The Effect of Medium Concentration and Nitrogen Source on the Productivity and Biochemical Composition of Arthrospira platensis

The effect of different diluted medium concentrations (25, 50 and 100%) and two nitrogen sources: standard Zarrouk medium (SZM) and modified Zarrouk medium with urea (MZM-U), were analyzed in the Spirulina culture in two different strains: Spanish (SS) and Malaysian (MS). The productivity was slightly lower using 25% of both mediums. The highest growth biomass was obtained in 50% SZM for SS, and in 50% MZM-U in MS. The internal carbon, nitrogen and protein content decreased when the lowest percentage (25%) was used, mainly using urea in both strains. In contrast the carbohydrates content were higher using 25% of medium, especially when urea was used. Its content was slightly higher in MS. For lipid concentration, the lowest content was observed in the 25% MZM-U in both strains. The pigment content was much lower when 25% MZM-U was used in both strains. Both strains were able to grow with low medium concentrations without losing their properties, which suggested that the cost of Spirulina production could be significantly reduced.