Engineer the Industrial Microorganism Acidithiobacillus ferrooxidans

Kernan, Timothy Michael

Acidithiobacillus ferrooxidans is an important industrial organism used in the mining industry where it participates in passive bioleaching processes used to produce about 20% of the world’s copper supply. The bacterium thrives in strong mineral acids at ambient temperatures and derives metabolic energy from the oxidation of ferrous iron, sulfur, and reduced inorganic sulfide compounds to fix CO2 and N2. This unique metabolism provides new opportunities to engineer this organism for the production of fuels and chemicals from CO2. While A. ferrooxidans has been studied extensively for 60 years, the tools and methods necessary for a robust genetic system to manipulate and further study this bacterium are not well developed and published techniques are generally difficult to reproduce. This research focuses on developing the means to genetically modify this species to experimentally study its physiology and engineer the organism for the production of chemicals from CO2. This includes developing a robust and reproducible system to generate and select mutant strains, heterologous expression of exogenous genes, characterizing endogenous inducible promoters, and developing new plasmids to expand the repertoire of tools available for this organism.