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“The bacteria are capable of continuously generating electricity at levels that could be used to operate small electronic devices. As long as the bacteria are fed fuel they are able to produce electricity 24 hours a day [...] These bacteria are very diverse in their metabolic capabilities, including the food that they can consume. That means that these bacteria can convert a large number of different food sources into electricity,” says Milliken. “The technology could be used to assist in the reclamation of wastewaters, thereby resulting in the removal of waste and generation of electricity.”

The summary of the presentation at the ASM meeting goes into a bit more detail:

Strain DCB2 was tested for direct electrode reduction in a two-chamber fuel cell equipped with graphite electrodes. Electricity generation was dependent upon growth of the bacterium on the surface of the anode and was sustained after repeated exchange of the medium in the anode chamber without the addition of an exogenous electron carrier. Yeast extract, ethanol or formate served as a fuel source with power densities exceeding 20 mW per m2 of the anode surface. Recovery of electrons was 95% with formate used as fuel.

In addition, as the bacteria are spore-forming, under adverse environmental conditions, rather than simply dying, they can go dormant.

This is not an early indicator of a scenario of all of the world's power coming from the bubbling microbial froth. Rather, it's another indicator that we should stop thinking of electricity generation being separate and distinct from other activities. The bright green future will include power production as an inherent aspect of much of our material life; clearly, this will include wastewater cleanup and environmental remediation.