Effect of Sulfuric Acid on Pretreatment of YSS-10R Variety of Sorghum and Analysis of Its Interaction with Temperature and Time

Suhail J. Choudhary, Sajid Mehmood, Hajra Naz, Hawa Z. E. Jaafar, Muhammad Zia-Ul-Haq


Considering the possible threats to the oil supply due to the rapid depletion of oil reservoirs and the negative environmental impacts of petroleum use, developing an environmentally friendly biofuel such as bioethanol is needed. Pretreatment is a critical step in the production of lignocellulosic bioethanol. In this study, the effect of sulfuric acid on the pretreatment of the YSS-10R variety of sorghum was evaluated. Response Surface Methodology (RSM) was employed to develop an experimental design matrix and evaluate the effect of pretreatment parameters on the release of fermentable sugars. Sorghum straw was treated with sulfuric acid concentrations of 0.5, 1.75, and 3% (V/V) at temperatures of 70, 100, and 130 °C for reaction times of 10, 20, and 30 min. The maximum glucose yield was 7.66 g/L (0.064 g/g) and was obtained via pretreatment with 0.5% H2SO4 at 100 °C for 10 min. That of xylose was 7.62 g/L (0.064 g/g), obtained via pretreatment with 0.50% H2SO4 at 130 °C for 20 min. The pretreatment conditions for maximum xylose yield were determined to be 2% H2SO4, 130 °C, and 20 min. Results indicate that sulfuric acid is an efficient catalyst for pretreatment at high temperatures and relatively long reaction times.


Sulfuric acid; Pretreatment; Sorghum; Bioethanol; Lignocellulose

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