Sterol profiles were obtained from cyanobacteria Phormidium autumnale, cultivated in a heterotrophic system using three distinct sources of carbon: glucose, sucrose, and agroindustrial slaughterhouse wastewater. A simultaneous saponification-extraction ultrasound-assisted method was performed to determine sterol and other non-saponified compounds in the dry biomasses. A total of 24 compounds were observed in the biomasses, including hope-22,29-en-3-one, squalene, and 22 other sterols. Using wastewater as a carbon source, the microalgae biomass produced a diversity of sterols such as stigmasterol (455.3 μg g-1) and β-sitosterol (279.0 μg g-1). However, with glucose it is possible to produce ergosterol (1033.3 μg g-1). Squalene was found in all the cultures, with 1440.4 μg g-1, 225.4 μg g-1, and 425.6 μg g-1 for glucose, sucrose, and slaughterhouse wastewater biomasses, respectively. Several intermediate compounds from those sterols were found. These data provide the construction of the sterol metabolism according to the literature for P. autumnale heterotrophically cultured.
Keywords: Gas chromatography; Metabolic pathways; Microalgae; Non-saponified compounds; Phormidium autumnale.
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