Microalgae have enormous potential for human nutrition, yet the European Commission has authorized the consumption of only eleven species. Strains of fifteen rarely researched microalgae from two kingdoms were screened regarding their nutritional profile and value for human health in two cultivation phases. Contents of protein, fiber, lipids, fatty acids, minerals, trace elements and heavy metals were determined. In the growth phase, microalgae accumulated more arginine, histidine, ornithine, pure and crude protein, Mg, Mn, Fe and Zn and less Ni, Mo and I compared to the stationary phase. Higher contents of total fat, C14:0, C14:1, C16:1, C20:4, C20:5 and also As were observed in microalgae from the chromista kingdom in comparison to microalgae from the plantae kingdom ( < 0.05). Conversely, the latter had higher contents of C20:0, C20:1 and C18:3 as well as Ca and Pb ( < 0.05). More precisely, appeared to have great potential for human nutrition because of its high nutrient contents such as fibers, carotenoids, C20:6, Mg, Ca, Mn, Fe, Se, Zn, Ni, Mo and I. In summary, microalgae may contribute to a large variety of nutrients, yet the contents differ between kingdoms, cultivation phases and also species.