Usually, when biodiesel producers are using algae to provide the feedstock oil to produce the green fuel, they have to destroy the algal cells to get the oil. But this article from Phys.org says Australian researchers might have found a way to “milk” the oil from the algae species Bortyococcus braunii so they can keep producing more biodiesel feedstock.
Murdoch University School of Veterinary and Life Sciences Algae R&D Centre researcher Dr Navid Moheimani and his team, in collaboration with the University of Tsukuba (Japan) have been investigating a non-destructive approach rendering the algae to be ‘milked’ and ‘remilked’ every five days.
By using a compatible solvent (n-heptane) they were able to extract oil from non-growing state algae repeatedly—producing significantly more hydrocarbon (oil) and requiring significantly less expensive nutrients (as opposed to rapid growth phase).
Dr Moheimani says B. braunii could replace its external hydrocarbon after five days [after milking] in cultures with one per cent CO2 addition.
“The overall external hydrocarbon productivity using non-destructive extraction was at least 20 per cent higher compared with B. braunii grown in conventional semi-continuous culture,” he says.
The researchers go on to say the efficiencies come from having not to regrow the algae after each extraction, which saves on fertilizer and waste biomass disposal costs, and they’ve been able to re-milk the algae for more than two months. The only real challenge might be getting those little milking stools and tiny buckets under each cell (but at least they don’t kick like an old holstein).