Fungal Batteries Will Store Alternative Energy

Researchers from DTU Bioengineering and Aalborg University have joined the quest to find mould fungi that are particularly good at producing pigments—quinones—which can be used to store energy.

The researchers have designed a fungal battery prototype, and with a new donation of EUR 2 million from The Novo Nordisk Foundation, the researchers will speed up their search for suitable fungi.

Great Potential in Fungal Quinones

“There is great interest in developing new batteries to replace batteries using toxic metals such as lithium, copper and zinc. Fungal quinones offer a very promising alternative, and unlike similar substances extracted from oil, fungal quinones are 100 per cent degradable,” says Jens Christian Frisvad, Professor at DTU Bioengineering and co-applicant to the research project ‘Fungal Batteries for Storing Sustainable Energy’.

The idea of using fungi in batteries was developed by researchers at Aalborg University. To speed up their research, the researchers teamed up with DTU, enabling them to gain access to suitable fungi in DTU Bioengineering’s large fungal collection.

Jens Christian Frisvad explains that the researchers have identified two fungi that produce large quantities of quinones that can be used in either the positive or negative pole of a battery, where they can accumulate or discharge the energy. The quinones in question come from the two mould fungi Penicillium and Alternaria.

At DTU, undergraduate student Jonathan Eggertsen Rørth will investigate whether the mould fungus Penicillium can grow and produce quinones on sustainable and affordable growth media—such as apple peels—which can subsequently be composted or used as animal feed.

Researchers at DTU Bioengineering will also screen a large number of other mould fungi to find the most suitable ones. They are investigating whether the fungi produce toxins that could be difficult to get rid of at a later stage, and they sequence the fungi’s genomes in order to clarify which fungi can be used in industrial production. Finally, they examine how the quinones from the fungi can be purified.

“We focus on making the production of the batteries as green as possible. This applies to the batteries’ entire manufacturing process, but also to what we do with the batteries once they have outlived their use. We need to know whether the mould fungi's quinones are toxic, when they leach from the batteries and seep into the ground. The knowledge we have about fungal metabolites tells us that they will be broken down by bacteria in the soil, but these environmental effects must also be described in the project,” says Jens Christian Frisvad.

Meanwhile, researchers from Aalborg University examine what it takes to connect the fungal batteries to the existing electricity grid, and to develop batteries that can be connected to wind turbine and solar cell installations,” explains Jens Muff, Associate Professor at Aalborg University.

“Fungal batteries are of a type called redox flow batteries, which have particularly favourable properties when it comes to storing large amounts of energy. Furthermore, they are cheap to produce and easy to get rid of in a sustainable way. However, they will be bigger than ordinary batteries, since fungal quinones are not as energy-dense and therefore not as suitable for mobile technologies, where the size of the battery is crucial,” says Jens Muff.

The researchers from DTU and Aalborg University have three years to develop a demonstration model of a sustainable battery, to find a cheap way to produce mould fungi and to extract the quinones the batteries will be composed of. In addition, their research will describe how the batteries can be connected to the existing electricity grid.

Unique Fungal Collection

DTU Bioengineering's fungal collection contains approximately 40,000 fungi, which have been chemically characterized and which represent many species used in biotechnology, but also those that destroy foodstuffs and those found in indoor environments or in soil and marine environments. Many species are represented by several hundred isolates, which means that the variation within these species are known, and consequently the best strain for a specific biotechnological purpose can be selected.