Enzymatic Modification of Palmarosa Essential Oil: Chemical Analysis and Olfactory Evaluation of Acylated Products by Jade Ramilijaona, Elsa Raynaud, Charfeddine Bouhlel, Elise Sarrazin, Xavier Fernandez, and Sylvain Antoniotti* Institut de Chimie de Nice, UMR 7272, Universite ´ de Nice – Sophia Antipolis, CNRS, Parc Valrose, FR-06108 Nice cedex 2 (e-mail: sylvain.antoniotti@unice.fr) We have developed an enzymatic protocol to modify the composition of palmarosa essential oil by acylation of its alcohol components by three different acyl donors at various rates. The resulting modified products were characterized by qualitative and quantitative analyses by gas chromatography, and their olfactory properties were evaluated by professional perfumers. We showed that our protocol resulted in two types of modifications of the olfactory properties. The first and most obvious effect observed was the decrease of the alcohol content, with the concomitant increase of the corresponding esters, along with their fruity notes (pear, most notably). The second and less obvious effect was the expression of notes from minor components (( E)-b-ocimene, linalool, b-caryophyllene, and farnesene), originally masked by the sweet-floral-rose odor of geraniol, present in 70% in the palmarosa essential oil used, and emergence of citrus, green, spicy and clove characters in the modified products. This methodology might be considered in the future as a sustainable route to new natural ingredients for the perfumer. Introduction. – The use of enzymes in the synthesis of fine chemicals, from laboratory to industrial scale, is now in many instances a competitive alternative to conventional synthesis [1 – 5] , with advantages such as the control of the chirality of the products [6] [7], the mild operating conditions, and the overall sustainable aspects of the processes [8] [9]. Such trends are also observed in the field of flavors and fragrances, with the additional advantage of providing transformations eligible to the valuable natural label [10 – 13]. Existing enzyme-based methodologies typically deal with single-molecule manipulation [14 – 16] . On the other hand, essential oils of various origins, and more generally, odoriferous natural extracts have been used in fragrances since perfumery was born. As a consequence of their complex composition, their olfactory impact on perfuming compositions is also complex [17]. Today, modern perfumery uses both essential oils and synthetic materials, and innovation in fragrance chemistry is focused on the use of new sources of natural extracts [18] , new techniques of extraction [19 – 21], and the design of novel synthetic odorants [22]. However, the status of essential oil alone does not guarantee the access to the perfumers shelf, and superior olfactory properties are necessary. As a result, the price range for essential oils can vary significantly from a few Euros to more than 10,000 per kg, depending on supply and demand. In this context, we have been interested in providing new ingredients for the perfumer by modifying essential oils with enzymes. In particular, we became interested CHEMISTRY & BIODIVERSITY – Vol. 10 (2013) 2291  2013 Verlag Helvetica Chimica Acta AG, Zürich