FUEL ETHANOL-PRODUCTION FROM AGRICULTURAL LIGNOCELLULOSIC FEEDSTOCKS - A REVIEW

Over the past three decades significant efforts have been made towards the conservation of fossil-based fuels and the exploration and exploi tation of new renewable sources. The focus primarily has been on the o utlook for alternatives to the petroleum products. In this spectrum al cohol manufacture from biomass has attracted a large attention all ove r the world which could be used as an alternative source to petrol or in blends with petrol. The National Research Council (NRC) has substan tially emphasized on the reduction of CO2 emissions and the other so-c alled green house gases. The NRC committee also recommends better eval uations of the processes for converting the biomass/lignocellulosic wa stes to ethanol that will lessen the U.S. dependence on foreign oil. A mong the factors behind the move to bio-based materials are the enviro nmental concerns, the availability of abundant, renewable agricultural and forest resources that are both inexpensive and under-utilized. Th is paper provides a comprehensive review of the ethanol fermentation f rom the food crops as well as the lignocellulosic materials. Different processes involved including acid and enzymatic hydrolysis, enzyme pr oduction, fermentation, and lignin conversion are discussed. Also the energy balance considerations of the process are elucidated.