Background. Efficient methods of cultivating microalgae have been developed for the fuel industry in photobioreactors or open recirculation tanks. Reduced world fuel demand makes the production of thirdgeneration biofuels less profitable. Algae producers are looking for alternative applications for them and have high hopes for the food industry. Algae biomass is an excellent  source of food ingredients – it is rich in easily digestible and well-balanced protein and is characterized by a high content of macro- and microelements occurring in easily digestible forms as  complex or organometallic compounds. The presented study shows the results of an experiment aimed at examining the effect of adding microalgae in various forms (Arthrospira platensis and  Ascophyllum nodosum – dried, granulated and smoked) to rye bread on the nitrogen, phosphorus, iron and iodine content. In order to test the bioavailability of these elements, the produced  bread was subjected to a simulated in vitro digestion process. The dialysates and mineralized bread samples obtained were used to analyze the content of the above-mentioned macro- and  microelements using spectrophotometric methods.
Results and conclusion. The results obtained indicate a statistically significant effect of the addition of algae on an increase in the level of the elements discussed. The largest differences in  the content of the analyzed macro- and microelements compared to the bread without additives were observed for the samples containing dried spirulina (Arthospira platensis) and  Ascophyllum nodosum in the form of granules. The microalgae introduced into the rye bread also increased the bioavailability of iron and iodine.