Algae-based biofuel production

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Decreases in national and world fossil fuel reserves along with increases in national security, economic, environmental and regulator pressures have encouraged exploitation of various alternative fuel sources.

Biodiesel is the fastest growing alternative fuel in the U.S. Annual biodiesel production has increased from less than 0.1 million gallons in 1998 to over 25 million gallons. It is anticipated that the biodiesel production capacity will increase to 1-2 billion gallons by 2010, which represents only 2% of the projected demand for diesel.

Oilseed crops such as soybean and rapeseed have met early market demand, but additional renewable sources will be needed when the demand is expected to reach 60 billion gallons of biodiesel by 2015. Algae may be used to used to produce biofuel and has a number of advantages over oilseed crops.

Algae can synthesize and accumulate large quantities of lipids and oils in their cells that can be extracted and converted into renewable fuels such as biodiesel, aviation fuel, or other transportation fuels.

The major advantages of algae over oilseed crops for biodiesel production are:

  • High cellular oil content (40-60% of dry weight)
  • High growth potential (>1 doubling time a day)
  • 5-10-fold higher areal oil production than oilseed plants
  • Thrive in saline/brackish water
  • Can be coupled with wastewater treatment
  • Can be coupled with carbon sequestration
  • Can use desert, arid/semi-arid lands and/or off-shore areas
  • Potential genetic manipulation for strain improvement
  • Culture conditions can readily be controlled
  • Algal culture process can be automated

At ASU, we have designed and evaluated several types of photobioreactors under both laboratory and outdoor conditions. A proprietary modular flat-plate photobioreactor has proved to be the most efficient and cost-effective culture system. We have also isolated a number of algal species that possess the ability to synthesize large quantities of neutral lipids.

In addition, we have demonstrated that some of the algal isolates can thrive at high concentration of carbon dioxide (up to 20% CO2) and take up waste nutrients (mainly N and P) rapidly from various types of wastewater. Our experimental results indicate that a sustainable production of algal biodiesel is technically and economically feasible.

Arizona is an ideal place for algae biofuel production because of abundant solar energy throughout the year, mild climate, large quantity of saline groundwater that is unsuitable for crop irrigation and vast land areas with minimal competition from conventional agriculture.

It is estimated that only 0.25% of the state land area could produce enough algal feedstock to meet the present U.S. demand for diesel fuel.

LARB's research in biofuels is supported by:

  • Heliae LLC
  • Science Foundation Arizona
  • Boeing

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