Biogas production by anaerobic digestion is an established technology that allows farmers to generate more income from biomass waste and closing nutrient cycles. These synergies can be extended even further if microalgal cultivation is added to produce algae-based bioproducts. The side-products of biogas production, namely CO2, waste heat, and digestate, are used to increase culture productivity and lower production costs.

Products from microalgae, such as feed and feed additives, can again be used in the agricultural sector, which closes material cycles and extends the value chain for the biogas operator. We propose to take this synergistic approach a step further and focus on issues, which so far have received less attention.

Is it possible to produce biomass of sufficient quality so that it can be used as feed or feed additive? To this end, we take advantage of our large in-house photobioreactor to scale up laboratory experiments and test, whether microalgal biomass of feed-grade quality can be produced while relying on the above mentioned side products. We also investigate to what degree pests and contaminations affect the robustness of continuous cultivation and what measures can be applied to stabilize it.

Furthermore, we will determine whether waste heat can be used to prolong the cultivation season in a Swiss climate. Finally, the legal aspects of producing algae-based feed will be researched and documented.