The improvement of industrial processes is still today of scientific and commercial interest, with great projection due to, among other factors, the contribution of natural marine products extracted from microalgae. In this sense, there have been numerous culture studies of autotrophic green microalgae and their adaptation to more economic forms (mixotrophic and/or heterotrophic), however, few of them are with diatoms despite them being an interesting group given that they are the most common in the natural environment and their role in the development of aquaculture is key. Therefore, the objective of this project is the study of the adaptability of Skeletonema costatum (autotrophic diatom) to more economic culture mediums such as the mixotrophic and heterotrophic medium. Specifically, algae growth was compared in autotrophic conditions (control) with different mixotrophic cultures, varying the amount of organic matter dissolved and the autotrophic culture with different heterotrophic cultures in which the composition of the medium was modified, adding glucose as a carbon source and nitrogen groups such as neopeptone and yeast extract. The results obtained show that the mixotrophic culture that allows for a similar biomass to the autotrophic culture is the one which contains the highest concentration of organic matter. On the other hand, for the heterotrophic culture, although the highest biomasses are obtained by applying an organic substrate composed of glucose, the levels observed did not reach those in the autotrophic condition. These results, in the absence of further optimization of the heterotrophic culture conditions, are quite promising and demonstrate the ability of S. costatum to adapt to other culture media.

Keywords: Microalgae, Autotrophic Culture, Mixotrophic Culture, Heterotrophic Culture