The idea of turning waste (or biomass) into electrical power is one which has a lot of research behind it. For years, it's been known that microbes can generate electricity by consuming sources, such as underwater sediments and mud. NASA has believed that such microbes could be used to recycle waste on long space flights.

Findings from a team at Belgium's Ghent University created fuel cells containing such microbes. Over a 200 day trial, they supplied the cells with waste materials, including hospital and potato processing factory wastes. By the end of the study, the short-term power densities (power produced per unit mass) tripled, and they found that connecting the cells in parallel created consistently stronger currents.

One of the most intriguing aspects, however, is that the cells, which initially consisted of a diverse mix of microbes, went through a form of communal evolution, with the Brevibacillus agri microbe becoming the majority when performance reached its maximum.

The detailed findings are reported in a paper in the May 15 issue of the Environmental Sciencce & Technology journal.