Transcript Algae Production, Biology and Species

Algae Production, Biology and
Species
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Biology
Microalgae: microscopic single-celled
eukaryotic planktonic algae
To be magnified 100 – 400X in order to recognize
family
Reproduction by cell division
Some species have own movements by flagella,
other drift passively
Divided in 9 divisions according to pigment types
etc.
Photoautotrophic (also heterotrophic) organisms
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Photosynthesis
As with all plants, algae photosynthesise, i.e. they
convert carbon into organic matter. Light is the
source of energy, which drives this reaction with
wavelength and photoperiod the main factors.
Photosynthesis: 6CO2 + 6H2O = C6H12O6 +
6O2
In the dark, algae shifts from photosynthesis to
respiration, and the equation is reversed and glucose is
needed for energy
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Growth dynamics
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Growth dynamics
1. Lag or induction phase
This phase during which little increase in cell density occurs is relatively
long when an algal culture is transferred from a plate to liquid culture.
2. Log or exponential phase: the cell density increases as a function of
time according to a logarithmic function.
3. Phase of declining growth rate; cell division slows down when
nutrients, light, pH, carbon dioxide or other physical and chemical factors
begin to limit growth.
4. Stationary plateau phase: the limiting factors and the growth rate are
balanced, which results in a relatively constant cell density.
5. Death or "crash" phase: water quality deteriorates and nutrients are
depleted to a level incapable of sustaining growth. Cell density decreases
rapidly and the culture eventually collapses.
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Light
Energy source
Intensity; not to low, not to high (photo-inhibition)
Fluorescent tubes
emitting either in the
blue or the red light
spectrum are
preferred, as these are
the most active
wavelengths for
photosynthesis.
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Nutrients
As the concentrations of cells in phytoplankton cultures are
generally higher than those found in nature, algal cultures must
therefore be enriched with additional nutrients and mineral to
make up for the deficiencies in the seawater.
Nutrients as nitrate and
phosphate are
important for synthesis
of DNA
Minerals, trace elements
and vitamins are
important for synthesis
of pigments, enzymes
etc.
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Criteria for choosing the right species
 Sufficient nutritional requirements for both the
fish larvae and rotifers
 Not poisonous for the predators
 Sufficient cell size and digestibility in order to be
filtered and digested by the rotifers
 High reproduction rate, reliable and sustainable
in standardized commercial growing systems
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Information about species
Different algal species are grown for different species of fish or
shrimp depending on the culture technique. The typical species
cultured are as follows;
Shrimp culture
Fish culture
Tetraselmis chuii
Tetraselmis
suesica
Nannochloropsis sp.
Isochrysis galbana
Isochrysis
galbana
Chlamydamonas sp.
Chaetoceros gracilis
Monochrysis
lutheri
Nannochloris atomus
Skeletonema sp
Chrorella sp.
Nannochloropsis oculata
Spirulina platensis
Spirulina
platensis
Pavlova lutheri
Dunaliella sp.
Pseudochrysis galbana
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Information about some microalgae
species
Prasinophyceae – greenish coloured algae
Tetraselmis chuii
 Large green flagellate, often
used in larval rearing of
shrimp, fish and shellfish
 Optimal salinity 15 - 36 0/00
 Optimal temperature 15 33C
 Typical densities in mass
culture 300-450 celles/ml
 Very high lipid content
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Prynesiophyceae – golden brown flagellate
Isochrysis sp.
 Used especially as a primary algae
in shellfish hatcheries
 Size: 3-5 um
 Spherical to pear shaped
Isochrysis galbana tahition
 Size: 5-6 um
 Prefer temperatures up to 30 C
and high light intensities
 High DHA level and is therefore
used for growing rotifers
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Eustigatophyceae – greenish yellow algae
Nannochloropsis





Small green flagellate
Size: 2-4 um
Used in rotifer production
Popular as greenwater
Keeps suspended in the
water column
 High total lipid content
and EPA level.
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Bacillariophyceae - Diatoms
Chaetoceros sp.
•non-chainforming marine diatoms
•golden brown, rectangular in shape
•Size:4-6 um
•Optimal temperature: 25 and 30 C
•Optimal salinity: 17 and 25 ppt
•Light intensity: 500 to 10,000 lux
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Nutritional value in some species
Vit C
Microalgae
(Ascorbic
Acid)
Tetraselmis
Chlorophyl
A
Protein
Carbohydrate
Lipid
EPA (20:5) DHA (22:6)
(% of Lipid) (% of Lipid)
0.25%
1.42%
54.66 %
18.31 %
14.27 %
9.3%
0%
Nannochloropsis 0.85%
0.89%
52.11 %
12.32 %
27.64 %
10.1%
0%
CHGRA
1.60%
1.04%
27.68 %
23.20 %
9.29 %
5.0%
0.5%
T-ISO
0.4%
0.98%
46.69 %
24.15 %
17.07 %
0.25%
8.5%
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Summary algae species
Microalgae Culture
Type
Nannochloropsis
Green Flagellate
CHGRA
(Chaetoceros gracilis)
T-ISO
(Isochrysis galbana)
Pavlova
Diatom
Yellow Flagellate
1.5-3
microns
Tetraselmis
Green Flagellate
Paste
Typical Culture
Concentration
Density
(cells / ml)
(cells / ml)
Tetraselmis
1.0 Billion
400,000
Nannochloropsis
51 Billion
20 Million
CHGRA
3.2 Billion
1.5 Million
T-ISO
6.2 Billion
Animals
Zooplankton, Marine Fish Larvae
6-9
Zooplankton, Shellfish, Penaeid
microns
Shrimp
5-6
microns
Brown Flagellate 5-6 micros
(Pavlova pinguis)
Culture
Cell Size
Zooplankton, Shellfish, Shrimp
Zooplankton, Shellfish
14-23
Zooplankton, Shellfish, Penaeid
microns
Shrimp, Abalone Larvae
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