Determinación de la cinética de fermentación alcohólica del mucílago de cacao CCN-51 en condiciones óptimas de operación de temperatura, pH y concentración de levadura”. caso: Ecuador - zona 6

Abstract

Cocoa mucilage is considered a useless and unprofitable residue generated by the cocoa industry. Ecuador -the country that occupies the fifth place worldwide in cocoa production, thus making it one of the biggest cocoa producers in the world- produces large amounts of mucilage, which can be used to produce bioethanol. The purpose of this research was to optimize the most relevant operation parameters like temperature, pH, and yeast concentration, in the process of fermentation of CCN-51 cocoa mucilage, by evaluating the final concentration of ethanol and also by determining the kinetics of alcoholic fermentation depending on the consumption of glucose under these conditions. The fermentation was developed in a stirred tank bioreactor, during a 24-hour period. The optimization was determined by a 2k full factorial design with two levels and three variables: temperature, pH and yeast concentration. The chemical kinetics was obtained by applying both the integral and differential methods, based on glucose consumption, which was measured by infrared spectrophotometry. The ethanol was quantified using the same technique and its chemical characteristics were analyzed by gas chromatography. In addition, yeast growth was evaluated by direct counts based on the Monod Model and by using Petrifilm plates. The optimal parameters of operation were 35°C, pH of 4, and 3g/L of yeast Saccharomyces Cerevisiae, obtaining 60,58 ± 0,813°GL. According to the applied methods, a zero-order and a pseudo-order of 0.17 were obtained. The yeast growth rate was 0,2h-1