Integrated Algal Bioenergy Platforms: Advances in Microbial Fuel Cell Integration and Nanotechnology-Enabled Biorefineries

The use of algae-based bioenergy platforms in establishing circular bioeconomy systems is due to their capacity to generate biomass of renewable origin, using solar energy and carbon dioxide (CO2), while the process also involves remediation and recovery of resources. The introduction of algae to bioenergy systems is still limited by obstacles related to biomass productivity, efficiency of harvesting, and energy demands of further utilization of biomass, not to mention lack of system integration. The present paper provides a review of the new developments in the area of algal bioenergy platforms, focusing on the use of algae-assisted microbial fuel cells (MFCs) and biotech solutions based on nanotechnology. The combination of algae with MFC technology allows for the generation of bioelectricity and the use of algal systems for carbon fixation, nutrient removal, bioconversion of biomass, etc. Meanwhile, nanotechnology has become an important approach to enhance the development of algal bioenergy technologies by providing better cultivation activity, light absorption, nutrient transport, biomass extraction, catalysis, and electrodes. Advanced nanomaterials, such as magnetic nanoparticles, metal oxides, carbon-containing nanostructures, and combined nanomaterials, have allowed the industry to overcome the most important problems in algal biomass processing and bioelectrochemical energy production. At the same time, integrated algal biorefineries make it possible to transform a variety of biomass forms into biofuels or something even more valuable. Nevertheless, despite achieving significant resolution of many concerns, the scalability of technologies and the safety of the nanoparticles are still among major challenges to industrial implementation. The further development of algae-based technologies should allow sufficient integration of advanced nanomaterials, genetically engineered microbes, and scaling of reactor technologies. This review provides a unique integrated framework connecting algae cultivation, microbial fuel cell technologies, and nanotechnology-enabled biorefineries toward scalable circular bioenergy systems.