Optimisation of pressed pericarp fibre delignification for glucose recovery using response surface methodology

Abstract

In this study, pressed pericarp fibres (PPFs) were subjected to chemical pretreatment for bioconversion of lignocellulosic biomass to fermentable sugars. The effectiveness and comparison between pretreatments using acid (HCl) and alkaline (NaOH) to reduce the lignin content was studied. Alkali pretreatment showed better lignin removal than acid pretreatment. Subsequent experiments were then carried out using a statistical design of experiments (DoE) for the optimisation of PPF delignification. The effect of NaOH concentration, incubation time and temperature were chosen as the independent variables, while the percentage of lignin removal as the response. The response surface methodology (RSM) coupled with central composite design (CCD) were used to develop the models to correlate the effect of process variables to the response. Temperature was identified by the analysis of variance (ANOVA) to be the most significant factor on the delignification of PPF. The optimum operating conditions for the process delignification of PPF (54% of lignin removal) were at 5.96% (w/v) of NaOH, 118.02oC and time for 4.92 hours. Three sets of experiments were carried out in order to validate the simulated model and the results were in agreement with the simulated values with an average error of ±1.29.