Effect of thermal pretreatments on hydrocarbon recovery from Botryococcus braunii

Thermal pretreatment were tested to increase the recovery of hydrocarbons from Botryococcus braunii/water mixtures via extraction with hexane. The effectiveness of treatment temperature was dependent on the B. braunii strain and the lowest temperatures which recovered over 90% of hydrocarbons were 60, 85 and 75 °C for the Yamanaka, Showa and Kawaguchi-1 strains respectively. The holding times of thermal pretreatment had less of an influence on hydrocarbon recovery than treatment temperature and, depending on the strain, recoveries of between 74.9% and 94.9% were achieved after thermal pretreatments at 80–90 °C for only 2.5 min. These results suggest thermal pretreatment could reduce the energy consumption of oil recovery process from wet B. braunii cells.