Ultrasonic-assisted Extraction - Definition, Glossary, Details - Oilgae
Oil extraction method based on ultrasonic waves
The disintegration of cell structures (lysis) by means of ultrasound is used for the extraction of intra-cellular compounds.
In microbiology, ultrasound is primarily associated with cell disruption (lysis) or disintegration (Allinger 1975). When sonicating liquids at high intensities, the sound waves that propagate into the liquid media result in alternating high-pressure (compression) and low-pressure (rarefaction) cycles, with rates depending on the frequency. During the low-pressure cycle, high-intensity ultrasonic waves create small vacuum bubbles or voids in the liquid. When the bubbles attain a volume at which they can no longer absorb energy, they collapse violently during a high-pressure cycle. This phenomenon is termed cavitation. During the implosion very high temperatures (approx. 5,000K) and pressures (approx. 2,000atm) are reached locally. The implosion of the cavitation bubble also results in liquid jets of up to 150m/s velocity. The resulting shear forces break the cell envelope mechanically and improve material transfer. Source