Photosynthetic Pigments from Marine Algae: Isolation, Characterization, Biological Properties, and Life Cycle Assessment

Marine algae's photosynthetic system is distinguished by the existence of phycobiliprotein pigments, along with chlorophyll and carotenoid pigments. Photosynthetic pigments have recently garnered interest for their biological activity. The aim of this study was to optimize the extraction, purification, and evaluation of the antioxidant and pro-oxidant activities of photosynthetic pigments. Primarily, photosynthetic pigments were extracted and characterized from four marine algal sources, utilizing environmentally friendly procedures and solvents, followed by comparative data for pigment extracts, including total pigment content and antioxidant activity. Secondly, a novel and sustainable procedure was suggested for extracting and analyzing photosynthetic pigments from spirulina, followed by a new workflow to purify photosynthetic pigments and convert them into more stable pigments without the need for pretreatment using flash chromatography. The precise effects of individual photosynthetic pigments on antioxidant and prooxidant characteristics have not been completely understood. a comparison of the antioxidant and pro-oxidant properties of isolated extracts and individual pigments was carried out. Finally, the sustainability of the approaches for extracting pigments from marine algae was evaluated using a gate-to-gate life cycle assessment (LCA). The results of the proposed method for purifying chlorophyll pigments showed a high yield of individual chlorophyll derivatives, pheophytin a and pheophorbide a with high purity. The results also showed that all the purified photosynthetic pigments possessed antioxidant and free radical activity, with chlorophyll derivatives showing a much stronger ability compared to other pigments. The LCA results showed that water may be a suitable solvent for extracting the three photosynthetic pigments green, orange, and blue from the same batch of Spirulina through a synergy between mechanical processes such as ultrasound and non-mechanical processes such as freezing and thawing. Furthermore, based on this life cycle analysis of pigment production, electricity had the greatest environmental impact in most categories of extraction procedures. This study could constitute a starting point for expanding the extraction of marine algae pigments and their use as antioxidants in various applications.