Abstract

                               Pearl millet biomass represents an unused source for biofuel production. Pretreatment is required to break down complex structure and prepare the pearl millet biomass for enzymatic hydrolysis. The efficiency of chemicals (Ortho-phosphoric acid (H3PO4), alkaline H2O2 and lime) pretreatment on pearl millet was investigated in the present study. Acid (16 % of acid, 12.5 % of total solid loading, 121°C of temperature and 3 h of incubation time) pretreated biomass sample showed highest (0.418 g / g of biomass) sugar release, crystallinity index (36.43 %) and inhibitor concentration (4.02 %). The parameters were optimized by using Response Surface Methodology in a Optimal Custom Design. The studies confirmed that lime pretreatment was promising as it had high crystallinity index (70.18 %), fermentable sugar release (0.234 g/g of biomass) and minimal production of inhibitors, required less energy input and environmentally safe. Pretreated biomass was further characterised by SEM and X-ray diffraction (XRD).

Key words : Ortho-phosphoric acid, Alkaline H2O2, Lime, Pearl millet, Pre-treatment