Bioethanol production from cashew (<i>Anacardium occidentale L.</i>) apple juice by batch fermentation using <i>Saccharomyces cerevisiae</i> E450

Abstract

Large amounts of cashew apples from Côte d’Ivoire are left over as waste in the plantations after nut separation, while it can be transformed into bioethanol. This study aimed at producing bioethanol from cashew apple juice by Saccharomyces cerevisiae E450 yeast. S. cerevisiae E450 was used as ferment at 107 CFU/mL in anaerobic and aerobic conditions at temperatures of 30 °C and 33 °C. The fermentation was carried out in batch mode with sampling every 24 hours. The determination of ethanol and glycerol was performed by Gas Phase Chromatography and sugars (glucose, fructose and sucrose) by HPLC. The amounts of ethanol obtained at 30 °C and 33 °C respectively were of 65.10 and 73.17 g/L in anaerobic conditions and 62.05 and 75.79 g/L aerobic conditions. The fermentations carried out at 33 °C gave the highest ethanol concentrations with the maximum in aerobic which was 75.79 g/L. The fermentation carried out at 30 °C in anaerobic yields the lowest value of 62.05 g/L. This study showed the influence of temperature on the growth of cells and the synthesis of ethanol marked by the presence of oxygen which decreases fermentation time and thus improves productivity. It also revealed that cashew apple has great potential as a biofuel feedstock for bioethanol production.

Keywords: Cashew apple juice, Saccharomyces cerevisiae, alcoholic fermentation, Bioethanol, Côte d’Ivoire.