Microalgae culture systems

DONALDSON J (1991) Commercial production of microalgae at Coast Oyster Company, in Fulks W and Main K L (eds). Rotifer and microalgae culture systems. Honolulu, HI The Oceanic Institute, 229-239. 

Plate II Examples of microalgae culture systems used in hatcheries, (a) 2 L bottle and 10 L carboy cultures for scale-up (b) 1000 L tub cultures (c) 500 L polythene bag cultures and (d) 180 L annular photobioreactor culture. Photos (a), (b) and (c) courtesy, W. O Connor, Industry and Investment, NSW, and (d) Dion Frampton... 

Figure 17. Microalgae culture in open system (raceway) and close photobioreactor (Almeria University and Palmerillas Research Center).

Microalgae can be grown batchwise in photobioreactors. In case biomass concentrations become too high the culture is diluted, and biomass is harvested, after which growth is allowed to continue again. Microalgae production systems can also be operated in a continuous manner based on a chemostat or turbidostat mode of operation. Flere these three different... 

Ideally, the culture system has to enable optimal control of growth conditions, but it also has to meet the many and varied practical and economic tied to different microalgae applications, from small-scale lab production to mass-scale solar culture. 

JAMES c M and al-khars a m (1990) An intensive continuous culture system using tubular photobioreactors for producing microalgae. Aquaculture, 87, 381-393. 

Between 1980 and 1987, the ASP funded the development of two larger-scale microalgae mass culture systems—one at the University of California and one at the University of Hawaii. Both systems utilized open raceway designs and performed their studies in ponds lOOm or less. The effects of fluid flow patterns, light intensity, dissolved O2 levels, pH, and algae harvesting methods were studied in both systems and locations. 

The microalgae are cultured in bioreactors under solar or artiflcial light in the presence of carbon dioxide and salts. The bioreactors may be closed systems made of polyethylene sleeves rather than open pools. Optimal conditions for pigment production are low to medium light intensity and medium temperatures (20 to 30°C). Pigment extraction is achieved by cell breakage, extraction into water or buffered solution, and centrifugation to separate out the filtrate. The filtrate may then be partly purified and sterilized by microfiltration and spray dried or lyophilized. 

It is important to develop a cheap and easy control system of culture medium temperature, in order to keep the higher productivity. Also, utilization of a thermophilic microalgae is considered to be an effective choice in summer. 

---