Optimization of [Amim]Cl Pretreatment Conditions for Maximum Glucose Recovery from Hybrid Pennisetum by Response Surface Methodology

Because of a complex chemical ultra-structure of lignocellulosic biomass, pretreatment is a necessary step for its conversion into bio-ethanol. In the present study, pretreatment conditions using the ionic liquid (IL) 1-allyl-3methylimidazolium chloride ([Amim]Cl) were optimized for a relatively new model energy crop, hybrid Pennisetum (P. americanum × P. purpureum) to maximize the yield of fermentable sugars (glucose). The design of experiment programs employed a central composite design (CCD), with variables of temperature (102 to 187 °C), retention time (0.5 to 5.5 h), and solids loading (2 to 15 wt%). These factors were further optimized using response surface methodology (RSM). The proposed quadratic model to predict the glucose recovery from hybrid Pennisetum was verified by variance analysis (ANOVA). The model displayed high F and R values, indicating that it could be successfully used to identify the relationship among the independent variables studied. A maximum glucose recovery of 72.2% was found with temperature conditions of 139 °C, 2.97 h retention time, and 9.1 wt% solids loading.