Microalgae: Impacts of different culture media on the macromolecular and antioxidant properties of Spirulina ( <i>Arthrospira platensis</i> ) biomass

Abstract Microalgae have high nutritional value and spirulina (Arthrospira platensis) is one of the commercially available biomasses for food purposes. The aim of the present study was to investigate operational variables and compare the effects of different culture media on the productivity and biochemical composition of spirulina biomass. Arthrospira platensis was obtained from the microalgal culture collection of the Laboratory of Algal Cultivation and Biotechnology (Santa Catarina State University), Brazil. The species was initially cultivated in a 250-mL Erlenmeyer flask and gradually expanded to a volume of 5 L using different culture media: Zarrouk’s medium and a commercial fertilizer (Novatech). Zarrouk’s medium provided a culture with higher cell density (39 x 104 cells mL-1; dry mass = 0.246 g L-1) compared to Novatech (31.9 x 104 cells mL-1; dry mass = 0.221 g L-1). In the biochemical analysis, Zarrouk’s medium was composed of carbohydrates (10.7%), lipids (2.8%), polyphenols (0.6%), and antioxidant activity (45%, which corresponds to 10.24 μM Trolox g-1 of biomass). The carbohydrate concentration was higher in the Novatech medium (28.5%), but the concentrations of lipids (1.32%), polyphenols (0.14%), and antioxidant activity (31.3%, which corresponds to 6.72 μM Trolox g-1) were lower. No significant differences were found in protein content (49% for Zarrouk and 44% for Novatech). Overall, the culture media yielded good results and the use of the commercial fertilizer proved viable compared to the data obtained for the conventional Zarrouk medium.