2. Microorganisms can be consumed as food known as edible microorganism.
Micro-organisms used are fungi , yeast, algae & bacteria.
The following table shows average different compositions of main groups
of micro– organisms (% dry wt.)
3. COMPARISION OF MICRO-ORGANISMS
ADVANTAGES DIS ADVANTAGES
FUNGI Easy to grow & harvest Lower growth rates & lower
protein content
ALGAE Easy to grow & harvest &
high quality protein
Non –digestible cellulosic
cell wall, concentrate
heavy metals
YEAST Larger in size, lower NA
content , familiarity &
acceptability
Poor digestibility, low
protein content, slow
growth rate
BACTERIA High protein content,
digestible cell wall
High NA content, small in
size, low density
4. Blue green Algae (genus Spirulina) harvested and eaten for centuries by
the Aztecs in Mexico and Africa
Mushrooms , the fruiting bodies of microorganisms that live on decaying
lignocellulosic soil one of the highly prized food items.
Fermentationplaysseveralroles:
enrichment of the
human diet.
Preservation of food.
enrichment of food
substrates biologically.
5. Protein quality is increased by the synthesis of essential amino acids such as lysine, first
limiting amino acid in rice. In the Malaysian tape fermentation the content of lysine is
raised, improving its protein quality.
Microbial protein can be extracted from the cells and converted to meat substitutes.
Mold Rhizopus oligosporus cheap source of protein and enriches food with vitamin B12
and increasing the niacin and riboflavin content.
The grasses are the most efficient fixers and utilizers of carbon dioxide, producing
sugars, starches, and cellulose.
Grasses can double their cell-mass in two to three weeks. A 1000 kg harvest of grass can
be repeated every two to three weeks.
yeasts are much more efficient in this regard. A yeast (1000 kg) grown in tanks on
limited land space can produce 168,000 kg of cells containing 84,000 kg of protein
every two weeks
6. There is much hunger, starvation, and malnutrition in parts of the world today,
and the world population is predicted to reach eight to twelve billion by the year 2050.
As world population increases, the supply of meat and other animal products
available per person is likely to decrease.
7. Only about twenty-five species of more than two thousand edible fungi are widely
accepted as human food
The four most important mushrooms :
■ white mushroom or button mushroom (Agaricus campestris)
■ black forest mushroom shiitake (Lentinus edodes)
■ straw mushroom (Volvariella volvacea)
■ oyster mushroom (Pleurotus ostreatus).
9. Mushrooms can be grown on inexpensive, non enable substrates like
cereal straws, banana leaves, sawdust, animal manure.
Mushrooms high in essential amino acids and have great nutritional
value.
Mushrooms, a microbial product, are thus likely to play an important role
in feeding the world in the future
10. Single cell oil
■ Lipids obtained from microbes or single celled entity.
■ Obtained from yeast , bacteria and microalgae.
■ Lipid accumulation by microorganisms depends on :
genetic constituents
different culture conditions ( pH , temp , culture time )
Single cell oil might be defined as
the edible oils obtainable from microorganisms being similar In type and
composition to those oils and fats from plants or animals
11. Some Application Of Microorganisms
Food products
■ Alcoholic drinks
■ Dairy products
■ Bread Vinegar
■ Pickled foods
■ Mushrooms
■ Single-cell protein
Products from
microorganisms
■ Enzymes
■ Amino acids
■ Antibiotics
■ Citric acid
13. Probiotics as ‘Live microorganisms’ which when administered in adequate
amounts confer a health benefit on the host.
There are large numbers of probiotics currently used and available in dairy
fermented food, especially in yogurts.
The most beneficial organisms include those of:
Lactobacillus.
Bifidobacterium.
Streptococcus.
Lactococcus.
Saccharomyces.
14. The physiological effects related to probiotic bacteria include:
Reduction of gut pH,
Production of some digestive enzymes and vitamins
Production of antibacterial substances, e.g., organic acids.
Antibiotic therapy.
Reduction of cholesterol level in the blood
Stimulation of immune functions.
Suppression of bacterial infections.
Removal of carcinogens.
Improvement of calcium absorption.
