Production of Bio-ethanol from Waste Materials

Abstract

This work finds the production of bio-ethanol using suitable enzymes and yeast strains. It further tests for the presence of bio-ethanol in the fermented product both quantitatively and qualitatively in the laboratory. Moreover, it aims to evaluate the feasibility of bio-ethanol production from different cellulosic waste materials like wheat straw, waste paper, corn cob, groundnut shell, wood bark, saw dust, bagasse and a combined mixture of all. Two strains of Saccharomyces cerevisiae were used for fermentation and analyzed for comparison; one was fermenting yeast (brought from Imtech, a research center) and the other was isolated from the soil (produced naturally). Two enzymes were used for the hydrolysis of the biomass, namely, amylase and cellulase which were isolated from soil and produced in the laboratory. Cellulase was used for the hydrolysis of cellulose and hemi-cellulose; and amylase was used for the hydrolysis of starch present in the raw materials. Fermentation of the hydrolyzed samples was done using Saccharomyces sp. To produce ethanol from biomass, two key processes were followed: first, the starch or hemi-cellulose and cellulose portions of the biomass were broken down into simple sugars through a process called saccharification. Second, the sugars are fermented to produce ethanol.

Keywords: Bio-ethanol, waste material, amylase production, cellulase production, aerobic fermentation, anaerobic fermentation