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

Author:
Nobre, B.P., Villalobos, F., Barragán, B.E., Oliveira, A.C., Batista, A.P., Marques, P.A.S.S., Mendes, R.L., Sovová, H., Palavra, A.F., Gouveia, L.
Source:
Bioresource technology 2013 v.135 pp. 128-136
ISSN:
0960-8524
Subject:
Enterobacter aerogenes, Nannochloropsis, biorefining, ethanol, fatty acids, fermentation, hydrogen production, lipid content, microalgae, oils, pigments
Abstract:
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 33glipids/100gdrybiomass were found to be at 40°C, 300bar and a CO2 flow-rate of 0.62g/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 45glipids/100gdrybiomass 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 60.6mL/gdrybiomass.
Agid:
505177