Abstract

                                Lignocellulosic plant material implies an untouched source of fermentable sugars for significant ethanol produc- tion. Pearl millet is potentially a viable feedstock for bioethanol production. The efficiency of Ortho-phosphoric acid, alkaline hydrogen peroxide, lime, and hydrothermal pretreatment as a potential chemical pretreatment on pearl millet was investigated in the present study. Based on the experimental results a mathematical model was developed for each pretreatment. Among the different pretreatment acid pretreated biomass showed highest sugar yield of 41.8 g /100g of biomass and inhibitor yield of 4.02 %. The raw biomass showed (34.76 %) the lowest crystallinity index (CrI) because it has a higher content of hemicellulose and lignin, which are amorphous in nature. The specific surface area of acid pretreated biomass increased significantly and the CrI of the pretreated biomass apparently increased (75.79 %) after the pretreatment. The main aim of pretreatment is to separate the hemicel- lulose and lignin for maximum recovery of fermentable sugars. Pretreated biomass was characterised by scanning electron microscope SEM and X-ray diffraction.

Key words : Ortho-phosphoric acid, alkaline hydrogen peroxide, lime, hydrothermal pretreatment, pearl millet bio- mass