Based on the optimum cultivating conditions of C. vulgaris using
organic and inorganic fertilizer, a simple cost analysis was
conducted. The cost of organic fertilizer purchased at local market
was 1.2 USD per pack (400 g) whereas the overall cost to prepare
the inorganic fertilizer (BBM) was 15–25 USD per liter. In addition,
for the preparation of organic nutrients, electricity cost for stirring
and cost for solid residue filtration were included. Consequently,
the total cost of nutrients required to produce 1 kg of C. vulgaris
biomass was estimated to be 2.5–3 USD and 60–85 USD for organic
and inorganic fertilizer, respectively. Hence, utilization of cheap
nutrient sources such as organic fertilizer will be more beneficial
in large scale microalgae cultivation system, typically in terms of
cost saving and better environmental protection.