1. The document discusses different methods for cultivating microalgae, including open pond systems, closed pond systems, and photobioreactors. 2. Open pond systems include shallow ponds with paddle wheels to keep algae suspended, while closed ponds have greenhouse covers to control the environment. 3. Photobioreactors provide the most control over growing conditions and come in designs like horizontal tubes, vertical panels, and flat plates to optimize sunlight exposure.

1. By: ANJALI KRISHNAN
Department of Botany
The Institute of Science,Mumbai,India

2.  Open pond system
 Closed pond system
 Air-lift method
 Marine /Open Ocean cultivation
 Desert cultivation
 Photobioreactors
• Types of photobioreactors
 Reference

3.  Open pond systems can be categorized
into two :
 Natural waters(lakes, lagoons & ponds).
 Artificial ponds or containers .
 The most commonly used systems include
shallow big ponds, tanks, circular ponds
&raceway ponds
 This method have been employed since
1950s.

4.  The ponds in which the algae cultivated
are known as “raceway ponds”.
 In these ponds, the algae, water,
nutrients, circulate around a race track.
 With the paddle wheels providing the flow,
algae are kept suspended in the water,&
are circulated back to the surface on a
regular frequency.
 The ponds are usually kept shallow
because the algae needs to be exposed to
sunlight ,&sunlight can only penetrate

5. the pond water to a limited depth .
 The ponds are operated in a continuous
manner with CO2 & nutrients being
constantly fed to the ponds, while algae
containing water is removed at the other
end.

7.  The algae cultivated are:
o Anabaena
o Nostoc
o Chlorella
o Dunaliella
o Arthrospira

9.  ADVANTAGE
• One of the major advantages of open
ponds is that it is easier to construct
&operate than the closed ponds.
 DISADVANTAGE
• There is poor light utilization by the cells,
evaporative losses, diffusion of CO2 to the
atmosphere and requirement of large
areas of land

11.  An alternative to open pond system.
 Control over the environment is much
better than the open ponds.
 A closed pond is to close it off, to cover a
pond or pool with green house.
 Takes care of problems associated with an
open system.
 It allows more species to be grown &
remain dominant.
 The growing season can be extended by
heating.

12.  It is possible to increase the amount of
CO2 in these quasi-closed systems, there
by increasing the rate of growth of algae.
 The closed systems are usually
constructed using plexiglass.

13. Horizontal photobioreactors.
 Vertical systems.
 Flat plate reactors.

14.  This system includes tubes laid on the
ground to form a network of loops.
 Mixing of microalgal suspended culture
occurs through a pump that raises the
culture vertically at timed intervals into a
photobioreactor.

16.  These reactors use vertical polythene
sleeves hung from an iron frame.
 Glass tubes can also be used
alternatively.
 Microalgae are also cultured in vertical
alveolar panels (VAP)which a type of
photobioreactor .
 2 main types of vertical photobioreactors
are the Flow through VAP & the Bubble
Column VAP.

20.  Flat plate reactors(FPR)are built using
narrow panels & are placed horizontally to
maximise sunlight input to the system.
 The concept behind FPR is to increase
the surface area to volume ratio such that
the sunlight is effectively used.
 It reduces oxygen build up.

23.  This method is used in indoor cultivation &
production of microalgae; where air is moved
within a system in order to circulate water
where microalgae is growing.
 The culture is grown in transparent tubes that
lie horizontally on the ground & are connected
by a network of pipes.
 Air is passed through the tube such that air
escapes from the end that rests inside the
reactor that contains the culture & creates an
effect like stirring.

25.  Spirulina spps

26.  Marine algae comes in two forms, some
marine algae are small &only be seen
under microscope while others are very
large called macroalgae or seaweeds such
as macrocystis, a species of kelp.
 The most common name of marine algae
is “seaweed”.

27.  Isochrysis galbana
Tetraselmis spps
Chlorococcum littorale
Synechococcus spps
Chlamydomonas sp.
Nanochloropsis salina
Pheodactylum tricornutum
Dunaliela tertiolecta
Chaetoceros muelleri
Botryococcus braunii
Emiliania huxleyi

29.  Algae can be grown in salt water ponds in
the deserts.
 Algae cultivation in desert is done for
biodiesel production.

30.  Haematococcus pluvialis
 Microcoleus vaginatus
 Chlamydomonas perigranulata
 Synechocystis

32.  A bioreactor is an installation for the
production of microorganisms outside their
natural but inside an artificial environment.
The prefix “photo” particularly describes the
bio-reactors property to cultivate
photoautotrophic microorganisms, or
organisms which grow on by utilizing light
energy like microalgae, macroalgae ,
mosses & cyanobacteria.

33.  It is a closed equipment which provides a
controlled environment & enable high
productivity of algae.
PBRs facilitate better control of culture
environment such as CO2 supply, water
supply, optimal temperature, efficient
exposure to light, culture density, pH
levels, gas supply rate mixing regime, etc.

34. 1. From the feeding vessel, the flow progress
to the pump which moderates the flow of
the algae into the actual tube.
2. The PBRs itself are used to promote
biological growth by controlling
environmental parameters including light.
The tubes are made up of acrylic & are
designed to have light & dark intervals.

35. 3. The PBR has an built–in cleaning system
that internally cleans the tube without
stopping the production.
4. After the algae have completed the flow
through the PBR, it passes back to the
feeding vessel. As it passes through the
hoses ,the oxygen sensors determine
how much oxygen has been built up in
the plant. It is also at this stage that the
optical cell density sensor determines the
harvesting rate,

36. 5. When the algae is ready for harvesting,
they pass through the connected filtering
system. This filter collects the algae that
are ready for processing, while the
remaining algae passes back to the
feeding vessel.
6. The flow continues.

38. 1. TUBULAR PBRs
 Made up of plastic tubes, tubular
PBRs consist of straight, coiled or looped
transparent tubing arranged in various
ways for maximizing sunlight capture.

41. 2. Christmas Tree Reactor
This reactor is built in a tapered
geometry which carries a helically
attached , translucent double hose circuit
system. The result is a layout similar to a
christmas tree.
A location is not crucial ,& therefore non-
arable land is suitable as well.

43. 3. Flat Plate Reactors
Flat-plate photobioreactors are made of
transparent materials for maximum utilization
of solar light energy. Accumulation of dissolved
oxygen concentrations in flat-plate
photobioreactors is relatively low compared to
horizontal tubular photobioreactors. It has been
reported that with flat-plate photobioreactors,
high photosynthetic efficiencies can be
achieved.
Flat-plate photobioreactors are very suitable
for mass cultures of algae

45.  www.oilage.com
 www.earthmagzine.com
 www.biotechnologyforums.com
 www.wekipedia.com
 www.google.com