PEER-REVIEWED ARTICLE bioresources.com Choudhary et al. (2015). “Sorghum H2SO4 treatment,” BioResources 10(2), 2103-2112. 2103 Effect of Sulfuric Acid on Pretreatment of YSS-10R Variety of Sorghum and Analysis of Its Interaction with Temperature and Time Suhail J. Choudhary, a * Sajid Mehmood, b Hajra Naz, a Hawa Z. E. Jaafar, c, * and Muhammad Zia-Ul-Haq d, * 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. Keywords: Sulfuric acid; Pretreatment; Sorghum; Bioethanol; Lignocellulose Contact information: a: Department of Biochemistry, University of Karachi, Karachi, Pakistan; b: Department of Biochemistry and Molecular Biology, University of Gujrat, Gujrat, Pakistan; c: Department of Crop Science, Faculty of Agriculture, University Putra Malaysia, Selangor, Malaysia; d: The Patent Office, Karachi, Pakistan; * Corresponding authors: suhail.javed@yahoo.com; hawazej@gmail.com; ahirzia@gmail.com INTRODUCTION Energy usage in the world is increasing every day. Oil is the major source of energy for many industries and for transportation (Krichene 2002; Lun et al. 2013). In developing countries, oil consumption is rapidly increasing due to the development of industries and increasing transportation requirements (Asif and Muneer 2007; Alam et al. 2013). About 55% of worldwide oil consumption is by the transportation sector, and this proportion is increasing. Due to the continuous increase in oil consumption, it is anticipated that the production of oil will soon reach its peak and decline thereafter, resulting in greater consumption than production (Koppelaar 2005; Sorrell et al. 2009). The burning of oil causes emissions of greenhouse gases (GHGs). These gases cause negative environmental and climatic changes that affect living creatures and the basic infrastructure of buildings and transportation. The scientists are therefore concentrating their research towards biofuels from natural sources which are believed to be eco- friendly.