Most of the developing countries of the world are facing a major problem of malnutrition. Due to rapid growth in the population deficiency of protein and nutrients are seen in human food and as well as animal feed. It has been estimated that if necessary measures are not taken the malnutrition condition will lead to some major crisis in the developing countries. Therefore it is very important to increase protein production and also its availability to the population by utilizing all the available ways and also methods. The increased world demand for food and in particular feed protein spurred the search for non-conventional protein sources to supplement the available protein source.

The need for large scale production of single cell protein is the need for more protein in the diet of humans. Single cell protein typically refers to proteins extracted from pure culture or mixed culture of microorganisms such as algae, yeasts, fungi or bacteria. These extracted protein are used as a substitute for protein-rich food in humans and as well as animal feeds. The term single cell protein was first coined by a group of scientists at Massachusetts Institute of Technology (MIT) during 1996.

On an average microbial biomass contains around 45 to 55% of protein, although in some types or strains of bacteria protein content is as high as 80%. The microbial biomass also contains other types of essential nutrients required in the human diet as well as animal feed.


Yeast has been used in bread and beverage production since 2500 BC. In 1781 methods are discovered to produce high concentration of yeast. The term single cell protein was coined by Carol L. Wilson during 1966.

Advantages of Single Cell Protein:

In many countries, use of microorganisms or biomass of microorganisms as a diet supplement has met with scepticism because of certain pschycological barriers. But in the future even in these countries microbial biomass will play a major role via single cell protein feeds to the animals which will in turn be consumed by humans. Large scale production of microbial biomass as single cell protein has the following advantages

1. Microorganisms have a high rate of multiplication

2. Microorganisms have high content of protein

3. Microorganisms can utilize a variety of carbon sources as major energy source, and some of the waste material can also be used as carbon source.

4. Microbial strains with high yield as well as good composition can be selected or produced and cultured in large quantity in laboratory conditions.

5. Microbial biomass production as single cell protein is independent of seasonal as well as climatic variations.

Disadvantages of Single Cell Protein:

There are some disadvantages also, of using microorganisms or microbial biomass as diet supplement or as single cell protein.

1. Many types of microorganisms produce some substances which are toxic to the human and also to the animals. Therefore it has to be made sure that the produced microbial biomass does not contain any of these toxic substances.

2. Sometimes the microbial biomass when taken as diet supplement may lead to indigestion

3. Sometimes the microbial biomass when taken as diet supplement may lead to allergic reactions in humans.

4. The high nucleic acid content of many types of microbial biomass products is also undesirable for human consumption as single cell protein. Sometimes this high level of nucleic acid content in microbial biomass will lead to kidney stone formation or gout.

5. The high nucleic acid content of many types of microbial biomass may lead to poor digestibility, gastrointestinal problem and also some skin reactions in humans.

6. The possibility of presence of toxins or carcinogenic compounds may lead to some serious health problems in humans as well as in animal stock.

7. Single cell protein production is a very expensive procedure as it needs high level of sterility control in the production unit or in the laboratory.

8. Single cell protein grown as animal feed on agricultural residues will be beneficial in the future economy of developing nations.


Further research and development will ensure usage of microbial biomass as single cell protein or as diet supplement in developing countries. However it is noteworthy that the company called as Dabur in India is manufacturing and also selling spirulina as diet supplements for humans.

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