title: Evaluating microalgal integrated biorefinery schemes: empirical controlled growth studies and life cycle assessment.
abstract: Two freshwater and two marine microalgae species were grown under nitrogen replete and deplete conditions evaluating the impact on total biomass yield and biomolecular fractions (i.e. starch, protein, and lipid). A life cycle assessment was performed to evaluate varying species/growth conditions considering each biomass fraction and final product substitution based on energy consumption, greenhouse gas emissions (GHG), and eutrophication potential. Lipid for biodiesel was assumed as the primary product. Protein and carbohydrate fractions were processed as co-products. Composition of the non-lipid fraction presented significant trade-offs among biogas production, animal feed substitution, nutrient recycling, and carbon sequestration. Maximizing total lipid productivity rather than lipid content yielded the least GHG emissions. A marine, N-deplete case with relatively low lipid productivity but effective nutrient recycling had the lowest eutrophication impacts. Tailoring algal species/growth conditions to optimize the mix of biomolecular fractions matched to desired products and co-products can enable a sustainable integrated microalgal biorefinery.
authors.affiliation: Department of Chemical and Environmental Engineering, Yale University, United States.
authors.forename: Lindsay
authors.initials: L
authors.lastname: Soh
authors.forename: Mahdokht
authors.initials: M
authors.lastname: Montazeri
authors.forename: Berat Z
authors.initials: BZ
authors.lastname: Haznedaroglu
authors.forename: Cuchulain
authors.initials: C
authors.lastname: Kelly
authors.forename: Jordan
authors.initials: J
authors.lastname: Peccia
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Eckelman
authors.forename: Julie B
authors.initials: JB
authors.lastname: Zimmerman
mesh_terms: D020418:Algal Proteins / Q000378:metabolism; D019149:Bioreactors / Q000382:microbiology*; D004952:Esters / Q000378:metabolism; D005068:Eutrophication; D005227:Fatty Acids / Q000378:metabolism; D017752:Greenhouse Effect; D058086:Microalgae / Q000254:growth & development*; D013213:Starch / Q000378:metabolism; D013816:Thermodynamics
chemical_list: D020418:Algal Proteins; D004952:Esters; D005227:Fatty Acids; D013213:Starch
keywords: Algae; Biodiesel; Integrated biorefinery; Life cycle assessment