Degradación de las enzimas fibrolíticas de Trametes sp. EUM1, Pleurotus ostreatus IE8 y de Fibrozyme®.

Ruminal degradation of enzymes produced by fungi Trametes sp. EUM1, Pleurotus ostreatus IE8, and from a commercial product (Fibrozyme®) was determined trough ammonia nitrogen (N-NH3) released. For each enzyme results were analyzed as a factorial experiment (3x2x2); factors were: substrate (xylan, carboximethycellulose and no substrate), protein level of enzyme (1 or 2) and times of contact enzyme-substrate previous incubation (0 or 1 h). The NH3-N concentration in ruminal fluid was different (p£0.05) between substrates on all studied enzymes. The protein level of enzyme had effect (p£0.05) on NH3-N concentration from Trametes sp. or P. ostreatus enzymes, but not from Fibrozyme. The substrate by protein level had effect (p£0.05) in the NH3-N concentration in the Trametes sp. and P. ostreatus enzymes. The time of contact enzyme-substrate effect was not significant for any of studied enzymes. Because minor N-NH3 concentration was observed when enzymes were incubated with a substrate, this indicates that degradation of enzymes in ruminal liquid was reduced in presence of a substrate; therefore substrate is important in the stability of studied enzymes.Se determinó la degradación en líquido ruminal de las enzimas producidas por los hongos Trametes sp. EUM1, P. ostreatus IE8 y de las presentes en un producto fibrolítico comercial (Fibrozyme®) mediante la medición del nitrógeno amoniacal (N-NH3) liberado. Para cada enzima los resultados se analizaron como un experimento factorial (3x2x2) con los factores: sustrato (xilano, carboximeticelulosa y sin sustrato), nivel de proteína de la enzima (1 ó 2) y el tiempo de contacto de la enzima con el sustrato previo a la incubación (0 ó 1 h). La concentración de N-NH3 en líquido ruminal fue diferente (p£0,05) entre sustratos en todos las enzimas estudiadas. El nivel de proteína de la enzima tuvo efecto (p£0,05) sobre la concentración de N-NH3 en el líquido ruminal con enzimas de Trametes sp. y P. ostreatus, pero no en el incubado con Fibrozyme. La interacción sustrato por nivel de proteína tuvo efecto (p£0,05) en la concentración de N-NH3 en las enzimas de Trametes sp. y P. ostreatus. Se observaron menores concentraciones de N-NH3 al incubar las enzimas con un sustrato, por lo que se considera un factor importante en la estabilidad de las enzimas estudiadas

The Effect of Aeration for 6-Pentyl-alpha-pyrone, Conidia and Lytic Enzymes Production by Trichoderma asperellum Strains Grown in Solid-State Fermentation

International audienceIn recent years, the production of biopesticides has gained great attention in the scientific word because it is an important alternative to replace the much debated chemical pesticides used on the field crops. Fungal lytic enzymes, conidia and secondary metabolites like 6 pentyl-alpha-pyrone (6-PP) play a very important role in the biological control of pests. On the present study, the influence of application of air through a solid-state fermentation using three Trichoderma asperellum strains to produce conidia, 6-PP and essential enzymes were evaluated. A mix of vine shoots, potatoes flour, jatropha, olive pomace and olive oil as substrates was used. T. asperellum TV104 showed the best 6-PP production (3.06 ± 0.15 mg g DM−1), cellulases activities (34.3 ± 0.4 U g−1), and amylase activity (46.3 ± 0.6 U g−1) however, T. asperellum TF1 produced the higher levels of lipase (30.6 ± 0.3 U g−1), under air conditions. The production of these same enzymes was less efficient without the application of forced aeration. The forced aeration increased the conidia production, the best value was observed with T. asperellum TF1 (2.23 ± 0.07 × 109 g DM−1)