This document summarizes the cultivation of Spirulina using geothermal energy in Greece. Spirulina is a type of blue-green algae with many health benefits and is 50-70% protein. Two companies in Therma-Nigrita, Greece cultivate Spirulina using geothermal fluids, which provide heat and carbon dioxide for optimal growth. The cultivation process involves growing Spirulina in production ponds heated by geothermal water, bubbling in CO2 from geothermal fluids, then harvesting, drying and packaging the Spirulina biomass. Using geothermal energy reduces production costs and optimizes the photosynthesis of Spirulina.

1. THE CULTIVATION OF
SPIRULINA:
AN INNOVATIVE
GEOTHERMAL APPLICATION
IN GREECE
• Prof. Michael Fytikas
School of Geology, Aristotle University of Thessaloniki, Greece
• Dr. Apostolos Arvanitis
Division of Geothermal Energy, I.G.M.E., Olympic Village, Acharnae, Attica, Greece
GEOFAR EUROPEAN CONFERENCE
“INNOVATIVE SOLUTIONS FOR GEOTHERMAL ENERGY FINANCING”
Athens, March 17th-18th 2011

2. Various Spirulina species
- Spirulina (Arthrospira):
microscopic, multi-cellular and filamentous
cyanobacterium (blue green alga)
Cyanobacteria have probably appeared on
earth 3.5 billion years ago.
- 1st among the microalgae
- Its name derives from the spiral or helical
nature of its filaments.
- These filaments have a variable length (100-
200 μm) and a diameter close to 6-12 μm.
The helix diameter varies from 30 to 70 μm.
- Spirulina → two main species:
Arthrospira platensis
Arthrospira maxima
- Biologically it is characterized as a
thermophilic (optimum 35oC) and an
alkalophilic (pH: 9-11) organism.
- Spirulina is able to photosynthesize using
sunlight, CO2 and nutrition elements
contained in a fresh water culture.

3. - Spirulina biomass is an excellent source of proteins,
amino acids, vitamins, lipids, dietary minerals,
photosynthetic pigments and nucleic acids.
- Proteins: 50-70% (dry weight)
- Amino Acids: Total amino acids: 6200 mg/10 g dry mass
8 essential Amino Acids (isoleucine, leucine, lysine,
methionine, phenylalanine, threonine, tryptophan, valine)
10 non-essential Amino Acids
- Carbohydrates: 15-25% (dry weight)
- Vitamins: Vitamins B-1, B-2, B-3, B-6, B-9, B-12, pro-Vitamin A
(β-carotene), Vitamins C & E, Biotin, pantothenic acid
- Lipids: 5-7% (dry weight)
Fatty acids (ω-3 and ω-6): mainly γ-linolenic acid & linoleic acid -
palmitic acid, oleic acid – neutral lipids, galactolipids, polar lipids
(sulfolipids)
- Free sterols, terpenes, saturated hydrocarbons,
polysaccharides
- Dietary minerals:
calcium (Ca), phosphorus (P), magnesium (Mg), potassium (K),
iron (Fe), manganese (Mn), copper (Cu), selenium (Se), chromium
(Cr), zink (Zn) and sodium (Na).
- Natural pigments:
phycocyanin, chlorophyll, carotenes, xanthophylls, zeaxanthin etc
- Nucleic acids:
RiboNucleic Acid (RNA), DeoxyriboNucleic Acid (DNA)

4. Spirulina is an excellent dietary supplement with vast and
unique content in precious dietary components, without
any toxicity. It offers multiple health advantages:
- It strengthens and stimulates the immune system.
- It provides protection from various diseases, reduces major illness
risks and improves detoxication.
- It has antioxidant properties and increases antioxidant protection.
- It has anticancer properties and positive effects for the prevention of
some cancers (leukemia).
- It has antiviral effects and activity against some viruses such as
viruses HSV-1, HSV-2, HCMV, HIV, measlevirus, mumpsvirus,
influenza A virus, enterovirus.
- It decreases LDL-cholesterol, total lipids, triglycerides and free fatty
acids (as well as systolic and diastolic blood pressure) protecting from
atherosclerosis.
- It has positive effects on Diabetes, Obesity and Arthritis.
- It supports cardiovascular function.
- It improves the gastrointestinal and digestive tracts.
- It improves substantially all body efficiencies, especially in athletes
(it protects skeletal muscles from oxidative damages, postpones the
time of exhaustion during exercise, promotes the recovery from
sports fatigue, improves athlete’s sport ability etc).
- It has positive effects on allergic inflammation.
- It has antibacterial and prebiotic effects.
- It can be introduced along with medicine as a therapeutic & dietary
supplement in the treatment of asthmatics.
- It has positive effect on the cure of low hematocrit, iron deficiency
Anemia and the menstrual syndrome.
- It shows radiation protective activity.

5. Microalgal cultivation is based upon the logic of the
photosynthetic process: solar energy is used for the
synthesis of organic compounds out of non-organic
substances.
The technological scheme for production of Spirulina
biomass is easily realized. It envisages the use of
sunlight, CO2, alkaline waters, mineral salts and
installations of simple construction.
Installations for Spirulina cultivation
The technological process does not envisage
any use of pesticides. The equipment should
be disinfected. Fast drying prevents
compound’s destruction. No preservatives or
additives are used. No irradiation is applied.
Therefore, the ecological purity of Spirulina
biomass is guaranteed. The production
process does not pollute the environment.

6. Principle technological scheme
for Spirulina biomass
production and applications
Inputs-CO2
+
Water
+
Nutrients
+
Algae Strain
+
Sunlight

7. The overall cultivation process includes
the following stages :
museum algal culture of Spirulina
inoculation (intensification of the
cultivation process)
cultivation in production ponds
separation
drying and packaging
Installation for storage of algal collection
(Museum algal culture of Spirulina)
Laboratory collection of different kinds Spirulina
strains is maintained as liquid cultures under suitable
extensive conditions (illumination of approximately
2000 lx and t = 20-22οC).
Intensive cultivation under specific conditions and
growth with nutrition medium up to reaching the
amount necessary for inoculation.
Transfer at semi production installations and
production ponds. Pedals wheels do stirring.
Separation of the algal yield & Drying
Production ponds

8. Cultivation installations and
secondary buildings situation -
Typical site organization
1: Installations of 3 m2 - 2 installations
2: Installations of 12 m2 - 2 installations
3: Installations of 100 m2 - 1 installation
4: Installations of 500 m2 - 4 installations
5: Laboratory
6: Dryer
7: Centrifuges
8: Mechanical and electric maintenance
9: Compressors, receivers, vacuum
10: Storage

9. Nutrition medium is very important for the growth
rate of Spirulina. High NaHCO3 content is of vital
importance for Spirulina to:
- maintain pΗ of the algal suspension between
9.0 and 10.5
- limit possible contamination from other algae
and microorganisms.
Nutrition Medium + Temperature + Light
determine photosynthetic intensity.
Spirulina shows an optimum growth between 35
and 38οC.
A high quality control over the cultivation
process requires measurements of the
following parameters:
- algal suspension density
- pH of the algal suspension
- algal suspension temperatures (20-38oC)
- biological state of the culture (physiological
conditions of culture - contaminants)
- algal purity
- O2 and CO2 concentrations
- moisture in the final product

10. Influence of some of the
main climatic and
technological factors on
the productivity of large-
scale algal cultures
The amount of Spirulina produced depends mainly on the genus/species,
photoperiod and total amount of light, temperature, pH, rate of removal of cells from
the medium, turbulence and nutrient composition of the medium, CO2-supply etc.

11. Use of thermal waters, geothermal energy and CO2 increases micro-algal production and
reduces its cost. The CO2 supply accounts for 27.4% of the algal cultivation expenses.
Different methods of algal technology optimization by geothermal energy, CO2 and
thermal water application have been discussed:
- Use of geothermal energy and CO2 for optimizing photosynthesis.
- Use of geothermal water for nutrition algal media preparation.
- Use of geothermal energy for algal biomass drying.
According to the parameters of the different geothermal resources some or all of the
above mentioned applications could be realized.
CO2 is the inorganic carbon substrate for photosynthesis. The right quantity of CO2
provided to the algal cells can guarantee an intensive photosynthesis, a good
physiological state and low contamination.

12. Optimization of the temperature and radiation regime, respectively photosynthesis,
is realized through water suspension heating. Mass algal cultivation is accompanied
by daily and seasonal changes in temperature and radiation.
Heating of suspension is extremely important for growth of Spirulina and entire
cultivation process. It is also important for maintaining an optimum night
temperature and an effective start of the cultivation day.
It should be emphasized that if geothermal water contains toxic heavy metals or
other components accumulating in the algal cells, such water should not be used
directly for algal cultivation.
Photosynthetic intensity of Spirulina (with and without heating up)

13. An innovative use
of geothermal fluids
for aquaculture application
in Greece refers to the
cultivation of Spirulina
in Therma - Nigrita, Serres
(Macedonia, Northern Greece)

14. Area of the proven geothermal field : ~ 10 km2
The geothermal reservoir is located at depths of
70 - 500 m in basal conglomerates.
The geothermal anomaly in the area occurs mainly
due to fault systems trending NE-SW and NW-SE.
Temperature of geothermal waters : 40 - 64oC
The geothermal waters with TDS values 2.3-3.6 g/l
are of the Na-HCO3 type. They are rich in
Νa+, Κ+, Μg2+, SO4
2-, CI- & SiO2 contents.
Significant quantities of gases are encountered.
The dominant gas is CO2 (up to 99.3%).
The geothermal waters contain 3.5-4.7 kg CO2/m3 of
water produced.
Geothermal wells in the Therma-Nigrita low enthalpy field

15. Two Companies
producing Spirulina
have been established
in Therma - Nigrita.
Both are located in the
same area very close to
each other.
The installations use
geothermal fluids
coming from the same
geothermal production
well.
Map from Google Earth showing the
location of two companies cultivating
Spirulina (“Spirulina Cultivation” on
the map) and the site of the
geothermal production well.

16. In Therma – Nigrita,
the two Companies
that produce Spirulina
biomass are:
ALGAE S.A
&
Hellenic Bio-Spirulina
Ltd
Map from Google Earth showing
the exact locations of the two
companies producing
Spirulina biomass and
the site of the geothermal
production well.

17. Both facilities for Spirulina
cultivation use geothermal fluids
coming from the same geothermal
production well.
This well is about 300 m deep and
produces 80 m3/h geothermal
water of 47-51oC.
The water contains about
4 kg CO2 /m3 of produced water.
The geothermal water cannot be
used directly in the cultivation
ponds, something that would be
desirable, since it contains about
0.50 mg/l As. The geothermal well that produces fluids (water + CO2)
for Spirulina cultivation in Therma - Nigrita

18. Separator CO2 / water
installed outside the facilities of
ALGAE S.A. Company in Therma - Nigrita
The geothermal water is first
directed to a separator.
CO2 is separated from
geothermal water and it is
used for Spirulina cultivation
to optimize photosynthesis.
After the separation, the
geothermal water flows
through a specially-designed
heat exchanger system, that
allows easy inspection and
cleaning in case that calcium
carbonate scaling occurs.

19. The installations are located in greenhouses covered with plastic foil.
Covering the cultivation installations is of crucial importance for:
(a) the protection of the algal culture from harmful weather conditions (rain,
dust etc)
(b) the contribution to optimum heating effectiveness
(c) the reassurance of good temperature during hours with good light intensity
Production ponds into the facilities of ALGAE S.A. Company in Therma - Nigrita

20. In Therma - Nigrita, the overall cultivation process includes the following
stages :
museum algal culture of Spirulina
inoculation (intensification of the cultivation process)
cultivation in semi-production and production ponds
separation
drying and packaging
Laboratory collection of different
kinds Spirulina strains is
maintained as liquid cultures under
suitable extensive conditions
(illumination of approximately
2000 lx and t = 20-22οC). No special
temperature control is required.
Museum algal culture of Spirulina - ALGAE S.A. Company, Therma - Nigrita

21. Intensive cultivation installation - ALGAE S.A. Company
The algal culture is transferred
from the collection to an
intensive cultivation installation.
Intensive cultivation installation
Hellenic Bio-Spirulina Ltd Company

22. Semi-production tanks – ALGAE S.A. Company
As a result of its growth and
dilution with nutrition medium,
suspension volume increases
up to reaching the amount
necessary for inoculation
in semi-production tanks.
Semi-production tanks –
Hellenic Bio-Spirulina Ltd Company
Pipe for CO2-supply
Tubes carrying geothermal water
CULTIVATION IN
SEMI-PRODUCTION TANKS

23. Then, algal suspension is transferred to
the production ponds.
The production ponds are oval and made
of concrete.
Pedal wheels do stirring (velocity of
suspension cultivation is about 15
m/min).
Production ponds – ALGAE S.A. Company
Production pond – Hellenic Bio-Spirulina Ltd Company
CULTIVATION IN PRODUCTION
PONDS

24. The heating of the suspension is extremely important for the growth of Spirulina.
The cultivation season is prolonged and the daily yield increases by 20-30%.
Production pond -
Hellenic Bio-Spirulina Ltd
Company
CULTIVATION IN PRODUCTION PONDS

25. Pipes carrying geothermal water
Production pond –
Hellenic Bio-Spirulina Ltd Company
The heating of the algal suspension is extremely important for:
- the growth of Spirulina and the entire cultivation process
- maintaining an optimum night temperature and an effective start of the cultivation day
- optimization the temperature and radiation regime because the effect of temperature
and light on algal growth are in correlation
CULTIVATION IN
PRODUCTION PONDS

26. Production pond – Hellenic Bio-Spirulina Ltd Company
Pipe for CO2-supply
The CO2 required for the
photosynthesis is provided
through tubes immersed in the
suspension close to the turbine
(paddle wheel) in the direction
of the algal suspension flow
within the cultivation pond.
In this way, a fuller absorption
of CO2 from the algal
suspension may be achieved.
Control over CO2 supply is
implemented through pH
(maintained between 9 and 10.5)
or control device and execution
mechanism.
The CO2 emitted from the
geothermal waters in Therma-
Nigrita does not any
compression because its
amount is high.
Τhe use of geothermal CO2 increases significantly
micro-algal production and reduces its production cost.
CULTIVATION IN PRODUCTION PONDS
White arrows show
the direction of the
algal suspension flow

27. At night, after the cultivation day is over, the algal suspension is stored
at constant mixing.
In Therma - Nigrita, fresh water heated by the geothermal waters is used
for Spirulina cultivation.
Production ponds and semi-production tanks (on the left) – ALGAE S.A. Company
CULTIVATION IN PRODUCTION PONDS

28. Photos:
Spirulina separation
from the algal
suspension using
special Vibrating
screen and then return
of the liquid phase into
the respective pond –
Hellenic Bio-Spirulina
Ltd Company
SEPARATION & WASHING OF THE SEPARATE
Separation is carried out within the limits of the
cultivation day depending on the productivity and
through flow separation.
Biomass harvesting is carried out through either
vibrating screens or filtration.
As soon as the biomass is separated, it is
washed.

29. SEPARATION
The biomass separation from the algal
suspension is performed using vacuum
filters and/or filter centrifuges.
The filtration devices should not tear
the filaments.
The principal advantage of centrifuges
is that they have a greater productivity.
Every endeavour was made to be found
an optimum solution for the daily
separation of the algal yield.
The supernatant is returned to the
respective installation after having
being enriched with appropriate mineral
elements. The purpose is to maintain
the algal suspension density between
1.2 and 1.8 g/l.
Centrifuge of the Alpha - Laval type -
ALGAE S.A. Company

30. Product drying
under natural
conditions on a
table –
Hellenic
Bio-Spirulina Ltd
Company
Generally, drying is done under natural conditions. The drying of the wet product is
accomplished in a neighbouring greenhouse by laying the product on plastic
tables.
The admissible moisture of the dried biomass is no more than 5%.
However, within ALGAE S.A. facilities, some geothermal heating is also supplied by
circulating geothermal water through finned metallic pipes in the drying area.
DRYING

31. DRYING
Tables
for Spirulina biomass
drying
inside a neighbouring
greenhouse -
ALGAE S.A. Company

32. In Hellenic Bio-Spirulina Ltd
facilities, biomass drying
is also performed in a
neighbouring special
greenhouse at 70οC using
electrical resistances as an
auxiliary heat source along
with solar energy.
Spirulina drying at 70οC using electrical resistances –
Hellenic Bio-Spirulina Ltd Company
DRYING

33. The dried biomass is milled and the product is packed.
The packed biomass is stored in a dark, dry, airy and
clean place.
Milling of dried
biomass using special
milling machine.
Powder of 60-80
MESH.
Hellenic Bio-Spirulina
Ltd Company
Milling machine for treatment of dried Spirulina
biomass - ALGAE S.A Company
MILLING AND PACKING

34. Storage room for packaged Spirulina biomass -
ALGAE S.A Company
STORAGE

35. METHODS OF CONTROLLING THE CULTIVATION PROCESS
The analysis methods to be
applied are standard.
Apparatuses are standard too:
thermometers, pH-meter,
spectrophotometer, analytical
scales, lab dryer, lab vacuum
pump, vacuum filter,
microscopes, lab glasses,
flasks, laboratory bottles etc.
The growth of the algal cells
is controlled by nephelometry
and measured gravimetrically.
The principal parameters subject to control are: temperature, pH, algal suspension
density, biological condition of the culture, algal purity, O2 & CO2 concentrations.
Research Lab – Hellenic Bio-Spirulina Ltd Company

36. ALGAE S.A. Company was
established in 1996 in Therma -
Nigrita.
The investment took place in 1997
as part of the European Program
LEADER II.
It was partially financed (60%) by
E.U.
The total investment cost was
1.5 million €.
The investment was awarded as
the most innovative idea in
Greece for 1998.
The facilities cover an area of
about 20,000 m2 of greenhouses
and buildings (laboratories &
packing rooms).
External view of facilities - ALGAE S.A. Company

37. Internal view of facilities - ALGAE S.A. Company
Research Lab - ALGAE S.A. Company

38. The installations for Spirulina
cultivation are oval and made up of
concrete.
Their total area is 1,950 m2, split in
installations of various sizes in view
of their gradual inoculation.
Eight (8) cultivation ponds
occupying an area of 225 m2 each
one.
Smaller ponds (2x1.8 m2, 2x4,5 m2,
1x50 m2, 1x100 m2) are used for the
initial stages of the algal production.
Production ponds under construction -
ALGAE S.A. Company

39. The installations are located in greenhouses covered with French foil allowing for
80% transparency.
The nutrition medium for Spirulina cultivation is based on the classical recipe but it
has been modified depending on mineral salts prices and results on the growth rate
of Spirulina.
Using geothermal energy the cultivation season has been prolonged (from March
until November) and the daily yield has increased by 20-30%.
The average output of Spirulina biomass is estimated to be 30-40 kg/day.
A centrifuge of the Alpha-Laval type is used for daily separation of the algal yield.
Semi-production tanks and production ponds - ALGAE S.A. Company

40. Panoramic photos of production ponds - ALGAE S.A. Company

41. Drying is done in natural conditions in a
neighbouring greenhouse by placing the
product on plastic tables. The drying
season lasts from August to November,
so most of the greenhouse heating
comes from the sun. However, some
geothermal heating is also supplied by
circulating geothermal water through
finned metallic pipes in the drying area.
Drying of Spirulina biomass - ALGAE S.A. Company
Microscopic view of Spirulina sp. (ALGAE S.A.) cultured in
a photobiorector of IBRB/NHRF

42. The dried Spirulina product is available in form of
tablets, capsules and powders.
Since 2000, Spirulina production is certified by
TUV AUSTRIA with EN-ISO9002.
Since 2005, the product has also been certified as
‘organic product’ by the German certification
organization BCS ÖKO-GARANTIE GmbH.
Annual production has shown upward trend. The
estimated annual growth rate was 200-300% until
2008.
2006 → 1500 kg
2007 → 4000 kg
2008 → 4500 kg

43. Typical analysis of Spirulina biomass
from ALGAE S.A. Company
About 95% of the Company's sales
goes to the domestic market and
the remaining 5% in the pilot
markets of Germany, the Czech
Republic, Bulgaria and Cyprus.

44. Hellenic Bio-Spirulina Company Ltd
was established in 2001 and it has been
active in Spirulina cultivation since
2007.
The facilities of Hellenic Bio-Spirulina
Company Ltd in Therma - Nigrita were
constructed in 2009-2010.
The total investment cost was about
700,000 € included lab equipment, offices
etc.
The total area of greenhouse covering
8 cultivation ponds is 2,500 m2.
The cultivated alga is Spirulina.
The Spirulina seed is certified by ‘algae
bank’ in Germany.
Installed capacity: 100 Hp (paddle wheels,
electric light, pumps, vibrating screens
etc).
External view of facilities -
Hellenic Bio-Spirulina Ltd Company

45. The CO2 needed for the photosynthesis
is derived from the same geothermal well.
The geothermal well that produces fluids (water + CO2)
for Spirulina cultivation in Therma - Nigrita
Geothermal water used for Spirulina cultivation
outside the facilities
An amount of about 40 m3/h of geothermal
water from the neighbouring production well
is used for Spirulina cultivation and heating
8 stremmas (0,8 ha) of greenhouses.

46. High quality fresh
water (‘bottled
water quality’) is
used for Spirulina
cultivation. An
ultraviolet (UV)
sterilization
system is used for
the disinfection of
the water.
UV sterilization system for the disinfection of the water for Spirulina cultivation -
Hellenic Bio-Spirulina Ltd Company (2011)

47. Tanks containing fresh water beside
the facilities.
The fresh water is disinfected by the
ultraviolet (UV) sterilization system and
then it is used for Spirulina cultivation
within the ponds.

48. The water for Spirulina
cultivation is heated by
the geothermal water.
The optimum temperature
of fresh water for Spirulina
cultivation is 35oC.
Fertilization is performed by
fully water-soluble chemicals
with a purity of 99.5%.
Recipes from the University
of California are used.
Production pond – Hellenic Bio-Spirulina Ltd Company (2011)
Pipes carrying geothermal water

49. Spirulina biomass is separated from the algal
suspension using special Vibrating screen
and then the liquid phase returns into the
respective production pond.
Drying is done under natural conditions. The
drying of the wet product is accomplished
in a neighbouring greenhouse by laying the
product on plastic tables.
Biomass drying is also performed at 70οC using
electrical resistances as an auxiliary heat
source along with solar energy.
The dried biomass is milled using special
milling machine. Powder of 60-80 MESH.
Spirulina separation from the algal suspension using
special Vibrating screen and then return of the liquid phase
into the respective pond –
Hellenic Bio-Spirulina Ltd Company

50. The product is stored in plastic bags with
oxygen absorption. These bags are placed
in special food containers.
The time-life of product is 3 years.
The powder is packed in tablets of 400 mg in
blister form (package of 120 tablets).
Since June 2010 and for a period of 6 months,
a total amount of about 2,500 kg of Spirulina
biomass has been produced.

51. Typical analysis of Spirulina biomass from Hellenic Bio-Spirulina Ltd Company
Energy (kcal/100 g) 367.8
Moisture 5.8%
Ash (Minerals) 6.3%
Proteins 69.94%
Carbohydrates 14.8%
Fats (lipids) 3.2%

52. Acknowledgements to:
Mr. Michael Zouloumidis
Chairman and Managing Director of ALGAE S.A. Company
Mr. Evangelos Koultsiakis
Owner of Hellenic Bio-Spirulina Ltd Company
Dr. Theodore G. Sotiroudis
Director of Research IBRB/NHRF, National Hellenic Research
Foundation (N.H.R.F.) - Institute of Biological Research &
Biotechnology (I.B.R.B.), Scientific cooperator of ALGAE S.A.
Dr. George Tsiropoulos
Scientific cooperator of Hellenic Bio-Spirulina Ltd Company