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SINGLE-CELL PROTIEN
Any of a group of complex organic macromolecules that contain carbon,
hydrogen, oxygen, nitrogen, and usually sulphur and are composed of one
or more chains of amino acids.
Proteins are fundamental components of all living cells and include many
substances, such as enzymes, hormones, and antibodies, that are
necessary for the proper functioning of an organism.
They are essential in the diet of animals for the growth and repair of
tissue and can be obtained from foods such as meat, fish, eggs, milk, and
legumes.
Essentials amino
acids
FAO
recommendation
Minimum
Phenylalanine
Methionine
Leucine
2.2
2.2
2.2
1.1
1.1
1.1
Valine
Lysine
Isoleucine
1.6
1.6
1.4
0.8
0.8
0.7
Threonine
Tryptophan
Total
1.0
0.5
12.7
0.5
0.25
6.35
WHY DO WE NEED ALTERNATIVE SOURCES OF
FOOD?
 About 50 years ago (1934-1938) the less
developed areas of the world were the main
exporters of grain to the developed world.
 Since 1948 the food flow has reversed, from
the developed world to the less developed,
mainly due to the rate of growth of the world's
population which was much higher in the less
developed countries.
 This means that during the 35-year period
(1980-2015) we must produce as much food as we
have since the dawn of agriculture about 12000
years ago.
REALITY
Death from starvation, malnutrition and related
diseases is a reality in many countries today.
The World Health Organisation (WHO) estimates
that 12,000,000 people die of hunger and starvation
related diseases every year. Half are children under
the age of 5.
HISTORY
• Used to named as Microbial Proteins.
• 1966: M.I.T Professor Carroll L.Wilson renamed it as “Single Cell
Proteins”
• Transportation of food was common in the past but with the
increase in population, energy crisis has encounter the world.
• In 60s’, idea that the dried cells of micro-organisms can become
an ultimate part to solve this problem.
• Thus gained research interest among the scientists & industries
(specifically oil industry).
• In 20th Century, the SCP technology for the
production of protein-rich contents from
the microbes on the large scale was
established.
• 1950s: Food-from-oil.
• 1960s:
British
Petroleum
Industry
developed technique named as “Proteinfrom-oil Process” using yeast fed on waxy
paraffin, a product of oil refineries.
ADVANTAGES OF USING MICROORGANISMS
1. MO grow at very fast rate under optimal conditions
2. Quality and quantity is better than higher plants and
animals
3. Wide range of raw materials can be used
4. Culture and fermentation conditions are simple
5. MO can be genetically manipulated
It has high protein and low fat content.
It is good source of vitamins particularly B-complex. e.g. Yeasts
It can be produced through-out the year.
Waste materials are used as substrate for the production of these
proteins.
It reduces the environmental pollution and helps in recycling
of materials.
SCP organisms grow faster and produce large quantities of SCP from
relatively small area of land and time.
These have proteins with required amino acids that can be easily
selected by genetic engineering.
During the production of SCP biomass, some organisms produce useful
by products such as organic acids and fats.
It can be genetically controlled.
It causes less pollution.
Algal culture can be done in space which is normally unused.
All single-celled microorganisms of interest from the industrial
point of view have a nondigestible envelope, which makes protein
assimilation difficult.
The content of nucleic acids in the unicellular biomass is higher
than the permissible level and may cause disorders of purine
metabolism in the human body.
The biomasses of some unicellular microorganisms have an
unpleasant color (algae), taste, and smell, which make them
unsuitable even for animal consumption.
Food grade production of SCP is more expensive than other
sources of proteins, as it depends on the raw materials.SCP
for human consumption is 10-12 times more expensive than
SCP for animal feed.
Digestion of microbial cells is rather slow, and is frequently
associated with indigestion and allergy reactions.
SINGLE CELL PROTEINS
SINGLE CELL PROTEINS
• The term “Single Cell Protein” refers to the total
protein extracted from the pure cultures of
microorganisms (e.g. yeast, algae, filamentous
fungi, bacteria) and can be used as a protein-rich
food supplements by humans and animals.
• Also known as ”Microbial Protein”
• Single-cell proteins develop when microbes ferment waste materials
(including wood, straw, cannery, and food-processing wastes,
residues from alcohol production, hydrocarbons, or human and
animal excreta).
• 60-80% dry cell weight; contains nucleic acids, fats, CHO, vitamins and
minerals Rich in essential amino acids (Lys-Met)
• The problem with extracting single-cell proteins from the wastes is
the dilution and cost.
• Found in very low concentrations, usually less than 5% .
• Engineers have developed ways to increase the concentrations
including centrifugation, flotation, precipitation, coagulation, and
filtration, or the use of semi-permeable membranes.
Microorganisms
Bacteria
Methylophilus methylotrophus
Pseudomonas sp.
Brevibacterium sp.
Yeasts
Lactobacillus bulgaricus
Candida lipolytica
Bakers yeast
Kluyveromyces fragilis
Fungi
Trichoderma viridae
Aspergillus niger
Actinomycetes
Nocardia sp
Thermomonospora fusca
Algae
Chlorella and
Spirulina
Mushrooms
Agaricus
Morchella
Vovariella
A wide range of substrates can be used to
grow microbial proteins
• whey, orange peel residue, sweet orange residue, sugarcane bagasse,
paper mill waste, rice husks, wheat straw residue, cassava waste, sugar
beet pulp, coconut waste, yam waste, banana pulp, mango waste,
grape waste, sweet potato
Protein
Fat
Ash
Nucleic
Acids
Fungi
Algae
Yeasts
Bacteria
30-45
2-8
9-14
7-10
40-60
7-20
8-10
3-8
45-55
2-6
5-9.5
6-12
50-65
1.5-3.0
3-7
8-12
1. Yeasts and Fungi
Filamentous Fungi used for SCP production are Chaetomium celluloliticum,
Fusarium graminearum, Paecilomyces varioti which grows on cellulose waste,
starch, and sulphite waste liquor respectively and content about 30 – 55 %
protein.
SCP is produced from yeasts viz. Candida utilis, Candida lipolytica, Saccharomyces
cervicea.
Torula yeast (which grows on Ethanol) as a food is obtained through fermentation
using molasses as substrate and it has high protein–carbohydrate ratio than
forages. It is rich in lysine but poor in methionine and cysteine. Saccharomyces
consists of high protein with good balance of amino acids and rich in B–complex
vitamins. It is more suitable as poultry feed.
Yeast are higher in lysine content.
Strict aseptic conditions are required when using Yeast as a SCP production.
Disadvantages:
High nucleic acid content.
Slow growth is observed in Fungi vis-à-vis than yeast & bacteria.
Contamination risk.
Mycotoxins are also produced.
2. BACTERIA
• They have more than 60% protein but are poor in sulphur containing
amino acids.
• Brevibacterium uses hydrocarbons while Methylophilus methylitropous
uses methanol as a substrate.
Disadvantages:
• It has high nucleic acid content.
• Recovering the cells is a bit problematic.
• Endotoxin production should be carefully tested.
3. ALGAE:
• Chlorella, Scenedesmus acutus and Spirulina maxima are grown for
SCP.
• These have about 60% protein with good amino acid composition but
less in sulphur containing amino acids.
• Chlorella and Spirulina are used for commercial scale production in
Taiwan, Thailand, Japan, Israel, Mexico and USA.
• It is spray dried and sold as pills and powders.
Disadvantages:
• As they are rich in Chlorophyll, it is not advised for human
consumption (except Spirulina).
• It has low density.
• There is lot of risk of contamination during growth.
Microorganism
Substrate
Used as
Used commercially
Chlorella sp.
CO2 + sunlight
Feed
Yes (Japan and Taiwan)
Scenedesmus acutus
CO2 + sunlight
-
Spirulina maxima
CO2 + sunlight
Feed
Yes (Mexico)
1. Confectionery
-
Yes (U.K.), Symba process
2. Ethanol
Feed
Yes (USA)
3. Sulphite liquor
-
Yes (Europe, USA, Russia)
Whey
-
Yes; Vienna process
Whey
-
Yes; Kiel process
C. lipolytica
n-alkanes (C10 - C23) +
ammonia
-
Yes (Russia)
Kluyveromyces fragilis
Whey
Food
Yes (France); Le Bel process
Saccharomyces cerevisiae
Molasses
(Food)*
Yes
Chaetomium cellulolyticum
Cellulosic wastes
-
Promising
Fusarium graminearum
Starch hydrolysate
Paecilomyces varioti
Sulphite liquor
-
Yes (Finland); Pekilo process
Brevibacterium sp.
C1 - C4 hydrocarbons
-
Process developed
Methylophilus
methylotrophus
Methanol
Feed
Yes (U.K.),
Algae
Yeasts
Candida utilis (Torula Yeast)
C. intermedia
C. krusei (+ Lactobacillus
bulgarius)
Fungi
Yes (U.K)
Bacteria
Organism
Mass Doubling
Bacteria and yeast
10-120 min
Mold and Algae
2-6h
Grass and some plants
1-2wk
Chickens
2-4 wk
Pigs
4-6 wk
Cattle
1-2 mo
People
0.2-0.5 yrs
Efficiency of protein production of several protein sources in 24 hours (16)
Organism
(1,000 kg)
Amount of Protein
Beef Cattle
Soybeans
Yeast
Bacteria
1.0 kg
10.0 kg
100.0 tn
100x10,000,000 tn
Protein
Fat
Ash
Nucleic
Acids
Fungi
Algae
Yeasts
Bacteria
30-45
2-8
9-14
7-10
40-60
7-20
8-10
3-8
45-55
2-6
5-9.5
6-12
50-65
1.5-3.0
3-7
8-12
Egg
7.6
7.7
4.6
3.9
2.8
6.3
7.8
Threonine
5.4
4.8
4.6
-
2.9
5.0
4.6
Methionine
2.0
1.7
1.4
1
1.5
3.2
2.4
Cysteine
-
-
0.4
-
2.5
2.4
-
Tryptophan
-
1.0
1.4
1.25
1.1
1.6
-
Isoleucine
5.3
4.6
6.0
3.2
3.3
6.8
6.4
Valine
6.5
3.9
5.4
3.9
4.4
7.4
6.9
Phenylalanine
4.6
4.1
5.0
3.9
4.4
7.4
6.9
Histidine
7.8
2.7
-
2.8
2.0
6.3
4.9
Arginine
6.4
2.4
-
-
4.8
-
-
Cow
milk
Wheat
PeniciIllium
notatum
Spirulina
maxima
Saccharomyce
s cerevicia
Cellulomonas
Lysine
 The vitamins of micro-organisms are primarily of the B type, B12 occurs mostly in
bacteria, while vitamin A is usually found in algae. Table shows the vitamin content
of various food MO; Vitamin content of various food micro-organisms (mg/100 g
dry weight)
The quality of SCP is an important factor for commercial
production.
1. First parameter which reflects the quality of a protein, is
the is the percentage of the total nitrogen Digestibility
Coefficient (DC) consumed which is absorbed from the
digestive tract.
2. Estimation of the Biological Value (BV) is a measure of
nitrogen retained for growth or maintenance.
3. An accurate method to evaluate the quality of proteins
is the determination of the Protein Efficiency Ratio (PER),
expressed in terms of weight gain per unit of protein
consumed by the test animal in short-term feeding trials.
4. Finally, the Net Protein Utilization (NPU) -equivalent to
the calculation BVxDC-is a measure of the digestibility of
the protein and the biological value of the amino acids
absorbed from the food.
Source
Nitrogen
(%)
Crude Protein
(%)
Filamentous fungi
5-8
31-50
Algae
7.5-10
47-63
Yeast
7.5-8.5
47-53
Bacteria
11.5-12.5
72-78
Milk
3.5-4.0
22-25
Beef
13-14.4
81-90
Egg
5.6
35
Rice
1.2-1.4
7.5-9.0
Wheat Flour
1.6-2.2
9.8-13.5
Corn meal
1.1-1.5
7.0-9.4
About 70-80% of the total cell nitrogen is represented
by amino acids while the rest occurs in nucleic acids.
This concentration of nucleic acids is higher than other
conventional proteins and is characteristic of all fast
growing organisms.
The problem which occurs from the consumption of
proteins with high concentration of nucleic acids (78
g/100 g protein dry weight) is the high level of uric acid in
the blood, sometimes resulting in the disease gout.
Uric acid is a product of purine metabolism.
 Most mammals, reptiles and molluscs possess the
enzyme uricase, and the end product of purine metabolism
is allantoin.
 Man, birds and some reptiles lack the enzyme uricase
and the end product of purine degradation is uric acid.
 The removal or reduction of nucleic acid content of
various SCP's is achieved with one of the following
treatments: chemical treatment with NaOH; treatment of
cells with 10% NaCl; thermal shock.
 These methods aim to reduce the RNA content from
about 7% to 1% which is considered within acceptable
levels.
Production Of SCP:
• Production of SCP involves following steps:
1.
2.
3.
4.
5.
Selection of Strain of microbe and Substrate
Fermentation
Harvesting
Post harvest treatment
Processing of SCP
Selection of Strain of Microbe &
Substrate:
• Very Crucial step.
• Microbe selected shouldn’t produce toxicity
in its biomass.
• It should not be harmful for a consumer to
consume.
• Selected microbe should produce a large
quantity of protein.
• Substrate should be cheap, effective, allow
favorable growth and ease of isolation.
Fermentation:
• Is done in a large chamber either of glass or
stainless steel called “Fermentor”.
• Fermentation should be done under
sterilized conditions.
• Controlled conditions as necessary e.g.
Temperature, Pressure, pH, Humidity etc.
• Usually fed-batch cultures are used for the
fermentation of microbes.
Harvesting
• For the producing and harvesting of microbial proteins cost is a major
problem.
• There are many methods available for concentrating the solutions like
filtration, precipitation, centrifugation and the use of semi-permeable
membranes.
• The equipment used for these methods of de-watering is expensive and
so would not be suitable for small scale productions and operations.
• Single cell proteins need to be dried to 10% moisture or they can be
condensed and denatured to prevent spoilage.
Post-harvesting Fermentation:
• Isolated microbial colonies are subjected to various differential
techniques.
• E.g. Centrifugation, Washing, Drying etc.
• Produced protein contain impurities in it e.g. carbohydrates,
nucleic acids, lipid contents, salts etc
• Pure protein isolation can be done by disrupting the cell wall
through crushing, crumbling, cycles of freezing & thawing,
grinding & thermal shocks.
• Nucleic acid can be remove by:
1. By treatment with Nacl 10%
2. By Chemicals e.g. NaoH
3. Thermal shocks
4. Enzymes Treatment e.g. ribonucleases
Raw material
Cheese whey
Ethanol
N-paraffins
Sulfite waste
liquor
Organism
Scale
Product
Organization
Kluyveromyces fragilis
5000 tons/year
Food yeast
fermentation nutrient
Universal Foods
Corporation,
Juneau, Wisconsin
Candida utilis
10,000
tons/year
Torula yeast, food
ingredient
Pure culture
products, Hutchinson,
Minnesota
Candida guillienmondis
20,000 to
40,000
tons/year
Food yeast
All Union Research
Institute of Protein
Biosynthesis,
USSR
Torula yeast
Rhinelender paper
corporation
Rhinelender
Wisconsin
Candida utilis
15 tons/year
Raw material
Organism
Scale
Product
Organization
Glucose (Food
Grade)
Fusarium graminearium
50-100
tons/year
Mycoprotein
(human food)
Ranks Hovis Mc Dougall,
High Wycombe,UK
Cheese whey
Penicillium cyclopium
300 tons/year
Animal feed
Heurty , S.A.,France
Coffee waste
Trichoderma harzianum
40,000 lit
Animal feed
ICAITI,Guatemala and El
Salvador
Paecilomyces varioti
10,000
tons/year
Animal
feed(Pekilo
protein)
Tampela and Finnish Pulp
and paper Research
Institute,Jamsankoski,
Finland
Animal
feed(Waterloo
process)
Envirocon Ltd,Vancouver,
BC, Canada;University of
Waterloo,Ontario
Sulfite waste
liquor
Pulp mill wastes
Chaetomium cellulyticum
1 tons/day
Organism
Chlorella sp.
Raw material
CO2
Production
Producer or developer
2 metric
tons/day
Taiwan Chlorella
Manufacture Co.Ltd,
Taipei
Scenedesmus
acutus
CO2,Urea
20
Central Food Technological
grams/
Research
square
Institute,Mysore,India
meter/day
Spirulina
maxima
CO2, or
NaHCO3,
Na2CO3
320 metric
tons/year
Sosa Texococo,SA Mexico
City
i. Products obtained via microbiological synthesis must be
competitive with traditional food sources.
ii. When estimating costs involved in SCP production, such major
factors as the biomass yield, cooling, and oxygen requirements
should be taken into consideration.
iii. They depend not only on the choice of substrate, but on the choice
of the microorganism as well. All this determines the cost of
production and economic feasibility.
iv. It is obvious that one of the major factors limiting the use of
hydrocarbon yeast is the residual hydrocarbon content.
v. Demands of the country or its separate regions for protein of a
particular type
vi. Expenditures for the delivery of finished products to the places of
their consumption
vii.Disposal of by products.
• Raw materials used in production of SCP are the main safety hazard.
•The acceptability of SCP when presented as a human food does not
depend only on its safety and nutritional value but also the mind
frame of people to consume material derived from microbes which is
concerned to social and ethical issues like psychological, sociological
and religious implications.
•A more intensive clinical and toxicology testing including short-term
acute toxicity testing (animal species) and followed by extensive and
detailed long term studies.
•And in return incurs a huge scientific and financial investment.
Biolipsticks and herbal face creams are produced in Japan
from the phycocyanin pigment of Spirulina.
APPLICATIONS
1. As protein supplemented food•
•
Also source of vitamins, amino acids, minerals,
crude fibers, etc.
Supplemented food for undernourished children.
2. As health food•
Controls obesity
•
Provides instant energy .
•
Example- Spirulina- part of diet of US Olympic
team.
3.
In therapeutic and natural medicines• Reduce body weight, cholesterol, stress.
• Lowers blood sugar level in diabetic(due
to presence of B - linolenic acid)
• Prevents accumulation of cholesterol in
body.
• Healthy eyes and skin (beta carotene)
• Beta carotene ( anti cancer substanceUN National Cancer Research Institute)
• Increase lactation.
MEDICINAL USES OF SPIRULINA
• Strengthen and improve immune system
• Phycocyanins build blood cells
• Increase antiviral activity
• Exhibits anti cancer activity
• The US Olympic teams take spirulina tablet as a source
of instant energy.
Studies showed that spirulina consumption of 4 weeks
reduced serum cholestrol level in human beings by 4.5%
and significantly reduced body weight by 1.4±0.4 kg
after 4 weeks.
There is no changes in clinical parameters (Blood
Pressure) or in biochemical variables (haemoglobin,
blood cells, sedimentation rate) and absence of adverse
effects.
4. In cosmetics• Important role in maintaining healthy hair
(vitamin A and B).
• Many herbal beauty products.
• Biolipstics and herbal face cream(Phycocyanin).
• Capable of replacing coal tar dye based
cosmetics.
5. Poultry and cattle feed• Excellent, convenient source of protein and
other nutrients.
• Used to feed cattle, fishes etc.
6. In the technical field as:
• Paper processing, leather processing
and as foam stabilizers
.
CONCLUSION
• At present SCP production is in its infancy. One of the ways to enhance
productivity and quality is genetic improvements of micro-organisms.
• Using microbial biomass as a food source deserves serious consideration because
of insufficient world food supply and high protein content of most microorganisms.
For future
First,
food technology problems have to be
solved in order to make it similar to
familiar foods and
Second,
the production should compare
favourably with other protein sources.
Sample of the single cell protein
biosolids after the drum dryer.
THANK YOU
-PHARMA STREET