Sugar Fuel Cell

From Crumb Trail comes this very interesting story: bq. In the recent article by Chaudhuri and Lovley [2] the authors describe a fuel cell that uses glucose (a carbohydrate monomer) as the fuel and a microorganism as the catalyst. The microorganism, Rhodoferax ferrireducens, completely oxidizes glucose to carbon dioxide at neutral pH and transfers the electrons liberated from this reaction to the anode of a fuel cell with 83% efficiency in the absence of a molecule for shuttling electrons from the microorganism to the anode. Although other microbial fuel cells have been reported in the literature [3] (e.g. one of the earliest examples of electrical energy derived from either a microorganism or an isolated enzyme was demonstrated by Davis and Yarbrough in 1962 [4]), the article by Chaudhuri and Lovley is significant for three reasons. bq. First, the microbial fuel-cell oxidizes glucose to completion, liberating all 24 electrons stored in each molecule of glucose, compared with fuels that are being used or targeted for use in conventional fuel cells � hydrogen (2 electrons) or methanol (6 electrons). On a mass basis (i.e. joules per kilogram) the energy density of hydrogen is the highest of the three fuels but because it is a gas at 103 atmospheres of pressure the energy densities of fuels to be used in a fuel cell are more often compared on a volume basis (i.e. joules per liter). In this case, the energy density of glucose is the most energy-dense of the three fuels. Very cool - as the article says, there have been other examples of microbial fuel cells but none of them have had this level of efficiency. No word on commercial production - this is still very much a laboratory curiosity but if it scales, this could be very nice... The website for the two scientists can be found here and they have links to additional papers and press releases.