Use of Palmaria palmata and Fucus vesiculosus hydrolysates for Yarrowia lipolytica biomass and erythritol production

The relatively low protein content of Fucus vesiculosus and Palmaria palmata compared to other seaweeds, combined with their high carbohydrate content, makes these seaweeds particularly suitable as biorefinery feedstocks. This study explored the two algae F. vesiculosus and P. palmata to obtain hydrolysates and use them as substrates for Yarrowia lipolytica NCYC 2904 cultivation in stirred-tank bioreactors. Hydrolysates from F. vesiculosus (FH), non-washed P. palmata (PH), and washed P. palmata (WPH) were obtained after hydrothermal pretreatment (121 °C, 30 min) followed by enzymatic hydrolysis (Cellic CTec3). Y. lipolytica efficiently assimilated different carbon sources from PH and WPH (glucose, xylose, and formic acid), and from FH (fucose, mannitol, glucuronic acid, and acetic acid). To date, the consumption of fucose and glucuronic acid by Y. lipolytica has not been described. The yeast consumed high amounts of xylose (60 g·L −1 ) and produced erythritol from PH and WPH, a feature not previously reported. The highest erythritol concentration (40 g·L −1 ) and protein content in yeast biomass (29%, w/w, dry basis) were obtained in PH cultures, while the highest cellular lipids accumulation (15%, w/w, dry basis) was attained using WPH. Lipids produced under all conditions were enriched in mono- (71%–78%) and polyunsaturated (20%–22%) fatty acids, while the yeast biomass from PH, WPH, and FH exhibited a well-balanced amino acid profile, including essential amino acids. These findings have significant implications for the development of sustainable blue biorefineries based on Y. lipolytica as a microbial platform for valorizing seaweed biomass into bioproducts, such as protein-rich yeast biomass (approved for human consumption), lipids, and erythritol, supporting sustainable food and feed applications.