INSTITUTO DE BIOTECNOLOGIA Y BIOLOGIA MOLECULAR
Unidad Ejecutora - UE
congresos y reuniones científicas
Investigation of Inorganic and Enzyme Based Materials Oriented to the Generation of Biodiesel
MATKOVIC S.R.; NILSSON J.F.; VALLE G.M.; MORCELLE DEL VALLE S.R.; FAIT M.E.; LLERENA SUSTER C.R.; BRIAND L.E.
Workshop; VII Workshop on Biocatalysis and Biotransformations / 1° Simposio Latinoamericano de Biocatálisis y Biotransformaciones; 2014
INTRODUCTION Basic, acidic and enzymatic catalysts are currently investigated in order to develop new technologies in heterogeneous phase for the simplification of the production process of biodiesel. It is well known that heteropoly compounds (HPCs) with Keggin structure are suitable catalytic materials in esterification. Matkovic et al. showed that Wells Dawson type has a higher number of acid sites and acid strength than the Keggin heteropoly acid. Novozym® 435 is the commercial biocatalyst used industrially in production of biodiesel. Other sources of lipases are latices from the plant species Carica papaya and Araujia sericifera, which are less studied in this kind of esterification reactions, and they could be interesting alternatives to Novozyme®435 due to its easy production. In this context, the investigation and screening of potential catalysts in biodiesel production is presented. RESULTS AND DISCUSSION The esterification of oleic acid with methanol was chosen as a reaction test in order to establish the catalytic activity of various inorganic and enzyme based materials such as, bulk H6P2W18O62.xH2O (HPA) and oxide supported Wells Dawson heteropoly acid (HPA/TiO2), a partially substituted cesium salt, Novozym® 435, and the lipases from Araujia sericifera (ASL) and Carica papaya (CPL). The reaction was followed through the acidity index of fatty acids and infrared analysis. The IR analysis involved the investigation of two bands centered at 2924 cm-1 and 2854 cm-1 attributed to the stretching vibration of the C-H bonds belonging to the methylene groups. The intensification of such signals and the presence of a new signal centered at 1743 cm-1 attributed to vibrations of the C=O bonds are evidences of the presence methyl oleate (typical component of biodiesel). Additionally, the vibrations at 1242, 1197 and 1172 cm-1 due to the C-O bond belonging to an ester provided further evidence of the presence of methyl oleate. The inorganic materials catalyzed the esterification of oleic acid with methanol in 1:1 molar ratio at 85 °C. In this context, the specific activity of bulk HPA and 18% HPA/TiO2 were 1.10 and 6.40 µmol.mg-1.h-1, respectively. The cesium salt Cs2H4P2W18O62 showed inactive. The self-supported lipases CPL and ASL extracted from natural sources catalyzed the esterification of the oleic acid at 45°C with excess of metanol (typically, 1:4 oleic acid: methanol molar ratio). CPL and ASL presented specific activities equal to 9.30 and 60.7 µmol.mg-1.h-1, respectively. The latter is more active than the commercial biocatalyst Novozym® 435 that showed 7.23 µmol.mg-1.h-1 at 65 °C. CONCLUSION The results demonstrated that ASL is a promising biocatalyst in the esterification of fatty acids (such as oleic acid) that are present in the composition of the feedstock used for biodiesel production. On the other hand, highly acid materials such as bulk and oxide supported Wells Dawson heteropolyacid are active in the esterification of oleic acid towards methyl oleate at higher temperatures than the assayed biocatalysts.