Estudio comparativo de la producción de alcohol en los procesos fermentativos de mucílago de cacao CCN-51 a partir de células de levadura libre e inmovilizadas en cáscara de cacao

Abstract

In the present investigation, the immobilization of yeast cells “Saccharomyces cerviciae" in cocoa shell was carried out by the adsorption method. Cells were previously reproduced in cultures and pre-cultures using enriched culture media, identifying 1.88x109 [cells / ml]. The scanning electron microcopy (SEM) of the immobilization supports (cocoa shell) revealed the adsorption of the cells in their pores where a concentration of approximately 1.77 x109 cells / ml was obtained. With the cells immobilized in the cocoa shell, discontinuous fermentations were carried out with CCN51 cocoa mucilage and also fermentations with free cells with which the production of ethanol was compared and analyzed, letting us see that with the immobilized cell system the ethanol yield is improved 2.4 times in relation to the free cell system. The fermentations were carried out in a stirred tank bioreactor under the same operating conditions: pH [4] and Temperature 35 ° C with an initial concentration of sugar [250 g / l]; During the fermentation process, almost 100% of the total sugar was consumed, generating 60 [g / l] of ethanol and 25 [g / L] for the immobilized cells and free cells, respectively. Simultaneously, biomass quantification was carried out using the lyophilization method for both the immobilized cell system and the free cell system; under these conditions, a final biomass concentration of 16 [g / l] was obtained after 50 hours of fermentation and 40 [g / l] after 44 hours of fermentation in the immobilized cells and free cells, respectively