**7. Conclusion and prospects**

The cryptophytes are secondary endosymbionts that inherited many red algae characteristics, but differences involving morphology and physiology make them unique and not completely understood. The functioning of PBPs as a secondary antenna into the thylakoid and its connection to photosynthesis, the PBPs as an energy reserve, to understand why these cells still have a vestigial nucleus NM with three chromosomes, the way the nucleus coordinates the activities of NM and plastid are some of the mysteries for the scientist to solve. From an applications point of view, cryptophytes have high nutritive value that includes a balanced PUFA profile, high protein content, and the possibility to induce a high content of PCY or PER, antioxidant pigments, as well as having a very stable fluorescence making it attractive for use in research, thus its future looks promising and applications using cryptophytes should grow. From a production perspective, these cells have some advantages compared to other producers of PBPs, they have only one type of pigment. Cryptophytes lack of a cell wall facilitating digestion and nutrient absorption by organism and the extraction of products, and in addition have high content of PBPs with a lower molecular weight. The low growth rates and how to achieve the scaling necessary for high biomass with high pigments content will continue to be a challenge in the near future. Improvements will come probably by improved understanding of its physiology. Also, needed is to increase the variety of organisms in collections, improve the culture procedures including photobioreactors, and finally make more accessible purification methods.
