Alternative fuel production is of increasing interest throughout the U.S. and the world as cost and demand increase while fossil fuel supplies decrease on a global scale. The state of Arizona presents a unique situation as we have an abundance of sunny days which provide an ideal environment for the growth of plants that could be utilized as feedstocks for production of fuels. The goal is to design a system to primarily produce ethanol from biorenewable feedstocks in a sustainable manner that requires low inputs of nutrients, energy, and water. An ideal system for Arizona integrates an appropriate adapted feedstock grown with recycled or reclaimed water. Agriculture in Arizona is abandoning traditional cotton growth due to recent economic changes and so there are facilities across the state which have available land and available allocated water resources. Working collaboratively, we are investigating optimization of ethanol production from sweet sorghum and/or algae. Sweet sorghum is chosen as a feedstock since it is salt tolerant and requires less seed, fertilizer, pesticide, irrigation water, and tillage than other crops currently used for ethanol production. CO2 utilized by algae in photo-bioreactors is the second system investigated because it can produce carbohydrates year-round that are used as feed for the fermentation vessel and use recycled/reclaimed water. Both systems however have limitations. Sweet sorghum has a high sucrose content in addition to fructose and glucose which presents fermentation challenges. Furthermore, there are large quantities of cellulosic material and transportation of this material may be too costly. Fermentation results and a preliminary optimization strategy for balancing production costs will be presented.

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