Continuous non-destructive hydrocarbon extraction from Botryococcus braunii BOT-22

Abstract

In-situ extraction of microalgal oil without cell destruction has been proposed as a cost-effective alternative solution for the production of algal biofuel. This study examines the viability and efficiency of n-dodecane in both column and shake flask systems for the continuous extraction of botryococcene from Botryococcus braunii (BOT-22). Botryococcene from B. braunii was found to be non-destructively extracted using n-dodecane without negatively affecting the growth and photophysiology of the microalgae. Recirculation of the culture (23 times per day) through a column system containing n-dodecane with a daily effective extraction time of 276 s resulted in 21% higher botryococcene extraction (25.1 mg g−1 biomass) when compared to a constantly stirred shake flask consisting of both algae culture and n-dodecane together in a vessel. Botryococcene extraction was highest in the first 24 h of extraction when compared to the rest of the extraction period. These results suggest that recirculation of B. braunii culture through a column system containing n-dodecane is efficient for the non-destructive extraction of botryococcene and less toxic compared to other previously tested solvents.