A new study led by Filomena Freitas from the Biochemical Engineering Research Lab at UCIBIO-NOVA has been published in the Journal of Environmental Chemical Engineering. The paper, titled "Heterotrophic cultivation of Chlorella vulgaris yellow mutant on sidestreams: Medium formulation and process scale-up" presents an innovative approach to microalgae cultivation using food waste and industrial sidestreams as nutrient sources.
Microalgal protein is a promising alternative to traditional protein sources, requiring less land and water while offering sustainable production methods. Mafalda Trovão, the first author of the study, explains that "this study focused on Yellow Chlorella vulgaris, a chlorophyll-deficient strain with improved sensory properties. We explored heterotrophic cultivation methods, which can produce higher biomass and require a smaller land area than traditional autotrophic methods.”
The research team formulated a waste-based medium using food waste, rich in nitrogen, and corn molasses, which provided a high glucose concentration. The waste-based medium was tested at laboratory scale and in larger reactors, achieving similar biomass productivity and growth rates compared to traditional inorganic mediums. When scaled up, the process produced microalgae biomass with high protein content, confirming the efficiency of the waste-based medium.
The study addresses the global challenge of food waste, as highlighted by the United Nations Environment Programme, which reported that one-fifth of food produced for human consumption was wasted in 2024. By developing a tailored medium from industrial sidestreams, the researchers successfully established Yellow Chlorella vulgaris as a feasible industrial product and potential alternative protein source.
In addition to developing a more sustainable production process, the study demonstrated the potential for organic certification and improved market value for this microalgal biomass. These advances contribute to the broader effort of promoting sustainable protein alternatives and reducing the environmental footprint of food production.
Original article:
Heterotrophic cultivation of Chlorella vulgaris yellow mutant on sidestreams: Medium formulation and process scale-up
Journal of Environmental Chemical Engineering
Mafalda Trovão, Ana Barros, Adriana Machado, Ana Reis, Humberto Pedroso, Gonçalo Espírito Santo, Nádia Correia, Monya Costa, Sara Ferreira, Helena Cardoso, João Varela, Joana Silva, Hugo Pereira, Filomena Freitas
DOI: 10.1016/j.jece.2025.115361