This engineered fungus cuts emissions and tastes like meat

"There is a popular demand for better and more sustainable protein for food," says corresponding author Xiao Liu of Jiangnan University in Wuxi, China. "We successfully made a fungus not only more nutritious but also more environmentally friendly by tweaking its genes."

Sustainable Protein and the Need for Alternatives

Animal agriculture accounts for about 14% of global greenhouse gas emissions. It also requires large amounts of land and fresh water, both of which are increasingly strained by climate change and human activity. Because of these challenges, microbial proteins found in yeast and fungi have gained attention as promising alternatives to meat.

Among the many mycoprotein sources studied so far, the fungus Fusarium venenatum has become a prominent choice because its natural flavor and texture closely mimic meat. It has already been approved for consumption in several regions, including the United Kingdom, China, and the United States.

Why Fusarium venenatum Needed Improvement

Even with its advantages, Fusarium venenatum has thick cell walls that limit how well humans can digest it. Producing it is also resource intensive. Growing even modest quantities of mycoprotein requires significant inputs, and the spores must be cultivated in large metal tanks filled with sugar-rich feedstock and added nutrients such as ammonium sulfate.

Liu and his colleagues wanted to determine whether CRISPR could make this fungus easier to digest and more efficient to grow while still avoiding the introduction of foreign DNA into the organism.

Key Gene Edits That Boost Efficiency

To explore this approach, the researchers removed two genes linked to the enzymes chitin synthase and pyruvate decarboxylase. Removing the chitin synthase gene resulted in a thinner cell wall, which made the internal protein more accessible for digestion. The deletion of the pyruvate decarboxylase gene fine-tuned the fungus's metabolism, reducing the amount of nutrients needed for protein production.

Their analyses revealed that the modified strain, named FCPD, used 44% less sugar to create the same amount of protein as the original strain and did so 88% more quickly.

"A lot of people thought growing mycoprotein was more sustainable, but no one had really considered how to reduce the environmental impact of the entire production process, especially when compared to other alternative protein products" says first author, Xiaohui Wu of Jiangnan University.

Life Cycle Footprint and Global Comparisons

The team then assessed the environmental footprint of FCPD across its entire life cycle, from laboratory spores to inactivated meat-like products, at an industrial scale. They modeled production in six countries with different energy systems, including Finland, which depends largely on renewable energy, and China, which relies more heavily on coal. In every scenario, FCPD produced lower environmental impacts than conventional Fusarium venenatum. Across its full life cycle, FCPD production reduced greenhouse gas emissions by up to 60%.

How FCPD Compares to Animal Protein

The researchers also compared the impacts of FCPD production to those associated with raising animals for food. Against chicken production in China, FCPD required 70% less land and lowered the potential for freshwater pollution by 78%.

"Gene-edited foods like this can meet growing food demands without the environmental costs of conventional farming," says Liu.

This work was supported by the Key Research and Development Program of China, the Jiangsu Basic Research Center for Synthetic Biology, the Natural Science Foundation of Jiangsu Province, and the Postgraduate Research & Practice Innovation Program of Jiangsu Province.