Biorefinery Approach Applied to the Production of Food Colourants and Biostimulants from Oscillatoria sp

• Published in: Biology (Basel, Switzerland) Vol. 11; no. 9; p. 1278
• Main Authors: Morillas-España, Ainoa, Bermejo, Ruperto, Abdala-Díaz, Roberto, Ruiz, Ángela, Lafarga, Tomás, Acién, Gabriel, Fernández-Sevilla, José María
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 28.08.2022; MDPI
• Subjects: Algae; Auxins; Beverages; bioeconomy; Biomass; biorefinery; biostimulants; Cosmetics; Cyanobacteria; Cytotoxicity; Economic analysis; Fertilizers; Food; Freeze-thawing; Functional foods & nutraceuticals; Humidity; Ionic strength; microalgae; Oscillatoria; phycocyanin; Phycocyanins; Production costs; Proteins; Seeds; Software; Toxicity; United States > US; Japan; Spain
• ISSN: 2079-7737; 2079-7737
• DOI: 10.3390/biology11091278

In this study, a biorefinery based on Oscillatoria sp. is developed to produce high-value compounds such as C-phycocyanin, used in food colourant applications, and biostimulants, used in agriculture-related applications. First, the Oscillatoria biomass production was optimized at a pilot scale in an open raceway reactor, with biomass productivities equivalent to 52 t/ha·year being achieved using regular fertilizers as the nutrient source. The biomass produced contained 0.5% C-phycocyanins, 95% of which were obtained after freeze–thawing and extraction at pH 6.5 and ionic strength (FI) 100 mM, with a purity ratio of 0.71 achieved in the final extract. This purity ratio allows for use of the extract directly as a food colourant. Then, the extract’s colourant capacity on different beverages was evaluated. The results confirm that C-phycocyanin concentrations ranging from 22 to 106 mg/L produce colours similar to commercial products, thus avoiding the need for synthetic colourants. The colour remained stable for up to 12 days. Moreover, the safety of the extracted C-phycocyanin was confirmed through toxicity tests. The waste biomass was evaluated for use as a biostimulant, with the results confirming a relevant auxin-like positive effect. Finally, an economic analysis was conducted to evaluate different scenarios. The results confirm that the production of both C-phycocyanin and biostimulants is the best scenario from an economic standpoint. Therefore, the developed biomass processing scheme provides an opportunity to expand the range of commercial applications for microalgae-related processes.