title: Influence of biogas flow rate on biomass composition during the optimization of biogas upgrading in microalgal-bacterial processes.
abstract: The influence of biogas flow rate (0, 0.3, 0.6, and 1.2 m(3) m(-2) h(-1)) on the elemental and macromolecular composition of the algal-bacterial biomass produced from biogas upgrading in a 180 L photobioreactor interconnected to a 2.5 L external bubbled absorption column was investigated using diluted anaerobically digested vinasse as cultivation medium. The influence of the external liquid recirculation/biogas ratio (0.5 < L/G < 67) on the removal of CO2 and H2S, and on the concentrations of O2 and N2 in the upgraded biogas, was also evaluated. A L/G ratio of 10 was considered optimum to support CO2 and H2S removals of 80% and 100%, respectively, at all biogas flow rates tested. Biomass productivity increased at increasing biogas flow rate, with a maximum of 12 ± 1 g m(-2) d(-1) at 1.2 m(3) m(-2) h(-1), while the C, N, and P biomass content remained constant at 49 ± 2%, 9 ± 0%, and 1 ± 0%, respectively, over the 175 days of experimentation. The high carbohydrate contents (60-76%), inversely correlated to biogas flow rates, would allow the production of ≈100 L of ethanol per 1000 m(3) of biogas upgraded under a biorefinery process approach.
authors: Department of Chemical Engineering and Environmental Technology, University of Valladolid , Dr. Mergelina s/n, Valladolid 47005, Spain.
authors: Mayara L
authors: ML
authors: Serejo
authors: Esther
authors: E
authors: Posadas
authors: Marc A
authors: MA
authors: Boncz
authors: Saúl
authors: S
authors: Blanco
authors: Pedro
authors: P
authors: García-Encina
authors: Raúl
authors: R
authors: Muñoz
mesh_terms: D001419:Bacteria / Q000254:growth & development*; D056804:Biofuels / Q000032:analysis*; D018533:Biomass; D002245:Carbon Dioxide / Q000378:metabolism; D000431:Ethanol / Q000378:metabolism*; D006862:Hydrogen Sulfide / Q000378:metabolism; D058086:Microalgae / Q000254:growth & development*; D058433:Photobioreactors / Q000382:microbiology*
chemical_list: D056804:Biofuels; D002245:Carbon Dioxide; D000431:Ethanol; D006862:Hydrogen Sulfide