Life cycle assessment of butanol production in sugarcane biorefineries in Brazil

Butanol production by the sugarchemistry route (fermentation of sugarcane juice) was evaluated considering different arrangements for its process integration in sugarcane biorefineries: first and second generation butanol production using acetone-butanol-ethanol (ABE) fermentation with wild and genetically modified microorganisms. The whole production chain was investigated, from the agricultural stage, through transportation of sugarcane and vinasse, to the industrial process and butanol final use when applicable. Life cycle inventories and mass and energy balances for the industrial stage were taken from computer process simulation obtained from the literature. Butanol production from bagasse and straw pentoses using genetically modified microorganism presents the best environmental performance among the investigated technological scenarios. Comparison with the oil-based production route and use as liquid fuel for vehicles evidenced environmental advantages for bio-based butanol in terms of global environmental impacts, such as abiotic depletion, global warming and ozone layer depletion potentials. Additionally, the introduction of butanol and the by-product acetone to the product portfolio of biorefineries led to increased revenues in comparison to base scenarios, which can ultimately help to mitigate environmental impacts of the biorefinery in monetary terms. (C) 2014 Elsevier Ltd. All rights reserved.