Microalgal cell disruption in a high-power ultrasonic flow system.

A 2-kW continuous ultrasonic flow system (UFS) was found effective in the disruption of two microalgal strains: Scenedesmus dimorphus and Nannochloropsis oculata. Compared to the control, cell debris concentration of UFS treatments increased up to 202% for S. dimorphus and 112% for N. oculata. Similarly, Nile red stained lipid fluorescence density (NRSLD) increased up to 59.5% and 56.3% for S. dimorphus and N. oculata, respectively. It was also found that increasing ultrasound intensity improved cell disruption efficiency indicated by up to 54% increase in NRSLFD of the two strains. Increasing sonication-processing time to 3-min resulted in 33.0% increase for S. dimorphus and 45.7% increase for N. oculata in NRSLFD compared to the control. Cell recirculation was found beneficial to cell disruption, however, higher initial cell concentration significantly reduced cell disruption efficiency, indicated by 98.2% decrease in NRSLFD per cell when initial cell concentration increased from 4.25 × 10(6) to 1.7 × 10(7)cells ml(-1).