Nav: Home

Anammox bacteria generate energy from wastewater while taking a breath

June 29, 2020

A type of anaerobic bacteria responsible for more than 50 percent of nitrogen loss from marine environments has been shown to use solid-state matter present outside their cells for respiration. The finding by KAUST researchers adds to knowledge of the global nitrogen cycle and has important energy-saving potential for wastewater treatment.

Living organisms use oxidation/reduction reactions to harvest the energy they need for survival. This involves the transfer of electrons from an electron donor to an electron acceptor with energy generation. In humans, electrons are released from the food we digest and accepted by soluble oxygen inside our cells. But in many bacteria, other strategies are used for oxidation/reduction, with different types of electron donors and acceptors.

Anammox are anaerobic bacteria found in oxygen-lacking marine and freshwater environments, such as sediments. They derive energy by using ammonium as their electron donor and intracellular soluble nitrite as the acceptor, with the release of nitrogen gas--or so scientists thought.

"We found that freshwater and marine anammox bacteria can also transfer electrons from ammonium to extracellular electron acceptors, like graphene oxide or electrodes in microbial electrolysis cells," says Ph.D. student, Dario Shaw. This novel extracellular electron transfer by anammox bacteria had been conjectured by scientists for more than a decade, but had not been properly explored.

Environmental biotechnologist Pascal Saikaly led a team that found, by looking into the anammox genome, that these bacteria had iron-containing proteins called cytochromes that are also present in types of bacteria known for their ability to transport electrons outside their cells. "We wanted to know if anammox bacteria could also perform extracellular electron transfer," says Saikaly.

They found that electrons were transferred from ammonium inside the bacteria to solid-state matter outside the cell. For this to happen, the electrons crossed three different barriers, starting from inside an anammox cellular organelle called the anammoxosome. "This means that we have demonstrated for the first time a type of bacteria that can transfer electrons through three different membranes," says Saikaly. "This finding challenges our perceptions of cell biology."

"Our findings are a breakthrough in the fields of microbial ecology, bioelectrochemistry and sustainable wastewater treatment," adds Shaw. Anammox bacteria are already used to make wastewater reusable by removing ammonium. They save energy compared to the conventional use of aerobic bacteria, which require oxygen as the electron acceptor for ammonium oxidation. Providing oxygen through an aeration system requires a lot of energy. Anammox bacteria used for wastewater treatment do not need oxygen, but they do currently need nitrite as the electron acceptor. This is provided by another type of bacteria that needs oxygen, and thus energy, to produce it.

The new finding suggests that anammox alone could be used for ammonium removal, while also producing energy in the form of an electric current or energy-rich hydrogen gas in microbial electrolysis cells.
-end-


King Abdullah University of Science & Technology (KAUST)

Related Bacteria Articles:

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.
Bacteria uses viral weapon against other bacteria
Bacterial cells use both a virus -- traditionally thought to be an enemy -- and a prehistoric viral protein to kill other bacteria that competes with it for food according to an international team of researchers who believe this has potential implications for future infectious disease treatment.
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

Listen Again: Meditations on Loneliness
Original broadcast date: April 24, 2020. We're a social species now living in isolation. But loneliness was a problem well before this era of social distancing. This hour, TED speakers explore how we can live and make peace with loneliness. Guests on the show include author and illustrator Jonny Sun, psychologist Susan Pinker, architect Grace Kim, and writer Suleika Jaouad.
Now Playing: Science for the People

#565 The Great Wide Indoors
We're all spending a bit more time indoors this summer than we probably figured. But did you ever stop to think about why the places we live and work as designed the way they are? And how they could be designed better? We're talking with Emily Anthes about her new book "The Great Indoors: The Surprising Science of how Buildings Shape our Behavior, Health and Happiness".
Now Playing: Radiolab

The Third. A TED Talk.
Jad gives a TED talk about his life as a journalist and how Radiolab has evolved over the years. Here's how TED described it:How do you end a story? Host of Radiolab Jad Abumrad tells how his search for an answer led him home to the mountains of Tennessee, where he met an unexpected teacher: Dolly Parton.Jad Nicholas Abumrad is a Lebanese-American radio host, composer and producer. He is the founder of the syndicated public radio program Radiolab, which is broadcast on over 600 radio stations nationwide and is downloaded more than 120 million times a year as a podcast. He also created More Perfect, a podcast that tells the stories behind the Supreme Court's most famous decisions. And most recently, Dolly Parton's America, a nine-episode podcast exploring the life and times of the iconic country music star. Abumrad has received three Peabody Awards and was named a MacArthur Fellow in 2011.