This book describes Bioethanol production from sugars obtained from plant biomass (lignocellulosic materials) by using pretreatment and saccharification and fermentation. Microorganism converts such sugars into ethanol (alcohol) in beer and wine. The production of bioethanol is rapidly increasing due to the growing use of bioethanol as a car fuel. With an annual world production scenario, bioethanol is already the largest product of the fermentation industry. Bioethanol should of course preferably be produced from resources that do not compete with food production. For this reason in this book, efforts are made to produce second- generation bioethanol, using agricultural residues such as wheat stem, pearl millet stem and sorghum stem. However, when the sugars from these raw materials are released, significant quantities of acetate are formed. Acetate can slow down or even halt bioethanol production by yeast. In this book several combination of enzymes were tried in saccharification process to enhance the bioethanol production and mixed flora of yeasts for best fermentation.