Solid-state fermentation (SSF) is used in enzyme and antibiotic production, bioethanol and biodiesel as an alternative energy source, biosurfactants with environmental goals, and the production of organic acids and bioactive compounds. The present project determined the quantity of secondary metabolites and the antioxidant activity of the extracts obtained by the solid-state fermentation of apple and agave mezcalero bagasse over 28 days, inoculated with the Pleurotus ostreatus strain. The extraction was carried out with three solvents: acetone and water (80:20 v/v), 100% methanol and 100% water. The results showed a higher presence of phenolic compounds, flavonoids, total triterpenes and antioxidant activity in the apple bagasse from the SSF on day 21 in the extract of acetone and water (80:20 v/v), 100% methanol and aqueous; while the agave bagasse showed a significant presence of phenolic compounds and flavonoids only in the aqueous extract. In conclusion, the presence of secondary metabolites exhibiting antioxidant activities from the solid-state fermentation in the residues of the cider and mezcal industry is an alternative use for wasted raw material, plus, it reduces the pollution generated from the agroindustrial residues.

In this work, the enzymatic cocktail produced by Pleurotus djamor fungi extracted at pH of 4.8 and 5.3 was employed for castor cake solid-state treatment. Proximal, X-ray powder diffraction and scanning electron microscopy analysis of the pristine castor cake were carried out. First, Pleurotus djamor stain was inoculated in castor cake for the enzymatic production and the enzymatic activity was determined. The maximum enzymatic activity was identified at days 14 (65.9 UI/gss) and 11 (140.3 UI/gss) for the enzymatic cocktail obtained at pH 5.3 and 4.8, respectively. Then, the enzymatic cocktail obtained at the highest enzymatic activity days was employed directly over castor cake. Lignin was degraded throughout incubation time achieving a 47 and 45% decrease for the cocktail produced at pH 4.8 and 5.3, correspondingly. These results were corroborated by the SEM and XRD analysis where a higher porosity and xylan degradation were perceived throughout the enzymatic treatment.

No abstract

La agroindustria genera cantidades importantes de residuos lignocelulósicos. Estos son utilizados como sustrato en la producción de hongos del género Pleurotus, que a través de la fermentación en estado sólido (FES) producen metabolitos secundarios. El objetivo de este trabajo fue determinar la cantidad de compuestos fenólicos totales y la actividad antioxidante de extractos de metanol obtenidos de la FES en bagazo de manzana con la cepa Pleurotus ostreatus durante 28 días. La fermentación sólida se realizó en los días 0, 7, 14, 21 y 28 de los extractos de metanol. Posteriormente, se evaluaron el contenido de compuestos fenólicos totales y la actividad antioxidante por los métodos 1,1-difenil-2-picrilhidracilo (DPPH•) y 2,2’-azino-bis (3-etilbenzotiazolina)-6 sulfonato de amonio (ABTS+). Las 45 muestras fueron analizadas a través de un análisis de varianza y prueba de medias de Tukey. Los resultados mostraron la biosíntesis de compuestos fenólicos totales a partir del día 21 de la FES, con una concentración de 0,39 ± 0,07 mg equivalentes de ácido gálico/g sustrato en base seca (mg de EAG/g sustrato bs). La actividad antioxidante en ambos métodos también se manifestó en el día 21 con actividades equivalentes, de 342,10 ± 1,08 mg/mL para DPPH y 323,02 mg/mL en ABTS. En consecuencia, los compuestos fenólicos extraídos de la FES del residuo de manzana con la cepa P. ostreatus pueden considerarse como una alternativa de valorización de un subproducto que actualmente es considerado como un desecho agroindustrial.