ORIGINAL PAPER Lipase Induction in Yarrowia lipolytica for Castor Oil Hydrolysis and Its Effect on c-Decalactone Production Adelaide Braga • Nelma Gomes • Isabel Belo Received: 21 April 2011 / Revised: 11 November 2011 / Accepted: 2 December 2011 / Published online: 28 December 2011 Ó AOCS 2011 Abstract c-Decalactone is an aromatic compound of industrial interest, resulting from the biotransformation of ricinoleic acid, the major constituent of castor oil. In order to increase the availability of the substrate to the cells for the aroma production, castor oil previously hydrolyzed can be used. This hydrolysis may be promoted by enzymatic action, more specifically by lipases. In this work, the influence upon the aroma production of the lipase produced by Yarrowia lipolytica, a microorganism able to carry out the biotransformation, was studied. In a first approach, lipase induction conditions were analyzed using different Y. lipolytica strains and culture conditions, such as the inoculation mode of the lipase production medium. Lipase production was not affected by the cells centrifugation, so this step was eliminated, reducing the time and phases of the process. Moreover, Y. lipolytica W29 was shown to be the most adequate strain for lipase production. To inves- tigate the importance of castor oil hydrolysis, the pre- addition of an inducer of lipase production (olive oil) to the biotransformation medium was tested. Results showed that the highest aroma production (1,600 mg L -1 ) was obtained without a lipase inducer. However, the pre-induction of lipase decreased the lag phase for c-decalactone secretion. Keywords Castor oil  c-Decalactone  Lipase  Yarrowia lipolytica Introduction The production of aromas by means of biotechnological processes has proved to be of great interest, since the acceptability of these products to use in the food industry is greater than similar products obtained by chemical syn- thesis [1]. c-Decalactone is an aromatic compound that can be obtained from the biotransformation of ricinoleic acid (the major constituent of castor oil, which is the raw material most commonly used in the biotechnological production of this aroma) by several microorganisms, among which is the aerobe Yarrowia lipolytica [2], the yeast used in the present work. Castor oil needs to be hydrolyzed in order to release ricinoleic acid to be used in the process. There are some chemical and physical methods available in the literature to hydrolyze oils. However, enzymatic hydrolysis, contrarily to the other techniques, works at moderate temperatures, allowing the production of an odorless and light-colored ricinoleic acid [3]. Neto et al. [4] studied the influence of castor bean oil previous hydrolyzed, by different microbial lipases, in c-decalactone production with two fungi strains (Geotrichum fragrans and Geotrichum sp.) and concluded that the addition of hydrolyzed castor bean oil to the culture medium enhances c-decalactone production. In c-decalactone production by Candida guilliermondii, Far- bood and Willis [5] used a lipase (steapsin) to previously hydrolyze castor oil. Lipases (triacylglycerol acylhydrolases EC 3.1.1.3) are enzymes comprised from the hydrolases family whose main biological function is catalyzing the hydrolysis of insoluble triglycerides to generate free fatty acids, mono and diglycerides and glycerol. In addition, lipases can catalyze reactions of esterification, interesterification and transesterification in a non-aqueous medium [6]. A wide A. Braga  N. Gomes  I. Belo (&) Institute for Biotechnology and Bioengineering (IBB), Centre of Biological Engineering , University of Minho Campus de Gualtar, 4710–057 Braga, Portugal e-mail: ibelo@deb.uminho.pt 123 J Am Oil Chem Soc (2012) 89:1041–1047 DOI 10.1007/s11746-011-1987-5