November 7, 2024

What is Single Cell Protein (SCP)?

Protein is consumed by both humans and animals as a source of nitrogen and critical amino acids, which are used to create new structural and functional (such as hormones and enzymes) proteins that are necessary for survival. In dire situations, proteins can also be used as a source of energy. Dietary protein typically contains 20 amino acids, of which some (such as phenylalanine, valine, threonine, tryptophan, methionine, leucine, isoleucine, lysine, and histidine, with arginine, cysteine, glycine, glutamine, proline, and tyrosine also beneficial) cannot be synthesized by humans. An amino acid profile is what determines a protein's.

Researchers have examined how an increase in the demand for meat and dairy protein will call for improvements in animal husbandry as well as a readiness to consider new sources of protein, both for use as animal feed and for human consumption. Theoretically, animal and dairy production can continue to rise in order to fulfil the anticipated demand, even in 2050 when the world's demand for meat will exceed 400 M tons and that for dairy 800 M tons. However, because the conversion of plant protein into meat protein is fairly inefficient (6 kilograms of plant protein must be used to make 1 kg of meat protein), increasing meat production to satisfy the rising demand is eventually unsustainable (WHO, 2015).

These procedures are primarily non-animal and environmentally friendly, but they could also include cutting-edge methods like the production of "cultured" meat, in which meat protein is produced more successfully in vitro than by rearing an entire animal. Although they also require water and arable land, which will become increasingly rare as we seek to fulfil the world's protein demand, beans are a nutritionally valuable source of protein. Meat typically contains around 45 percent protein, compared to 25% in milk and 35% in soybeans. [1]

The cultivation of different microorganisms and algae, ideally those with a biomass that contains more than 30% protein and may offer a healthy balance of necessary amino acids, is another method for producing protein. Single cell protein (SCP) is the term used to describe microbial protein, despite the fact that some of the bacteria that produce it, like filamentous fungi or filamentous algae, may be multicellular. In addition to their direct use as SCP, microbes indirectly increase the protein amount or quality of fermented foods, which increases the need for protein. Despite the fact that microbial protein only makes up a minor fraction of present human nutrition, the increasing worldwide demand for protein is anticipated to make SCP more crucial.

Processes that offer substantially higher efficiency and/or sustainability than traditional agriculture are the result of high growth rates or the ability to use special substrates, like CO2 or methane.

Single-cell protein refers to the raw, refined, or edible protein isolated from dead, dried cell biomass, or pure microbial cultures. They can be used by both people and animals as a protein supplement. The biomass of microorganisms including bacteria, fungus, yeast, and algae has very high protein content. Inexpensive substrates like agricultural waste, such as wood shavings, sawdust, maize cobs, etc., as well as human and animal waste can be used to produce these bacteria.

  • Single Cell Protein: Definition

To make single cell proteins, a variety of microbes and substrates are employed. Because of its superior nutritional value, yeast is appropriate for the generation of single cell proteins. Cereals that have single cell proteins added to them, particularly yeast, are as good as animal proteins. The evidence of the absence of hazardous and carcinogenic substances derived from the substrates, biosynthesized by the microorganisms, or generated during processing is a need for the use of SCP. Two of the most significant problems limiting the nutritional and toxicological usefulness of yeast for animal or human diet are its high nucleic acid content and low cell wall digestibility. Purine compounds, which are found in human diets and are components of nucleic acids, are primarily metabolized to produce uric acid, whose high concentration can cause gout or renal stones.

Per acre, per year, pond-grown algae may generate 20 tons (dry weight) of protein. Bacteria often have high protein content (50 to 80 percent) and a quick pace of growth. The following are the main drawbacks:

  • Small and low-density bacterial cells make harvesting from the fermented medium challenging and expensive.
  • Compared to yeast and fungus, bacterial cells contain a higher amount of nucleic acids. An additional processing step must be added in order to lower the nucleic acid content, which raises the cost.
  • The general populace believes that all microorganisms are dangerous and can cause illness. To dispel this myth and convince the public to embrace bacterial protein, a comprehensive education campaign is needed.

However, SCP for human use is normally manufactured from food grade substrates. It is hoped that techniques will be developed to generate SCP from economical waste materials from the food and beverage processing sectors, as well as directly from forestry and agricultural sources. Regulatory considerations must constantly be made. Production from CO2 has become conceivable with the addition of algae to microbial protein producers, while methane, a greenhouse gas, is offering a brand-new source of carbon for SCP produced by bacteria.


References:

  • Bogdan Constantin Bratosin, Sorina Darjan, Dan Cristtian Vodnar. Single cell protein: A Potential Substitute in Human and Animal Nutrition. Sustainability. 2021; 13(16).
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