Main Article Content

Short communication: The effect of ultrasound at 256 KHz on Microcystis aeruginosa, with and without gas vacuoles


S Jachlewski
M Botes
TE Cloete

Abstract

The effect of ultrasound on the growth of M. aeruginosa confirmed to contain gas vacuoles and on a laboratory culture with no gas vacuoles was investigated. Both cultures were treated continuously for 9 d with an ultrasonic flow device. To evaluate the influence of ultrasound during the treatment, the chlorophyll-a concentration was measured daily. Furthermore, changes in culture characteristics, e.g., flotation and gas vesicle formation, were determined. The results showed that, in contrast to the control, both ultrasonic-treated cultures had a lower chlorophyll-a concentration and cell aggregates were disrupted. Transmission electron microscopy confirmed a collapse of gas vacuoles in the environmental culture, while the laboratory culture, which did not contain gas vacuoles, showed many membrane-damaged cells. It was concluded that ultrasonic treatment of M. aeruginosa caused the disruption of gas vacuoles and destruction of cell membranes.

Keywords: Ultrasound, cyanobacteria, Microcystis aeruginosa, chlorophyll, gas vacuoles


Journal Identifiers


eISSN: 1816-7950
print ISSN: 0378-4738