Single Cell Protein:
The term SCP was coined by Carol L Wilson 1966 at the Massachusetts Institute of Technology- USA. The population of the planet is always growing. With current consumption rates, the world population could reach 9.3 billion by 2050, which would result in a 1250 million tons annual rise in the need for animal-derived protein. On the other hand, current data have showed that there were over 690 million undernourished individuals in the world in 2019 (8.9% of the total population), and this number is expected to rise to over 840 million by 2030. Africa, Asia, Latin America, and (to a lesser extent) the Caribbean are the areas most impacted. Forecasting studies have revealed that economic growth will coexist with population growth, raising the level of life for around 3 billion people.
The Food and Agriculture Organization (FAO) of the United Nations refers to proteins as macromolecules since they are the structural constituents of cells, tissues, muscles, and organs. Proteins are a source of nitrogen for both humans and animals, forming the structural and functional components required for life. Proteins are also important for metabolic activity. A protein's nutritional value can be determined by the amino acid content of its components. The most typical are essential amino acids that neither humans nor animals can produce. To satisfy these demands, we eat meat or other types of protein.
Single cell proteins (SCPs) are derived from the cells of microorganisms with high protein content as dried cells and/or purified proteins. SCPs have many desirable characteristics as a dietary supplement for humans, including a high protein content with a wide variety of amino acids, low lipid content, and a higher protein: carbohydrate ratio than forages. Along with minerals, nucleic acids, lipids, and critical amino acids like lysine and methionine, SCPs contain vitamins like thiamine, riboflavin, pyridoxine, nicotinic acid, pantothenic acid, folic acid, biotin, cyanocobalamin, ascorbic acid, and tocopherol. Up until this point, SCPs have been used for a variety of tasks, from the creation of paper and lead to food (aroma carriers, vitamin carriers, emulsifying acids, etc.) and feed (pigs, poultry, cattle, fish).
SCPs typically come from garbage, byproducts, flammable or combustible waste, and raw materials (such starch, fruit, and fruit waste) (natural gas, petroleum byproducts, ethanol, methanol, biomass, etc.). Since methanol is soluble in the aqueous phase at all concentrations, it can be readily extracted from harvested biomass. Even though ethanol is a good substrate, the method is not profitable. Utilizing waste for SCP manufacturing has various benefits, including the decrease of environmental pollution and the conversion of inexpensive organic waste into usable products. Natural sources of SCP that are appealing are the cellulose, hemicellulose, and lignin of waste wood that comes from forestry and agricultural sources. To convert cellulose into fermentable sugars, they must first undergo chemical (acid hydrolysis) or enzymatic (cellulase) pretreatment. [1]
Industrial-scale SCP production from non-waste sources was created in the 1970s, although it lagged behind other protein supplements in terms of price. Recently, interest in SCP has increased, in part due to the discovery of new, more affordable production methods, but primarily as a result of the realization that the production of SCP has significantly greater potential environmental benefits than that of conventional protein supplements in animal feed.
Background History of SCP:
Numerous microbes have been eaten directly. In less affluent communities where malnutrition is a serious and potentially fatal issue, SCPs can save lives. Spirulina was cultivated many years ago in Africa's Lake Chad and afterwards consumed by the local population to make up for their lack of protein. During World War I, the Germans reportedly used a specific type of Candida in their food, including soups and sausages. Since then, bacterial, fungal, and algal protein production has been widely used in food and as food. This technique gave rise to the idea of SCP, and these proteins are currently utilized often.
Applications of Single Cell Protein:
Commercially produced SCP is employed:
- In animal nutrition and feed, as well as in the stuffing and fattening of pigs, calves, and laying hens.
- To boost the nutritional value of baked goods, prepared foods, soups, etc.; as food additives (vitamin and aroma carriers and emulsifying agents); and as starter cultures (baker's, brewer's, and wine yeast).
- As a foam stabilizer and in the processing of leather and paper in industrial processes.
Production of Single Cell Proteins:
- Substrates can be divided into several categories, including:
- Natural gas, gas oil, ethanol, methanol, n-alkanes, and acetic acid are all high-energy substances.
- Renewable plant resources include cellulose, sugar, and starch.
- A variety of wastes, including fruit waste, molasses, whey, milk, and sulfite waste liquor
- Carbon Dioxide
The substrate is chosen based on price, availability, the amount of oxygen needed during fermentation, the amount of heat produced, the fermenter's cooling capacity, as well as the cost of post-treatment processing. Certain substrates are used by microorganisms including bacteria, algae, fungi, and yeast as a growth medium to increase their cell mass, which is made up of SCP.
After the fermentation process is finished, the available biomass is harvested and used as a source of protein. Purification, cell disruption, washing, and protein extraction are further processing steps used to the biomass to produce high production rates and high yields.
The demand for protein is rising as a result of changes in dietary habits. However, it is eventually unsustainable to rely solely on the supply of dairy products and meat to satisfy the rising need for protein. Therefore, it is important to look for other sources of food for both people and animals.
References:
- Sirada Patthawaro, Chewapat Saejung. Production of single cell protein from manure as animal feed by using photosynthetic bacteria. Microbiology Open. 2019; 8(12).