Univ. Aix-Marseille III				Gladys Gabriela Pérez
gladysgabriela77@yahoo.com.mx Tél :				Adresse postale : Departamento de Biotecnología, Universidad Autónoma Metropolitana-Iztapalapa, Mexique				Ecole doctorale : Sciences de l'Environnement
Sujet de la thèse : Production of enzymes involved in cell wall degradation of agro-industrial residues by solid state fermentation
Co-direction : G. Saucedo-Castañeda, A. Ramírez-Coronel, (UNAM) I. Perraud-Gaime et S. Roussos (IMEP-IRD)				Dep. III IMEP : Processus fonctionnels et Valorisation de la Biodiversité Equipe : ECOLOGIE MICROBIENNE et BIOTECHNOLOGIES
Composition du comité de pilotage de thèse : en cours de constitution
Mode de financement : Bourse Organisme financeur : Dates de début et de fin de financement : Organisme gestionnaire : U 3
Date de première inscription en thèse : Octobre 2008 - Date de soutenance envisagée :

Journée des doctorants IMEP - Juin 2010 Production of enzymes involved in cell wall degradation of agro-industrial residues by solid state fermentation The agro-industrial by-products generated in the different process of the food industry are estimated in millions of tons per year; residues as coffee pulp and corn stover are produced in considerable quantities in Mexico. In both materials, a promising group of natural compounds are present in the cell wall: the hydroxycinnamic acids (HA). These compounds are particularly valuable because of their high antioxidant activity, in cosmetic products are used to reduce ultraviolet radiation or as flavor precursors in the food industry. Cell wall composition is very important to release the compounds, depends of the type of material: Monocotyledon or dicotyledon. The cell wall complexity requires of the sinergistic interaction of a feruloyl esterase and hydrolytic enzymes that helps to extract the HA depending of the cell wall polysaccharides (xylan or pectin). In the case of coffee pulp, a pectinase is essential for the degradation of cell wall; while for corn stover is suitable a xylanase. Solid state fermentation (SSF) has been used for the treatment of agro-industrial residues for recovering added value products and enzyme production.

Coffee pulp ------------------------- Aspergillus tamari ---------- Solid State Fermentation ------- Fermented pulp in columns

The aim of this work was to produce an enzymatic extract with feruloyl esterase, pectinase and xylanase activities from a filamentous fungus cultivated by solid substrate fermentation using coffee pulp and corn stover as substrates for degrading cell wall and recovering HA. A strain of Aspergillus tamarii V12307 was selected for its ability to produce feruloyl esterase, pectinase and xylanase activities. Plate assay methods were used. Enzymatic production was carried out in SSF using coffee pulp with non linked HA as substrate and added with different proportions of a culture medium reported for feruloyl esterase production Solid state fermentation was realized in the coffee pulp inoculated with a spore suspension of A. tamari. On-line monitoring of respiratory metabolism was evaluated by gas chromatography. Enzymatic activity was determined using methyl ferulate as substrate. Products of the reaction were analyzed by HPLC. Feruloyl esterase activity was determined at different times of fermentation depending of the culture medium selected.