text: In 1781, processes for preparing highly concentrated forms of yeast were established. Research on Single Cell Protein Technology started a century ago when Max Delbrück and his colleagues found out the high value of surplus brewer’s yeast as a feeding supplement for animals. During World War I and World War II, yeast-SCP was employed on a large scale in Germany to counteract food shortages during the war. Inventions for SCP production often represented milestones for biotechnology in general: for example, in 1919, Sak in Denmark and Hayduck in Germany invented a method named, “Zulaufverfahren”, (fed-batch) in which sugar solution was fed continuously to an aerated suspension of yeast instead of adding yeast to diluted sugar solution once (batch). In post war period, the Food and Agriculture Organization of the United Nations (FAO) emphasized on hunger and malnutrition problems of the world in 1960 and introduced the concept of protein gap, showing that 25% of the world population had a deficiency of protein intake in their diet. It was also feared that agricultural production would fail to meet the increasing demands of food by humanity. By the mid 60’s, almost quarter of a million tons of food yeast were being produced in different parts of the world and Soviet Union alone produced some 900,000 tons by 1970 of food and fodder yeast.
  In the 1960s, researchers at British Petroleum developed what they called "proteins-from-oil process": a technology for producing single-cell protein by yeast fed by waxy n-paraffins, a byproduct of oil refineries. Initial research work was done by Alfred Champagnat at BP's Lavera Oil Refinery in France; a small pilot plant there started operations in March 1963, and the same construction of the second pilot plant, at Grangemouth Oil Refinery in Britain, was authorized.
  The term SCP was coined in 1966 by Carroll L. Wilson of MIT.
  The "food from oil" idea became quite popular by the 1970s, with Champagnat being awarded the UNESCO Science Prize in 1976, and paraffin-fed yeast facilities being built in a number of countries. The primary use of the product was as poultry and cattle feed.
  The Soviets were particularly enthusiastic, opening large "BVK" (belkovo-vitaminny kontsentrat, i.e., "protein-vitamin concentrate") plants next to their oil refineries in Kstovo (1973) and Kirishi (1974). The Soviet Ministry of Microbiological Industry had eight plants of this kind by 1989. However, due to concerns of toxicity of alkanes in SCP and pressured by the environmentalist movements, the government decided to close them down, or convert to some other microbiological processes.
  Quorn is a range of vegetarian and vegan meat-substitutes made from Fusarium venenatum mycoprotein, sold in Europe and North America.
  Another type of single cell protein-based meat analogue (which does not use fungi however but rather bacteria) is Calysta. Other producers are Unibio (Denmark) Circe Biotechnologie (Austria) and String Bio (India).
  SCP has been argued to be a source of alternative or resilient food.