Whey represents an important disposal problem in the dairy industry. This work sought to optimize a culture medium based on sweet whey for the culture of microalgae (a Nannochloropsis gaditana strain was used for this study). The Deproteinized whey was then supplemented with various concentrations of heavy metals, vitamins, sodium nitrate and sodium dihydrogen phosphate, identical to that used in the F/2 Guillard medium, twenty combinations are made. Nannochloropsis gaditana was able to grow in all whey-based mediums at different growth rates.Results show that deproteinized whey does not provide a good yield of cellular biomass. the high productivity in biomass (by providing the F/2 Guillard control medium) has been observed in media composed principally of deproteinized whey and heavy metals. Maximum cell number was 988.33x10 5 from the 11 th day on the deproteinized whey + NaHPO4 + heavy metals composed medium. However, The Nannochloropsis gaditana strain was faster in specific growth speed and generation time on a medium composed of deproteinised whey and heavy metals, than the other media, as well as a better biomass yield on the latter. A comparative study of growth kinetics carried out with the same strain has shown that growth takes place according to a classic pattern of discontinuous culture.