Evaluation of fermentation efficiency and ethanol production potential of sweet sorghum genotypes in Çukurova region of Türkiye

Bioethanol is a renewable energy source with lower environmental impact and the potential to partially replace fossil fuels. In this study, the sugar content, ethanol fermentation efficiency, and ethanol production potential of 21 different sweet sorghum genotypes, were evaluated under the Çukurova region of Türkiye. Field experiments were conducted under second-crop conditions in the experimental fields of the Eastern Mediterranean Agricultural Research Institute, during the 2016 and 2017 growing seasons. Analyses were carried out on the juice obtained from the sorghum stalks. Alcoholic fermentation was carried out using Saccharomyces cerevisiae Fermivin yeast after optimizing the conditions (different cultures, temperatures and pH levels). Fermentation was conducted at pH of 5.5 and 30°C. Based on two-year averages, the sugar contents of the genotypes ranged from 112.03 to 185.64 g L-1, ethanol concentrations from 48.35 to 84.60 g L-1, total sugar yields from 3628.5 to 8986.4 kg ha-1, fermentation yield from 0.4072 to 0.4560 g alcohol g-1 sugar, and ethanol yields from 2017.6 to 4871.0 L ha-1. Under the second crop conditions of the Çukurova region, the Tracy, UNL-Hyb-3, No91, Grassi and M81E genotypes, which produced more than 4300 liters of ethanol per hectare were identified as the most promising genotypes for bioethanol production. These results indicate that sweet sorghum has considerable potential as a feedstock for both sugar and bioethanol production in the Çukurova region.