A biorefinery from Nannochloropsis sp. microalga – Extraction of oils and pigments. Production of biohydrogen from the leftover biomass

• Autor(a) principal: Nobre, B. P.
• Data de Publicação: 2013
• Outros Autores: Villalobos, Fidel, Barragan, Blanca E, Oliveira, Ana Cristina, Batista, Ana Paula, Marques, Paula, Mendes, Rui L., Sovová, H., Palavra, António F., Gouveia, Luisa
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10400.9/1679
• topic: Nannochloropsis sp.; Oils; Carotenoids; Biohydrogen; Biorefinery

The microalga Nannochloropsis sp. was used in this study, in a biorefinery context, as biomass feedstock for the production of fatty acids for biodiesel, biohydrogen and high added-value compounds. The microalgal biomass, which has a high lipid and pigment content (mainly carotenoids), was submitted to supercritical CO2 extraction. The temperature, pressure and solvent flow-rate were evaluated to check their effect on the extraction yield. The best operational conditions to extract 33 glipids/100 gdry biomass were found to be at 40 °C, 300 bar and a CO2 flow-rate of 0.62 g/min. The effect of adding a co-solvent (ethanol) was also studied. When supercritical CO2 doped with 20% (w/w) ethanol was used, it was possible to extract 45 glipids/100 gdry biomass of lipids and recover 70% of the pigments. Furthermore, the remaining biomass after extraction was effectively used as feedstock to produce biohydrogen through dark fermentation by Enterobacter aerogenes resulting in a hydrogen production yield of 60.6 mL/gdry biomass.