Аннотация:Immobilized microalgae (MA) are widely used for the production of biomass andhigh value-added metabolites, the biocapture of nutrients and heavy metals, and for thedestruction of organic pollutants in wastewater. The use of chitosan (CH) as a carrier forMA cultivation has many advantages, including its availability, non-toxicity, biodegradability, biocompatibility and high sorption capacity. However, for successful CH application, itis crucial to increase the cost-effectiveness of microalgae–chitosan systems as comparedto traditional technologies. One of the prospective approaches is the synthesis of composites on the basis of chitosan and natural polysaccharide-containing wastes (PCWs) likeapple pomace (AP) and mycelium (M), which are the main by-products in the apple juiceprocessing industry and in mushroom farming.