Recycling of Dunaliella salina cultivation medium by integrated membrane filtration and advanced oxidation

beta-Carotene and other carotenoids are common food additives industrially produced by Dunaliella salina. However, the cultivation production costs are substantial and determine the economic viability of production in large-scale systems. There is a strong interest in recycling the cultivation medium in order to reduce the microalgae production costs. This work aims to study several oxidation techniques for treatment of permeate produced during harvesting of microalga Dunaliella salina by membrane filtration. The treated permeate produced is assessed for reuse as cultivation medium of Dunaliella salina. The permeate produced during membrane harvesting of Dunaliella salina was recovered and treated by ozonation and UV radiation. The different types of permeate produced were tested as cultivation media. The results obtained indicate that the permeate treated by UV with addition of H2O2 was best suited for the growth of Dunaliella salina during carotenogenesis. Nevertheless, although not performing as well as the selected cultivation medium, the use of untreated permeate seems a reasonable alternative to it, as the untreated permeate has potential to be the most cost efficient solution.