Resumen de Optimization of Growth Conditions and Biochemical Composition of Microchloropsis salina, Cultured with Three Macroalgal Aqueous Extracts

Mohamed S. Abdel-Kareem, S. M. Mohy El Din, El-Sayed M. Ibrahim

• The utilization of microalgae for the production of numerous biotechnological products is growing in importance and there are several large production systems for microalgae. Meanwhile, their production is subjected to high cost problems, and the need for clean and low-cost production demands many investigations on algal physiological response under different growth conditions. We investigated the growth, biomass, and biochemical composition of Microchloropsis salina using different concentrations of Ulva linza, Pterocladia capillacea and Sargassum hornschuchii aqueous extracts against conventional f/2 medium. M. salina was successfully cultured using the tested seaweed extracts and exhibited higher cell density and biomass when seaweed extracts were used as a supplement or an alternative medium. The growth of M. salina was optimized through the manipulation of several algal cultivation conditions such as light intensity, light/dark cycles, salinity and pH. When P. capillacea aqueous extracts were used as an alternative medium, microalgal recorded the highest values of total chlorophylls, total carotenoids and total carbohydrates. The maximum value of total lipids was recorded at S. hornschuchii extract, and the maximum value of total proteins was recorded at U. linza extract, compared with control (f/2 medium). Data are statistically significant at p < 0.05, according to the analysis of variance. In conclusion, we believe that the seaweed aqueous extracts evaluated in this study are able to provide the necessary inorganic nutrients and minerals for tested species growth and could be used as a cost-effective media in establishing microalgal populations.