Bioenergy Use from Pavlova lutheri Microalgae

A competitive price of biofuels is necessary for large-scale development. To reduce the overall costs of biofuels production from microalgae, a total use of feedstock was pursued in this research. Besides, the optimization of the different stages involved in biodiesel synthesis process was carried out. The use of algal waste, residue after biodiesel production, as raw material for pellets manufacturing, was analysed. In addition, other techniques as microwave irradiation or ultrasound were used to extract the algal oil and subsequently characterize the oil by gas chromatography. The highest yield of oil extracted (24.77%) was obtained when a microwave irradiation took place previously to ultrasound-assisted extraction. However, less than half of oil was extracted by ultrasound (11.74%). The results showed that high biodiesel conversions, about 50-67%, were achieved by direct transesterification. In addition, pellets from waste biomass could be used as fuel in biomass boilers. Therefore, an integral use of the microalgal raw material was accomplished. No residues were generated and two valuable biofuels were obtained: biodiesel and pellets.