Dilute Acid Hydrolysis for Optimization of Sugar Concentrations Frompennisetum Purpureum: a Conventional Approach

Abstract

The present study was conducted for the optimization of process variables used for the acid hydrolysis of lignocellulosic biomass, Pennisteum purpureum (Elephant grass) which is a renewable resource that can be used for the generation of bio-based chemicals. This research used dilute sulphuric acid as a catalyst for hydrolysis of elephant grass. The study was aimed at investigating the viability of elephant grass to generate hexose and pentose sugars which are major feedstock for the production of bio-based chemicals. The process variables such as acid concentration, temperature and contact time were varied and effect of these parameters on the production of sugars (xylose, glucose and arabinose) as well as on the formation of degradation products (furfural and hydroxymethylfurfural) in the hydrolysate (hemicellulosic fraction) were studied. From the preliminary analysis, each portion of the elephant grass had an average value of 38.56% and 16.14% for carbohydrates and hemicellulose contents respectively. The optimum conditions of 0.4 wt % H₂SO₄, 140 ºC, 180 minutes for acid concentration, temperature and contact time respectively was found. Under these conditions, the hydrolysate contained 5.453 g/L glucose, 2.719 g/L xylose, 1.106 g/L arabinose, 0.02195 g/L furfural and 0.0153 g/L 5-hydroxymethylfurfural.For effective production of sugar from elephant grass biomass high concentration of acid was found not favourable for the hydrolysis of the biomass. The conditions under which the experiment was conducted confirmed the possibility of generating pentose and hexose sugars from elephant grass with the potential of being used as feedstock for producing bio-based chemicals and products.