Reduce production cost of Arthrospira platensis by shrinking chemicals in culture medium

        On account of the nutrient-rich biomass sources, Arthrospira platensis (Spirulina) has been

widely used in food, feed, pharmaceutical, and cosmetic fields. However, the production cost

in Thailand is still high because it mainly depends on the price of fertilizers or chemicals used

for a medium. This study aimed to provide a cost-effective medium for pilot-scale production

of Spirulina biomass. Outdoor batch cultivation was carried out in 560 L in raceway ponds

(1×4×0.15 m, length × width × height) for 5 days with 4 consecutive cycles. Comparisons

of productivity and biochemical compositions in Zarrouk’s medium (control) and modified

Zarrouk’s medium which contained sodium bicarbonate and sodium nitrate only 48% and

34% of the amounts in the control medium were conducted. The results revealed that the

mean productivity of cells grown in the modified Zarrouk’s medium was similar to that

of the control medium. In addition, biochemical compositions; protein, carbohydrate, and

total fatty acids, of the cells grown in the modified Zarrouk’s medium were not significantly

different compared to those of the control. These results demonstrated that decreasing the

proper amounts of sodium bicarbonate and sodium nitrate gave approximate biomass

productivity and biochemical compositions as of control. Due to the fertilizer ingredient cost

being almost the biggest ratio in the total cost of Spirulina biomass production, using this

modified Zarrouk’s medium could reduce about 45% of the medium cost. Moreover, reducing

the fertilizer not only reduces the cost of production but also benefits the environment.