Valorization of the red seaweed Gracilaria gracilis through a biorefinery approach

This work was supported by the Portuguese Foundation for Science and Technology (FCT) through the Strategic Projects granted to MARE-Marine and Environmental Sciences Centre (UIDP/04292/2020 and UIDB/04292/2020), and Associate Laboratory ARNET (LA/P/0069/2020). FCT also funded the individual doctoral grants awarded to Marta V. Freitas (UI/BD/150957/2021) and Tatiana Pereira (2021. 07791. BD). This work was also financially supported by the project HP4A - HEALTHY PASTA FOR ALL (co-promotion no. 039952), cofunded by ERDF - European Regional Development Fund, under the Portugal 2020 Programme, through COMPETE 2020 - Competitiveness and Internationalisation Operational Programme.

The interest in seaweeds as an abundant feedstock to obtain valuable and multitarget bioactive ingredients is continuously growing. In this work, we explore the potential of Gracilaria gracilis, an edible red seaweed cultivated worldwide for its commercial interest as a source of agar and other ingredients for cosmetic, pharmacological, food, and feed applications. G. gracilis growth conditions were optimized through vegetative propagation and sporulation while manipulating the physicochemical conditions to achieve a large biomass stock. Green extraction methodologies with ethanol and water were performed over the seaweed biomass. The bioactive potential of extracts was assessed through a set of in vitro assays concerning their cytotoxicity, antioxidant, and antimicrobial properties. Additionally, dried seaweed biomass was incorporated into pasta formulations to increase food's nutritional value. Pigments extracted from G. gracilis have also been incorporated into yogurt as a natural colorant, and their stability was evaluated. Both products were submitted to the appreciation of a semitrained sensorial panel aiming to achieve the best final formulation before reaching the market. Results support the versatility of G. gracilis whether it is applied as a whole biomass, extracts and/or pigments. Through implementing several optimized protocols, this work allows the development of products with the potential to profit the food, cosmetic, and aquaculture markets, promoting environmental sustainability and a blue circular economy. Moreover, and in line with a biorefinery approach, the residual seaweed biomass will be used as biostimulant for plant growth or converted to carbon materials to be used in water purification of the in-house aquaculture systems of MARE-Polytechnic of Leiria, Portugal.

info:eu-repo/semantics/publishedVersion