BioMIC-FUEL · Bio-inspired photonics for enhanced microalgal photosynthesis in biofuels

Bio-inspired photonics for enhanced microalgal photosynthesis in biofuels

Microscopic photosynthesising algae are a very attractive source of biomass energy and much effort has been made to optimise biofuel production. The key challenge for making microalgal production commercially feasible is to improve the spatial efficiency at which algae can grow, because high cell densities lead to low photosynthetic efficiency as a result of self-shading. The development of photobioreactors that provide algae with artificial irradiation and regulate the flux of gases is a key approach to maximise algal photosynthesis. However, these systems are expensive and thus limit the scaling-up of bioenergy generation. Nature has found simple ways to grow microalgae with high photosynthetic efficiency at high densities. On tropical coral reefs, microalgae are harboured within the animal tissue of corals as part of a natural symbiosis. The current design of the coral-algal symbiosis represents the result of an optimisation process that has taken place over millions of years in response to environmental drivers such as the competition f or space and light. Corals are highly optimised photosynthesising systems that despite the high densities of algae have remarkable photosynthetic efficiency on a tissue systems level. This is largely because of the evolution of simple light scattering mechanisms within the coral tissue and skeleton and niche adaptation of the microalgae to different cell layers in order to best suit the local physico-chemical microenvironment. Project aims and approach: We apply a multidisciplinary framework that integrates concepts of aquatic microbial ecology and optics into the design of biologically inspired bioenergy generation. Specifically, we learn from corals how to grow microalgae for improved biofuel production. The specific objectives are to 1) explore the in vivo light field, optical properties and photosynthetic efficiency of a range of coral species from different light regimes, 2) understand the nanophotonic and structural properties of corals underlying the optimised light modulation and 3) apply the biophotonic insight to design novel photonic materials for the improved growth of microalgae. A coral-inspired design is developed in a CAD environment and optimised via optical optical modeling approaches and microecological theory. Microalgae are 3D bioprinted in hydrogels that serve as algal microhabitats with defined optical and chemical response. The energy budget of the artificial microalgal system is evaluated through direct measurement of photosynthetic efficiency. In contrast to other bionics approaches, this project additionally integrates concepts of micoroenvironmental ecology through investingating how the local physico-chemical environment shapes the life of the 3D bioprinted microalgal community. These research objectives have important societal impacts, especially within Europe where the development of a resource-efficient, low-carbon economy through biofuels is a key research agenda. The work concludes that the development of optically tunable hydrogel systems is a promising approach to cultivate microalgae. Commercial applications of our platform will depend on developing scalable low-cost biomaterials.

Data: CORDIS, © European Union