Mycoalgae Biofilm for Aquaculture Bioremediation and Animal-Feed Production

Lichen, a natural ecosystem with phototrophic algae and heterotrophic fungi symbiotically growing on the solid surface of rock or roof, is not readily applied in engineering field due to their low growth rate. A concept of “simulated lichen system” is recently developed by our UMN research group (UMN invention disclosure case # 20140274) that we can select different desired microalgae and fungal combinations that will be growing on the surface of some specific polymers to form the biofilm. Microalgae are naturally growing on the surface of the nutrient-rich water; however, biological treatment of polluted waters using microalgae is limited by problems associated with the settling and separation of algae downstream of the treatment site. The proposed methodology using bioaugment filamentous fungi in lichen biofilms overcomes this limitation, by efficiently retaining algae and recovering the nutrients and recycling of useful nutrients. We are extending this technology to aquaculture waste water bioremediation, and recycle the nutrients as proteinaceous microbial biomass feed for the aquatic animals. This process modification could make the aquafarming more efficient as commercial feeds may account for more than 50% of the total production costs. “Mycoalgae biofilm” also works on photosynthetic aeration to replace the conventional and energy intensive mechanical aeration for biological processes, and also the strains complement each other by the required respiratory gases. The biofilm composition can also be tailored based on the influent stream components, feasibility of the strains to grow together and its nutrition value as animal feed.