DEVELOPMENT OF A SINGLE STAGE BIODIESEL PRODUCTION FROM MICROALGAE GROWN IN WASTEWATER

Concerns about energy security and independence, environmental pollution and climate changes are promoting the development of sustainable and renewable biofuels. The common alternative to fossil energy sources today is biodiesel from agricultural crops, mainly corn. However, this alternative may cause a reduction in the world`s food sources. Microalgae are considered to be very promising for biofuel production, since they do not compete with plants for agricultural areas and can be cultivated in existing reservoirs of wastewater treatment stations. Microalgae exhibit high metabolic and biochemical flexibility, including lipid, carbohydrate and protein accumulation, which can be regulated by varying the cultivation conditions at high growth rates. A traditional scheme for biodiesel production includes two separate stages – extraction of triglycerides of fatty acids from the biomass and a trans-esterification reaction for conversion of the triglycerides into monoesters comprising biodiesel.

This study is dedicated to the development of biodiesel production from microalgae grown in wastewater. We developed a process that combines extraction and trans-esterification stages, which enables the performance of trans-esterification of triglycerides in situ. Conditions for high-yield production of monoesters were chosen by varying organic solvents, time and temperature first on model systems with a known composition (glyceryl trioleate and olive oil), and then on the biomass of microalgae grown in a novel grid bioreactor installed at a wastewater treatment station in the West Ariel industrial area. A waste-free scheme for production of biodiesel from microalgae biomass is proposed.