Research on cell disruption and DHA extraction of Aurantiochytrium sp.

In order to select the best method for cell disruption of Aurantiochytrium sp.， five cell disruption methods， including repeated freezing and melting， ultrasonication， high-speed homogenization， alkaline heating and trituration， were used to break up the cell wall of Aurantiochytrium sp.， then cell disruption efficiency of different methods and their influences on oil extraction and oil composition were analyzed and compared. In order to characterize the cell disruption efficiency of different methods， cell number was estimated by microscope observation， and cell morphology was observed using SEM. In order to explore the influences of different cell disruption methods on oil extraction， oil distribution was qualitatively analyzed using Nile red staining， then crude oil was extracted by n-hexane. In order to explore the influences of different cell disruption methods on oil composition， the specific composition of oils was analyzed using GC（Gas Chromatography） . Results showed that： （1）Alkaline heating had the best effect on cell disruption for its highest efficiency（95.51%）and biggest cell morphology changes. （2）The extracted crude oil after alkaline heating was the most and up to 61.33% of the dry biomass weight. （3）Highest DHA content in oil was 41.33% after alkaline heating， of which DHA production was much higher than the other methods and up to 2.192 g/L. From the perspective of high purity DHA production， alkaline heating is the most promising method for cell disruption of Aurantiochytrium sp.