Nav: Home

Conducting shell for bacteria

June 27, 2017

Under anaerobic conditions, certain bacteria can produce electricity. This behavior can be exploited in microbial fuel cells, with a special focus on wastewater treatment schemes. A weak point is the dissatisfactory power density of the microbial cells. An unconventional solution is now presented by Singaporean and Chinese scientists: as reported in the journal Angewandte Chemie, they coated live, electroactive bacteria with a conducting polymer and obtained a high-performance anode for microbial fuel cells.

The history of microbial fuel cells goes back to the beginning of the 20th century when scientists connected bacteria cells with electrodes to generate electricity. The principle is that, if no oxygen is present, the bacteria's metabolism changes to produce protons and electrons instead of carbon dioxide and water. These electrons can be used for current generation in an electrochemical cell. Such microbial fuel cells are currently heavily investigated for sustainable energy production and, especially, wastewater treatment. Their weak point is the power density. Much of the electrochemical potential of the bacteria is wasted because they do not transmit their produced electrons easily to the electrode. To make them more conductive, Qichun Zhang from Nanyang Technological University, Singapore, and his colleagues explored the idea of wrapping bacteria in a shell of electron-conducting polymers. The challenge with this is that the coated bacteria must still be viable.

The scientists relied on the polymer polypyrrole. "The modification of bacterial cells with polypyrrole is anticipated to improve the electrical conductivity of bacterial cells without reducing their viability," the authors explained. Iron ions were employed as "the oxidative initiator to make pyrrole monomers polymerized on the [bacterium's] surface." The organism of choice was the proteobacterium Shewanella oneidensis, which is known for its metal toleration and both aerobic and anaerobic lifestyles. Still living and active, the coated bacteria were tested for biocurrent generation with a carbon anode. Compared to their unmodified counterparts, they indeed displayed a 23 times smaller resistance (which means, enhanced conductivity), a fivefold increase in electricity generation, and a 14 times higher maximum power density of the anode in a microbial fuel cell. And if the bacteria were fed with lactate, the authors observed a pronounced current, which did not happen when uncoated bacteria were used.

Zhang's approach is a remarkable solution to the conductivity problem of a microbial anode. The authors believe that this coating scheme of live bacteria may add a new dimension to the exploration of microbial fuel cells, as well as general research on cell-surface functionalization.
About the Author

Qichun Zhang is Associate Professor at Nanyang Technological University, Singapore and leads the Exotic Materials and Applications group. His research interests range from organic semiconductors to OLEDs and bio-imaging.


Related Bacteria Articles:

Siblings can also differ from one another in bacteria
A research team from the University of Tübingen and the German Center for Infection Research (DZIF) is investigating how pathogens influence the immune response of their host with genetic variation.
How bacteria fertilize soya
Soya and clover have their very own fertiliser factories in their roots, where bacteria manufacture ammonium, which is crucial for plant growth.
Bacteria might help other bacteria to tolerate antibiotics better
A new paper by the Dynamical Systems Biology lab at UPF shows that the response by bacteria to antibiotics may depend on other species of bacteria they live with, in such a way that some bacteria may make others more tolerant to antibiotics.
Two-faced bacteria
The gut microbiome, which is a collection of numerous beneficial bacteria species, is key to our overall well-being and good health.
Microcensus in bacteria
Bacillus subtilis can determine proportions of different groups within a mixed population.
Right beneath the skin we all have the same bacteria
In the dermis skin layer, the same bacteria are found across age and gender.
Bacteria must be 'stressed out' to divide
Bacterial cell division is controlled by both enzymatic activity and mechanical forces, which work together to control its timing and location, a new study from EPFL finds.
How bees live with bacteria
More than 90 percent of all bee species are not organized in colonies, but fight their way through life alone.
The bacteria building your baby
Australian researchers have laid to rest a longstanding controversy: is the womb sterile?
Hopping bacteria
Scientists have long known that key models of bacterial movement in real-world conditions are flawed.
More Bacteria News and Bacteria Current Events

Trending Science News

Current Coronavirus (COVID-19) News

Top Science Podcasts

We have hand picked the top science podcasts of 2020.
Now Playing: TED Radio Hour

Warped Reality
False information on the internet makes it harder and harder to know what's true, and the consequences have been devastating. This hour, TED speakers explore ideas around technology and deception. Guests include law professor Danielle Citron, journalist Andrew Marantz, and computer scientist Joy Buolamwini.
Now Playing: Science for the People

#576 Science Communication in Creative Places
When you think of science communication, you might think of TED talks or museum talks or video talks, or... people giving lectures. It's a lot of people talking. But there's more to sci comm than that. This week host Bethany Brookshire talks to three people who have looked at science communication in places you might not expect it. We'll speak with Mauna Dasari, a graduate student at Notre Dame, about making mammals into a March Madness match. We'll talk with Sarah Garner, director of the Pathologists Assistant Program at Tulane University School of Medicine, who takes pathology instruction out of...
Now Playing: Radiolab

What If?
There's plenty of speculation about what Donald Trump might do in the wake of the election. Would he dispute the results if he loses? Would he simply refuse to leave office, or even try to use the military to maintain control? Last summer, Rosa Brooks got together a team of experts and political operatives from both sides of the aisle to ask a slightly different question. Rather than arguing about whether he'd do those things, they dug into what exactly would happen if he did. Part war game part choose your own adventure, Rosa's Transition Integrity Project doesn't give us any predictions, and it isn't a referendum on Trump. Instead, it's a deeply illuminating stress test on our laws, our institutions, and on the commitment to democracy written into the constitution. This episode was reported by Bethel Habte, with help from Tracie Hunte, and produced by Bethel Habte. Jeremy Bloom provided original music. Support Radiolab by becoming a member today at     You can read The Transition Integrity Project's report here.