Engineering A cidithiobacillus ferrooxidans growth media for enhanced electrochemical processing

The chemolithoautotroph Acidithiobacillus ferrooxidans has been proposed as a potential electrofuel synthetic platform, and its growth medium is engineered to increase its conductivity and energy density, thereby improving viability of the process. The ion V 3+ is used as an indirect electron supplier together with Fe 2+ to grow A. ferrooxidans to increase the energy density of the medium, overcoming the Fe 3+ solubility limit. A medium containing 10 mM Fe 2+ with 60 mM V 3+ was able to support cell growth to a final cell concentration very similar to medium of 70 mM Fe 2+ . Integration of the biological process with an electrochemical reactor requires, for economical operation, a medium with high ionic conductivity. This is achieved by the addition of salt, and Mg 2+ was found to be least toxic to the bacterium. A concentration of 500 mM Mg 2+ is optimal considering constraints on bacterial growth and electrochemistry. © 2014 American Institute of Chemical Engineers AIChE J 60: 4008–4013, 2014