Single Cell Protein is the Ultimate Alternative Protein

September 17. 2019. 6 mins read

There are people who live to eat and others who eat to live. This article is mostly going to appeal to the latter group – those who would be happy to nosh on 3D-printed pizza or exist on a steady diet of powdered soylents. We’ve been writing a series on the rise of alternative proteins to stone age mainstays like meat and milk. From growing beef in a lab to milking microbes for eggs, our food system is about to get very Jetsons-like very soon. Ironically, many of the advances rely on some of the most simple organisms on the planet: single-cell microbes like bacteria. Life wouldn’t be possible without these microorganisms, which are responsible for little things like soil fertility and human digestion. Soon they could be used as a major source of nutrition as part of a growing food sector known as single-cell protein.

What is Single-Cell Protein?

In the past, we’ve talked mainly about three different kinds of alternative proteins. One is the popular plant-based products like those created by Beyond Meat (BYND) and Impossible Foods. Then there are a ton of companies either growing meat or seafood using animal cells. Finally, there’s another cohort of startups genetically modifying microorganisms like yeast in order to use fermentation to brew proteins with similar structures to milk or even gelatin. In that case, microbes are separated from the final product and discarded.

A list of the most popular bacteria used in commercial applications of SCP.
A list of the most popular bacteria used in commercial applications of SCP. One comment: Ram horn? Credit: Frontiers in Microbiology

That brings us to Single-Cell Protein (SCP). If your preferred footwear in summer or winter is Birkenstocks with socks, then you’re probably familiar with a couple of types of SCPs such as nutritional yeast and spirulina. And if you talk with a funny accent, then you’ve also consumed Saccharomyces cerevisiae (the same species of yeast used in brewing) in the form of Vegemite or Marmite. In fact, there are a number of single-celled microbes and algae with commercial value as food, usually containing at least 30% protein and a healthy dose of amino acids.

Advantages of Single-Cell Protein

Not only are some single-cell proteins highly nutritious, but they’re extremely fast-growing and require much less input compared to Daisy the cow. For instance, the yeast used in the black tar known as Vegemite is a byproduct of the beer brewing process. In fact, one of the real advantages of SCPs is that they can be cultivated (i.e., fed) with waste products or even greenhouse gases like carbon dioxide and methane.

Click for company websiteWe’ve already introduced you to a few companies that are doing just that. For example, there’s Chicago-based Sustainable Bioproducts that is attempting to commercialize a bacterial species that makes its home in the hot springs of Yellowstone National Park. The microbes are fed cheap sugars like kids on Halloween night but contain all nine essential amino acids (unlike the pre-diabetic children).

Click for company websiteAnother startup we previously profiled, Calysta Energy out of Silicon Valley, recently raised another $30 million this summer led by British Petroleum’s venture arm to bring total funding to $118 million. The startup mixes a variety of gases, including methane, in a fermenter where they are metabolized by the microbes, requiring minimal water and zero agricultural inputs that lead to greenhouse gas emissions. The company has commercialized a product called FeedKind as an animal feed, especially for aquaculture, which is under pressure to become more sustainable with the emergence of alternative seafood companies.

Single-Cell Protein Startups

A number of other companies are trying to make big bucks off these tiny organisms:

List of companies and enterprises working on single cell protein.
Credit: Frontiers in Microbiology

Below we highlight some of the emerging SCP technologies.

Single-Cell Protein from Methane

Click for company websiteTechnically, London-based Unibio has been around since 2001, but the parent company was incorporated in just 2014. And while nominally headquartered in the UK, most of the microbial magic is based in Denmark. Whatever. The company raised $15 million last month to help bring its Uniprotein to the world. Its U-Loop fermentation technology is based on some 30 years of research, but it’s basically pretty simple (and similar to Calysta): Unibio converts methane emitted from natural gas and oil production sites into single-cell protein using the Methylococcus capsulatus bacterial species:

Unibio U-Loop System
Credit: Unibio

And like Calysta Energy, Unibio is concentrating on the fish and livestock market with its Uniprotein. In addition to that $15 million check, the startup also signed a $200 million agreement with Saudi Arabia in August to build a U-Loop facility in the oil-rich nation. That’s a lot of fish food.

Another company attempting to commercialize methane-munching microbes is String Bio out of Bangalore, India. Founded in 2013, the company raised an undisclosed amount of capital back in June. While the startup has big plans to use its String Integrated Methane Platform to make all sorts of products and ingredients from microbes, its initial focus is on developing a single-cell protein. Its first product, String Pro, is for animal feed.

Single-Cell Protein from Biofuel Waste

Click for company websiteKnipBio was founded in 2013 to create a single-cell protein for the aquaculture industry. The company has raised $4.9 million to date to develop the fermentation technology behind its KnipBio Meal (KBM) products, genetically tweaking the Methylobacterium extorquens microbe to bring out additional traits in the feed such as antioxidant carotenoids, which are the source of a salmon’s rich pink color. The company recently hit upon using condensed distillers solubles, a cheap and plentiful byproduct of the biofuel industry in the production of ethanol, as the solution to scale its feedstock for commercial production of KBM. It’s interesting to see how the biofuel industry, still struggling to be commercially viable, is getting a second life as a source of feed products.

Single-Cell Protein from Wastewater

If the conversation is about feeding the global population sustainably, then any discussion will eventually include China. Hong Kong-based iCell Sustainable Nutrition just completed its second full-scale production facility in China for animal feed using single-cell protein. And like any good Chinese company, its technology is based on intellectual property developed by an American company in California. iCell reportedly acquired Nutrinsic, which had raised $38.3 million, in 2016.

The technology involves running wastewater from food processing through “rapid control fermentation, cell-wall breaking enzymolysis, instantaneous air drying, sterilizing and other processes” that eventually turns the microbes into a nutrient-rich fish feed. iCell has partnered with a sugar production company in China that produces 10,000 tons of nutrient-rich wastewater per day at a disposal cost of $300,000 per day. iCell will help turn that loss into a gain with its single-cell protein line.

Single-Cell Protein from CO2

Click for company websiteOne of the investment companies originally behind Nutrinsic, Aquacopia, had focused on aquaculture. The firm shut down in 2016, but its former head is now leading a Silicon Valley-based company called NovoNutrients that is attempting to commercialize a single-cell protein based on microbes that metabolize carbon dioxide, the granddaddy of greenhouse gases. The startup only shows $300,000 in disclosed funds and is sticking with what it knows: aquaculture. The microbes used by NovoNutrients are so tough that they can feed on industrial waste gases piped directly from a cement plant or shipped in from an oil refinery. Eventually, the base protein will be enhanced with carotenoids, omega 3s, and other ingredients that make for a healthy and tasty fish.

NovoNutrients nutritional profile.
It may look like heroin, but we’re assured that it’s much better for you and the planet. Credit: NovoNutrients

Click for company websiteAnother Silicon Valley startup in Sunnyvale called Oakbio has raised about $50,000 in disclosed funding for its own system to convert CO2 into not just feed but bioplastics. The company combines raw gases from cheery places like cement factories and oil refiners with hydrogen into a bioreactor containing a solution of Oakbio’s proprietary microbes. Out comes proteins or plastics, depending on the cocktail of microbes and conditions.

Single-Cell Protein from Thin Air

Click for company websiteFounded in 2017, Finnish startup Solar Foods has raised about $2 million to create what its marketing team has called food out of thin air. The concept is pretty close to what other companies here are developing in terms of using microbes that metabolize CO2, but using only water and renewable electricity as the other primary inputs.

Solar Foods process for converting "thin air" into food.
Credit: Solar Foods

Solar Foods is also targeting its product, Solein, as a protein for the human feed market. The company claims its product is 100 times more climate friendly compared to plant or animal sources, and the end product looks and tastes just like wheat flour. It plans to go to market by 2021.


Single-cell protein checks all the boxes: it’s cheaper, more sustainable, and scalable. In the short-term to probably mid-term, the emphasis will remain on aquaculture and other animal feed solutions, but if people are willing to pay $15 for a burger made out of pea powder, just think what they’ll charge for a microbe meatball.


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  1. Good day. I am interested in your production. Can you sent more information about your product and machines. Thank you