Abstract

TEXCO-LOPEZ, Andrés et al. EFFECT OF HYDROTHERMAL PRETREATING (HIGH PRESSURE) AND ENZYMATIC HYDROLYSIS OF CLADODES OF Opuntia ficus-indica ON THE RELEASE OF SUGARS AND THEIR POTENTIAL USE IN BIOETHANOL PRODUCTION. Rev. Int. Contam. Ambient [online]. 2019, vol.35, n.4, pp.1039-1049.  Epub Dec 22, 2020. ISSN 0188-4999.  https://doi.org/10.20937/rica.2019.35.04.21.

The production of second-generation biofuels requires raw materials that meet certain characteristics, among which stand out availability, price, fast growth, easy manipulation, among others. Opuntia ficus-indica was analyzed in this work given its wide world distribution, tolerance to extreme environments of drought and temperature, as well as its high yield as a crop. In addition, in times of pruning, the cladodes are abandoned on the site generating pollution problems so it is necessary to generate usage proposals. The production of bioethanol from cactus cladodes has been previously proposed but a hydrothermal pretreatment (HTP) in a high-pressure reactor (HPR) has not been applied. The use of high pressures is a method used with relative success in the pretreatment of other lignocellulosic substrates. In this work, the effect of temperature (150, 175, 185 and 205 º C), the addition of H2SO4 (0, 0.5, 1, 1.5 and 2 %) and the residence time in a HPR (1, 5 and 15 min) was studied. The solid residue obtained in the HTP was subjected to an enzymatic treatment to improve high-pressure hydrolysis of this raw material; finally, an alcoholic fermentation was carried out with Saccharomyces cerevisiae. The results showed significant time saving by applying a HTP compared to a conventional pretreatment (carried out in autoclaves). A final hydrolysis of 70.4 % of the nopal cladodes (combination of thermal pretreatment and enzymatic hydrolysis) and bioethanol production of 6.6 g/L were achieved.

Keywords : alcoholic fermentation; biological hydrolysis; high pressure hydrolysis; reducing sugars.