A cost-effective medium for Spirulina production

Spirulina has been widely used as a dietary supplement for humans and animals due to its high nutritional content, which includes essential amino acids, essential fatty acids, carbohydrates, vitamins, and minerals. However, producing Spirulina biomass in Thailand requires imported chemicals, leading to high production costs. This study aims to formulate a cost-effective medium for Spirulina production. Arthrospira (Spirulina) platensis was cultivated in standard Zarrouk’s medium (control) with aeration and a modified medium. The modified medium featured reduced carbon and nitrogen concentrations while exploring three different nitrogen sources (NaNO₃, urea, and (NH₄)₂SO₄). The cultures were grown with either aeration or 1% CO₂ under a light intensity of 100 µmol photons m^-2 s^-1 at 35 °C for 48 hours. The growth was monitored daily, and the cell biochemicals were analyzed from dried cells. The results revealed that the modified medium, comprising reduced NaHCO₃ (8 g L^-1) combined with 10 mM NO₃-N or 10 mM Urea-N, yielded a higher biomass (0.51–0.57 g L^-1) compared to the control medium and the medium containing 5 mM NH₄-N. Additionally, the change in nitrogen source caused differences in biochemical contents. Similar protein content was observed in cells cultivated in 10 mM NO₃-N and 5 mM NH₄-N, whereas an increase in carbohydrate levels was observed when 10 mM urea-N was used. The study suggested that the modified Zarrouk’s medium can be applied as a low-cost medium for producing Spirulina biomass with the desired biochemical production.

Keywords: Spirulina, Low-cost medium, Nutrients