Using Bacteria “Factories” to Produce Animal Proteins

When it comes to addressing climate change, agriculture is often the elephant (or cow, or chicken...) in the room. Livestock production accounts for 14-18% of global greenhouse gas emissions, and more than two-thirds of agricultural land is used to grow feed for livestock. With such a significant carbon footprint, scientists at Tufts University’s Center for Cellular Agriculture (TUCCA) are exploring ways to reduce the climate impact of dairy and meat production with a focus on cellular agriculture, a way of producing animal products like meat, dairy, and eggs using cell cultures and biotechnology as opposed to livestock.  

TUCCA researchers recently studied how to more efficiently produce specific proteins that can help meat-like products appear and taste closer to real meat—an important factor to the success and reach of this potential climate solution. Their findings, published in ACS Biomaterials Science and Engineering, help pave the way for creating sustainable alternative meat options with more widespread public support.

Mimicking meat taste and texture with proteins

Although cellular agriculture is a promising alternative to raising livestock, public perception of lab-grown food affects how successful it could be in reducing climate impact. Less support of the products dampens its potential to help draw down emissions from agriculture. 

“The biggest challenge in the alternative protein industry is taste and texture,” explained James Dolgin, biomedical engineering Ph.D. candidate and lead author of the study. “People won’t buy meat produced from cellular agriculture if it doesn’t really look or taste like meat.”  

Regular meat gets its texture from myofibrillar proteins, which make up the structure of muscle fibers in animals. The TUCCA team’s research focused on two types of myofibrillar proteins that largely contribute to meat’s texture: actin and myosin. While these proteins are great options for texturizing alternative meats, producing them is time-consuming, low-yielding, and expensive.  

Producing actin and myosin more efficiently

Precision fermentation is a process that produces animal-based ingredients by inserting genetic instructions from animal DNA into microbes. The microbes then act as tiny factories, producing proteins through fermentation (similar to how yogurt cultures are produced). TUCCA scientists studied how to produce actin and myosin through this process, something that has remained largely inefficient and unexplored for these specific proteins. 

By attaching a solubility-boosting molecule to actin during the production process, the team was able to significantly increase actin yield. They tested the efficiency of producing myosin in fragments, as the protein is too large and complex to easily produce through precision fermentation. Their findings demonstrated that a mid-sized fragment was the most efficient size to create using precision fermentation and the fragment formed a gel when heated, mimicking the behavior of real meat.  

The team compared their approach to cell cultivation, another process of producing alternative meat that grows actual animal muscle cells in bioreactors that are then harvested and shaped into meat. They found that precision fermentation more quickly produced the same yield as cell cultivation (in three days compared to eight). Producing one gram of myosin with precision fermentation is about one-twelfth the cost  compared to cell cultivation. 

Optimizing the climate impact of cellular agriculture

“Our results demonstrate a quicker, cheaper way to produce these myofibrillar proteins that are essential to the market success of alternative meat options,” explained Dolgin. “We show that precision fermentation—mostly unexplored for producing actin and myosin until now—offers real potential to help address the industry's limitations.” 

With more efficient and affordable methods of actin and myosin production, improved access to these important texturizing proteins could help scientists better replicate the taste and texture of real meat, which is essential to grow support of sustainable food innovation.  

Learn more about TUCCA.