The effect of audible sound frequency on the growth and beta-carotene production of Dunaliella salina

Abstract

Sound vibrations as a cutting-edge technology considered for promoting the growth of microalgae. In this experiment, the authors have carried out a pilot study to observe the response of Dunaliella salina to audible sound frequencies (100, 200, 500, 1000 Hz). The growth and beta-carotene concentration as a secondary metabolite in optimal culture medium and sub-optimal medium with nitrate deficiency were investigated. The control was in an acoustic enclosure without any sound frequency exposure and cultured in the N-sufficient medium. The sound frequency of 200 Hz was found to promote biomass concentration and cell division up to 50% compared to control. Interestingly, the frequency of 200 Hz promoted growth when the nitrate concentration decreased by 75% in the culture medium. The simultaneous effect of audible sound frequency of 200 Hz and nitrate deficiency showed the amount of beta-carotene increased to 37% compared to control. In the absence of sound frequency, an increase of 18% in beta-carotene was observed. To the best of our knowledge, the frequency of 200 Hz is a good demonstration of the ability of sound stimuli to improve the growth as well as a secondary metabolite of D.salina.