title: Enzymatic production of biodiesel from Nannochloropsis gaditana lipids: Influence of operational variables and polar lipid content.
abstract: Fatty acid methyl esters (FAMEs, biodiesel) were produced from Nannochloropsis gaditana wet biomass (12% saponifiable lipids, SLs) by extraction of SLs and lipase catalyzed transesterification. Lipids were extracted by ethanol (96%)-hexane, and 31% pure SLs were obtained with 85% yield. When the lipids were degummed, SL purity increased to 95%. Novozym 435 was selected from four lipases tested. Both the lipidic composition and the use of t-butanol instead of hexane increased the reaction velocity and the conversion, since both decreased due to the adsorption of polar lipids on the lipase immobilization support. The best FAME yield (94.7%) was attained at a reaction time of 48h and using 10mL of t-butanol/g SL, 0.225gN435/g SL, 11:1 methanol/SL molar ratio and adding the methanol in three steps. In these conditions the FAME conversion decreased by 9.8% after three reaction cycles catalyzed by the same lipase batch.
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: Elvira
authors: E
authors: Navarro López
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain. Electronic address: arobles@ual.es.
authors: Alfonso
authors: A
authors: Robles Medina
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: Pedro A
authors: PA
authors: González Moreno
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: María J
authors: MJ
authors: Jiménez Callejón
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: Luis
authors: L
authors: Esteban Cerdán
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: Lorena
authors: L
authors: Martín Valverde
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: Beatriz
authors: B
authors: Castillo López
authors: Area of Chemical Engineering, University of Almería, 04120 Almería, Spain.
authors: Emilio
authors: E
authors: Molina Grima
mesh_terms: D056804:Biofuels / Q000382:microbiology*; D004952:Esters; D005227:Fatty Acids / Q000138:chemical synthesis*; D008049:Lipase / Q000737:chemistry*; D050356:Lipid Metabolism / Q000502:physiology*; D008055:Lipids / Q000737:chemistry*; D055672:Static Electricity; D058009:Stramenopiles / Q000378:metabolism*
chemical_list: D056804:Biofuels; D004952:Esters; D005227:Fatty Acids; D008055:Lipids; D008049:Lipase
keywords: Biodiesel; Lipase; Microalga; Polar lipid; Transesterification