MICROALGAE hundreds of micrometers. They are also




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Microalgae are
small single celled organism found in both fresh and salty waters, their size
ranges from a few micrometers to a few hundreds of micrometers.  They are also considered as microscopic
photosynthetic organisms and can be cultivated in indoor or outdoor
conditions.  They can exist individually
or in chain, depending with their species. Microalgae have the ability to grow
rapidly, efficiently use light energy and produce more biomass per surface than
any natural source. Microalgae produce bioactive products like sterols,
polymers, fatty acids, peptides, toxins and carotenoids. Microalgae do not have
root, stem or leaves. Microalgae are used to feed different groups of
commercially important aquatic organisms. They also play an important role in
cycling the nutrient and inorganic carbon fixing into organic molecules.


Microalgae are
classified into three; the green algae, diatoms and the golden algae. Green
algae are large and consist of chlorophyte and charophyte. Diatoms are the main
group of microalgae, they are single-celled although can form colonies in the
shapes of ribbons, stars or zigzag. The golden algae are large group of algaes,
are commonly found in fresh waters. Toxins that are produce by golden algae are
not harmful to humans, livestock or wildlife.


are pictures representing the three classes of algaes

Diatoms Algae


Green Algae


Golden Algae






are unique organisms and are the source of life producers on earth, a number of
species have been tested as feed. Their fast growth rates and the simple
structure make them significant organisms for biotechnological applications. Variety
of cosmeceutical products related to microalgae has been commercialized; this
is because microalgae have developed various compounds such as carbohydrates
and proteins with different biological properties and is important in
cosmeceuticals and functional foods applications.  Various activities of microalgae and their
compounds are said to increase their potential use in the present and future
cosmetic skin care products.

of the microalgae feed production occurs as living cultures. Marine
invertebrates depend on microalgae for their whole life cycle. Microalgae feed
directly or indirectly larval stages of shrimp, bivalves and some fish species in
intensive mono-culture systems.  This
means that they are either consumed directly by the target animals or by other
organisms like Daphnia, Rotifers which are later fed to the target larval
organisms.  Microalgae in extensive
polyculture systems are used for the growth of carp, shrimp and bivalves in
developing countries and are also contributing widely to the protein supply of
the most populated countries.

who produce fish need to include a microalgae production system in line with
their fish production. Though keeping live microalgae has got problems and to
solve this some attempts have been discovered to replace living algae by
possessing algae-based diets with a longer shelf life.

drying – Is good for producing an algae feed with a self life resulting in
diets that are almost identical to fresh diets regarding shape, size and
biochemical composition.

Spray drying – The commonly used
technique in preservation of microalgae as a sole feed or supplement to the
diet in aquaculture. The shelf life if stored at a low temperature can be up to
2 years.




Microalgae are very important
micro-organisms in the industry mostly in the production of biodiesel
feedstock, though there are a number of biological culture system limitations
that end up in low productivity of microalgae cultures there is a quick need to
enhance the yield and productivity of microalgae mass cultures. Now that there
has been advancement of molecular biology and engineering, the disadvantages
can be well taken care of and be approached by cultures system design and
genetic engineering. There is hope that with the advancement it will increase
the productivity of microalgae, transform microalgae cultivation technology
into a good industry with a lot of environmental benefits.

Microalgae are also approved as
potential valuable resources for human nutrition and nutraceuticals.  Metabolites from phototropic micro-organisms show
a positive effect on human health hence making those organisms important. This
also implies that they promote the health. Though using microalgae and
cyanobacteria and their products as nutraceuticals has to be considered as an
important issue, these products have to be free from unhealthy by products.