Bacteria 'to convert waste into power'

Bacteria by hearing this word first of all we will be afraid that we may get some disease, but most of people don’t know that fermented foods like yogurt, beer and so on need bacteria to get prepared.

From recent researches we get to know that bacteria not only used in preparing some food item now it can also be used in generating electricity.

A team, led by Prof Derek Lovley from the University of Massachusetts, isolated bacteria with large numbers of tiny projections, called pili, they were isolated from a strain of Geobacter sulfurreducens which they called KN400 that grew prolifically on the graphite anodes of fuel cells.

This isolated bacterium is efficient at transferring electrons to generate power in fuel cell than the bacteria with a smooth surface (which don’t have pili).

Scientists have claimed these bacteria which generate significant amounts of electricity can be used in microbial fuel cells to convert waste into power as well as provide electricity in remote environments.

This bacterium forms a thick biofilm on the anode surface, which conducted electricity. Scientists found large quantities of pilin, a protein that makes the tiny fibers (Bacterial pili are used in the exchange of genetic material during bacterial conjugation) that conduct electricity through the sticky biofilm.

Prof Lovley also mentioned that "The filaments form microscopic projections called pili that act as microbial nanowires using this bacterial strain in a fuel cell to generate electricity would greatly increase the cell's power output,"

The pili on the bacteria's surface seemed to be primarily for electrical conduction rather than to help them to attach to the anode; mutant forms without pili were still able to stay attached.

Microbial fuel cells can be used in monitoring devices in environments where it is difficult to replace batteries if they fail but to be successful they need to have an efficient and long-lasting source of power.

The scientists have also described in their experiment how G. sulfurreducens strain KN400 might be used in sensors placed on the ocean floor to monitor migration of turtles.
These findings were reported at the Society for General Microbiology's meeting at Heriot-Watt University, Edinburgh, on Monday.