Lipase-catalyzed synthesis of biodiesel
Sustainable process-product development & green chemistry
Sustainable & Clean Technologies-II: Energy Production (T1-5P)
Keywords: biodiesel, lipases, transesterification, vegetable oils, FAME
José M. Cerveró, José R. Álvarez, Susana Luque and José Coca
Department of Chemical and Environmental Engineering
University of Oviedo, 33071, Oviedo (Spain)
E-mail: sluque@uniovi.es
Among the alternative energies that could be produced from biomass, the use of vegetal oils and their derivatives, such as mixtures of fatty acids esters, the so-called biodiesel, is one of the most promising routes. Biodiesel has similar energy efficiency as the conventional diesel, and a reduced pollution load. Moreover, it can be used in the conventional diesel engines without the need of modifications. Since it can be obtained from low-cost raw materials, the resulting fuel may also be economically feasible
Biodiesel is produced at large scale by transesterification of the triglycerides present in animal fat or vegetable oils, by displacing glycerine by a low molar mass alcohol (typically methanol), using alkali catalysts. These resulting methyl esters are rather similar to the hydrocarbons that are present in the diesel.
This research work has been focused on the catalytic transesterification of sunflower and soybean oils with methanol and ethanol, employing enzymes as catalysts. Although the methyl esters are currently the only ones produced at industrial scale, the use of ethanol, which can be obtained from renewable resources, would generate a cleaner and more biocompatible fuel.
From a preliminary enzyme screening, the lipase B from Candida antarctica was found to give the highest yield. Reaction conditions, such as enzyme/substrate ratio, alcohol/oil ratio, and temperature were then optimized. Moreover, alkali-catalyzed reactions were also carried out, using NaOH and KOH, and the results were compared to those obtained by the biocatalyzed reaction.
Acknowledgements
Authors gratefully acknowledge the financial support given by the Spanish Ministry of Education and Science (project number CTQ2005-02401).
Presented Monday 17, 13:30 to 15:00, in session Sustainable & Clean technologies - II: Energy Production (T1-5P).
