Abstract— This study aims to investigate a novel pretreatment method of sugarcane bagasse (SCB) as an essential step for production of second generation bioethanol. Effect of tween 80 (TW) and polyethylene glycol 4000 (PEG) on SCB pretreatment using 1- butyl-3-methyl imidazolium chloride ([BMIM]Cl) as an ionic liquid (IL) was assessed. Various concentrations of TW and PEG were utilized to determine the optimum concentration of surfactant resulting in high cellulose conversion. Both of surfactants increased the sugar yield of enzymatic saccharification compared to IL only pretreated SCB and untreated SCB but, PEG in 3% w/w exhibited significantly enhanced enzymatic digestibility with an efficiency of 96.2% after 12 h of hydrolysis, which was 23% higher than the efficiency observed for the IL pretreated SCB. Keywords—1-butyl-3-methyl imidazolium chloride, Pretreatment, Sugarcane bagasse, Surfactant I. INTRODUCTION IGNOCELLULOSIC biomass has potential to serve as a low cost and renewable feedstock for bioconversion into fermentable sugars, which can be further utilized for biofuel production [1]. Pretreatment of lignocellulosic biomass prior to use as feedstock for biofuel and chemical production is required either to disrupt the crystalline structure of cellulose, remove hemicellulose, remove or modify the lignin to increase the exposure of cellulosic substrate to hydrolytic enzymes, decrease cellulosic substrate recalcitrance for enzyme attack and thus increase glucose yield [2]. The very complex structure of lignocellulosic biomass makes it highly resistant to enzymatic hydrolysis which results in low sugar yields [3]. Pretreatment is the most challenging step in bioethanol production from lignocelluloses. Pretreatment disrupts the compact and highly ordered structure of lignocelluloses so enhances the sugar yield of enzymatic hydrolysis of biomass. While all of the pretreatment methods result in enhanced enzymatic saccharification of the residual polysaccharide, an effective process that is inexpensive with low capital costs and minimal impact on downstream processing has yet to be developed. More recently, ionic liquids (IL) has emerged as a promising method for lignocellulosic pretreatment as they Niloofar Nasirpour is with the Tarbiat Modares University, Tehran, Iran (e-mail: [email protected]). Seyyed Mohammad Mousavi is with the Tarbiat Modares University, Tehran, Iran (corresponding author: Tel.: +98-21-82884917; fax: +98-21- 82884931 ; e-mail: [email protected]). exhibit outstanding physical and chemical properties [4]. Several reports were available on the pretreatment of lignocellulosic biomass using various ILs [1]-[5], but combination of surfactants and IL as a pretreatment agent has not been studied yet. Lignin is widely recognized to be an obstacle to efficient enzymatic hydrolysis. First, it unproductively adsorbs a large fraction of the cellulase, making it unavailable for enzymatic hydrolysis of cellulose [6]. On top of that, lignin impedes enzyme access to cellulose and hemicellulose, resulting in extended reaction times to achieve high conversions. Thus, it would be beneficial to use synergistic effect of IL and surfactant for delignification of biomass. In the present study, the surfactant-assisted ionic liquid pretreatment of sugarcane bagasse was investigated for enhanced enzymatic hydrolysis. Tween 80 and polyethylene glycol 4000 were as additive surfactants, and [BMIM]Cl was applied as the solvating ionic liquid. Experiments carried out at 130 °C for 90 minute. II. MATERIALS AND METHODS A. Feedstock and materials Sugarcane bagasse was supplied by the Iranian Research Organization for Science and Technology (IROST). Samples were ground in a cutter mill (Moulinex, AR1044) and passed through sieves of mesh size 30 and 70. Ionic liquid [BMIM]Cl was purchased from Sigma-Aldrich. Commercial enzymes of Celluclast 1.5 L (the cellulases from Trichoderma ressei) and Novozyme 188 (the cellubiase from Aspergillus niger) were purchased from Sigma- Aldrich. B. Surfactant assisted ionic liquid pretreatment The amount of solid biomass subjected to pretreatment was 0.5 g of pre-milled SCB based on dry weight. All samples were soaked into the surfactant of determined concentration over-night to assure sufficient penetration of liquid into the SCB solids. Subsequently, ionic liquid was added to sample tubes so that the ratio of IL to solid content was 10:1. The mixture was heated in an oil bath of 130 ºC for 90 min. Following pretreatment, 5 ml deionized water was added into the reaction mixture. The solution was mixed and centrifuged (Vifion, VF550) at 12000 rpm for 10 min. To remove the residual IL from the regenerated cellulose, biomass was washed with 10 ml deionized water for three times. Wet regenerated SCB was then freeze dried for 24 hours, prior to Impact of Surfactant on the Ionic Liquid Pretreatment of Sugarcane Bagasse Niloofar Nasirpour, and Seyyed Mohammad Mousavi L 3rd International Conference on Chemical, Ecology and Environmental Sciences (ICEES'2014) March 19-20, 2014 Abu Dhabi (UAE) 98