Single-cell proteins are dried cells from microorganisms like yeast, fungi, algae and bacteria that are used as a protein supplement. They have high nutritional value and are a sustainable alternative protein source. Microorganisms consume organic matter and convert it into biomass, which is then harvested and processed to extract protein. Research on single-cell proteins started over a century ago and was used during World Wars I and II to address food shortages. Today, they show promise in addressing global protein malnutrition issues.

1. Single-Cell Protein
 Presented To:
Dr. Kashif Rahim
 Presented By:
Muhammad Irfan

2. Single-cell proteins
 Single-cell proteins are the dried cells of microorganism such as yeast, fungi,
algae, and bacteria which are used as protein supplement in human foods or animal
feeds.
 SCP has been gaining popularity as an alternative source of protein due to its high
nutritional value and sustainability.
 The microorganisms consume organic matter and convert it into biomass, which is
then harvested and processed to extract protein.

3. History
 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.
 The term SCP was coined in 1966 by Carrol L. Wilson
of MIT.
Max Delbrück

4. CURRENT PROSPECTS AND SCENARIOS:
In Pakistan:
 4 out of 10 children under 5 years are stunned due
to protein malnutrition.
 Total 28.8% affected individuals.
 Under r years age children the prevalence of
protein energy malnutrition is 52.2 %. (National
nutritional survey2018-UNICEF).
AROUND THE GLOBE:
 2.2 Billion around 40% protein energy malnutrition
(Global nutrition report 2021-WHO)

5. CURRENT PROSPECTS AND SCENARIOS
Microbes are used for producing single cell protein (SCP) as an alternative source of protein
 Rapid growth
 High protein content
 Sustainability
YEAST:
 50kg can produce 250 tons of proteins within an hour.
 Produce proteins with high Vitamin content.
ALGAE:
 Can produce 10-15 times more proteins higher then soybeans and 20-50 times more as
compared to corn per year per acre.
 On same one acre produce 20 tons of protein (Dry weight) per year

6. Sources of Single Cell Protein
 Fungi
 Yeast
 Algae
 Bacteria

7. Microorganism and substrates used for
single cell protein production
MICROORGANISIM SUBSTRATE
Lactobacillus spp. Glucose, Amylase, Maltose
Pseudomonas fluorescence Uric acid, Glucose
Acinetobacter calcoascenticus Ethanol
Bacillus megaterium Non-protein nitrogenous compounds
Aspergillus niger Cellulose, Hemicellulose
Candida tropicalis Maltose, Glucose
Candida novellas n-alkanes
Amoco torula Ethanol
Chondrus crispus Carbon dioxide through photosynthesis

8. Substrates used for SCP production:
Several substrates used for production of SCPs.
 Renewable plant resources
• starch, sugar, cellulose
 High energy resources
• gas-oil, natural gas, ethanol, methanol n-alkanes and acetic acid
 various wastes
• sulfite waste liquor, molasses, whey, milk and fruit waste
 Carbon dioxide

9. Production of Single-Cell Protein
1. STRAIN & SUBSTRATE
SELECTION
Pre requisites.
Strain and specie
selection.
Substrate selection.
2. FERMENTATION
Microbial growth.
Protein production
3. HARVESTING
Extraction of protein
4. PROCESSING OF SCP
purification
5. POST HARVEST TREATMENT
Dehydration
preservation

10. Processing of SCP
Produced protein contain impurities in it e.g. carbohydrates, nucleic
acid, lipid contents, salts etc
Pure protein isolation can be done by disrupting the cell wall through crushing, crumbli
ng, cycles of freezing & thawing, grinding & thermal shocks.
Nucleic acid removed by
 By treatment with NaCl 10%
 By Chemical e.g. NaOH
 Thermal shocks
 Enzyme treatment e.g. Ribonuclease

11. Production of
Single-Cell Protein

12. Advantages of Single-Cell Protein
Microorganisms have a high rate of multiplication
Large quantity of biomass can be produced in a comparatively shorter
duration.
The microbes can be easily genetically modified to vary the amino acid
composition.
A broad variety of raw materials, including waste materials, can be used as
a substrate. This also helps in decreasing the number of pollutants.
Production is independent of climatic conditions.

13. Disadvantages of Single-Cell Protein
High level of nucleic acid in biomass makes it difficult for consumption as it may
lead to gastrointestinal problems.
The biomass may trigger an allergic reaction if the digestive system recognizes
it as a foreign product.
The presence of nucleic acids in high content leads to elevated levels of uric
acid.
In certain cases, the development of kidney stone and gout if consumed in high
quality.
Possibility of the presence of secondary toxic metabolites which results in
Hypersensitivity and other skin reactions.
The capital cost of production is high as sophisticated machinery is required.

14. Applications of Single-Cell Protein
Provides instant energy.
It is extremely good for healthy eyes and skin.
Provides the best protein supplemented food for undernourished children.
Serves as a good source of vitamins, amino acids, minerals, crude fibres,
etc.
Used in therapeutic and natural medicines for:
Controlling obesity.
Lowers blood sugar level in diabetic patients.
Reducing body weight, cholesterol and stress.
Prevents accumulation of cholesterol in the body.

15. Applications of Single-Cell Protein
Used in Cosmetics products for:
Maintaining healthy hair.
Production of different herbal beauty products, like- Biolipstics, herbal
face cream, etc.
Used in Poultry:
As it serves as an excellent and convenient source of proteins and other
nutrients, it is widely used for feeding cattle, birds, fishes etc.

16. Conclusion
Single celled protein (SCP) production, referring to the fact that most of the
micro-organisms used as producers grow as single or filamentous
individuals rather than as complex multi-cellular organism such as plants or
animals.
 Use of microbes in the production of proteins gives many advantages over
the conventional methods.
 Microbes have shorter generation time, allow easy transformation, utilize
many substrates, have no requirements in arable land or any particular
season to grow and have the possibility of continuous production in any
part of the world.
 The cell yield varies according to the substrate and type of microorganism.