Scientists Say This Fungus Makes Food Waste Edible

There’s a fungus among us—and it’s tasty, according to scientists at the University of California—Berkeley. In a new study published on August 29, 2024 in Nature Microbiology, researchers go into detail about how this novel fungus can turn food waste into delectable desserts and main courses.

Of course, eating fungus isn’t new. Mushrooms are a type of nutritious fungus. And fungi have been used for centuries to ferment foods and turn them into other food products—like how milk is turned into cheese and yogurt or how grain transforms water into alcohol. 

But this latest concept turns food waste into edible creations—which would cut down on the amount of food ending up in our landfills. And even this concept isn’t totally new. It’s been happening in Indonesia for a long time. Natives from the Java region in Indonesia take the leftover soy pulp from making tofu and create red oncom, made from mold that grows on the soy pulp. They also take the leftover waste from pressing peanuts to make peanut oil and make black oncom. Both types of oncom are used in stir-fries, as fried snacks and with rice as a dumpling filling.

The lead researcher of this study, Vayu Hill-Maini (formerly Vayu Maini Rekdal) became intrigued by this concept because he’s not only a scientist—a postdoctoral fellow at UC Berkeley—but he’s also a chef. So he’s found a way to combine his love of food with his love of sustainability. 

“Our food system is very inefficient,” says Hill-Maini in a press release about the study. “A third or so of all food that’s produced in the U.S. alone is wasted, and it isn’t just eggshells in your trash. It’s on an industrial scale. What happens to all the grain that was involved in the brewing process, all the oats that didn’t make it into the oat milk, the soybeans that didn’t make it into the soy milk? It’s thrown out.”

How Was This Study Conducted & What Does It Suggest?

Hill-Maini and his team of researchers took 10 samples of red oncom from Java and analyzed the genetics of the fungus responsible for making red oncom. They determined that Neurospora intermedia was the main fungus in all 10 samples. 

How it works is that the Neurospora fungus takes certain types of fiber, including cellulose and pectin, and makes them digestible. It’s important to understand that fiber is the part of the plant that doesn’t get digested in humans. Instead, it goes into your gut, bulks up your poop, and moves it through your digestive tract and out of your body. 

“The [Neurospora] fungus readily eats those [types of fiber] and in doing so makes this food, and also more of itself, which increases the protein content,” says Hill-Maini. “So you actually have a transformation in the nutritional value.”

Nutritive value isn’t the only thing that this fungus changes. It also changes the taste. “Some of the off-flavors that are associated with soybeans disappear,” says Hill-Maini.

And you don’t have to wait long for the transformation. The process of turning food waste into edible creations takes place fairly quickly—about 36 hours. 

Hill-Maini and his team also analyzed black oncom and found that a different fungus is responsible for that food transformation. Various species of the fungus Rhizopus were found in the black oncom. This is the same fungus responsible for making tempeh, which is made from fermenting fresh soybeans.

Hill-Maini and his team dove deeper into the genetics of the Neurospora fungus to compare the genes of Neurospora found on red oncom and those of the Neurospora strains that are not found on oncom. They discovered that there are wild strains and domesticated strains of the Neurospora fungus. And the domesticated strains are better at breaking down the cellulose fiber. 

The researchers took the domesticated strain of Neurospora and applied it to 30 different kinds of plant waste, including sugar cane bagasse, tomato pomace, almond hulls and banana peels. The filamentous fungus grew and covered the plant waste—and without any toxins that can come from some fungi, like certain types of mushrooms and molds.

While the Neurospora fungus shows promise in reducing food waste, its success also depends on taste. After all, if people won’t eat it, it will still be thrown out.

“The most important thing, especially for me as a chef, is, ‘Is it tasty?’” says Hill-Maini. “Sure, we can grow it on all these different things, but if it doesn’t have sensory appeal, if people don’t perceive it positively outside of a very specific cultural context, then it might be a dead end.”

So Hill-Maini teamed up with Rasmus Munk, head chef and co-owner of the Copenhagen restaurant, Alchemist. They presented red oncom to 60 people who had never tried it before to get their opinions. According to Hill-Maini, the feedback was mostly positive with taste testers consistently rating the taste above 6 out of 9 possible points. They described the taste as earthy, nutty and mushroomy. 

In addition, the chefs at Alchemist grew Neurospora on peanuts, cashews and pine nuts, all of which also had favorable reviews. Hill-Maini and Munk state that while the underlying taste of Neurospora is a mild savory umaminess, different food waste can produce various underlying tones, including sweet, fruity aromas.

Hill-Maini and Munk plan on continuing down this path of turning parts of food that would normally be thrown out into tasty culinary creations. “The science that I do—it’s a new way of cooking, a new way of looking at food that hopefully makes it into solutions that could be relevant for the world,” says Hill-Maini. 

The Bottom Line

Though scientists and chefs like Hill-Maini and Munk are producing food with Neurospora, this isn’t some science experiment the rest of us should do in our own kitchens. While many molds and other fungi are edible, many others are toxic, so it’s best to leave the edible experimenting to the biochemists. Speaking of which, if you happen to be in Pocantico, New York, stop by the Blue Hill at Stone Barns restaurant. You may be one of the first to taste one of Hill-Maini’s creations—orange Neurospora grown on rice bread. It’s been said that when it’s fried, it tastes like a grilled cheese sandwich.