The history of the use of blue-algae as a high value food source
Fast growing algae as a nutrition source of the future is not only an
idea found in science fiction books, or case studies of NASA. In fact
the WHO describes on especially promising species Arthospira/Spirulina
platensis as a “Health-improving-Agent” (Reder, 2003) and other aid
organisations have already used these algae in various settings. It has
also become a “trendy” health food supplement in the industrialized
countries, and is therefore produced at an industrial scale.
The use of algae goes much further back in history
than one would believe however. In 1940 the French occupation troops of
French Equatorial Africa (now Republic of Chad) made a strange
discovery on on of the markets of Massakory, a village near Lake Chad.
Their pharmacist described a material called Dihe, which was consumed
by the local population. These green mats consisted of dried blue-algae
(the cyanobacteria Arthospira/Spirulina platensis) the local population
collected in small ponds around the lake, and which where used as an
ingredient for various meals (Ciferri, 1983). This use seems to go back
to the 9th century Kanem empire and has continued until today mostly by
the local tribe of the Kanembu (Abdulqader, 2000).
Usually one can find this blue-algae in most of the alkali lakes (pH
8-11) in that area, where they are by far the most abundant species,
and provide the well adjusted lesser flamingoes with their main source
of food; In fact they have evolved to be able to filter them very
efficiently out of the water (Ciferri, 1983).
25 years later this same discovery was reconfirmed
by a better equipped research team, which analysed these bacterial mats
more carefully and found them to be a extremely valuable source of
proteins for human consumption (up to 60-70 % of the dry
weight)(Ciferri, 1983).
About the same time scientists also discovered that
before the Spanish conquest, it seemed to be quite common around the
lake of Tenochtitlan (today’s Mexico City) to consume another, but
closely related blue-algae: Arthospira/Spirulina maxima. With fine nets
it was collected from the lake and then baked into special breads
called Tecuitlatle. But historians can only find descriptions of this
practise in Mexico until the end of the 16th century, when this
practise seems to have become forgotten (Ciferri, 1983).
Depiction of harvest of spirulina and the cakes made from the algae.
Illustration from the Florentine Codex, Late 16th century. (Public
Domain/Wikipedia)
Thus today only the common traditional use in east Africa remains, but
due to its extremely efficient protein production, its other nutritious
values and the relatively easy production it is likely that the growth
of this algae is also possible in an poor urban area with relatively
simple means.
Recent developments
In recent years its quick growth characteristics and ease of
cultivation has led to a “rediscovery” by several development aid
organisations. However their focus was mostly of medium to large scale
local production, which was shown to be effective. It has been proven
already that it is possible to cultivate Spirulina algae outside of
their natural habitat and use it for enhancing nutrition supply in poor
communities (Antenna Technologies 2007). The approach used so far
involves however quite a lot of space, investment and outside expertise
to create the ponds and supply the algae with sufficient nutrients.
Large scale Spirulina platensis production in India (from Antenna Technologies 2007)
Purpose
We decided to investigate if a small scale cultivation in discarded PET
bottles with household level means can produce a sufficient amount of
Spirulina algae for personal consumption.
Method
We ordered a sample culture of Spirulina maxima form the SAG culture collection of algae (University of Göttingen, Germany):
| SAG Strain number | 84.79 |
| Genus | Spirulina / Arthospira |
| Species | maxima |
| Division | Cyanobacteria |
| Isolated from | Natron lake; Republic of Chad |
| Isolated by | M. Lefevre; 1963 |
Spirulina Algae strain
The recommended culture medium (based on S. Aiba and T. Ogawa 1977)
which allows optimal growth, is mainly made out of NaHCO3, Na2CO3,
K2HPO4, NaNO3, K2SO4, NaCl, some trace elements and a set of
vitamins/micro-nutrients (and all is adjusted to a pH of 9-10). However
this culture medium is not suitable for our intended usage due to high
costs and difficulties to obtain the required substances and equipment.
But one can find ( http://spirulinesociale.free.fr/SPIRULIN.htm ) other
low cost culture media recipes which we tried to uses as a basis for
our purposes:
| Lye made out of wood ash | 400l (26.6kg ash) |
| Water | 400l |
| Sea salt | 4kg |
| Urine | 3.2l |
| Iron-syrup (diluted in tea) | 104g |
Low cost Spirulina culture medium;
Ash for Lye needs a 2 week reaction time.
Iron-syrup is made out of nails and vinegar
with a reaction time of 2 weeks.
After the arrival of the culture sample the main objective was to find
a culture medium to cultivate the living cells as quick as possible
however, as they survive only 2 weeks in their original sample medium.
Therefore a first quick attempt was done to create a culture medium
(culture medium V1)
| Newspaper ashes | ~5g |
| „Kaisernatron“ NaHCO3 | 19g |
| “Jodsalz” NaCl | 1-2g |
| Tab water (cologne waterworks) | 1l |
Spirulina culture medium V1;
“Kaisernatron” from HOLSTE (Bielefeld, Germany)
pH measured: 7-8 (Merck pH indicator paper 1.09526.0003)
This initial culture medium was inoculated with 0,5ml of the Spirulina
maxima sample culture and incubated at room temperature (~20°C) in an
old plastic bottle (ALDI orange juice) near a window facing to the west
(relatively low light conditions). But even after several days no
living Spirulina cells could be detected near the surface where they
should float if alive.
Subsequently a new culture medium with all needed nutrients was
developed (culture medium V2) which was also adjusted to the optimal pH
level of 9-10 with 1M NaOH.
| „Multivitamin + Mineral“ nutrition supplement | 1 pellet |
| „Eisen + Vitamin C“ nutrition supplement | 1 pellet |
| „Kaisernatron“ NaHCO3 | ~20g |
| “Jodsalz” | ~1-2g |
| Urine | ~250ml |
| Tab water (Cologne waterworks) | 1,8l |
| 1M NaOH (10%) | 12ml / 15ml |
Spirulina culture medium V2
“Kaisernatron” from HOLSTE (Bielefeld, Germany); pH measured: 9/10 (Merck pH indicator paper 1.09526.0003);
„Multivitamin + Mineral“ (source dm-drogeriemarkt): 60mg Vitamin C,
18mg Niacin, 10mg Vitamin E, 6mg Pantothenic acid, 2mg Vitamin B6,
1,6mg Vitamin B2, 1,4mg Vitamin B1, 200µg Folic acid, 150µg Biotin, 1µg
Vitamin B12, 175mg Potassium, 90mg Sodium, 120mg Calcium, 45mg
Magnesium + Other substances for pellet, taste and color; „Eisen +
Vitamin C“ (source dm-drogeriemarkt): 171mg Iron, 1220mg Vitamin C +
Other substances for pellet, taste and color; “Jodsalz”: 99,9% NaCl,
0,07% Potassium fluoride, 0.003% Potassium iodate and
Sodiumferrocyanide (separating agent, no amount specified)
Again this culture medium was inoculated with 0,5ml of the Spirulina
maxima sample culture and incubated at room temperature (~20°C) in two
old plastic bottle (ALDI orange juice) near a window facing to the west
(relatively low light conditions). The first culture had a pH value of
9 while the second had a pH value of 10. To extend the daylight
conditions cultures where illuminated with a 11 W florescent light bulb
after sunset for 3-5 hours each day.
After 24 hours very few Spirulina cells could be detected near the
surface of the culture medium, subsequently these disappeared however
and no further growth other than that of contaminants could be detected
in the following 2 weeks.
Culture media V2
A last attempt to cultivate the Spirulina algae was done with nutrition
supplement Spirulina pellets as the base of the culture medium (Culture
medium V3). In theory this should provide the cells with all needed
nutrients.
| Spirulina dried nutrition supplement | 2 crushed pellets |
| NaCl | ~1-2g |
| „Kaisernatron“ NaHCO3 | ~1-2g |
| Tab water (cologne waterworks) | ~300ml |
| 1M NaOH | Adjust to pH 9-10 |
Spirulina culture medium V3
“Kaisernatron” from HOLSTE (Bielefeld, Germany); pH measured: 9/10
(Merck pH indicator paper 1.09526.0003); Spirulina nutrition supplement
pellets from the “Reformhaus”. Culture medium sterilized in microwave
oven before inoculation.
This culture medium was also inoculated with 0,5ml of the Spirulina
maxima sample culture and incubated at room temperature (~20°C) in a
glass jar near a window facing to the west (relatively low light
conditions). This time some initial algae growth could be detected, but
contaminants were growing much quicker and after 7 days no surviving
Spirulina cells could be detected.
Spirulina nutrition supplement pellets and culture media V3
Results
Contrary to what we expected however, culturing Spirulina maxima seems
to be quite difficult if you do not have the right equipment, chemicals
and expertise. The high level of contaminants and the generally very
low rate of growth would make it impossible under the current
conditions to make any use of the biomass produced. This might be
solely due to the fact that the low light and temperature conditions of
central Europe are too far away from the optimal growth conditions of
Spirulina maxima. But the result definitely shows that it is more
complex that originally thought, and that growing Spirulina algae in
PET bottles might also not be feasible at all.