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  • Writer's pictureMira Korulski Rosenthal

The hype around fermentation, but what is fermentation?

What is fermentation?

For centuries people have been drinking beer, wine and many other foods which are the result of fermentation (comes from the Latin word fervere, meaning boiling). Fermentation comes down to a process where microorganisms use enzymes that can transform sugar into a new product, without using oxygen (O2). For us, it may sound like a story from the time of the big bang, but there are many microorganisms that can generate energy without using O2 and live thanks to fermentation being an anaerobic pathway. Depending on the organism and what the end product is, fermentation can be categorized into two technical types: lactic acid fermentation and alcoholic fermentation. Both the initial sugar and the final product in these two pathways are different from one another, and we as humans use both of these methods to produce different consumables.

Lactic acid fermentation uses the sugar lactose and can be used to preserve food by creating a more acid environment (the end product lactic acid) which inhibits the growth of other microorganisms that can rotten our food.

The alcoholic fermentation uses the sugar glucose and the end products include ethanol and CO2 (which we are familiar with as the gas in beer and what helps our bread to rise). The ethanol can also be used as a preservative.

Additionally, to the technical categorization of fermentation, there are three main ways the microorganisms can be cultivated in the context of alternative protein: traditional fermentation, precision fermentation and biomass fermentation.

So how does all this come together with the multi-million-dollar worth alternative protein industry, and how is fermentation used to make fake meats and other types of food?

Figure 1. The potential of genomics and synthetic biology to further improve applications of fermentation. Source: Teng et al, EMBO reports, 2021

Traditional fermentation

In the day-to-day when we hear people mention fermentation, they most likely think about traditional fermentation, in bread or yogurt making for instance. This process is basically lactic fermentation as described above, where the lactic acid end product adds to the taste, texture, and nutrients of our food. Traditional fermentation has its name due to the history of humans producing food according to this process.

Precision fermentation

Using precision fermentation, it is possible to instruct the microorganisms to produce a different end product. Over the years genetic engineering has become a cheap and efficient method. The most common process to genetically engineer a strain is by adding a piece of DNA that encodes for the desired protein (or any other type of molecule we instruct it to make) into the DNA of the microorganism. When the microorganism will read its own DNA, it will also read the added DNA and produce the protein of our choice. Once the strain is created, it can be grown on a large scale and increase the quantity of the protein. Using precision fermentation we use the microorganisms as factories in our favor, enabling us to add to the production of alternative protein foods. It holds its name from the precision we can instruct a living organism to produce healthy plant-based ingredients for us.

Biomass fermentation

Creating big volumes of protein in a fast and relatively cheap way. Companies often rely on biomass fermentation. Microorganisms with specific characteristics are grown in large quantities and harvested to be processed as ingredients for alternative proteins. They have a high protein dry weight -animal-free-, making them a nutritional addition to our food.

Why do companies choose to use fermentation?

The scale, nutritional factors, and financial aspects of fermentation are the key drivers why companies are shifting to choose this option when making alternative protein. Whether it is using traditional fermentation to create dairy-free cheese (e.g., Casa del Fermentino, Grounded Foods and NoMoo), precision fermentation for cultivated meat or dairy-free milk (e.g., Wild Earth Inc and ReMilk) or biomass fermentation for high protein substitutes (e.g., Quorn, MoreFoods and Revyve), fermentation can make it all happen. More often companies will combine fermentation techniques to get to their desired final product. Some of the reasons for people to choose alternative protein products are health concerns, environmental impact and financial reasons. Creating protein-rich food (even higher than in some animal products) via biomass fermentation is very healthy, fast, safe, cruelty-free, small environmental footprint, and cost effective.

About the author: Mira holds a PhD from Weizmann Institute of Science and is published in renowned scientific journals. She had the opportunity to present her research at international conferences, as well as review/edit a variety of scientific articles and data. Over the years, she gained experience working for major pharma organizations where she specialized in clinical trials. She is currently freelancing for Rosen & Ko ( as a food-tech consultant and scientific writer.


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