PRATIBHA: INTERNATIONAL JOURNAL OF SCIENCE, SPIRITUALITY, BUSINESS AND TECHNOLOGY (IJSSBT), Vol. 3, No. 1, Dec 2014 ISSN (Print) 2277—7261 60 Utilization of Cereal Grains for Bioethanol Production: A Critical Review Sheetal B. Gawande 1 , Dr. I. D. Patil 2 1 Research Student, SSBT`s, COET, Bambhori, Jalgaon (MS), India 2 Professor and Head, Department of Biotechnology, SSBT`s, COET, Bambhori, Jalgaon (MS), India 1 sheetal_deshmukh11@rediffmail.com Idp72@yahoo.co.in Abstract: Bioethanol produced from renewable biomass, such as sugar, starch, or lignocellulosic materials. Bioethanol is one of the alternative energy resources; this is both renewable and environmentally friendly. Although, the priority in global future ethanol production is put on lignocellulosic processing, which is considered as one of the most promising second-generation bio-fuel technologies, cereal grains for fuel ethanol is still underutilized. Sugar-based that is molasses, sugar cane, sugar beet and starch- based that is corn, wheat, triticale, potato, rice, etc., feed stocks are still currently predominant at the industrial level. They are, so far, economically favourable compared to lignocelluloses. Currently, approximately 80 % of total world ethanol production is obtained from the fermentation of simple sugars by yeast. In this paper, a review of the state of the art in bio ethanol production and availability is discussed. Pointing out the progress possibilities on starch-based production are discussed, in the respect of feedstock choice, pre-treatment, optimization of fermentation and process integration. It is observed that utilization of cereal grains for bioethanol production is the best option after food application. Key words: Cereal grains, Bio-ethanol, amylose, amylopectin. 1. Introduction: Cereal grains are used mostly for food and feed. Due to overproduction of cereals and advanced technology in seed production, tillage, sowing, harvesting and storage, cereals can be used as energy source. In recent decades, plant-breeding activities have made good progress in increasing grain yields and improving the genetic make-up of crops to increase nutrient utilization efficiency and to improve their adaptability for better environmental condition. As per estimates provided by Food Corporation of India (FCI) huge quantities of cereal grains are getting spoiled every year due to unfavourable climate condition, and become unfit for human and animal consumption; and these are very cheap. There are about one million tonnes of damaged grains lying unutilised in FCI stores (Suresh et al, 1999). The damage includes discoloration, breakage, cracking, attack by fungi, insect damage, chalky grain, partial softening by being damp, dirty and bad smell etc., The damaged grains used for ethanol production are ten times cheaper than fine quality. High starch contents in cereal grains make them good feed stocks for conversion into bio- fuels and other bio-based products. Ethanol is the only bio fuel that has been produced commercially from these feed stocks in large quantities. The amount of grain utilised neither for food, nor for feed purposes has grown in recent years. There has been an annual increase of around 10% from 2006 to 2008. Prior to that, the increase has been smaller and the amount was fairly stable prior to 2004 (C. Wrigley, I.L. Batey, 2010). The main industrial use of grains is to isolate the starch component and then process it further. Starch comprises 60 to 80 % of dry matter in most cereal grains. It is isolated industrially from maize and wheat, and to a lesser extent from rice. The resulting starch may be utilised or may be processed further. Modified starches (anionic, cationic and cross linked) have wide range of purposes in food and non food applications. A significant amount of starch is digested by enzymatic or acid/enzymatic treatment to produce glucose. Some of this glucose is converted to high fructose syrups for use as a sweetener. The starch may also be subjected to fermentation to ethanol. This use has traditionally been for production of alcoholic beverages, but high oil prices have caused the amount of grain being converted into automotive fuel production. Much of increase in amount of grain being used for purposes other than food and feed that is for ethanol production. The two main types of liquid biofuels are biodiesel and bioethanol. Biodiesel can be blended with diesel and bioethanol is primarily blended with petrol. Currently, the majority of vehicle engines are designed to run on