Extracción de azúcares fermentables a partir del nopal (opuntia ficus) de la estación experimental Tunshi-Riobamba mediante hidrólisis ácida como fuente de obtención de bioetanol

Abstract

The objective of the study was to extract fermentable sugars from prickly pear cactus (Opuntia ficus) located at “Estación Experimental Tunshi-Riobamba” through acid hydrolysis, in order to obtain bioethanol. It used biomass of nopal cladodes from 6 to 12 months old, determining that the nopal biomass presented moderate acidity, low presence of salts and high water content. Despite its low starch content, its high cellulose and hemicellulose content suggests a high potential for bioethanol production from the hydrolysis of this kind of molecules. At the same time, its fermentable sugar content indicates a high potential for bioethanol production, identifying optimal conditions for the production of total sugars from the hydrolysis of nopal biomass. The results indicated when temperature, time, and acid concentration values increase; a higher degree of hydrolysis is obtained. The maximum yield obtained was 12 grams at a temperature of 60°C, a time of 1.5 hours and an acid concentration of 1 normal. On the other hand, the quality evaluation of the nopal bioethanol produced by acid hydrolysis indicated that the values obtained for ethanol, acidity, electrical conductivity, density and evaporation residues are significantly lower than those established by the technical standard for anhydrous ethanol. Furthermore, the results indicate that the ethanol content obtained from nopal is much lower than the obtained from other biomass sources such as: sugarcane or corn. Finally, it is recommended to optimize the bioethanol production process from prickly pear cactus, explore enzymatic hydrolysis, select a suitable yeast strain and take advantage of prickly pear pulp, or peel residues to improve yield and reduce agroindustrial waste in bioethanol production.