Physiology and Cultivation of
Algae and Cyanobacteria
4.
Biogechemical role of algae
• Energy flow in the environment
• Limiting nutrients
– Liebig’s Law of the Minimum
 = max [LM] / [LM] + Km
algal major elements (99.9% biomass) – C, O, H, N, P, S, Ca, K, Na, Cl, Mg, Fe, Si
• Cycles of nutrients
• Phosphorus
• Nitrogen
• Sulphur
• Carbon & Oxygen
• environmental factors
Phosphorus
• PO4
3•
membranes, coenzymes, DNA, RNA, ATP
• orthophosphate; metaphosphate (polyphosphate);
“organic” phosphate
Nitrogen
• diazotrophs
• N-fixation (N2 >> NH3)
– N2>diimide(H2N2)>imide(H4N2)>amonia(2NH3)
• assimilation (NO3
-&NH4
+ >> organic N)
• mineralization (organic N >> NH4
+)
• nitrification (NH4
+&NO2
- >> NO3
-)
• denitrification (NO3
- >> NO, N2O, N2)
• nitrogenase; MoFe(V)-protein; PS I;
• Nostoc, Anabaena, Trichodesmium,
Katagnymene
Silicon
• [Si(OH)4]; (SiO2 . nH2O)
• silica-forming organism
• Chrysophyceae
• Bacillariophyceae (diatoms)
• Dictyochlorophyceae
• cell wall; sediments
Sulphur
• aminoacids (Cys, Pro, cystine)
• SO2, SO4
2-, H2S,
• APS (adenosine-5’-phosphosulphate)
• PAPS (3’-phosphoadenosine-5’-
phosphosulphate)
• DMS (dimethyl sulphide)
• DMSP (dimethylsulphonium propionate)
Carbon & Oxygen
• CO2, H2O, CO, O2, HCN, CH4, CaCO3,
CFC, HCFC
• photosynthesis
• oxidizing atmosphere
• Coccoliths - Haptophyta
Algae & Men
• macroalgae (commerce - 42 countries)
• food
– Laminaria (China, N.,S.Korea, Japan, Philipines, Chile,
Norway, Indonesia, U.S., India)
– Porphyra, Kappaphycus, Undaria, Euchema, Gracilaria
– Nori (Porphyra yezzoensis) – 13mil. t/y
• microalgae
• carotenoids, pigmenst, proteins, vitamins, …
– nutraceuticals, pharmaceuticals, animal feed additives,
cosmetics, fertilizers
– Dunaliella, Haematococcus, Arthrospira, Chlorella