Using genetic modification, researchers have elevated the production of heme and ergothioneine in koji – a type of filamentous fungus – enabling it to be formulated into a meat alternative with a convincing texture and boosted nutrition.
Koji mould is a type of filamentous fungus with a long history in Japan’s fermentation industries, including soy sauce, sake, bean curd seasoning, and vinegar production. The mould is a promising source of innovation within the food industry. Through genetic modification, researchers were able to enhance both the sensory and nutritional properties of the mould.
The team, from the University of California, Berkeley, the Joint BioEnergy Institute, and the Novo Nordisk Foundation Center for Biosustainability, developed a gene editing toolkit using and are exploring various ways the genes of Aspergillus oryzae, also known as koji mould, can be modified to create different tastes and textures.
The study, published in Nature Communications, used genetic engineering techniques to modify A. oryzae. The researchers aimed to enhance the mould’s suitability as a food source by using CRISPR-Cas9 gene editing technology.
Vayu Hill-Maini, a postdoctoral researcher at the Biosciences Area at Lawrence Berkeley National Laboratory (Berkeley Lab) and co-author of the study, said, "We developed a gene editing system that can make consistent and reproducible changes to the koji mould genome."
Using genetic modification, the team was able to elevate the production of both heme, improving the sensory appeal, and ergothioneine, the nutrition, in the mould. Heme is an iron-based flavour and colour molecule, abundant in animal tissue, and ergothioneine is a potent antioxidant exclusively found in mushrooms.
The result was a red-coloured fungal biomass, that after removing excess water and grinding, could be formed into patties and pan-fried.
Koji mould has minimal ingredients and a simplified production process, making it a potential disrupter within the alternative protein space. While many plant-based alternatives currently on the market, such as cultivated meats, produce considerably less water and air pollution than conventionally raised meats, they do have drawbacks, including complex ingredient lists and high price points.
The rise of plant-based meats surged in 2019, with a notable co-launch from Burger King and Impossible Foods, a company that makes plant-based meat alternatives using soy protein and coconut oil, among other ingredients. The release of the Impossible Whopper in Burger King’s across the US signalled the potential for plant-based meats to further penetrate the mainstream market.
Despite this growth, in 2021 sales of plant-based meats began to decline, according to Circana, a consumer behaviour research firm, cited in a 2023 report by US cooperative bank, CoBank. Impossible Foods began offering voluntary buyouts to employees in late 2022 and made operational changes in 2023, leading to layoffs across the US.
According to data from the Good Food Institute, plant-based meat is two to four times as expensive as traditional meat. Additionally, because of their frequently long list of ingredients and processing, plant-based meats tend to fall into the ultra-processed food (UPF) category, which is often negatively perceived by consumers.
One recent large-scale study found that two-thirds of the 10,000 European consumers surveyed perceived UPFs as unhealthy and likely to cause health issues, such as obesity, diabetes, and other lifestyle-related issues later in life.
Koji mould may be able to address many of the shortfalls associated with ultra-processed plant-based meats. According to the researchers, the engineered edible fungus can be readily formulated into meat-like patties without the need for extensive processing, protein purification, or ingredient addition. It is also an easy-to-grow protein source with simpler ingredient lists compared to current meat substitutes.
The team is exploring further enhancements in texture to improve the consumer experience with fungal-based products. Hill-Maini aims to create a more meat-like texture and mouthfeel. He explains: "We think that there's a lot of room to explore texture by varying the fibre-like morphology of the cells.”
Fi Global Insights covered the growing interest in koji mould among product developers in 2022. At the time koji was identified as a top trend by market research and consumer insights company WGSN and was beginning to gain traction in the plant-based packaged foods space.
Jennifer Creevy, head of food and drink at WGSN, told Fi Global Insights that the industry was only scratching the surface of what koji could help achieve within the food and drink space.
Since then, koji has garnered even greater attention. Within the plant-based meats space, Prime Roots, a koji-based product manufacturer, uses the mould as a base for its plant-based deli and charcuterie meats, while in the plant-based dairy space, the Canadian company Nuts for Cheese, uses koji in its cheeses and spreads.
