Single cell protein—Is this space technology ready for aquaculture?
by Bryan P Tracy PhD, White Dog Labs, USA
The concept of using single cell organisms (bacteria, yeast, fungus and algae) as a protein source was developed during the cold war for space travel. Today, UK's Quorn Foods sells over US $250M of beef and chicken substitute, which utilises protein from fungus grown in large fermenters.
But could Single Cell Protein (SCP) become an alternative protein for fishmeal?
Creating an alternative for fishmeal has turned out to be quite a challenge. Vegetable protein is cost effective and scalable, but does not have the essential amino acid content, to match the quality of fishmeal. As early as twenty years ago, Norferm, a Statoil and DuPont Joint Venture, has produced high quality SCP for aquaculture.
The company leveraged excess natural gas in the North Sea, as feedstock for methanotropic bacteria, that utilises methane as the energy and a carbon source in fermentation. The project was abandoned in 2006, due to high capital and operating cost, as well as lack of production worthiness – problems which still face recent attempts to revive the technology.
A large number of algae start-ups, a decade ago, planned to leverage the sun and CO2 to produce a high-quality protein. However, open ponds proved to be susceptible to contamination, while closed systems had high operating costs. Today, there is a flurry of start-ups leveraging municipal waste to produce insect protein. While the product quality is good, it is way too early in the technology cycle to determine ultimate cost and ease of scalability.
Based in the Netherlands, Rabobank is an international financial service provider, operating on the basis of cooperative principles. Yet, with all these issues, Rabobank's Senior Seafood Analyst, Gorjan Nikolik, predicts that 'novel feed ingredients will boost marketability of farmed fish and can reduce the cost of production.'
White Dog Labs (WDL) is working very hard to prove Gorjan Nikolik right!
A new approach
WDL was established in 2012 in Delaware, USA, on the foundation of biotechnology and bioprocess development. It has invented a proprietary process, ProtocolB™, for the isolation, selection and cultivation of microbiome-derived Clostridia. Clostridia is a long known, but less understood, class of bacteria, with promising implications for nutrition and health.
The company has also developed MixoFerm™, a fermentation technology that consumes sugar and CO2, thus increasing the cost effectiveness of bioproducts ranging from food and feed, to biofuels and chemicals.
WDL's first product is ProTyton™ - a non-GMO Single Cell Protein ingredient. It is produced from corn and it exhibits upwards of 80wt percent crude protein and over 40wt percent essential amino acids. Figure one compares ProTyton to other protein ingredients.
The product is highly digestible and performs well in multiple aquaculture diets. Due to its high crude protein and essential amino acids, ProTyton allows incorporation of lower cost ingredients to reduce total feed costs, as summarised in figure two.
ProTyton is produced by anaerobic fermentation, and it is well known that anaerobic SCP can also contain immuno-stimulating secondary metabolites and nucleotides. Moreover, ProTyton SCP also contains low levels of butyrate, a short chain fatty acid commonly used as a terrestrial feed additive, to support gut health and reduce antibiotic use.
ProTyton was thus expected to provide health benefits, beyond its nutritional value, and has indeed demonstrated an ability to counter Early Mortality Syndrome (EMS) in shrimp.As can be seen in figure three,20 percent inclusion of ProTyton has one-third the mortality rate of a commercial diet that is formulated especially for shrimp health.
While all the tests reported above were carried out by the Centre for Aquaculture Technologies Canada (CATC), several major aquafeed companies have qualified the product and WDL has already secured off-take for its first plant.
The company is currently producing ProTyton for qualification by major feed companies in its pilot facility in Delaware, using the 18,000-litre fermenter shown in figure four.
ProTyton fermentation, similar to that of ethanol, is a simple anaerobic process, thus allowing straightforward use of ethanol plants for ProTyton production. WDL has reached an agreement to locate its first plant inside the MRE ethanol plant in Sutherland, Nebraska. The plant will produce 3000 tons/year of ProTyton, starting in the fourth quarter of 2019.
For every one kilogram of ProTyton, the plant will produce threekilogrammes of MiruTyton – a Butyrate rich co-product. Since MiruTyton is a valuable feed-additive in its own right, the plant is expected to be profitable even at a ProTyton price of US $1000/ton.
WDL has developed a strategy for rapid production expansion by licensing ethanol plants the right to produce ProTyton. There are over 200 ethanol plants in the US because, in 2007, the Renewable Fuels Standards (RFS) mandated a market for corn-derived ethanol. Even with the RFS in place, ethanol plants have experienced boom and bust cycles that have hurt the industry.
These cycles, combined with the uncertainty of the RFS renewal in 2022, have created a desire for product diversification. WDL has received positive responses from small and large ethanol producers, and have already granted the first license for a full plant conversion. Converting each one percent of the US ethanol capacity will result in 200,000 tonnes/year of ProTyton.
This is only part one of the WDL story – please stay tuned – we hope to prove Rabobank's Gorjan Nikolik right next year!