Biotransformation of R-(+)- and S-(‒)-limonene by Fusarium oxysporum Gustavo Molina a , Renata Lino da Costa a , Ana Paula Dionísio a , Juliano Lemos Bicas b , Gláucia Maria Pastore a a Department of Food Science, School of Food Engineering, University of Campinas (UNICAMP). Campinas, São Paulo, Brazil (gustavomolinagm@gmail.com) b Cap, Federal University of São João Del Rey. Ouro Branco, Minas Gerais, Brazil ABSTRACT In the past few years much work has been done on the biotransformation of limonene, an inexpensive hydrocarbon monoterpene, which is one of the most widely distributed terpene in nature. Recently, the strain F. oxysporum 152b has been selected based on its high production of extracellular alkaline lipase and other publications have also described the biotransformation of R-(+)-limonene into R-(+)-α-terpineol catalysed by the same strain. The main characteristics of this conversion were described in recent papers but no information deals with the bioconversion of its isomer, S-(‒)-limonene. Thus, this paper focused on the biotransformation of S-(‒)-limonene by F. oxysporum 152b, partially characterized and compared with the characteristics involved in α-terpineol production from R-(+)-limonene. In former studies, it was proven that the enzyme responsible for the production of α-terpineol by the biotransformation of R-(+)-limonene was enantioselective and enantiospecific, has an intracellular nature and acts in anaerobic conditions. In this study, it was observed that the production of limonene-1,2-diol from S-(‒)-limonene has also an intracellular nature but it was higly influenced by an aerobic system and seemed to be cofactor dependent, considering that the product was not detected with an anaerobic biotransformation. The production of the intermediate limonene-1,2-epoxide was not detected, indicating that the reaction proceeds mainly for the diol production. These results encourage further studies with this biocatalyst and the characterization of its enzyme system involved in the biotransformation of S-(‒)-limonene and other terpenes is of great importance, and could be source of novel aroma compounds with industrial interest. Keywords: S-(-)limonene; limonene-1,2-diol; Fusarium oxysporum; terpenes; aroma compounds. INTRODUCTION Extensive research has been devoted to the biotechnological production of flavours and fragrances [1]. Via biotransformation or bioconversion ‘‘natural’’ flavours can be produced, applying to the consumers’ demand for natural products [2]. Terpenes and especially their oxygenated derivatives are extensively used in the flavour industry. Via biotransformation, monoterpene precursors are converted into their more valuable oxygenated derivatives [3]. The biotransformation of terpenes thought microorganisms is recognized as being of great economic potential because can allow the production of enentiomerically pure flavors and fragrances under mild conditions and the products may be considered as “natural”, increasing the interest in this area [4]. But, in the other hand, this complex process is technically difficult because of monoterpenes chemical instability, low solubility, toxicity and volatily and also because can occur multiple metabolic pathways leading to a mixture of products; low product concentrations and yields or the absence of product accumulation [3]. In the past few years much work has been done on the biotransformation of limonene, an inexpensive hydrocarbon monoterpene, which is one of the most widely distributed terpene in nature. As its chemical structure is similar to that of many oxygenated monoterpenoids presenting a pleasant fragrance, e.g. perillyl alcohol, carveol, carvone, menthol and α-terpineol, it may be used as a precursor in the synthesis of these flavor compounds [5]. Many papers describe enzyme production by species of the genus Fusarium, e.g. F. graminearum, F. solani and F. oxysporum [6]. Recently, the strain F. oxysporum 152b has been selected based on its high production of extracellular alkaline lipase [7]. Simultaneously, other publications have also described the biotransformation of R-(+)-limonene into R-(+)-α-terpineol catalysed by the same strain [8,9]. The main characteristics of this conversion were described in recent papers [6] but no information deals with the bioconversion of its isomer, S-(‒)-limonene.