UC Berkeley

As fossil fuels are increasingly linked to environmental damage, the development of renewable, affordable biological alternative fuels is vital. Shewanella oneidensis is often suggested as a potential component of bioelectrochemical cells because of its ability to act as an electron donor to metal surfaces. These microbes remain challenging to implement, though, due to inconsistency in biofilm formation on electrodes and therefore current generation. We have applied DNA hybridization-based cell adhesion to immobilize S. oneidensis on electrodes. High levels of current are reproducibly generated from these cell layers following only 30 min of immobilization without the need for the formation of a biofilm. Upon incorporation of DNA mismatches in the microbe immobilization sequence, significant attenuation in current production is observed, suggesting that at least part of the electron transfer to the electrode is DNA-mediated. This method of microbe assembly is rapid, reproducible, and facile for the production of anodes for biofuel cells.