A 1.2 kW, 2450 MHz resonant continuous microwave processing system was designed and optimized for
oil extraction from green algae (Scenedesmus obliquus). Algae-water suspension (1:1 w/w) was heated to
80 and 95 C, and subjected to extraction for up to 30 min. Maximum oil yield was achieved at 95 C and
30 min. The microwave system extracted 76–77% of total recoverable oil at 20–30 min and 95 C, compared
to only 43–47% for water bath control. Extraction time and temperature had significant influence
(p < 0.0001) on extraction yield. Oil analysis indicated that microwaves extracted oil containing higher
percentages of unsaturated and essential fatty acids (indicating higher quality). This study validates for
the first time the efficiency of a continuous microwave system for extraction of lipids from algae. Higher
oil yields, faster extraction rates and superior oil quality demonstrate this system’s feasibility for oil
extraction from a variety of feedstock.