A brief account of Algal culture

1. ALGAL CULTURE : SCOPE AND METHODS
Dr. Saji Mariam George
Associate Professor
Assumption College Autonomous
Changanacherry

2. ALGAL CULTURE : SCOPE & METHODS
• Farming of Algae.
• A form of Aquaculture
SCOPE
• Algae can be grown in large quantity within a short period of time.
• In recent times, there is much interest in dietary supplements of
algal origin and bio-fuels.
• Algae can also be exploited for the commercial production of
various products like dyes, fodder, bio-plastics etc.

3. Algae are commercially cultivated (cultured) for many
purposes .
i) Algae as Food
• The total food production by marine algae is
estimated to be eight times than that by land plants.
• The algae are rich source of proteins, fats, vitamins A,
B, C and E ; omega -3 fatty acids etc.
• Several algae are edible. E.g. Ulva , Porphyra,
Laminaria, Chlorella, Gracilaria, Gelidium etc.
• Many algal products are used in food industry.
e.g Agar, Carageenan etc.

4. ii ) Algae as source of Dyes and Food
colorants
• Phycoerythrin is a red pigment
extracted from red algae.
Porphyridium cruentum is the most
commonly used species for
Phycoerythrin production.
• Phycocyanin is a blue pigment
derived from blue green algae.
Spirulina platensis is the most
popular algal source of this pigment.
• Phycocyanin is used as a food
colorant in fermented milk products,
milk shakes , ice creams, chewing
gum, soft drinks, alcoholic drinks,
desserts, cake decoration etc.
• Food colorants and dyes obtained
from algae have nutritional value and
are non-toxic.

5. iii ) Algae as Organic Fertilizers
• Algae , particularly brown and red
algae can be used directly as organic
fertilizers.
• Algae can be made into compost –
the compost of Blue - Green Algae
and Azolla (Azolla - Anabaena
symbiosis) – can be used in paddy
fields to increase yield.

6. iv) Algal Bioplastics
• Alternative to the plastics
• Eco friendly
• Biodegradable
• A sustainable green initiative
to combat plastic pollution.
Images https://mymodernmet.com/ooho-edible-
water-container/
http://eatinnovation.com/seaweed-bottles-drink-
water/

7. v) Algae as a source of
Pharmaceuticals
• Certain algae are rich
sources of various
bioactive compounds
that have nutraceutical
or therapeutic potentials
and can be exploited in
pharmaceutical industry.

8. vi) Algal Fuels
• Algae can be used for the production of making biodiesel, biobutanol, biogasoline,
Methane, etc.
e.g Dunaliella, Chlorella etc.
• An alternative to petroleum based fuels.
vii) Algae as bioremediators
• Algae also has the potential to be used as bioremediators for Pollution Control.
E.g Scenedesmus, Cladophora etc. have the capacity to remove heavy metals.
viii) Algal cultures for research purposes
• Algal cultures are needed for research purposes.
• They can be used for morphological , physiological, cytological, genetical and
ecological studies on algae.

9. Types of Algal Culture
1. Unialgal cultures - contain only one kind of
alga, usually a clonal population (may
contain bacteria, fungi or protozoa).
2. Axenic cultures - contain only one alga (no
bacteria, fungi or protozoa).

10. Culture conditions should resemble the alga’s
natural environment as far as possible .
Requirements:
• Water
• Carbon dioxide
• Minerals
• Light
• Temperature (15˚C - 35˚C. )

11. Culture (Cultivation) of Macroalgae
• Culture of macroalgae like Laminaria, Porphyra, Gracilaria, Ulva , Chondrus
etc.
Steps :
1. Collection
2. Isolation
3.Culture
4. Harvest

12. 1 . Collection
Requirements:
• Suitable containers
• Chisel or small knife
• Forceps
• Gloves
• Mesh or cloth bag
• Ice-filled cooler
Method :
• Wear gloves
• Mark containers with date, depth, location, whether the water is saline,
brackish or fresh etc.
• Collect entire or a part of algal specimen from shallow or deep water.
• Large specimens should be shaken or gently squeezed on collection to
remove excess water.
• Gently place the specimen in the container with sufficient water .
• Place the containers in an ice – filled cooler.

13. 2. Isolation
• Manual isolation
• Use of membrane filters for separation of
filamentous algae from bacteria.
• Use of mixtures of ethanol (40–50%) and sodium
hypochlorite (1%) for the removal of microepibionts .
• Antibiotic screening to eliminate fungal contaminants
( e.g. Nystatin 100mg/ml ).

14. 3 ) Culture (Cultivation)
Methods :
i )Fragment Culture
• Small fragments of algal thallus are placed in a suitable
environment that will support their growth .
a) Single Rope Floating Raft (SRFR) method
(Long line cultivation or Line or rope farming or Monoline system)
• A long rope or Nylon twine of 10 mm diameter is attached to 2
wooden stakes with 2 synthetic fiber anchor cables and kept afloat
with synthetic floats.
• The algal fragments are put in the twists of ropes or tied to Nylon
twine and cultured in the sea shore area.
• The whole thallus can be harvested leaving a small piece that can
be used for further cultivation.
• Used for cultivation of Gracilaria edulis, Gelidiella acerosa etc.

15. Single Rope Floating Raft (SRFR) method (Long line cultivation (Line or rope
farming )

16. b)Use of Nets
• Nets are fixed to bamboo frames or
wooden poles forming a raft like structure
that is anchored to the sea bottom and held
at a fixed depth with floats and can be used
for algal culture.

17. c ) Pond culture
• A pond of 0.5 - 1.0 ha. with access to both salt and
freshwater is needed so that the salinity can be
adjusted and the water can be changed every 2-3
days.
• Water change is usually made using tidal flows, with
gates to control the in flow and out flow of water.
• The pH of the pond water is important- slightly
alkaline (pH 8) (e.g. Cultivation of Caulerpa,
Gracilaria etc.)
• The pond should be drained to a depth of 0.3 meters.
• Plant the algal cuttings in the mud.
• After planting, flood the ponds slowly to a depth of
about 0.5 to 0.8 m.

18. Pond used for Gracilaria cultivation
http://www.fao.org/

19. Harvesting of Gracilaria from Pond
http://www.fao.org/

20. d ) In tanks (Tumble Culture)
• Translucent tanks of 0.6 to 0.9 m depths are
needed .
• The algae that are tumbled in a tank by the
upward water current generated by aeration
are exposed to the surface light for a very
brief period of time (10 seconds) and then
immersed in to the bottom of the tank.
• Used for culture of Chondrus crispus,
Palmaria palmata.

21. e) Seaweed cultivation at sea bottom
• Place the seaweed into the sea bottom.
• Attach to sand-filled plastic tubes and place
on a sandy bottom.
• Culture in the sea shore area.

22. f ) Green house culture
• A greenhouse with controlled
environmental conditions can
be used for algal culture
• Enhanced productivity.
• Reduction in contamination.

23. g) Spray culture
• Macro algae can be cultivated on land using
saline or sea water under controlled
environmental conditions of sunlight,
temperature, moisture, nutrients etc.
• A water sprayer can be used on sand or in a
multiple tier array to maintain a thin film of
seawater enriched with nutrients on the
surface of the macro alga and this can be
recycled.

24. h) Tissue culture
A part of the terminal portion of the thallus,
0.3 cm – 5.0 cm or the blade or hold fast can
be used as an explant.
• The explants can be cultured in enriched or
artificial sea –water culture media containing
growth regulators and this may result in
callus formation and regeneration.
e.g. Chondrus crispus , Laminaria angustata
etc.

25. Tissue culture of Macroalgae

26. ii)Reproductive Method
• Different kinds of spores
like Zoospores,
Monospores, Tetraspores ,
Carpospores etc. are
collected and used for
culture.

27. Cultivation of macro algae from spores

28. 4) Harvest
• Hand picking
• Use of Rotary cutters
• Nets
• Harvester
• Robotics

29. Culture of Microalgae
• Microalgae are very small, unicellular algae.
• The size ranges from a few micrometers to a few hundred micrometers.
• Include freshwater and marine forms.
e.g. Green algae (Chlamydomonas, Chlorella, Volvox)
Diatoms (Pinnularia, Cyclotella, Navicula )
Blue green algae (Nostoc, Oscillatoria )
Dinoflagellates (Peridinium , Gonyaulax )
Steps
1. Collection
2. Isolation
3. Culture
4. Harvest

30. 1. Collection of Microalgae
• Water sample can be collected in
small containers and put in an ice-
filled cooler.
• Some algae form scums on the
water surface . In such cases, scoop
a small sample from the surface.
• Floating microalgae can be collected
with mesh net.
• A deep water sampler can be used
to collect water several meters
below the surface.
Images
https://www.landcareresearch.co.nz
https://askabiologist.asu.edu
Alga collection using mesh net, Scooping
Algal scum, Deep water sampler

31. 2. Isolation of Microalgae
i) Micropipette Method
Microalgae can be
separated from the
samples using
micropipette under
microscope. Single cells
can be isolated by
micropipettes.

32. ii) Washing or Centrifugation Method
• Repeated washing or
centrifuging the water
samples results in the
isolation of larger
organisms.
Image
https://www.youtube.com/watch?v=0Sgq
FjpsSOY
Algae Centrifuge

33. iii) By exploiting the
phototactic movement
• By this method the
motile algae will move
to one direction and
can be isolated with a
micro pipette.
iv ) Serial dilution
Agarplate method
A unialgal culture may
grow in one of the
higher dilution tubes.
Figure - uploaded by Dr.-Ing Samuel Kofi
Tulashie

34. • Required algal species can
be picked up with an
inoculation needle under a
microscope and then can
be streaked on the surface
of agar plates and incubate
under suitable conditions
of light and temperature.
• The developed algal
colonies can be transferred
to culture tubes for
obtaining pure culture.
Figure uploaded by Nutan Prasad Rout

35. 3. Culture of Microalgae
• Microalgae can be
cultured in
photobioreactors
(fiberglass tubes,
plastic bags , flat-
panels etc.) or in
round shallow tanks.
Images: http://solar-components.com/
https://news.algaeworld.org/2017/08
https://phys.org/news/2012-11-

36. Culture media for algal culture
Culture medium or nutrient medium is an
artificial or synthetic medium in which algae can
be grown.
1. Bold's Basal medium (BBM – Medium) with
vitamins
• This is a freshwater algae medium without
the need for soil-extract or vitamins .
• BBM is used to grow a variety of green algal
cultures.
e.g. For culture of Chlorella, Chlorococcum etc.

37. 2. Modified Chu No. 10 medium
• Widely used for both prokaryotic and eukaryotic
algae
e.g. Blue green algae, diatoms, green algae
3. Chu 13 Medium
• CHU 13 contains essential minerals and
trace elements that are required by algae for growth,
but with no carbon source and hence this medium is
suitable only for the growth of phototrophs.
• It is used as a growth medium for the alga
Botryococcus braunii.

38. 4. Miquel's solution
• This medium is suitable for freshwater diatoms .
5. F/2 medium
• The most common and widely used general enriched
seawater medium for growing marine algae, especially
diatoms .
6. Walne's medium
• Used for the cultivation of marine microalgae.
7. Schreiber's solution
• Used for culture of diatoms.
8. TMRL medium
• Used for culture of microalgae.

39. HARVESTING OF MICROALGAE
Harvesting should not cause contamination of
the biomass or influence biomass quality.
Harvesting of microalgae can be done by various
methods such as
• Coagulation and flocculation
• Flotation
• Centrifugation
• Sedimentation
• Filtration or a combination of various
techniques.

40. Coagulation and Flocculation
https://doi.org/10.1016/j.biortech.2015.06.
097
• The coagulation-
flocculation processes using
coagulant (FeCl3·6H2O), various
flocculants based on
polyacrylamide , polyethylenoxide
facilitate the removal of suspended
and colloidal particles and
concentrate the algae suspension.
• Flocculation allows for effective
removal of algae from large
amounts of liquid media.
• The microalgal biomass (0.05%,
w/w) needs to be concentrated to a
paste with 15% – 25% water
content.

41. Flotation
https://doi.org/10.1016/j.biombioe.2018.11.0
18
Dispersed air floatation and
dissolved air flotation can be
applied in microalgae harvesting
and dewatering.

42. Centrifugation
Centrifugation as a secondary
dewatering step will reduce the time
and costs associated with dewatering.

43. Sedimentation
• Tanks are cylindrical with a funnel shaped
bottom so that the settled microalgae are
concentrated near the outlet. The outlet is
placed at the bottom of the tank so that the
collection of the settled microalgae can easily
be recovered.

44. Filtration
• Filtration techniques can concentrate
microalgae cells in the suspension upto 5-
18% .
Vacuum filtration harvesting technique is
most suited for large microalgae cells (greater
than 10 μm).

45. THANK YOU