Development of and Applications of Mycoprotein

Mycoprotein is a single-cell protein product produced from Fusarium venenatum. F. venenatum is a fungus with hyphae that resemble the structure of muscle cells from other common meat protein sources. The production of mycoprotein began in the year 1964. Research to find a single-cell protein source was pushed forward by the scare of a potential food shortage crisis around the 1950s (1). By 1955, the United Nations had established the Protein Advisory Group to address concerns about protein malnutrition and the effects on children (2). This eventually led to the United Nations Food and Agriculture Organization and the United Nations International Children’s Emergency Fund to set standards for protein products designed to be consumed by humans. In 1968 a food company by the name of Ranks Hovis McDougall, RHM, began working of the concept of single-cell protein—a hot topic at the moment. RHM wanted to create a product that was not only safe for the use of feed but also for human consumption. The original intent was to produce enough fungal biomass using wheat starch as an energy source. The biomass could then be altered to meet desired nutritional values. RHM also planned to produce a dry product from the fungal biomass such as dried milk, however, the fungal biomass was similar enough to the structure of other meat products that it could be converted into its own product. This product would soon be termed mycoprotein by the Foods Standards Committee. Mycoprotein is commonly known by the public as Quorn® (1).

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 There are many options for creating single-cell proteins for consumption. RHM could have selected to work with yeast or bacteria as many other researchers were doing at the time, so what separates fungus from these other potential protein sources? Mushrooms have been consumed throughout the ages (1). One such popular fungus is Agaricus bisporus. A. bisporusis varies widely in its consumption since they can be referred to as many different names based on their age and coloration. Common names for A. bisporus that are consumed include, but are not limited to, button mushrooms and portobello mushrooms. In general, fungus has better organotrophic characteristics then bacteria and yeast. This means that fungus appeals to our senses such as taste, smell, and touch more so than what bacteria or yeast would. The fungal biomass looks similar to that of a raw pastry. When cooked, the fungal proteins share a chewy property to that of other meat products.  It even retains added dyes and flavors after being cooked (1). Overall, the consumers’ interests are kept in mind during the development of mycoprotein products. They attempted to imitate natural meat products to have a sense of familiarity. With every product there are always flaws. Mycoprotein is not juicy like meat when being cooked. This means there are changes to preparation of mycoprotein when compared to conventional meat products. Mycoprotein also struggles to produce large biomass amounts when compared to yeast and bacteria (3). Although fungus cannot grow as fast as bacteria or yeast, they do produce fewer nucleic acids than either one (1). The nucleic acids, particularly RNA, can be dangerous due to large quantities in cells. The RNA is converted to uric acid in the body for disposal by the kidneys, but if too much is consumed, crystalline deposits can build up in joints and other tissues. These crystalline deposits can result in symptoms resembling Gout (4).

 RHM began searching for a suitable fungus to use for the production of mycoprotein. Parameters for a suitable fungus included a biomass consisting of a minimum of 30% protein, presence of specific amino acids, a Net Protein Utilization of .75, one that could be sustained in terms of growth rate and mycoprotein production, and non-toxic to consumers. Overall, the fungus needed to be safe for consumption, provide quality nutrition, and be somewhat pleasant to consume. The Net Protein Production is calculated as the net nitrogen retained divided by the total intake of nitrogen (1). Early work began on Penicillium notatum-chrysogenum. P. notatum-chrysogenum was first isolated from a farm in Ashford, Kent and met all the protein requirements, but it grew too quickly. It spread throughout the fermenter in such a way that it reduced the amount of oxygen present throughout the biomass. This decrease in oxygen levels reduced the amount of biomass that could be harvested. In search of a more promising fungus to produce mycoprotein, RHM began a three year-long search for other potential fungus. Over the course of the search, 3,000 non-toxic strains of fungus were found worldwide typically from collected dirt samples. Of the 3,000 non-toxic strains, only 20 of them were capable of producing enough biomass to be used for the creation of mycoprotein (1). One of these isolates was F. venenatum which at the time was misidentified as Fusarium graminearum Schwabe or F. graminearum A 3/5 (5). F. venenatum was promising when grown on an M9 plate with a biotin additive at 30°C. F. venenatum’s protein concentration was roughly 42%, it had a slow doubling time between 2-5 hours, and toxicology reports indicated no toxicity to animals or humans. No indication of pathogenicity to wheat or corn was identified, however, F. graminearum is known to cause fusarium head blight to wheat plants (6). This is dangerous due to the mycotoxins which are left within the wheat, and if consumed by other organism such as livestock or humans, it can result in symptoms ranging from vomiting to more serous symptoms such as liver damage and reproductive defects. The misidentification may explain why such a disease would have failed to demonstrate pathogenicity to wheat and corn.

 F. venenatum was grown using wheat starch as a carbon source. The wheat starch was hydrolyzed to simpler sugars prior to being added to F. venenatum cultures. F. venenatum was cultured in a continuous flow culture system. The continuous flow system allows for a large production of biomass with a limited amount of F. venenatum by maintaining a near exponential growth rate; It also allows easy collection of the fungal biomass. Batch cultures were suboptimal due to variations between batches and the production of less biomass for harvesting (7). The continuous flow system works by placing F. venenatum in a fermentation tank. The fermentation tank is maintained at 30°C and pH between 5-6. The tank contains a stirrer to introduce fresh oxygen throughout the biomass. A pipe attached to the fermentation tank adds fresh media to the culture to maintain balance between biomass being siphoned through a hose and replication of the biomass. The carbon source is limited due to F. venenatum’s high affinity for glucose. The siphoned biomass needs to undergo an RNA reduction to reduce nucleic acids present in the final product through a heat shock process. The heat shock occurs by increasing the temperature to 64°C for 20-30 minutes. This stresses the F. venenatum; Upon being stressed, F. venenatum releases RNAses which will destroy its own RNA (8). This process does lead to some reduction in protein and structure. Although not favorable to lose protein or structure, if the nucleic acids are not reduced an adult human would not be able to consume more then 20 grams of mycoprotein. The reduction reduces the overall RNA eight-to-nine-fold. This allows an individual to safely consume over 100g of mycoprotein daily. Water is then filtered from the biomass till it is 30% solid mass. A set of machines then aligns and sets the hyphae to better resemble meat fibers. Egg whites are then added to set the hyphae fibers in their preferred confirmation. The mycoprotein is then shrunk and frozen for preservation (1).

 Before mycoprotein could be sold to the public for human consumption, a ten-year long evaluation was carried out by the U. K. Ministry of Agriculture, Fisheries, and Food between 1970 and 1980. The test began by feeding the newly synthesized mycoprotein to eleven different animals as a sole protein source. None of the animal experienced adverse reactions to the consumption of mycoprotein. The animals ranged from cattle to monkeys. Eventually a human trial was performed with 2,500 participants. None of the participants experienced adverse reactions to the mycoprotein. The study also concluded that mycoprotein was not an efficient nutrient source for bacteria when compared to other meat products. This vigorous ten-year period has set a standard for new alternative protein sources in development (1).

  With mycoprotein being approved for human consumption, the production of mycoprotein needed to drastically increase to meet demands. In 1984, RHM sought the aid of Imperial Chemical Industries to aid in expansion of mycoprotein. ICI had a large air-lift fermenter from their discontinued single-cell protein project. The two companies formed a joint venture by the name Marlow Foods in a small village named Quorn in Leicestershire, England. The new fermenter no longer uses a stirrer to introduce oxygen into the biomass. Instead, the new fermenter includes a mass transfer system generated by heat. The mass transfer system moves all the biomass through a series of tubes and creates air bubbles which pass through the biomass—delivering oxygen to the fungus; This also allows carbon dioxide to escape the system through a valve at the top of the system. The heater also ensures that the temperature of the biomass remains at 30°C for optimal growth. The fermenter also has a valve to introduce new nutrients into the fermenter as well as a valve to extract the biomass. The extraction valve leads to another chamber that uses steam to heat the biomass to 64 °C for and RNA reduction (1). The constant conditions and constant flow of nutrients becomes a limiting factor for the longevity of the biomass even though it allows the exponential growth of F. venenatum. This has to do with the emergence of clonal mutants within the biomass. These mutants tend to have shorter hyphae which are more branched. It is unknown why these clonal mutants out-compete the wild type F. venenatum, but the reduced hyphae length becomes problematic in the production of mycoprotein since the length is directly correlated to the texture similarity to meat. These clonal mutants begin to be detected within 500 to 1000 hours of constant conditions. Some mutants can prove to be beneficial such as those that can yield a higher amount of biomass, however, if clonal mutants become established, the biomass must be discarded (1).

 Even though there are complications with growing mycoprotein like any product, there are always benefits as well. The scare of food shortages in the 1950s may now pose some threat. Today there are concerns about the sustainability of current food production levels and the effects that it has on the environment particularly the meat industry (9). In 2014, livestock were responsible for up to 14.5% of greenhouse gas emissions that is more than what vehicles produce annually (10). Current projections estimate that the population will continue to increase to 9 billion by the year 2050 (11). With an increase in population comes an increase in demand for resources. Protein derived from animals is expected to increase by 76%. This means that the production rate of greenhouse gases will also continue to rise with the demand for livestock to feed these demands. Livestock require lots of resources including large quantities of produce and water to maintain. The large amounts of resource required to maintain these livestock have great impacts on the landscape such as habitat destruction and species loss as a result of deforestation to accompany these required resources (12). The large demand for livestock has also led to widespread use of antibiotics to treat infections spread between livestock; The large use of antibiotics has caused bacteria to become heavily resistant to many different antibiotics. These heavily resistant bacteria are now becoming a problem when they infect humans due to the difficulty in treating these infections (9). Dangers not only come from growing livestock, they also come from the consumption of processed and red meats. These meats have been linked to weight gain, Type 2 diabetes, heart disease, and particular cancers (13).

 Quorn® can solve many of these problems. Quorn® is much more efficient to produce compared to typical livestock. Two kilograms of wheat can produce 1 kilogram of Quorn® while producing 1 kilogram of beef can require up to 48 kilograms of feed or 1 kilogram of chicken can require up to 4 kilograms of feed (9). In general, 80% of all agricultural land is dedicated to making feed to supply livestock (14). Replacing livestock with Quorn® would reduce the amount of agricultural land dedicated to making feed to only 8%. This would not only reduce the number of crops dedicated to making feed, but it would also decrease the amount of water that is dedicated to hydrating livestock and watering the crops being produced for livestock feed since the water footprint of Quorn® is one tenth of the water footprint of cows. Similarly, Quorn® also has a much smaller carbon footprint foot print when compared to the production of beef and chicken. Quorn’s® carbon footprint is 13 times smaller than beef’s and 4 times smaller than chicken’s. The consumption of Quorn® will replace or reduce the amount of meat that we consume. Quorn® contains high amounts of protein with low fat contents; It also contains a healthy dose fiber. Quorn® may be the solution to fixing diet associated problems with the consumption of red and processed meats such as the obesity epidemic (9).

 Quorn® was created in response to the 1950’s foot shortage scare. Though it may have been a premature scare, Quorn® provides a healthy alternative to many problems we face today. There may not be a food shortage today, but the continuing growth of the population means that the supply of food needs to increase as well. This puts an intense strain on our planet as the production of greenhouse gases continues to rise with the destruction of our wild life to secure enough resources to feed the growing population. It is crucial that new methods to provide food to the world be developed to such as Quorn® to reduce the impact that we have on the world such as the development of other mycoprotein food products. One such example is a strain of Neurospora sitophila and Chaetomium cellulolyticum which are capable of converting complex sugars such as cellulose to protein products (15).

Works Cited

Trinci APJ. 1992. Myco-protein: A twenty year overnight success story. University of Manchester. Microbiology Research Group. Department of Cell and Structural Biology [Internet]. [cited 7 Dec 2018]. (1):1-13 Available from. http://www.davidmoore.org.uk/21st_Century_Guidebook_to_Fungi_PLATINUM/REPRINT_collection/Trinci_quorn_myco-protein.pdf

Semba RD. 2016. The rise and fall of protein malnutrition in global health. Annuls of nutrition and metabolism. [Internet]. [cited 7 Dec 2018]. 69(2):79-88. Available from. https://www.ncbi.nlm.nih.gov/pubmed/27576545

Solomons GL. 1985. Production of biomass by filamentous fungi: Comprehensive Biotechnology, Vol. 3, Pergamon Press: Oxford, UK 483-505 p.

Riviere J. 1975. Microbial proteins: Industrial Applications of Microbiology, Surrey University Press’ East Kilbride, U.K. 116-120

Hallen H and Volk T. 2005. Gibberella zeae or Fusarium graminearum, head blight of wheat. University of Wisconsin. [Internet]. [cited 7 Dec 2018]. Available from. http://botit.botany.wisc.edu/toms_fungi/aug2005.html

Bai G and Shaner G. 2004. Management and resistance in wheat and barley to fusarium head blight. Annual Review of Phytopathology [Internet]. [cited 7 Dec 2018]. (42):135-161 Available from. https://www.annualreviews.org/doi/abs/10.1146/annurev.phyto.42.040803.140340

Pirt SJ .1975. Principles of microbe and cell cultivation. Blackwell. Oxford, U.K.

Solomons GL. 1983. Single cell protein. CRC Critical Reviews in Biotechnology I, 21-58 p.

 Needham L. 2017. Sustainable development report 2017. World Land Trust [Internet]. [cited 7 Dec 2018]. Available from. https://www.quorn.us/files/content/Sustainable-Development-Report-2017.pdf

Bailey R, Froggatt A, and Wellesley L. 2014. Livestock – climate change’s forgotten sector: global public opinion on meat and dairy consumption. Chatham House, the Royal Institute of International Affairs. [Internet]. [cited 7 Dec 2018. Available from.  https://www.chathamhouse.org/publication/livestock-climate-change-forgotten-sector-global-public-opinion-meat-and-dairy

United Nations, Department of Economic and Social Affairs, Population Division. 2015. World population prospects: the 2015 revision, key findings and advance tables. working paper no. ESA/P/WP.241.

Froggatt A, Happer C, and Wellesley L. 2015.Changing climate, changing diets – pathways to lower meat consumption. The Royal Institute of International Affairs, London [Internet]. [cited 7 Dec 2018]. Available from. https://www.chathamhouse.org/sites/default/files/publications/research/CHHJ3820%20Diet%20and%20climate%20change%2018.11.15_WEB_NEW.pdf

Keats S, Wiggins S. 2014. Future diets: implications for agriculture and food prices. Office for International Development [Internet]. [cited 7 Dec 2018]. Available from. https://www.odi.org/sites/odi.org.uk/files/odi-assets/publications-opinion-files/8776.pdf

Food and Agriculture Organization of the United States. 2017. Animal production: FAO’s role in animal production [Internet]. [cited 7 Dec 2018]. Available from. http://www.fao.org/animal-production/en/

Moo-Young M, Chisti Y, and Vlach D. 1993. Fermentation of cellulosic materials to mycoprotein foods. University of Waterloo, Ontario, Canada. [Internet]. [cited 7 Dec 2018]. (11): 469-.479 Available from. http://turwww1.massey.ac.nz/~ychisti/VlachBA.pdf