EFFECT OF LOW-DOSE ULTRASONIC TREATMENT ON SPIRULINA-MAXIMA

Spirulina maxima exposure to ultrasound (16 and 18 W) for 5 s generall y resulted in decrease in growth, protein concentration, and superoxid e dismutase (SOD) activity, while chlorophyll a concentration was not significantly affected at the 5% level. However, lower doses (8 W) of ultrasound showed a 5% increase in growth in samples receiving a one-t ime dose of ultrasound on the first day and day 7 of the experiment (U S-D-1,7) compared to the control and the ultrasound every other day tr eatment (US-EOD). Chlorophyll a concentration was not significantly di fferent between the control and US-D-1,7 treatment, but increased in t he US-EOD treatment. In addition, protein concentration and SOD activi ty were decreased in both of the ultrasound treatments compared to the control. For the production of Spirulina on an industrial scale, low doses of ultrasound may provide an environmentally safe method for enh ancing the growth of this organism. Conversely, higher doses of ultras ound may provide an environmentally safe method for reducing the growt h of harmful cyanobacterial species in growth systems for animal aquac ulture (C) 1998 Elsevier Science B.V. All rights reserved.