Whilst some of first generation biofuels like corn and soy based ethanol are proving to be more trouble than their worth, scientists are working hard on second and third generation alternatives that should add to our energy mix without damaging our food supply. One new development is microbial fuel cells (MFCs) – bacteria that breaks down garbage and conducts electricity. Scientists think by digesting our waste these cells could replace up to 25% of the fuels we currently use.
In a microbial fuel cell, the bacteria acts on the anode of the circuit, breaking down waste with oxidation. As a byproduct they produce electrons. Normally a bacteria would transfer these electrons to a nearby oxygen molecule but if the fuel cell has no oxygen in it, the microbe must move these electrons elsewhere and an MFC uses this to drive an electrical current.
Researchers are beginning to make headway in creating self-contained microbial fuel cells. Biofilms are bacteria that create matrices of material to attach themselves to the anode. This mix of sugars, proteins and cells is thought to contain tiny conducting nanowires that help move the electrons into the electrical circuit, making the whole clump of bacteria act like a big living anode. If this works, people aren’t going to be leaving their litter on the streets any longer. It’ll be too valuable!