First and Second Generation of Ethanol Production for Five Sweet Sorghum Cultivars during Soft Dough Grain

This study we aimed to identify how the harvest period of the stems from 5 sweet sorghum cultivars influences the production of sugar and ethanol under rainfed conditions in the municipality of Itambé, state of Pernambuco. Subsequently we evaluated the ethanol production from juice and bagasse of the different cultivars. The field experiment was evaluated in a factorial arrangement with two factors (5 cultivars and 3 harvest periods) and fours replications. The fermentation experiments, pretreatment and enzymatic hydrolysis were delineated in a completely randomized design in quadruplicate. Data obtained for all variables evaluated were submitted to an Analysis of Variance and the means compared by the Tukey test at 5% of probability. Results showed that the harvest period influenced the total soluble solids, and the harvest period of soft dough was chosen for assessments of ethanol production of first and second generation. Ethanol production from juice differed among cultivars with the best performance by cultivar SF 15. Significant differences were observed for the chemical composition of bagasses between cultivars, but there where no difference in efficiencies of enzymatic hydrolysis. The average conversion of cellulose in glucose was 64.87%. The cultivars of sweet sorghum biomass developed and adapted for the Northeastern region of Brazil showed potential for ethanol production from the juice and bagasse.