Optimization of an Alternative Culture Medium for Phycocyanin Production from Arthrospira platensis under Laboratory Conditions

Arthrospira platensis, known as spirulina, is a cyanobacterium with multiple nutritional benefits, as it contains substantial amounts of proteins, fatty acids, and pigments. However, the production of this microalga has faced significant challenges, primarily related to the cost and composition of the required culture medium for its optimal growth. This study focused on optimizing two nitrogen sources (urea and potassium nitrate) to maximize the growth of A. platensis and the production of phycocyanin, a photosynthetic pigment of significant commercial value. Optimization was performed using the response surface methodology (RSM) with a central composite design (CCD). Analysis of variance (ANOVA) was employed to validate the model, which revealed that the different concentrations of urea were statistically significant (p < 0.05) for biomass and phycocyanin production. However, potassium nitrate (KNO₃) showed no significant influence (p > 0.05) on the response variables. The RSM analysis indicated that the optimal concentrations of KNO₃ and urea to maximize the response variables were 3.5 g L⁻¹ and 0.098 g L⁻¹, respectively. This study offers valuable perspectives for the efficient production of A. platensis while reducing production costs for its cultivation on a larger scale.