Statistical Models for S.35 Sorghum Stems Conversion by Hydrothermal Treatment (2018)

Abstract: A three factor Doehlert design was adopted to build statistical models to optimize the action of temperature, time and liquid/solid ratio, on reducing sugars and total phenolic compounds content during sorghum stems hydrothermolysis. Therefore, the models revealed that increasing temperature and time allowed an increase of reducing sugars and total phenolic compounds content, while the impact of liquid/solid ratio was negatively significant. An augmentation of liquid/solid ratio was necessary for solubilization of hemicelluloses and lignin. Also, optimization of the concerted factors impacts for reducing sugars gave a combination of 210°C, 60 min, 10 mL/g with a maximal reducing sugar of 15.16 mg/mL, while optimization of total phenolic compounds content gave a combination of 210°C, 48 min, and 10 mL/g with a maximal total phenolic compound of 0.81mg/mL. Consequently, a compromise was found to obtain high sugar content (≥ 14 mg/mL) and, to obtain at the same time high total phenolic compounds content (≥ 0.8 mg/mL). It was also demonstrated that the best way of removing lignin from sorghum stem was to apply a lower temperature (150°C) and increase the pretreatment severity (meaning increase the reaction time). 

Statistical Models for S.35 Sorghum Stems Conversion by Hydrothermal Treatment.pdf