Bioethanol is a renewable energy major derived from sugar, corn, maize, wheat crops and many other crops. Bioethanol is majorly used as substitute of petrol for transportation. Bioethanol is majorly produced by the sugar fermentation process. However, it can also be manufactured by the chemical process of reacting ethylene with steam. Biofuel is an efficient substitute of petrol because it is a high octane fuel and has also replaced lead as an octane enhancer in petrol. Blending ethanol with petrol oxygenates the fuel mixture so that it burns completely and reduces harmful emissions. The most common blend of bioethanol is 90% petrol and 10% ethanol. Furthermore, the recent developments in the production of biomass are down-regulation of lignin synthesis, improved cellulase titers and re-engineering of cellulases, and process integration of the steps involved and they have increased the possibility of cheap bioethanol production that competes with the price of petroleum. Recently, the global companies have come forward for bioethanol production on a large scale.