Ethanol production by fermentation of fruits and cladodes of prickly pear cactus [<i>Opuntia ficus‐indica</i> (L.) Miller]

Abstract

Abstract Using prickly pear cladodes and fruits and different yeast strains of the genus Saccharomyces, both the chemical composition of the plant material and alcoholic fermentation were studied under controlled conditions. Before fermentation, fresh or previously dried cladodes were hydrolysed using cellulose or acid (HCl). The yield was determined by measurement of ethanol production by gas‐liquid chromatography. Two conversion indices, representing either the percentage of reducing sugars or the energy converted into ethanol, were considered. Using fresh or dried cladodes without fruits, the best results were always obtained after performing both types of hydrolysis. The enzymic method gave the highest sugar yield. However, ethanol production was similar to that obtained by acid hydrolysis of fresh cladodes, and only slightly higher than that of previously dried cladodes. The potential ethanol production that could be obtained from prickly pear cultivation in various regions (arid, semi‐arid and irrigated) is discussed.