We all consume protein as a source of nitrogen and essential amino acids which are used as the structural and functional units of our bodybuilding process. Proteins are also used as enzymes and hormones for our survival. Rarely, they may also be used as a source of energy. Single-cell proteins are the edible unicellular organisms and are represented in a short form SCPs. They are a form of proteins extracted from unicellular organisms hence the name single-cell proteins. As the world is bombarding with the food crisis, SCPs are one of the most affordable and easy methods in use to produce quality proteins. From the last 3 decades, the population has been drastically increasing but the production of food is declining; as a result, the world is witnessing a huge gap between the production and the consumption of the food. Children in some of the nations are still suffering from malnutrition as they purely rely on the traditional plant and animal proteins, additionally, these protein sources lack quality apart from consuming a lot of time for its production. Till date, SCP is commonly grown as agricultural waste products, however, they are also produced as autotrophs independently at homes and thanks to the high diversity of microbial metabolism which has provided versatile options of nutrients recycling, and a substantially increased efficiency compared to crops.
Importance and Sources of SCPs
Experiments have proved that a cow weighing 250 kg can produce hardly 200 g of proteins in a day. It is a poor number while considering the ratio between protein production and the bodyweight of the cow. On the contrary, microbes like Methylophilus methylotrophs can proportionately yield more protein than that of a cow. This is because microorganisms contain high biomass compared to other organisms. About 25 tons of protein can be generated daily from our day-to-day wastes. SCP contains biomass that can be used as an alternative source of animal proteins. SCPs can be prepared from the mixed cultures of algae, fungi, yeasts, and bacteria. As a scientific logic, it demands around 3-10 kg of grains to synthesize 1 kg of meat by an animal. But it is expensive and a long process when compared to the production of single-cell protein (SCP). Scientists are making every effort to produce microbial biomass using low-cost substrates and microbes like Spirulina. Spirulina is used in many energy drinks as it is healthy and can be cultured the wastewater, straw, molasses, animal manure and even on the sewage. However, care should be exercised as they are unsafe if we do not remove the excess of nucleic acids while the good thing is that SCPs have a high-quality protein with a lesser proportion of bad fats. Some of the most common microbes used in the synthesis of SCPs are Cyanobacteria – Spirulina, bacteria – Methylophilus methylotrophs, yeasts – Candida utilize and filamentous fungi – Fusarium gramiearum. Most of the bodies of the organisms contain the same 5 nutrients such as carbs, proteins, vitamins, minerals and fats. Microorganisms such as Fungi, Bacteria, Algae and Yeast are not an exclusion as they also contain these nutrients. SCPs are richly found in fungi such as Aspergillus fumigatus, Aspergillus niger, Rhizopus cyclopean. Some yeasts like Saccharomyces cerevisiae, Candida tropicalis and Candida utilis are also useful. Algae such as Spirulina, Chlorella pyrenoidosa and Chondrus crispus as well as bactrium belonging to Pseudomonas fluorescens, Lactobacillus, and Bacillus megaterium are often used in th elarge scale production of SCPs.
Advantages of SCP
It is very rich in high-quality protein aside containing considerably less fat content.
It helps the food industry by diminishing the burden on the traditional agricultural production systems.
Since SCPs production uses industrial wastes as the raw material, it can minimize environmental pollution to a larger extent.
SCPs can be produced in the laboratories throughout the year which can guarantee the production cycle irrespective of the season.
Apart from using the SCPs as food sources, they are used as therapeutic materials to control obesity, diabetes, cholesterol and stress management
SCPs can also be used for maintaining healthy hair apart form the production of herbal beauty products, like- Biolipstics and herbal face cream
In poultry, they serve as an excellent source of proteins and other nutrients hence farmers use them as feeds for cattle, birds and fishes.
Disadvantages of Single-Cell Protein
The presence of high nucleic acids content results in the excessive production of toxins such as uric acid.
In some cases, the excessive consumption of SCPs may result in kidney stones and gout ( joint disorder).
Some of the secondary toxic metabolites produced by SCPs can cause Hypersensitivity and other skin reactions.
The initial investment for high-quality SCPs is high because sophisticated machinery is required for SCPs.
SCPs have high nucleic acid content in their biomass makes it difficult for consumption as it may lead to gastrointestinal problems.
The biomass sometimes causes an allergic reaction if the digestive system recognizes it as a foreign product.
Mechanism of production
SCPs can be produced by subjecting the wastes, straw, cannery and the residues from alcohol into chemical processing. The processing is done by passing electricity to the properly segregated wastes which can dehydrate it to as low as 10%. Some large scale production units use centrifugation, flotation, precipitation, coagulation, and filtration to enhance the filtration rate.