Bugs make electricity from waste
doi:10.1038/nindia.2013.100 Published online 25 July 2013
Researchers have used Staphylococcus aureus, a disease-causing bacterium, as an electrocatalyst to generate electricity by degrading cellulose biomass. They isolated the bacterium from the rumen fluid of goat. This bacterium is promising to develop microbial fuel cells which can clean up waste by degrading cellulose.
Animals like cattle and goat can digest tough cellulose-containing food using microorganisms present in their rumen fluid. Cellulose is an abundant biomass making it an important resource as a biofuel. Previous studies had shown that bacteria-aided degradation of cellulose could generate electricity. However, no studies had revealed that bacteria could work as catalyst by transferring electrons from cellulose to electrode during electricity generation.
To pin down the catalytic role of bacteria in cellulose waste-based electricity generation, the researchers isolated S. aureus from the rumen fluid of goat. They cultured this bacterium and formed a biofilm which was deposited on a carbon felt electrode dipped in phosphate buffer solution.
Addition of layers of cellulose to the electrode increased current. Cellulose acts as electron donor and carbon felt electrode works as electron acceptor. During oxidation of cellulose, the bacteria transfer electrons from cellulose to the electrode generating current.
"The findings of this research provide the scope of electricity generation by degrading waste cellulose," says Sheela Berchmans, a co-author of the study.
- Alagappan, B. A. et al. Metamorphosis of pathogen to electrigen at the electrode/electrolyte interface: Direct electron transfer of Staphylococcus aureus leading to superior electrocatalytic activity. Electrochem. Comm.34, 25-28 (2013) | Article |