(753e) Wastewater Treatment Systems: The Next Biorefinery

Oleaginous yeasts are a type of microorganism that can produce up to 70 percent of their body weight in oil. The use of this type of microorganism as a source of oils for biofuel production is limited by the availability of cost effective carbon, water and other nutrient sources. A growth medium that has not been previously considered for cultivating oleaginous microorganisms is municipal and industrial wastewaters. This study is designed to determine the concentration of indigenous microorganisms that effect the growth and oil accumulation of oleaginous microorganisms when cultivated on wastewater. By using wastewater, the oleaginous microorganisms could produce an abundant amount of oil while treating this water to Environmental Protection Agency (EPA) required treatment levels. The cell mass yield, oil percentage, and oil yield are measured using well-established techniques such as plate counting, Bligh& Dyer, and transesterification. In addition, water quality is measured by determining the biochemical oxygen demand (BOD), the chemical oxygen demand (COD), and the amount of nitrates in the wastewater after the yeast growth stabilizes. These quantities will determine the efficacy of the oleaginous microorganisms assist in removing wastewater contaminants. Preliminary results show that the microorganisms can be cultivated on wastewater, accumulating approximately 10% of their weight in oil. Wastewater treatment facilities may be operated with oleaginous yeasts as the main consumers of BOD. This modification could potentially generate billions of gallons of oil for producing biofuels.