Feasibility of a biochemical conversion of drought resistant California Agave spp. to fuel ethanol without pretreatment

Biofuels constitute an important tool for satisfying California’s enormous gasoline appetite while simultaneously facilitating its progressive march towards creation of a greener and more sustainable energy future.  The state consumed roughly 15 billion gallons of gasoline in 2011, the highest in the United States.  Our work has shown that available cellulosic resources potentially available in the State, though abundant, could not successfully meet a large portion of the massive transportation fuel consumption.  Consequently, energy crops are needed to reduce the State’s dependence on fossil fuels.  Since irrigated land and water supplies are limited and expensive in California, an ideal energy crop should thrive on marginal lands with minimal water input.  The agave genus seems ideal as an energy crop for California due to its high water use efficiency and productivity on marginal arid lands.  In addition, its low lignin content potentially signifies low recalcitrance.  In light of these physiological advantages, this project focuses on elucidating the potential role agave types native to California could play in biofuels production. First, the compositional analysis method developed by the National Renewable Energy Laboratory was employed to determine the maximum theoretical sugar and ethanol yields from agave.  Then this project determined if enzymatic hydrolysis and fermentation of native California agave species is feasible without pretreatment.  Once characterized, the sugar contents and ethanol yields elucidated the biofuels potential of agave and how it could contribute to California’s goal of realizing a sustainable energy future consistent with its progressive vision.