Background. Mechanical stress was investigated as a mean to harvest microalgal lipids without affecting algal cells’ viability. Monoraphidium minutum was cultivated in laboratory-scale photobioreactors and suspension cultures were submitted to mechanical stress to compare a cyclone, a centrifuge and a homogenizer. Lipid content within the extracellular medium was analyzed prior to and after treatment, and the amount of released lipids was quantified. Algal cell viability was also evaluated before and after treatment.
Results. After mechanical-stress treatments, 7.0 to 12.7% of the intracellular lipids of Monoraphidium minutum were released and found in the extracellular medium, while recovered algal cells presented low levels of disruption after treatments.
Conclusions. To the best of our knowledge, this is the first proof-of-concept demonstration on the use of mechanical stress for lipid extraction from viable microalgae. Certain level of centrifugation proved to make algae release around 10% of their lipids to the extracellular medium. This mostly exploratory work calls for deeper investigation, paving the way for a biofuel production based on continuous lipid recovery and microalgae reuses.
Financed by the National Centre for Research and Development under grant No. SP/I/1/77065/10 by the strategic scientific research and experimental development program:
SYNAT - “Interdisciplinary System for Interactive Scientific and Scientific-Technical Information”.