For commercial production of microalgae, the production and
energy costs (e.g. use nutrients for culture, light source, cell harvesting
and oil extraction) should be reduced to be as low as possible.
Excluding the cost of infrastructure, when biomass
production of Thalassiosira sp. is conducted using air-lift photobioreactors
above the sea, the critical cost for culturing algae such as
seawater for the medium, sunlight for photosynthesis and free
air for the carbon source are free of charge. Furthermore, these basic
requirements for generating algal biomass are available all year
long. In terms of additional nutrient cost/L medium, the enriched
seawater medium cost was IDR 116, compared to the Walne medium
which was IDR 591. (Note: IDR 1 roughly equals USD 0.0001.)
Thus, the enriched seawater medium greatly reduced costs; it costs
80% less than the Walne medium.