Domesticated microalgae have the potential to significantly enhance the efficiency, sustainability, and resilience of global food and fuel production. However, large scale cultivation in open ponds is challenged by problems related to both the ecology of complex aquatic systems (e.g. grazers, competitors, and pathogens) and engineering (e.g. energy-intensive harvesting practices). One proposed solution to these problems is to use synthetic algal communities that are more robust to invasion and also possess traits that facilitate more streamlined and efficient methods for the extraction of bioproducts. Specifically, optimizing the chemical ecology of algal consortia by strategically employing strains that excrete useful extracellular metabolites has the potential to inhibit pests while also simplifying the harvesting process. Here we present recent results from multiple lines of research that provide insights into the role of chemically-mediated interactions in shaping algal productivity. Specifically, we show that green algae species vary in their sensitivity to allelopathic inhibition; that green algae excrete inhibitory fatty acids in species-specific quantities; that algal exudates can have effects ranging from inhibition to facilitation; and that the growth phase determines allelopathic effects. We also outline preliminary and ongoing work aimed at characterizing metabolites secreted by algae and their effects on productivity, as well as efforts to apply selective pressures to both increase extracellular lipid production and increase tolerance to these secreted lipids.

Primary Presenter: Patrick Thomas, Eawag (pkthomas88@gmail.com)

Authors:

Patrick Thomas, Eawag  (patrick.thomas@eawag.ch)

Anita Narwani, Eawag  (anita.narwani@eawag.ch)