ISSN 1330–9862 original scientific paper (FTB-1503) Production and Recovery of Aroma Compounds Produced by Solid-State Fermentation Using Different Adsorbents Adriane B. P. Medeiros 1 , Ashok Pandey 2 , Luciana P. S. Vandenberghe 1 , Gláucia M. Pastore 3 and Carlos R. Soccol 1 * 1 Bioprocess Engineering and Biotechnology Division, Chemical Engineering Department, Federal University of Paraná, CEP 81531–970, PR–Curitiba, Brazil 2 Biotechnology Division, Regional Research Laboratory, CSIR, 695019–Trivandrum, India 3 Food Engineering Faculty, FEA, State University of Campinas, Unicamp, CP 6121, CEP 13083–862, SP–Campinas, Brazil Received: April 27, 2005 Accepted: October 24, 2005 Summary Volatile compounds with fruity characteristics were produced by Ceratocystis fimbriata in two different bioreactors: columns (laboratory scale) and horizontal drum (semi-pilot scale). Coffee husk was used as substrate for the production of volatile compounds by so- lid-state fermentation. The production of volatile compounds was significantly higher when horizontal drum bioreactor was used than when column bioreactors were used. These results showed that this model of bioreactor presents good perspectives for scale-up and application in an industrial production. Headspace analysis of the solid-state culture detected twelve compounds, among them: ethanol, acetaldehyde, ethyl acetate, ethyl pro- pionate, and isoamyl acetate. Ethyl acetate was the predominant product in the headspace (28.55 mmol/L/g of initial dry matter). Activated carbon, Tenax-TA, and Amberlite XAD-2 were tested to perform the recovery of the compounds. The adsorbent columns were con- nected to the column-type bioreactor. All compounds present in the headspace of the co- lumns were adsorbed in Amberlite XAD-2. With Tenax-TA, acetaldehyde was adsorbed in higher concentrations. However, the recovery found by using the activated carbon was very low. Key words: aroma production, solid-state fermentation, recovery, Ceratocystis fimbriata, cof- fee husk, adsorption, activated carbon Introduction Agro-industrial residues have been used as efficient substrates in several bioprocesses such as the produc- tion of organic acids (1), production of enzymes and bio- logical detoxification of coffee husks (2). The application of agro-industrial residues not only provides alternative substrates for solid-state fermentation (SSF), but it also helps to solve pollution problems (3). Cassava bagasse, sugar cane bagasse, apple pomace, giant palm bran, and coffee husk have been used as substrates for aroma pro- duction in SSF (4–7). It is estimated that around 100 aro- ma compounds are produced industrially by microbial fermentation (8). Strains of the fungi Ceratocystis have been identified as aroma producers. Christen et al. (9) studied the pro- duction of aroma compounds by employing different substrates (wheat bran, cassava bagasse, and sugar cane bagasse complemented with a synthetic medium). It was concluded that the type of aroma depended on two 47 A.B.P. MEDEIROS et al.: Aroma Compounds Produced by Fermentation, Food Technol. Biotechnol. 44 (1) 47–51 (2006) *Corresponding author; Phone/Fax: ++55 41 33 613 191; E-mail: soccol@ufpr.br