title: Dual-mode cultivation of Chlorella protothecoides applying inter-reactors gas transfer improves microalgae biodiesel production.
abstract: Chlorella protothecoides, a lipid-producing microalga, was grown heterotrophically and autotrophically in separate reactors, the off-gases exiting the former being used to aerate the latter. Autotrophic biomass productivity with the two-reactor association, 0.0249gL(-1)h(-1), was 2.2-fold the value obtained in a control autotrophic culture, aerated with ambient air. Fatty acid productivity was 1.7-fold the control value. C. protothecoides heterotrophic biomass productivity was 0.229gL(-1)h(-1). This biomass' fatty acid content was 34.5% (w/w) with a profile suitable for biodiesel production, according to European Standards. The carbon dioxide fixed by the autotrophic biomass was 45mgCO2L(-1)h(-1) in the symbiotic arrangement, 2.1 times the control reactor value. The avoided CO2 atmospheric emission represented 30% of the CO2 produced in the heterotrophic stage, while the released O2 represented 49% of the oxygen demand in that stage. Thus, an increased efficiency in the glucose carbon source use and a higher environmental sustainability were achieved in microalgal biodiesel production using the proposed assembly.
authors.affiliation: LNEG I.P., U. Bioenergia, ed. F, Estrada do Paço do Lumiar, 22, 1649-038 Lisbon, Portugal.
authors.forename: C A
authors.initials: CA
authors.lastname: Santos
authors.affiliation: LNEG I.P., U. Bioenergia, ed. F, Estrada do Paço do Lumiar, 22, 1649-038 Lisbon, Portugal.
authors.forename: B
authors.initials: B
authors.lastname: Nobre
authors.affiliation: LNEG I.P., U. Bioenergia, ed. F, Estrada do Paço do Lumiar, 22, 1649-038 Lisbon, Portugal.
authors.forename: T
authors.initials: T
authors.lastname: Lopes da Silva
authors.affiliation: Centre for Biological and Chemical Engineering, IBB - Institute for Biotechnology and Bioengineering, Department of Bioengineering, Instituto Superior Técnico, University of Lisbon, Av. Rovisco Pais, 1049-001 Lisbon, Portugal.
authors.forename: H M
authors.initials: HM
authors.lastname: Pinheiro
authors.affiliation: LNEG I.P., U. Bioenergia, ed. F, Estrada do Paço do Lumiar, 22, 1649-038 Lisbon, Portugal. Electronic address: alberto.reis@lneg.pt.
authors.forename: A
authors.initials: A
authors.lastname: Reis
mesh_terms: D056804:Biofuels; D002245:Carbon Dioxide / Q000378:metabolism; D002708:Chlorella / Q000254:growth & development / Q000378:metabolism*; D005227:Fatty Acids / Q000096:biosynthesis; D005740:Gases; D052836:Heterotrophic Processes; D008055:Lipids / Q000096:biosynthesis*; D058086:Microalgae / Q000254:growth & development / Q000378:metabolism*
chemical_list: D056804:Biofuels; D005227:Fatty Acids; D005740:Gases; D008055:Lipids; D002245:Carbon Dioxide
keywords: Autotrophic; Biodiesel; Carbon dioxide fixation; Chlorella protothecoides; Heterotrophic