Damaged Tomatoes and Bread Mold: The Future of Energy?
Rotten food and fungus could one day power batteries and fuel cells
Researchers are looking high and low to find new sources of renewable energy. Two of the latest ideas: damaged tomatoes and bread mold.
Damaged tomato fuel cells
Florida farms produce tons and tons (literally) of less-than-perfect tomatoes that never make it to grocery stores and get thrown out. Now a group of scientists has developed a juicy idea for putting them to use — not in the kitchen but in biological-based fuel cells.
“We wanted to find a way to treat this waste that, when dumped in landfills, can produce methane — a powerful greenhouse gas — and when dumped in water bodies, can create major water treatment problems,” said Venkataramana Gadhamshetty, PhD, of the South Dakota School of Mines & Technology, in a press release from the American Chemical Society.
The team developed a microbial electrochemical cell that uses tomato waste to generate electric current.
“Microbial electrochemical cells use bacteria to break down and oxidize organic material in defective tomatoes,” said Namita Shrestha, a graduate student in Gadhamshetty’s lab.
The oxidation process, triggered by the bacteria interacting with tomato waste, releases electrons that are captured in the fuel cell and become a source of electricity. It turns out the lycopene in tomatoes — the pigment that makes them red — spurs the generation of electrical charges, according to the researchers.
According to calculations by Shrestha, in theory Florida generates enough tomato waste each year to meet Disney World’s electricity demand for 90 days using an optimized biological fuel cell (not yet developed).
Bread mold batteries
Bread mold gave us penicillin. Could it one day help power the world?
The red bread mold (Neurospora crassa) could in theory be used to power energy storage devices, particularly rechargeable lithium-ion batteries and supercapacitors, according to a group of researchers from the United Kingdom and China. How?
Living organisms, include fungi, produce minerals in a process known as biomineralization. The researchers found a way to get the mold to produce manganese carbonate. After “burning” the results (recipe: cook for 4 hours at 300 degrees C, or 572 degrees F), the biomass was turned into carbon, and the manganese carbonate decomposed to manganese oxide (MnO x). The scientists discovered this mixture of carbonized biomass and MnO x makes a nifty electrode material for a battery.
“This is the first demonstration of the synthesis of electrode materials using a fungal biomineralization process, thus providing a novel strategy for the preparation of sustainable electrochemical materials,” wrote the authors.
It could potentially power supercapacitors, too.
“The electrochemical properties of the carbonized fungal biomass-mineral composite were tested in a supercapacitor and a lithium-ion battery and it was found to have excellent electrochemical properties. So we prepared batteries and supercapacitors using this material and it worked!” researcher Geoffrey Gadd of the of the University of Dundee in Scotland, told SafeBee.
“The performance in some areas was better than some other materials that have been tested and the batteries could be charged-discharged 200 times without much loss of stability,” said Gadd.
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