Abstract

This study deals with the use of renewable lignocellulosic biomass to synthesis ethanol as an alternative energy
source to crude oil using a low-cost feasible process. Lignocellulosic biomass usually contains hemicellulose and
cellulose which could be converted to fermentable sugar like glucose. Renewable agricultural byproducts like
sugarcane bagasse, wheat straw, water hyacinth, ragi, and rice straw were selected for producing ethanol. They
were pretreated with mild, dilute acid using 2% H2SO4 (v/v), followed by enzymatic saccharification using locally
isolated fungal species Aspergillus niger to convert complex polysaccharide into simple sugar. Optimization of
reaction condition was carried out with the help of chemically predefined media at temperature of 38°C and
pH 4.8. The reduced sugars were estimated using the dinitrosalicylic acid method. Fermentation was carried
using yeast Saccharomyces cerevisiae by stationary fermentation method at temperature of 35°C under anaerobic
conditions. Produced ethanol was estimated using NaOH-Iodine precipitation method. Maximum ethanol yield
was obtained with sugarcane bagasse around 11.90 g/lit followed by wheat straw 9.56 g/lit, rice straw 8.84 g/lit,
ragi straw 7.01 g/lit, and water hyacinth 6.19 g/lit of ethanol in fermentation.