Researchers Extract Oil from Algae Without Wasting Them

Researchers from Murdoch University (Australia), in collaboration with counterparts from University of Tsukuba (Japan), have developed a non-destructive algal oil extraction method, akin to 'milking' the algae as opposed to the conventional harvest-and-destroy approach.

The researchers were able to extract oil repeatedly from the algae species Bortyococcus braunii by using a compatible solvent (n-heptane). The "milking" process is less expensive compared to conventional algal cultures since it eliminates the addition of expensive nutrients during repeated extraction. The algae could replace its external hydrocarbon five days after "milking" with one per cent carbon dioxide addition, which increases the overall external hydrocarbon productivity by 20 percent compared to conventional semi-continuous culture.

The research team is currently looking at possible explanations why the algal cells require addition of a limited amount of nutrients to stabilize the culture. They are also working on a potential continuous milking bioreactor.