Dominicky Cristina Serrano1, Marcos Lúcio Corazza1,2, David Alexander Mitchell1,3, Nadia Krieger4,5. 1. Postgraduate Program in Chemical Engineering, Federal University of Paraná, P.O. Box 19011, Central Polytechnic, Curitiba, Paraná, 81531-980, Brazil. 2. Department of Chemical Engineering, Federal University of Paraná, P.O. Box 19011, Central Polytechnic, Curitiba, Paraná, 81531-980, Brazil. 3. Department of Biochemistry and Molecular Biology, Federal University of Paraná, P.O. Box 19046, Central Polytechnic, Curitiba, Paraná, 81531-980, Brazil. 4. Postgraduate Program in Chemical Engineering, Federal University of Paraná, P.O. Box 19011, Central Polytechnic, Curitiba, Paraná, 81531-980, Brazil. nkrieger@ufpr.br. 5. Department of Chemistry, Federal University of Paraná, P.O. Box 19061, Central Polytechnic, Curitiba, Paraná, 81531-980, Brazil. nkrieger@ufpr.br.
Abstract
OBJECTIVE: Lipases are often used in immobilized form, but commercial immobilized lipases are costly. An alternative is to produce lipases in solid-state fermentation, dry the solids and then use the "dry fermented solids" (DFS) directly. We produced DFS by growing Burkholderia contaminans on a mixture of sugarcane bagasse and sunflower seed meal and used the DFS to esterify oleic acid with ethanol in subcritical and supercritical CO2 at 40 °C. RESULTS: Compared to a control without CO2 at atmospheric pressure, subcritical CO2 at 30 bar improved esterification activity 1.2-fold. Higher pressures, including supercritical pressures up to 150 bar, reduced activity to less than 80% of the control. At 30 bar, the esterification activity was improved a further 1.8-fold with the addition of 9% water (i.e. 9 g water per 100 g oleic acid) to the reaction medium. CONCLUSION: A subcritical CO2 atmosphere, with the addition of a small amount of water, improved the esterification activity of DFS containing lipases of Burkholderia contaminans.
OBJECTIVE: Lipases are often used in immobilized form, but commercial immobilized lipases are costly. An alternative is to produce lipases in solid-state fermentation, dry the solids and then use the "dry fermented solids" (DFS) directly. We produced DFS by growing Burkholderia contaminans on a mixture of sugarcane bagasse and sunflower seed meal and used the DFS to esterify oleic acid with ethanol in subcritical and supercritical CO2 at 40 °C. RESULTS: Compared to a control without CO2 at atmospheric pressure, subcritical CO2 at 30 bar improved esterification activity 1.2-fold. Higher pressures, including supercritical pressures up to 150 bar, reduced activity to less than 80% of the control. At 30 bar, the esterification activity was improved a further 1.8-fold with the addition of 9% water (i.e. 9 g water per 100 g oleic acid) to the reaction medium. CONCLUSION: A subcritical CO2 atmosphere, with the addition of a small amount of water, improved the esterification activity of DFS containing lipases of Burkholderia contaminans.