Nutraceutical assessment of Solieria filiformis and Gracilaria cornea (Rhodophyta) under light quality modulation in culture

Abstract

Seaweeds can produce certain pigments under specific light, salinity, and nutrient conditions. These pigments have important biological activities, which have been cited in numerous published literature; thus, they have been considered of nutraceutical importance. Solieria filiformis and Gracilaria cornea (Rhodophyta) have been studied for their ability to produce pigments, polysaccharides, and other nutraceuticals with antioxidant activity. Our group currently cultivates these species under an environmentally friendly integrated multi-trophic aquaculture (IMTA) system. In the present study, the ability of these seaweeds to synthesize carotenoids and phycobiliproteins by light quality modulation in laboratory cultures was determined. The experimental design used light-emitting diodes (LEDs) for the evaluation of individual light quality effects (white, blue, green, and red) and a combination of white + blue light for the combined effect. Five replicates per treatment were implemented. Seaweeds were kept in 800-mL polyethylene culture containers with Provasoli-enriched seawater at 22 °C for 3 weeks. The cultures were irradiated between 100 and 110 μmol photons m−2 s−1 with a 12:12 light:dark cycle. Growth parameters, pigment content, C:N ratio, and antioxidant activity were determined. The growth rate increased significantly when seaweeds were subjected to the combination of white + blue light, whereas chlorophyll a synthesis was improved under the green light treatment. As for phycobiliproteins, blue and green light resulted in the highest synthesis of phycoerythrin in S. filiformis and G. cornea, respectively. The synthesis of carotenoids increased with exposure to white light in both species whereas the antioxidant activity increased with the white + blue combination in G. cornea and with white light in S. filiformis. Light quality can promote growth and synthesis of certain compounds in red macroalgae; understanding these variables would be an advantage to control their nutraceutical quality in culture.