Plants as a recombinant protein expression platform

Current challenge

The aim of alternative protein products is to replicate and improve upon conventional meat, egg, and dairy with non-animal ingredients. One approach is to grow native animal proteins in non-animal hosts, traditionally via precision fermentation with microorganisms such as yeast or bacteria. Precision fermentation is a powerful technique, but improvements—particularly in cost, scale, and infrastructure needs—would make it more amenable to low-cost food ingredient production. Using plants as recombinant protein hosts (i.e., molecular farming) is another method with good potential, and there are ample opportunities to enhance its commercial viability.

Proposed solution

Molecular farming development has historically focused on developing pharmaceutical therapeutic end products (e.g., antibodies, antigens, enzymes), but recent advances demonstrate its promise for alternative protein production. A few alternative protein companies have leveraged plants as recombinant protein expression platforms for native animal proteins—such as casein and chymosin for animal-free cheese production or animal-free growth factors for cultivated meat media. These companies use plants rather than microbes because plants require less expensive equipment to grow and harvest, are easier to maintain, and are more scalable. Molecular farming is unlikely to experience the severe infrastructure and manufacturing capacity constraints currently facing the microbial fermentation sector.

To validate and improve the commercial viability of this technology for alternative protein applications, techno-economic models that directly compare crop versus microbe platforms would elucidate which is more cost-efficient and provide insights into the bottlenecks for each platform. Moreover, different crops should be compared for their ability to express specific proteins in various tissues and their ease of fractionation and downstream purification to obtain the desired end product. Thus far, soybeans, pea, barley, rice, safflower, and duckweed crops have demonstrated promise. Lastly, the environmental safety of these plants should be assessed, especially those used for molecular farming of non-food components such as growth factors or other recombinant proteins used in cell culture media for cultivated meat. Traditional crop fractionation methods may not be optimal for these recombinant proteins, so innovations in extraction may also be necessary.

Anticipated impact

Molecular farming and microbial precision fermentation are incredibly impactful technologies that can more efficiently produce native animal proteins through animal-free methods. As a result, alternative products can be created with the same ingredients (and accompanying functionalities) as animal products.

Because of the possibility of open field production, molecular farming could create proteins at a much larger scale and with substantially lower infrastructure costs and constraints than microbial precision fermentation. Furthermore, adding valuable ingredients to crops that have uses in alternative protein or other industries can promote zero-waste economies through whole crop valorization.

Related efforts

• Nobell Foods (formerly Alpine Roads) has applied genetically modified soybeans to produce casein protein. 
• Moolec Science uses soybean, pea, and safflower crops to produce bovine- and porcine-based proteins. 
• ORF Genetics creates plant-based growth factors for cultivated meat media using barley.
• Other companies applying molecular farming to develop alternative protein ingredients and cultivated meat media include Mozza, Greenovation Protein, Tiamat Sciences,  Core Biogenesis, BioBetter, and InVitria.

GFI resources

The science of plant-based meat

Learn about the science of plant-based meat. Discover resources and research on the latest technological developments and key scientific questions.

The science of fermentation

Learn about the emerging role of microbial fermentation in building the next generation of alternative protein products.