The present paper aims to formulate a byproduct-supplemented medium suitable for the production of large amounts of protein rich Dunaliella salina biomass. Components of the MH basal growth medium were examined for partial replacement by cheese whey, beet molasses, and yeast fermentation liquor. Maximum growth rate was achieved after 8 days of incubation in the presence of 0.4% fermentation liquor that replaced ¾ of the weight of all medium components other than NaCl. Interestingly, the presence of fermentation liquor or cheese whey resulted in more than 1.5 and1.4-fold increases, respectively, in algal protein production. By application of three sequential multi-factorial experimental designs, medium composition was further optimized with respect to protein content in Dunaliella cultures. Among medium components, fermentation liquor was the most significant factor that affected the response. Compared to the basal condition, the optimized medium formula resulted in approximately a 1.7-fold increase in the protein content of Dunaliella salina cultures.