Transesterification of castor oil in a solvent-free medium using the lipase from Burkholderia cepacia LTEB11 immobilized on a hydrophobic support Alessandra Machado Baron a , Nathalie Barouh b , Bruno Barea b , Pierre Villeneuve b , David Alexander Mitchell c , Nadia Krieger d,⇑ a Departamento de Química, Universidade Tecnológica Federal do Paraná, Campus Apucarana, 86812-460 Apucarana, Paraná, Brazil b UMR IATE, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), TA 40/16, 73 rue JF Breton, 34398 Montpellier Cedex 5, France c Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Cx.P. 19046 Centro Politécnico, 81531-980 Curitiba, Paraná, Brazil d Departamento de Química, Universidade Federal do Paraná, Cx.P. 19081 Centro Politécnico, 81531-980 Curitiba, Paraná, Brazil highlights  First study of lipase-catalyzed ethanolysis of castor oil in a solvent-free system.  Over 90% conversion of castor oil to fatty acid ethyl esters was obtained in 6 h.  Results are comparable with published results obtained using n-hexane as solvent. article info Article history: Received 17 May 2013 Received in revised form 14 September 2013 Accepted 19 September 2013 Available online 1 October 2013 Keywords: Castor oil Lipases Burkholderia cepacia Biodiesel Transesterification abstract We demonstrate, for the first time, the lipase-catalyzed ethanolysis of castor oil in a solvent-free system. The lipase used was that of Burkholderia cepacia LTEB11, immobilized on Accurel EP 100. With a loading of 4.5% (mass of enzyme preparation in relation to the mass of triacylglycerols in the castor oil) and an ethanol to oil molar ratio of 3:1, 90% conversion of fatty acids to their corresponding ethyl esters was achieved in 6 h. These results are comparable to results reported in the literature for the lipase-catalyzed ethanolysis of castor oil in supercritical CO 2 and in systems containing n-hexane as the solvent. Our sys- tem has the advantage of being simpler to operate. Ó 2013 Published by Elsevier Ltd. 1. Introduction Over recent years, concerns about the forecast decline in petroleum production levels in the near future have stimulated the research and development of processes for the production of biodiesel from a wide variety of renewable feedstocks [1]. Most current industrial processes for biodiesel production involve the transesterification of vegetable oils with methanol through the addition of KOH or NaOH. Although this process produces high lev- els of biodiesel in reaction times as short as 30 min, it does present some disadvantages. Firstly, the oil used as the starting material must be quite pure. Its free fatty acid content must be less than 1%, in order to prevent the formation of soaps, and its water content must be below 0.5%, in order to avoid the hydrolysis of the triacylglycerols. Secondly, the final product must be washed with large volumes of water to remove the soaps and glycerol. This produces an alkaline wastewater that requires treatment [2–7]. Fi- nally, the glycerin produced is contaminated with residual catalyst, which decreases its commercial value [8,9]. Enzymatic catalysis of biodiesel synthesis has potential advan- tages over chemical catalysis. Especially important is the fact that the starting material can contain small amounts of water and can also be contaminated with fatty acids, because lipases will esterify the free fatty acids while transesterifying the triacylglycerols. Moreover, the need for extensive washing of the final product is avoided and the glycerin produced is of higher quality. However, the enzymatic process is significantly more costly than the chem- ical process, mainly due to the high costs of the enzyme and to the long reaction times. Efforts to reduce the costs of the enzymatic process have focused on, firstly, searching for new lipases with 0016-2361/$ - see front matter Ó 2013 Published by Elsevier Ltd. http://dx.doi.org/10.1016/j.fuel.2013.09.065 ⇑ Corresponding author. Tel.: +55 41 3361 3470; fax: +55 41 3361 3006. E-mail addresses: alessmachado@hotmail.com (A.M. Baron), nathalie.barouth@ cirad.fr (N. Barouh), bruno.barea@cirad.fr (B. Barea), pierre.villeneuve@cirad.fr (P. Villeneuve), davidmitchell@ufpr.br (D.A. Mitchell), nkrieger@ufpr.br (N. Krieger). Fuel 117 (2014) 458–462 Contents lists available at ScienceDirect Fuel journal homepage: www.elsevier.com/locate/fuel