Browsing by Author "Sanchez-Zurano, Ana"
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- Extraction and assessment of the colouring capacity of Arthrospira platensis-derived pigmentsPublication . Villaro-Cos, Silvia; Gouveia, Luisa; Vladic, Jelena; Sanchez-Zurano, Ana; Martínez-García, Irene; Lafarga, TomásABSTRACT: This study presents a zero-waste biorefinery approach for the sequential extraction of phycocyanin and chlorophyll from Arthrospira platensis, followed by the valorisation of the remaining biomass as a plant biostimulant. Natural deep eutectic solvents were screened for phycocyanin recovery, with the mixture proline:glycerol:sorbitol:water (1:1:1:13 molar ratio) showing the highest potential (1.15 g⋅100 g-1; p < 0.05). An initial ultrasound-assisted cell wall disruption step significantly enhanced phycocyanin yield by 400–450 % relative to the untreated control (p < 0.05). A response surface methodology optimised extraction achieved a recovery yield of 8.26 g⋅100 g-1 at 39.7 °C and 127.9 min. The phycocyanin-rich extract was used to mimic the blue colour of commercial blue gin, with a minimal colour difference (ΔE) of 4.53. Subsequent chlorophyll extraction from the phycocyanin leftovers yielded an extract that successfully coloured a commercial green alcohol-free apple liquor (ΔE = 3.93) and green gin (ΔE = 1.65). Finally, the residual biomass demonstrated a significant biostimulant capacity, increasing the germination index of various seeds by 80–150 % compared to water (p < 0.05). This work highlights the potential of A. platensis as a sustainable source for natural colourants and agricultural inputs.
- Optimizing Chlorella vulgaris production and exploring its impact on germination through microalga-N2-fixing bacteria consortiaPublication . Sanchez-Zurano, Ana; Vilaro-Cos, Silvia; Figueiredo, Daniel; Melkonyan, Lusine; Ferreira, Alice; Acien Fernandez, F. Gabriel; Lafarga, Tomás; Gouveia, LuisaABSTRACT: Microalgal biomass is increasingly valued in industrial and agricultural sectors due to its bioactive compounds. However, large-scale production remains costly, mainly due to nitrogen fertilizer expenses. A promising sustainable alternative is co-cultivation with N2-fixing bacteria, capable of supplying biologically available nitrogen. In this study, Chlorella vulgaris was grown in synthetic medium with and without nitrogen, as well as in co-culture with three different N2-fixing bacteria in nitrogen-free medium. Microalgal growth was assessed by dry weight, Fv/Fm ratio, and flow cytometry, which also allowed evaluation of population dynamics and cell viability. Biomass composition (proteins, carbohydrates, lipids, chlorophyll, and carotenoids) was analyzed under all conditions. Co-cultures in nitrogen-free medium showed comparable biomass productivity to nitrogen-supplemented controls, although Fv/Fm values indicated physiological stress in some cases. Moreover, the agricultural potential of the resulting biomass and supernatants was evaluated through germination bioassays using lettuce seeds. All cultures tested at 0.2 g & sdot;L-1 significantly improved the germination index. Also, applying the culture supernatant (biomass removed) also yielded positive effects, with GI increases exceeding 40 %. These results suggest that co-cultivation with N2-fixing bacteria can support efficient microalgal production while generating biomass and supernatants with biostimulant potential, contributing to sustainable agriculture and circular bioeconomy strategies.