Can Oyster Mushroom Mycelium Become a High-Protein Food?

Mycoprotein is food made from protein-rich fungal biomass. Instead of waiting for a fungus to produce caps and stems, a manufacturer grows the vegetative mycelium and uses that material as the ingredient.

This is not the same as plant protein with mushroom flavoring, and it is not automatically identical to the nutrition of an oyster-mushroom fruiting body. The species, strain, growth medium, harvesting method, and processing steps all affect the final biomass.

The idea is already established in food technology with other fungi. The Cornell work asked whether Pleurotus ostreatus—the familiar oyster mushroom—could be cultivated efficiently in submerged fermentation while producing uniform pellets and substantial protein.

The team isolated tissue from a store-bought oyster mushroom, cultured it, and confirmed the species through genome sequencing. Seed cultures were grown in liquid medium, fragmented into inoculum, and transferred to shaken laboratory flasks.

The researchers varied several factors separately: the size and amount of the starting inoculum, agitation speed, carbon source, carbon loading, nitrogen availability, and phosphorus availability. They measured dry biomass, protein, substrate use, and the size and shape of the resulting mycelial pellets.

That design was aimed at process optimization, not at producing a finished consumer food. The experiments identified how culture conditions affected fungal growth and protein measurements under controlled conditions.

In a moving liquid, filamentous fungi can grow as loose tangles, clumps, or compact spheres. Those forms change how oxygen and nutrients reach the cells and how easily the biomass can be mixed, pumped, separated, and processed.

Controlled fragmentation of the starting mycelium, inoculum density, and agitation helped the researchers produce more uniform pellets. Too much shear can damage growth; too little mixing can allow large irregular clumps or poor oxygen transfer.

The study’s maximum biomass concentration was 12.9 grams of dry mycelium per liter, with a reported productivity of 1.61 grams per liter per day under the combined optimized conditions.

Protein content rose as the researchers increased nitrogen availability and lowered the carbon-to-nitrogen ratio. The highest reported value was 39.7 percent of dry biomass, accompanied by 3.89 grams of protein per liter of culture.

“Dry biomass” is an important qualifier. Freshly filtered mycelium in the study contained roughly 90 to 96 percent moisture before drying. A 39.7-percent dry-weight protein value is therefore not the same as saying that a spoonful of wet culture is 39.7 percent protein.

The researchers estimated intracellular protein with a Bradford colorimetric assay after breaking open freeze-dried cells. The experiment did not, by itself, provide a complete consumer nutrition label, protein-digestibility score, amino-acid analysis of every treatment, sensory trial, shelf-life study, or safety assessment for a finished product.

Most fungal fermentation uses a sugar such as glucose for carbon. This study compared glucose, fructose, lactose, xylose, lauric acid, and oleic acid. Oleic acid supported oyster-mycelium biomass yields comparable to glucose and outperformed the other tested sugars under the reported conditions.

At the carbon-loading comparison’s highest tested level, glucose produced 31.1 percent protein in dry biomass, while oleic acid produced 22 percent. The study’s headline 39.7-percent result came from a separate nitrogen-ratio optimization, so it should not be described as protein grown from waste oil.

The oleic acid was an analytical-grade reagent purchased from a laboratory supplier. The researchers did not use collected restaurant oil, characterize fryer contaminants, or demonstrate a food-safe treatment process for used cooking oil.

Oleic acid is abundant in olive oil and many other plant oils, so the result suggests that lipid-rich food-industry side streams might eventually supply fungal fermentation. Using a residue instead of refined sugar could reduce feedstock cost and avoid competing directly with food crops.

Actual waste cooking oil is variable. It can contain water, food particles, cleaning residues, oxidation products, polymers formed during heating, and mixtures of fatty acids. A food process would need specifications, pretreatment, contaminant testing, traceability, and regulatory approval.

A practical system would also need to show that purification and fermentation do not use more energy, chemicals, or money than the recovered protein is worth. The present study establishes biological feasibility for one purified fatty acid, not the environmental performance of a waste-oil supply chain.

• Repeat the process in larger, instrumented fermenters where mixing, heat removal, oxygen transfer, and contamination behave differently.
• Characterize amino acids, digestibility, fiber, nucleic acids, allergens, flavor compounds, and any antinutritional or unwanted metabolites.
• Develop food-grade harvesting, washing, heat treatment, drying, texture formation, packaging, and shelf-life controls.
• Establish safe specifications for any waste-derived feedstock and prove that contaminants do not enter the biomass.
• Compare energy use, water use, emissions, cost, and protein yield against existing mycoprotein, plant protein, mushrooms, and animal products.
• Complete the regulatory and consumer-safety work required for the intended market and product form.

Cornell reported plans for pilot-scale work, including a move from bench flasks toward a 100-liter reactor. That scale-up step is where many promising fermentation results encounter new mixing, consistency, and cost problems.

No. Fruiting-body cultivation and liquid mycelium fermentation produce different foods, require different equipment, and serve different markets. A farm can grow recognizable mushrooms on straw, sawdust, or logs without operating sterile tanks and downstream processing equipment.

Submerged fermentation may eventually produce a consistent protein ingredient quickly and with a compact footprint. Conventional cultivation produces the texture, appearance, culinary behavior, and direct farm-to-customer identity of fresh oyster mushrooms.

The two methods are better understood as complementary uses of the same fungal species rather than competing versions of one product.

Yes: oyster-mushroom mycelium can be grown in liquid culture as protein-rich biomass. This study reached 39.7 percent protein on a dry-weight basis and clarified several conditions needed for productive, uniform growth.

Yes, with an important limitation: purified oleic acid supported strong growth as a sole carbon source. The experiment did not demonstrate food production from collected waste cooking oil.

The research provides a credible foundation for pilot-scale food technology. Whether the process becomes affordable, nutritionally complete, safe, appealing, and environmentally preferable will depend on the next stage of engineering and product testing.

The primary paper was first published by Sustainable Food Technology on March 18, 2026. Its authors were affiliated with Cornell AgriTech’s Department of Food Science. The work received a seed grant from the USDA Multistate S1075 program, and the authors declared no conflicts of interest.

• Sustainable Food Technology (2026): Oyster-mushroom mycelium fermentation study
• Cornell AgriTech: Research summary and planned pilot-scale work
• Journal of Food Science (2025): Review of mushroom mycelia as alternative proteins