Sweet Sorghum Juice and Bagasse as a Possible Feedstock for Bioethanol Production

Abstract

The aim of our study was to estimate the overall ethanol potential of a promising Hungarian sweet sorghum variety called ‘Monori Édes’ developed by Agroszemek Ltd. For ethanol production following parts of the plant can be utilized: the stem juice containing sucrose and the bagasse built up mainly from lignocellulose. As lignocellulosics have to be pretreated and hydrolyzed prior to fermentation, another purpose of our research was to apply weak alkaline pretreatment methods to enhance enzymatic digestibility of bagasse thus, to improve the ethanol yield. In our study the effect of two bases (NaOH and KOH) in two concentrations (1% and 2%) and at two temperatures (room temperature and 121 °C) was investigated on the efficiency of enzymatic hydrolysis. Every pretreatment type affected positively the hydrolysis efficiency but in different degrees. Best results were achieved with 2% NaOH at 121 °C. However highest ethanol conversion based on the glucan content of pretreated material was reached using 2% NaOH at room temperature. Summarizing the ethanol potentials of juice and bagasse an overall potential of about 8 300 L/ha was estimated.