Advancing Protein Recovery from Fungal Fermentation

Advancing Protein Recovery from Fungal Fermentation

With a growing population and limited land resources, InnoProtein and partners like Tecnalia are exploring innovative ways to supplement the global protein supply1. One promising approach is fungal solid-state fermentation (SSF), where fungi grow on solid substrates instead of the traditional, free-liquid culture. 

SSF can transform common cereals, legumes, and agricultural byproducts into protein-rich organic material, offering a way to produce high-quality protein, all while using less water and potentially reducing food waste23. However, protein produced through fungal SSF cannot be consumed directly by humans or animals. It must first be separated, refined, and prepared for use in food and feed applications.

The methods used to extract protein from SSF biomass are critical, as they influence how much protein is recovered and its functional properties, such as solubility, emulsification, and foaming ability456. Optimizing these processes is therefore essential to ensure that fungal proteins can be integrated into a variety of products and further support sustainable protein production at scale. 

By improving both how protein is produced and how it is extracted, the InnoProtein project aims to make these alternative protein sources more practical and efficient for wider usage.


From Biomass to Usable Protein 

Tecnalia employed a variety of methods for extracting protein while preserving biomass protein integrity before isolating the final protein powder. Some of these methods include: 

  • Three-phase partitioning (TPP)
  • Ultrasound-assisted extraction (US)
  • Accelerated solvent extraction (ASE)
  • Ultraturrax-assisted extraction (UT)
  • Natural deep eutectic solvents (NADES)

Among these methods, US and UT technologies significantly increased protein recovery yield in comparison to other extraction methods. After extraction, proteins must be separated and concentrated into a usable form, typically a protein-rich powder usable within a variety of food applications. This is referred to as downstream processing. It involves processing the liquid extract so proteins can naturally separate and be collected. In some cases, enzymes are used to break proteins into smaller components, improving their nutritional and functional properties. 

The researchers found that the best conditions for collecting proteins from A. oryzae (fungi) occurred at around pH 6, where the proteins separated most effectively from the liquid.


Looking Ahead: From Process to Application

Improving how protein is extracted and processed from fungal biomass is key to making these alternative proteins usable at scale. Efficient extraction increases how much protein can be recovered, while processing steps can enhance its nutritional quality and functionality in food systems.

For the InnoProtein project, this means turning protein-rich biomass into practical, high-quality ingredients that can be used in real applications. With continued refinement, these proteins could be incorporated into food products and animal feed, helping to reduce waste, lower production costs, and support a more sustainable and resilient global protein supply.

References

  1. Smith, K., Watson, A. W., Lonnie, M., Peeters, W. M., Oonincx, D., Tsoutsoura, N., Simon-Miquel, G., Szepe, K., Cochetel, N., Pearson, A. G., Witard, O. C., Salter, A. M., Bennett, M., & Corfe, B. M. (2024). Meeting the global protein supply requirements of a growing and ageing population. European Journal of Nutrition, 63, 1425–1433. ↩︎
  2. Chilakamarry, C. R., Mimi Sakinah, A. M., Zularisam, A. W., Sirohi, R., Khilji, I. A., Ahmad, N., & Pandey, A. (2022). Advances in solid-state fermentation for bioconversion of agricultural wastes to value-added products: Opportunities and challenges. Bioresource technology, 343, 126065. https://doi.org/10.1016/j.biortech.2021.126065 ↩︎
  3. Zwinkels, J., Wolkers‑Rooijackers, J., & Smid, E. J. (2023). Solid‑state fungal fermentation transforms low‑quality plant‑based foods into products with improved protein quality. LWT – Food Science and Technology, 184, 114979. https://doi.org/10.1016/j.lwt.2023.114979 ↩︎
  4. K. F. Chai and W. N. Chen, “Recovery of antioxidative protein hydrolysates with functional properties from fermented brewer’s spent grain via microwave-assisted three phase partitioning,” Dec. 2023, doi: 10.1016/j.ifset.2023.103551. ↩︎
  5. Zhang, Y., Wei, S., Xiong, Q., Meng, L., Li, Y., Ge, Y., Guo, M., & Luo, H. (2024). Ultrasonic-Assisted Extraction of Dictyophora rubrovolvata Volva Proteins: Process Optimization, Structural Characterization, Intermolecular Forces, and Functional Properties. Foods, 13. https://doi.org/10.3390/foods13081265 ↩︎
  6. Rusbjerg-Weberskov, C.E., Foley, J.D., Yang, L. et al. Combined Rhizopus oryzae Fermentation and Protein Extraction of Brewer’s Spent Grain Improves Protein Functionality. Food Bioprocess Technol 18, 9574–9593 (2025). https://doi.org/10.1007/s11947-025-03989-1 ↩︎