Single Cell Protein

SINGLE CELL PROTEIN ( SCP )

To meet the protein need of our growing population, it is important to include non-conventional protein sources in our diet. Important non – conventional sources are oil seed proteins, leaf protein concentrate (LPC), fish protein concentrate (FPC) and single cell proteins (SCP).

F   “ Single Cell Protein (SCP) refers to the dried microbial cells or total protein extracted from pure microbial cell culture (Algae, bacteria, filamentous fungi, yeasts), which can be used as food supplement to humans (Food Grade) or animals (Feed grade).”

• The term SCP was coined in 1966 by Carol L. Wilson. 

¶  Microorganisms like algae, fungi, yeast and bacteria, utilize inexpensive feedstock and wastes as sources of carbon and energy for growth to produce biomass, protein concentrate or amino acids.

¶  Various microorganisms are used for human consumption worldwide as SCP or as components of traditional food starters, including algae (Spirulina, Chlorella, Laminaria, Rhodymenia, etc.), bacteria (Lactobacillus, Cellulomonas, Alcaligenes, etc.), fungi (Fusarium, Aspergillus, Penicillium, etc.) and yeasts (Saccharomyces, Candida, Kluyveromyces, Pichia and Torulopsis)

¶  These are described as dried cells of microorganisms which are grown and allowed  multiplying in large fermeters.

HISTORY OF SCP :

v  Yeast was the first microorganism whose importance as animal feed supplement was recognized almost a century ago.

v  Microorganisms have the ability to upgrade low protein organic material to high protein food, and this phenomenon was employed in Germany during the First World War when the growth of Saccharomyces cerevisiae was exploited for human consumption.

·         Moreover, Candida arborea and C. utilis were used during the Second World War and about 60% of the country pre-war food input was replaced.

• Pruteen was the first commercial single cell protein used as animal feed additive. {Trade name for microbial protein produced by growing bacteria, Methylophilus methylotrophus, on methanol (derived from methane or natural gas); 70% protein in dry weight.}

·         In the 1960s, researchers at British Petroleum developed what they called "proteins-from-oil process": a technology for producing single cell protein by yeast fed by waxy n-paraffins, a product produced by oil refineries.

·         Several investigations were carried out using cellulose and hemicelluloses waste as a suitable substrate for increasing single cell protein production (Azzam, 1992; Pessoa et al., 1997; Bozakuk, 2002; Zubi, 2005).

APPLICATIONS OF SCP :

·         In animal nutrition as : fattening calves, poultry, pigs and fish breading.

·         In food it is used as : aroma carriers, vitamin carrier, emulsifying aids and to improve the nutritive value of baked products, in soups, in ready-to-serve-meals and in diet recipes.

·         In the technical field : in paper processing, leather processing and as foam stabilizers.

Criteria for production of SCP :

 If SCP is to be used successfully, there are five main criteria to be satisfied:

1.  The SCP must be safe to eat.

2.  The nutritional value dependent on the amino acid composition must be high.

3.  It must be acceptable to the general public.

4.  It must have the functionality, i.e. characteristics, which are found in common staple foods.

5.  The economic viability of the SCP process

PRODUCTION OF SCP :

The production of Single Cell Protein can be done by using waste materials as the substrate, specifically agricultural wastes such as wood shavings, sawdust, corn cobs, and many others like food processing wastes, residues from alcohol production, hydrocarbons, or human and animal excreta.

The process of SCP production from any microorganism or substrate would have the following basic steps:    

Ä  Provision of a carbon source; it may need physical and/or chemical pretreatments.

Ä  Addition, to the carbon source, of sources of nitrogen, phosphorus and other 
nutrients needed to support optimal growth of the selected microorganism.

Ä  Prevention of contamination by maintaining hygienic conditions. The medium components may be heated or sterilized by filtration and fermentation equipments may be sterilized.

Ä  The selected microorganism is inoculated in a pure state.

Ä  SCP processes are highly aerobic (except those using algae). Therefore, adequate aeration must be provided. In addition, cooling is necessary as considerable heat is generated.

Ä  The microbial biomass is recovered from the medium.

Ä  Processing of the biomass for enhancing its usefulness and/or storability.

Ä  The general approaches for the recovery of biomass are as follows: (1) bacteria-flocculation and floatation combined with centrifugation, (2) yeast : centrifugation,(3) filamentous organisms-filtration.

ADVANTAGES AND DISADVANTAGES OF SINGLE CELL PROTEIN

Advantages :

Large scale SCP production has some advantages over the conventional food production, these advantages are :

J  Microorganisms have a high rate of multiplication to hence rapid succession of generation (algae: 2-6hours, yeast: 1-3 hours, bacteria: 0.5-2 hours)

J  They can be easily genetically modified for varying the amino acid composition.

J  A very high protein content 43-85 % in the dry mass.

J  They can utilize a broad spectrum of raw materials as carbon sources, which include even waste products. Thus they help in the removal of pollutants also.

J  Strains with high yield and good composition can be selected or produce relatively easily.

J  Microbial biomass production occurs in continuous cultures and the quality is consistent since the growth is independent of seasonal and climatic variations.

J  Land requirements is low and is ecologically beneficial.

J  It is not dependent on climate.

Disadvantages :

L  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.

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

L  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.

L  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.

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

L  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.

SAFETY, ACCEPTABILITY, AND TOXICOLOGY OF SCP

There are several limitations regarding the widespread use of SCP :

§  Possibility of contamination with pathological organisms in SCP.

§  Association of carcinogenic and other toxic substances with SCP is often observed. The nature and production of these compounds depend on raw materials and the type of microorganism used.

§  Digestion of microbial cells is rather slow, and is frequently associated with indigestion and allergy reactions.

§  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

SPIRULINA

(Wonder Food of 21st Century )

Introduction :

Spirulina is a human and animal food or nutritional supplement made primarily from two species of cyanobacteria: Arthrospira platensis and Arthrospira maxima.

§  It is symbiotic, multicellular and filamentous blue-green microalgae with that can fix nitrogen from air.

§  Spirulina can be rod or disk shaped.

§  Their main photosynthetic pigment is phycocyanin, which is blue in colour.

@  The Aztecs in Mexico and the natives of Chad in Africa had been historically using Spirulina as part of their diet for centuries. In 1967 spirulina was established as a “wonderful future food source” in the International Association of Applied Microbiology.

@  In 1981, FDA (Food and Drug Administration) of USA certified that spirulina is “The healthy and safety product free from side effects”.

Physical Properties: 

Appearance – Fine powder

Color – Dark blue-green

Odor and Taste – Mild like seaweed

Bulk Density – .35 to .60 kg/liter

MASS CULTIVATION OF SPIRULINA :

A.  FOR SMALL SCALE PRODUCTION:

MUD POT SPIRULINA CULTIVATION  :

A simple and cheap technology has been developed for rural women to cultivate spirulina at home, requiring little space and investment. This can be a profitable industry as dried spirulina can be sold at about Rs. 300/- per kg.

Materials

Three mud pots of 35 to 40 litre capacity/25 sq.m. of exposed and protected space. 

Medium

Bio-gas slurry and 2-3 grams of sea salt or chemical medium (Potassium dihydrogen Phosphate, Cooking Soda and Sodium Chloride); and Pure Spirulina Culture. 

Working

 This method requires only 3 mud pots of 35 to 40 liters capacity and an exposed but protected open area. The medium for the cultivation is the bio-gas slurry which is very cheap and easily available. Then the sea-salt or a mix of Potassium dihydrogen Phosphate, Cooking Soda and Sodium Chloride, all this and pure Spirulina culture. The method of working is very simple. All the three pots are buried till the neck in the ground. These are then filled with water and the slurry medium. Next the pure Spirulina culture is added to the pots. These are to be kept in sunlight and need to be stirred at least 4 times a day. After 3-4 days of maturation the Spirulina is ready. It is now filtered in clean cloth and then washed in fresh water. Spirulina can be immediately used for consumption or if a powdered form is desired it should be dried immediately.

Advantages :

J  Spirulina grown in 3 earthen pots of 35-40 litre capacity is sufficient to provide 2 grams per day (per person) high-quality spirulina powder to meet 100% vitamin A and 200% vitamin B-12 requirement, daily.

B.  FOR COMMERCIAL PRODUCTION :

The largest commercial production of Spirulina is carried out in United States, Thailand, India, Taiwan, China, Pakistan and Myanmar (i.e. Burma).

a)      ADVANCED POND CULTIVATION SYSTEMS :

·           Most current commercial farms over the past 30 years have been designed with shallow raceway ponds circulated by paddlewheels. Ponds vary in size up to 5000 square meters (about 1.25 acres), and water depth is usually 15 to 25 centimeters. 

·           The production ponds are essentially back-to-back open raceways, 200 mm deep (culture depth 150 mm) and lined with HDPE (high density polyethelene). Eight fin paddle wheels provide the mixing at a linear rate of about 23 cms⁻¹, resulting in minimal aeration because of the large diameter. The outdoor ponds are operated as a series of batch reactors and have surface areas of 2.5, 25, 500, and 2,000 m². Inoculation volumes range between 20 and 25% of  the volumes of the next size cultures. CO₂ was supplied on demand following an increase in pH above pH 9.5.

·           Optimum temperature : between 25 and 35°C. 

·           Optimum light intensities : 30-40 klux

·           The filaments of Spirulina float on surface of water forming thick mat. Therefore, it can be harvested by fine mesh steel screens, nylon or cotton cloths, etc.

• When full growth of Spirulina is over, it is screened from the pond and added to aquaculture to feed fish or dried in a small solar drier for human food.

L  










Disadvantage : 
Open ponds are highly vulnerable to contamination by other microorganisms, such as other algal species or bacteria. Thus cultivators usually choose closed systems for monocultures. Open systems also do not offer control over temperature and lighting. The growing season is largely dependent on location and, aside from tropical areas, is limited to the warmer months.

b)        Tube, coil and vertical plate systems :

In these system, plexiglass tubes and coils act as solar collectors, increasing temperature and extending the growing season. Algae is pumped continuously through rows of connected flexible transparent tubes or coils. Much greater density can be maintained than in open ponds.

J Advantages are increased productivity, less water loss from evaporation, screening out contaminant algae, greater control over the culture, and ability to grow a pure culture of algae.

L  On the downside, algae may stick to the inside of the tubes and block sunlight, and tubes may get too hot. Excessive oxygen produced by the algae while growing can reduce growth. A vertical plate system has been designed that has a flexible orientation to the sun, and allows oxygen to be released at the bottom.

c)   Photobioreactors (PBR):

PBR consists of controlled indoor bioreactors using transparent tanks and artificial lights for growing spirulina.Outdoor commercial bioreactors are designed in modules with rows of transparent tubes stretched along the ground, or in vertical cylinders. Companies are offering bioreactors for high-value spirulina.

Shri A.M.M. Murugappa Chettiar Research Central (MCRC), Madras, and the other at Central Food Technology and Research Institute (CFTRI), Mysore. Madras centre is the biggest food grade Spiulina farm in India. 

HEALTH BENEFITS OF SPIRULINA :

• The Spirulina is the number one food for combating malnutrition.
• Large quantity of beta carotene present which is important in avoiding xerophtalmia or night blindness.
• As an antioxidant which is useful in reducing the progress of certain cancerous tumors and in neutralizing and eliminating free radicals produced by nuclear irradiation.
• The vitamin E and the superoxide dismutase found in Spirulina also are strong antioxidants which combat ageing and infection.
• The non-saturated fatty acid, gamma linolenic acid strengthens cell membranes, thus reducing infection. 
• Polysaccharides produced by Spirulina keep the HIV-1 virus from replicating.
• Spirulina rids the intestines of Candida albicans infections, which commonly lead to malnutrition in AIDS patients
• High level of readily assimilable iron in Spirulina and its great amount of vitamin B12 .

Dose Administration:

Dosage should be maintained according to physical condition and requirements of age.

Recommended dosage for

Adults - 2 to 4 grams par day.

Children - ½ to 3 grams per day.

NUTRITIONAL FACTS :

ADVERSE EFFECTS :

Some people have reported to experience some minor symptoms after taking Spirulina. These Spirulina side effects include:

N  Slight Fever ( this can be normal since the body needs to burn extra protein found in Spirulina )

N  Slight dizziness and nausea.

N  Thirst and constipation

N  Stomach ache and other gastrointestinal symptoms.

N  Slight body risk or skin itching.

N  Patient’s of Liver and Kidney should be taken cautiously due to high concentrated protein and nutrition.

J  [Increased water intake could be normalized such type of minor symptoms.]

J  Spirulina supplements come in the form of powder, tablet or capsule (pill form) or liquid extract. 

YEAST

Yeast is another source of Single Cell Protein, and have been produced since 2500 BC in bread and beverage production.

F  In World War I, Torula yeast (Candida utilis) was produced in Germany and used in soups and sausages.

F Few examples of yeasts that often used in SCP production are Candida utilis (Torula), Saccharomyces cerevisiae, Candida lipolytica, and many others.

Yeast has some advantages among other SCP sources, such as:

¶ Easy to harvest because of their size (larger than bacteria)

¶ High level of malic acid content

¶ High lysine content

¶ Can grow at acidic pH

¶ Long history of traditional use 

COMMERCIAL SCALE PRODUCTION OF YEAST

·         Yeasts are facultative anaerobes, and can grow with or without oxygen. In the presence of oxygen, they convert sugars to CO2, energy and biomass. In anaerobic conditions, as in alcoholic fermentation, yeasts do not grow efficiently, and sugars are converted to intermediate by-products such as ethanol, glycerol and CO2. Therefore, in yeast propagation, the supply of air is necessary for optimum biomass production.

·         Food and fodder yeast is  manufactured from waste materials, such as wood shavings, sawdust, strain, corn cobs, other agricultural wastes.

·         Yeasts are capable of assimilating diverse source of carbon.

·         Medium may be pretreated with acid to remove sulphides and heated to precipitate protein.

Factors Affecting the Yield of Yeast Biomass :

(i) Organic substrate and nitrogen ratio (optimum C : N ratio favoring high protein content should be between 7:1 and 10:1); 

(ii) pH of nutrient medium (pH should be in the range of 3.5 to 4.5 to minimize growth of bacterial contaminates); 

(iii) Temperature (it differs from organism to organism). Most yeasts have specific growth rate in the range of 30°C to 34°C. Some strains also grow in the range of 40-45°C; 

(iv) Oxygen (for growth on carbohydrates) : O₂ required should be 1 g/g of dried cells, and for growth on n-alkanes it should be about 2 g/g dried cells); 

(v) Maintenance of sterile condition throughout  the process and suitable strain of yeast.

Process :

During manufacturing, the strain is inoculated into a medium which contains molasses and corn-steep liquor as source of carbon, nitrogen and mineral salts. Temperature 25-26⁰C is maintained. It is properly aerated during incubation period. The yeast in the final trade bioreactor is concentrated by centrifugation and finally harvested by a filter press or a rotary vacuum filter, until it contains 27–33 % of dry cell mass. The yeast cake is blended with suitable amounts of water and emulsifiers and cutting oils (soybean or cottonseed oil) to obtain its extrudable form. The yeast is then packaged and shipped as compressed fresh baker’s yeast, or thermolysed and dried to form various types of dry yeast. Yeast cakes must be kept cool to preserve the cells and prevent spoilage by other microorganisms.

F Commercial products : Toprina , Torutein

 Advantages :

J  The mass cultivation of yeast for use as food is to compensate the dietary inadequacies of cheap food materials, especially in the regions where human malnutrition is chronic.

J  It is also used in lowering BOD of the effluents from industrial plants.

J  In pet food industry and as food seasoning.

J  It is an excellent source of protein and vitamins, especially the B-complex vitamins, whose functions are related to metabolism, as well as other minerals and cofactors required for growth.

J  It is also naturally low in fat and sodium. 

J  Yeast S. boulardii used to maintain and restore the natural flora in the gastrointestinal tract,  reduce the symptoms of acute diarrhea in children and  prevent re infection of Clostridium difficile.

FUSARIUM

·         Fungi have been influencing human affairs for thousands of years, whether as a direct food source, as a medicine, or in a food process.

·         Fusarium graminearum is the conidial stage of the Ascomycote fungus Gibberella zeae. The fungus exists mainly as a saprobiont in soil, although  it is capable of parasitising wheat and other cereals. It has a mycelium of narrow, branched and septate hyphae. Fusarium venenatum is also used for the same.

·         This basis for a naturally fibrous (and therefore 'chewy') texture has been exploited in the formulation of meat analogues, which enables it to be used as the major ingredient in a range of meat alternative products marketed by Marlow Foods under the Quorn ™ brand name.

@ Quorn is now available in supermarkets, marketed as a high-protein, low-fat, cholesterol-free ‘meat alternative’ in Europe and North America.

 Advantages :

J  No animal fat and no cholesterol; 

J  High content of protein (nutritive value as high as that of skimmed milk protein);

J  High dietary fibre content,

J  Contains useful amounts of trace elements and B vitamins. 

J  Control of body mass and the lower risk of heart disease. 

COMMERCIAL PRODUCTION OF FUSARIUM

• Medium : C source : food grade glucose syrup, N source : gaseous ammonia, Other mineral ions, including potassium, magnesium and phosphate, are also supplied, as well as trace elements, salts, and biotin. Carbon, nitrogen (C:N) ratio is required to be in the range of 5:1 to 15:1.
• pH is controlled at 6 by gaseous ammonia addition and temperature ranges from 25°C to 30°C.
• Stringent precautions are taken to avoid contamination with unwanted organisms which would ruin the product and compete with Fusarium for the substrate. These include the initial sterilisation of the fermenter, using steam. The incoming nutrients are heat sterilised and a filtered air supply is used.
• Air lift or loop fermenters run continuously for six weeks, after which there is a two week period for cleaning and preparing the fermenter for the next run. During the six week run, there is a steady input of nutrients and a corresponding output of medium containing the product

 Fermenters fed into the air inlet stream.Cell concentrations are 15-20g/L and a specific growth rate of up to 0.2h-1 is achieved.Following cyclone separation and an RNA reduction step, cells are recovered by rotary vacuum filtration and formulated into a range of products.

MUSHROOMS

Mushrooms are the members of higher fungi, belonging to the class Ascomycetes(e.g. Morchella, Tuber, etc.) and Basidiomycetes (e.g. Agaricus, Auricularia, Tremella,etc.).

Ex :  White mushroom (Agaricus bisporus), paddy-straw mushroom (Volvariella vovvacea), oyster mushroom etc.

Advantages :

Mushrooms are highly proteinaceous and are used as food. Protein is the most critical component which contributes to a lot of nutritional value of food.  Protein in mushrooms have 60-70 % digestibility and contains all the essential amino acids.

It has medicinal properties also. A high amount of retene is present in the button mushroom which is supposed to have an antagonistic effect on some forms of tumours.   

A large variety of free and combined fatty acids also occur in A. bisporus with high concentration of palmic acid, stearic acid and oleic acid.

They appear as a good source of several vitamins (thiamin, riboflavin, niacin, biotin, ascorbic acid, vitamin A, B, C, D, and minerals (sodium, potassium, calcium, iron, etc.), and essential amino acids (methionin, citralline, ornithin).

Cultivation Technology of White Button Mushrooms ( A. bisporus ):

The whole process of mushroom production can be divided into the following steps:

 (i)            Spawn production

(ii)            Compost preparation

(iii)           Spawning

(iv)           Spawn running

(v)             Casing

(vi)            Fruiting

(vii)           Harvesting and yield

(viii)          Packaging

1.      Spawn Production

Spawn is produced from fruiting culture / stocks of selected strains of mushrooms under sterile conditions. Stock culture may be produced in the lab or may be obtained from other reputed sources. Fruiting culture is mainly imported from various places including foreign sources which give higher yield than Indian strains and the spawn is produced in the lab. The spawn should be of good quality in terms of flavour, texture and size apart from having potential for high yield and longer shelf life.

2.      Compost Preparation

The substrate on which button mushroom grows is mainly prepared from a mixture of plant wastes (cereal straw/ sugarcane bagasse etc.), salts (urea , superphosphate / gypsum etc), supplements (rice bran/ wheat bran) and water. In order to produce 1 kg.of mushroom, 220 g. of dry substrate materials are required. It is recommended that each ton of compost should contain 6.6 kg. nitrogen, 2.0 kg. phosphate and 5.0 kg. of potassium (N:P:K- 33: 10:25) which would get converted into 1.98% N, 0.62% P and 1.5% K on a dry weight basis. The ratio of C: N in a good substrate should be 25-30 : 1 at the time of staking and 16-17 : 1 in the case of final compost.

3.      Spawning

The process of mixing spawn with compost is called spawning. The different methods followed for spawning are given below:

(i)                 Spot Spawning: Lumps of spawn are planted in 5 cm. deep holes made in the compost at a distance of 20-25 cm. The holes are later covered with compost.

(ii)               Surface Spawning: The spawn is evenly spread in the top layer of the compost and then mixed to a depth of 3-5 cm. The top portion is covered with a thin layer of compost.

(iii)             Layer Spawning: About 3-4 layers of spawn mixed with compost are prepared which is again covered with a thin layer of compost like in surface spawning.

The spawn is mixed through the whole mass of compost at the rate of 7.5 ml./ kg. compost or 500 to 750 g./ 100 kg. compost (0.5 to 0.75%).        

4.      Spawn Running

After the spawning process is over, the compost is filled in polythene bags(90x90 cm., 150 gauge thick having a capacity of 20-25 kg. per bag)/ trays(mostly wooden trays 1x1/2 m. accommodating 20-30 kg. compost) / shelves which are either covered with a  newspaper sheet or polythene. The fungal bodies grow out from the spawn and take about two weeks (12-14 days) to colonise. The temperature maintained in cropping room is 23 ± 2⁰ C. Higher temperature is detrimental for growth of the spawn and any temperature below than that specified for the purpose would result in slower spawn run. The relative humidity should be around 90% and a higher than normal CO₂ concentration would be beneficial.

5.   Casing

The compost beds after complete spawn run should be covered with a layer of soil (casing) about 3-4 cm. Thick to induce fruiting. The casing material should be having high porosity, water holding capacity and the pH should range between 7-7.5. Peat moss which is considered to be the best casing material is not available in India, as such the mixtures like garden loam soil and sand (4:1); decomposed cowdung and loam soil (1:1) and spent compost (2-3 years old); sand and lime are commonly used.

The casing soil before application should be either pasteurized (at 66-70⁰ C for 7-8 hours), treated with formaldehyde (2%), formaldehyde (2%) and bavistin (75 ppm.) or steam sterilized. The treatment needs to be done at least 15 days before the material is used for casing. After casing is done the temperature of the room is again maintained at 23-28⁰ C and relative humidity of 85-90% for another 8-10 days. Low CO₂ concentration is favourable for reproductive growth at this stage.

6.   Fruiting

Under favourable environmental conditions viz. temperature (initially 23 ± 2⁰ C for about a week and then 16 ± 2⁰ C ), moisture (2-3 light sprays per day for moistening the casing layer), humidity( above 85%), proper ventilation and CO₂ concentration (0.08-0.15 %) the fruit body initials which appear in the form of pin heads start growing and gradually develop into button stage.

N   Pest & Diseases :

The insect pests mostly observed are nematodes, mites and springtails. The crop is suspect to several diseases like Dry Bubble (brown spot), Wet Bubble (White Mould), Cobweb, Green Mould, False truffle (Truffle disease), Olive green mould, Brown plaster mould and Bacterial blotch.

  

7.  Harvesting and Yield : 

Harvesting is done at button stage and caps measuring 2.5 to 4 cm. across and closed are ideal for the purpose. The first crop appears about three weeks after casing. Mushrooms need to be harvested by light twisting without disturbing the casing soil.

8.  Packing and Storage :

(A)      Short Term Storage : They are highly perishable. Harvested mushrooms are cut at the soil line and washed in a solution of 5g. KMS in 10L. of water for removing the soil particles as well as to induce whiteness. After removing excess water these are packed in perforated poly bags each containing around 250-500 g. of mushrooms. They can be stored in polythene bags at 4-5⁰ C for a short period of 3-4 day. In developed countries, modified atmosphere packaging (MAP) and controlled atmosphere packaging (CAP) are in vogue.

(B)       Long Term Storage : By canning, freeze drying and pickling

References

• www.spirulinasource.com/earthfoodch6c.html
• http://www.springerlink.com/content/l7p0576454687636/fulltext.pdf
• www.newbioreactor.com/
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• http://biomaster2011.blogspot.com/2011/03/single-cell-protein-from-spirulina.html
• www.pelagiaresearchlibrary.com
• http://www.eplantscience.com/
• http://www.sc.ehu.es/qpwugmau/principal/RevUgalde.PDF
• http://www.ftb.com.hr/44/44-407.pdf
• http://www.krishiworld.com/html/mushroom.html
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