Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)The present work investigates as a first step the influences of pressure exposure time and depressurisation rate on the beta-galactosidase activity of permeabilized cells of Kluyveromyces marxianus CCT 7082 submitted to treatment with compressed carbon dioxide propane and n-butane In general results showed that the enzyme activity changes significantly depending on the experimental conditions investigated allowing the selection of proper operating conditions for advantageous application of this biocatalyst in hydrolysis reactions Further the stability of the enzyme after high-pressure pre-treatment was also experimentally monitored and the results demonstrated that the activities of this biocatalyst were always higher than those of the non-treated one Finally evaluation of synthesis of galactooligosaccharides (GOS) using beta galactosidase without treatment and after treatment in compressed fluids was carried out Results indicated promising possibilities since the use of n-butane-pre treated enzyme led to very satisfactory reaction conversions and selectivity (C) 2010 Elsevier Ltd All rights reserved125412351240Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)FAPERGSConselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FEA/UNICAMPURI - Campus ErechimCoordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)CAPES [PROCAD/CAPES 0337/05-6]