Fungi have the remarkable ability to transform both plant and animal byproducts into delectable foods like cheese, miso, and beer. A researcher suggests that a particular type of mold known as Neurospora intermedia might also be used to convert food waste into gourmet dishes. This process has primarily been embraced by Indonesians, who cultivate the mold on leftover soy pulp from tofu to produce a dish called oncom. A recent study indicates that this mold could be utilized to create innovative and flavorful foods from various types of food waste.
Vayu Hill-Maini, a chef turned chemist, is dedicated to the mission of converting food waste into delightful dishes through the use of fungi.
Among Hill-Maini’s collaborators is Rasmus Munk, the head chef and co-owner of the Michelin two-star restaurant Alchemist in Copenhagen. Munk has crafted a dessert that features an orange-hued Neurospora mold grown on rice, inspired by Hill-Maini’s work.
For the past two years, Hill-Maini has teamed up with chefs from Blue Hill at Stone Barns, another Michelin two-star restaurant located in Pocantico Hills, New York. Together, they have been experimenting with Neurospora mold cultivated from grains and legumes, including the pulp left from oat milk production. Soon, diners at Blue Hill may enjoy dishes like a grain patty topped with orange Neurospora, accompanied by a side of bread made with the same mold that, when fried, smells and tastes akin to a toasted cheese sandwich.
This is just the beginning for Hill-Maini, who is a Miller postdoctoral fellow at the University of California, Berkeley. In Jay Keasling’s chemical and biomolecular engineering lab at UC Berkeley, he is fully immersed in studying Neurospora intermedia, a widely used fungus in Indonesia for making oncom from soy pulp. His aim is to explore how this mold can be adapted to address food waste and culinary preferences in Western cuisine.
Hill-Maini notes, “Our food system is highly inefficient; around a third of all food produced in the U.S. is wasted. This isn’t limited to just eggshells in the trash; it’s on an industrial scale. What happens to the grains from brewing, the oats that are left from oat milk, and the soybeans unused for soy milk? They all end up being discarded.”
After a chef from Indonesia introduced him to fermented oncom, Hill-Maini realized it illustrated a perfect example of how waste can be fermented into human food. He expressed a desire to delve into this process and extract broader insights on tackling the problem of food waste.
Inspired by Hill-Maini’s insights on Neurospora, Blue Hill installed an incubator and tissue culture hood in its test kitchen this summer to enhance their exploration of fungal foods. Previously, chef Luzmore had been sending various substrates to Hill-Maini’s lab at the Joint BioEnergy Institute (JBEI) near UC Berkeley for experimentation. He has sampled many creations featuring Neurospora, with his favorite being one made from stale rice bread.
“It’s incredibly delicious. It resembles bread topped with grated cheddar cheese that has been toasted,” Luzmore remarked. “It provides a clear glimpse into the potential of these innovations.”
Many cultures worldwide have a long history of consuming foods that fungi transform – from grains fermented into alcohol by yeast to milk curds turned into blue cheese by Penicillium mold, and soy sauce made from soybeans utilizing koji mold (Aspergillus oryzae). However, oncom is distinctive as it is created specifically from food waste. Developed by native Javanese people ages ago, oncom is notably the only human food crafted solely through Neurospora mold, although that may soon change.
A forthcoming paper authored by Hill-Maini, which discusses the genetics of Neurospora intermedia strains used to process soy milk waste into oncom, as well as the fungi’s chemical transformations involved in converting 30 types of plant waste, is set to be published online on August 29 in the journal Nature Microbiology.
“In recent years, fungi and molds have garnered attention for their health benefits and environmental significance, yet there’s still so much we don’t know about the molecular processes these fungi employ to turn ingredients into food,” he explained. “Our findings unveil new possibilities and further highlight the role of fungi in promoting planetary health and sustainability.”
A nutritious snack in just 36 hours
In West Java, there are two kinds of oncom: red oncom, made by fermenting soy pulp leftover from tofu production, and black oncom, created from leftover pressed peanut oil. Both varieties are utilized in similar ways—whether in stir-fries, as fried snacks, or as dumpling fillings alongside rice.
One remarkable aspect of these mold-based creations that Hill-Maini discovered is how quickly the fungi convert indigestible plant material—specifically polysaccharides like pectin and cellulose from plant cell walls—into digestible, nutritious, and delightful food in approximately 36 hours.
“The fungus efficiently consumes these materials, resulting in both the creation of food and an increase in its own biomass, thus boosting the protein content,” he clarified. “There’s a notable change in nutritional value and flavor profile, as some off-flavors commonly associated with soybeans dissipate. Additionally, beneficial metabolites are produced in substantial quantities.”
Yeast, a single-celled fungus, is well-known for its transformative abilities, converting grains and fruits into alcohol. However, the fungus responsible for making oncom is distinct; it is a filamentous type of fungus that grows in filaments similar to mycorrhizae found in forest soil, which produces mushrooms. Unlike mushrooms, however, the oncom fungus does not produce them. Other filamentous fungi, such as the Penicillium mold that contributes to blue cheese and the koji mold involved in making soy sauce, miso, and sake, elevate ordinary foods to extraordinary levels.
Oncom stands out as one of the very few, if not the only, fungal foods grown a process relying on food-byproducts. In Hill-Maini’s new paper, he demonstrated that N. intermedia can thrive on 30 different forms of agricultural waste, ranging from sugar cane bagasse and tomato pomace to banana peels and almond hulls, all without generating any harmful toxins that can accumulate in some mushrooms and molds.
Further, he analyzed the genetics of the fungi involved in producing oncom, pinpointing that the fungus responsible for red oncom is predominantly N. intermedia—this was the primary fungus evident in all ten samples from West Java.
“It became clear that this fungus is likely central to making this food viable, thriving on cellulose-rich soy milk waste and completing the process within 36 hours,” Hill-Maini noted.
In contrast, the fungi found in black oncom were mostly from various Rhizopus species, depending on the location of production. This variety also harbored numerous bacteria. Another staple protein source in Javanese cuisine, tempeh, is likewise created using Rhizopus mold that ferments fresh soybeans.
Hill-Maini explored further into the genetics of the Neurospora in red oncom, comparing its genetic makeup with Neurospora intermedia strains not found in red oncom. He discovered a distinction between two types of the mold: one found in the wild, and another that has uniquely adapted to thrive on human-produced agricultural waste.
His conclusion is that as humans began to generate waste and by-products, a new niche was created for Neurospora intermedia.
According to Hill-Maini, this likely led to the creation of oncom. “We discovered that certain strains excel in breaking down cellulose. It seems there’s a fascinating journey from waste turning back into something valuable,” he noted.
But is it delicious?
Hill-Maini was curious if the domesticated Neurospora strain, which transforms cellulose from soy and peanut waste into a palatable food, could render other waste products delicious as well.
“As a chef, the primary question is: ‘Is it tasty?’ While we can cultivate this fungus on various materials, if it lacks sensory appeal or is viewed negatively outside of specific cultural settings, it might lead nowhere,” he stated.
In partnership with Munk from Alchemist, he introduced red oncom to 60 individuals unfamiliar with it and sought their feedback.
“We found that most of the participants, having never tried this dish before, attributed positive qualities to it — describing it as earthy, nutty, and mushroom-like,” Hill-Maini shared. “It consistently scored above six out of nine on taste tests.”
The chefs at Alchemist also cultivated Neurospora using peanuts, cashews, and pine nuts, all of which received favorable reviews, he added.
“Its taste isn’t as divisive or intense as blue cheese; it offers a milder, savory umami flavor,” Hill-Maini explained. However, diverse substrates lend distinctive notes, such as fruity flavors when cultivated on rice hulls or apple pomace.
This exploration inspired Munk to integrate a Neurospora dessert into Alchemist’s offerings: a layer of jellied plum wine topped with unsweetened rice custard inoculated with Neurospora, fermented for 60 hours, served chilled with a drizzle of lime syrup made from roasted leftover lime peels.
“We observed a dramatic transformation in the aromas and flavors throughout the process — introducing sweet, fruity scents,” Munk stated. “I was blown away by the discovery of flavors like banana and pickled fruit, purely from the fungi’s presence. Initially, we intended to create a savory dish, but the results led us to serve it as a dessert instead.”
This dessert was featured among other edible Neurospora fermentations discussed in a paper published last December in the International Journal of Gastronomy and Food Science, where Hill-Maini, Munk, and their colleagues detailed taste tests of oncom and similar foods grown on different substrates beyond soy.
“It’s incredible that as a restaurant, we can contribute this knowledge to the research community,” Munk emphasized. “Alchemist aims to change the world through gastronomy, and this project has extraordinary potential. I’m eager to explore what other culinary possibilities this research might reveal, especially using other waste materials from the food sector.”
Munk recently established a food innovation center called Spora, which initially concentrates on upcycling food industry side-streams and crafting diverse protein sources.
A culinary upbringing
Hill-Maini grew up in a cooking-centric household. His mother, of Indian heritage from Kenya, conducted cooking classes in their Stockholm, Sweden apartment during the 1990s, introducing Swedish locals to the rich spices and culinary techniques of India. His father comes from Cuban and Norwegian backgrounds.
“From a young age, I connected cooking with understanding my cultural roots and identity,” he recalled.
After finishing high school, he pursued his passion for cooking in New York City, taking on entry-level prep jobs across several restaurants until impressing one employer with his homemade sandwiches. At just 18, he was selected to redesign the menu for a well-known sandwich shop in Manhattan, with one of his creations being lauded as one of the city’s top veggie sandwiches by the New York Times.
Eventually, he returned to study while working as a chef for hire, growing interested in the science behind culinary chemical transformations. After earning his bachelor’s degree from Carleton College in Northfield, Minnesota, he joined the graduate program at Harvard University to study biochemistry, focusing on the gut microbiome for his Ph.D.
“I realized I wanted to return to the kitchen,” he said. “The Miller Fellowship presented an opportunity to blend my culinary training with my biochemistry and microbiology education. I aimed to explore how these disciplines could address the sustainability issues we face and tackle the wastefulness in our global food system.”
With fellowship support, he traveled to various restaurants, including Blue Hill, Alchemist, and the Basque Culinary Center in Spain, conducting fermentation workshops.
“This motivated me to revisit my research approach back in Berkeley,” Hill-Maini mentioned.
Over the past two years, Blue Hill has welcomed him five times, most recently in late June, to help launch the restaurant’s microbiology lab, where Luzmore hopes Hill-Maini and other chef-scientists will explore and experiment.
“We’ve thoroughly enjoyed collaborating with Vayu due to his embodiment of our vision,” Luzmore explained. Now, as the 20-year-old for-profit Blue Hill restaurant and the nonprofit Stone Hill Farm transition from advocating farm-to-table dining to emphasizing research, they aspire to become a center for innovation — essentially, a “sandbox” where people can engage in groundbreaking research like that of Vayu.
Besides contributing to Blue Hill’s endeavors, Hill-Maini will soon have his own space: a lab equipped with a kitchen at Stanford University, where he has been appointed as an assistant professor of bioengineering.
Taste test
While sautéing an oat milk waste burger he had crafted in his Berkeley apartment last June, Hill-Maini expressed his enthusiasm for the doors Neurospora could open, gratefully acknowledging the Javanese who historically repurposed the fungus for making oncom. He noted that Neurospora offers a different type of fermentation that complements the well-known koji mold, which chefs have increasingly used to transform numerous foods, making it somewhat tiresome, in his view.
“It’s an additional tool in a chef’s toolbox,” he affirmed.
He then plated the perfectly seared burger, indistinguishable from a beef patty, placed it on a cashew-avocado sauce, and accompanied it with roasted sweet potatoes and a fresh salad of cucumber and cherry tomatoes garnished with herbs and lemon. He sliced into the burger, dipped it into the sauce, and brought it to his mouth.
“Mmm, there you go — waste to food,” he noted. “It has a delightful texture, a savory essence, with hints of mushrooms and some intriguing fruity aromas.”
In future studies, he aims to understand how Neurospora generates these flavors and scents while also addressing food waste issues.
“The work I’m involved in — it represents a new approach to cooking, a fresh perspective on food that could lead to meaningful solutions for our world,” he concluded.
