Optimization of hydrothermal pretreatment for enzymatic hydrolysis of banana pseudo stem using response surface methodology

In this study different conditions of hydrothermal pretreatment were evaluated for conversion of banana pseudo stem to fermentable sugars. A Central Composite Design (CCD) was used to obtain regression equations in function of the following variables: solid/liquid ratio (1/10; 1/12.5; 1/15), temperature (170 °C, 190 °C, 210 °C) and reaction time (10 min, 15 min, 20 min). The cellulose digestibility improved in all conditions tested, with maximum digestibility achieved at 210 °C for 10 minutes and 1/15 of solid/liquid ratio. The Glucose yield at optimal conditions was 58.4 g/kg with an excellent recovery of cellulose of 98%. Thus, the hydrothermal pretreatment demonstrated to be an effective process in increasing cellulose concentration and producing fermentable sugar from recalcitrant lignocellulosic biomass. Furthermore, based on the design response surface methodology, an optimum condition of each pretreatment could be obtained from the statistical models built. All the variables studied influenced the enzymatic sugar release.