A novel approach to build algal consortia for sustainable biomass production

Abstract

In the last decade, microalgae have reemerged as a feedstock for biofuels and a diverse suite of bioproducts. Yet, considerable challenges must be overcome before algal biofuels and bioproducts become technoeconomically viable. At present, single algal strains selected for particular phenotypic traits, such as maximum specific growth rate or lipid content, are commonly scaled for cultivation in open, outdoor raceway ponds. Although this monoculture approach may maximize the production of end products, monocultures are particularly susceptible to crashes associated with environmental variability. An approach that has been proposed to generate more productive and stable microalgal crops is the use of eco-engineered communities, or consortia. However, attempts to construct productive consortia have not been consistently successful. We argue that failures stem from the lack of an eco-engineering approach to design species combinations. Here, we used an in silico method to build consortia before testing their performance against monocultures in the laboratory. Focusing on consortia of Nannochloropsis and Microchloropsis, we measured growth of strains along gradients of light and temperature, as well as in response to a salinity shift. With these data, we used a functional dispersion approach to generate over 8000 consortia combinations. We then tested the 50 most functionally diverse consortia in a laboratory experiment and found that consortia overwhelmingly outperformed monocultures. A positive net biodiversity effect and overyielding was found in the majority of consortia combinations. To our knowledge, this is the first application of an in silico approach to design functionally diverse consortia before laboratory and field testing. Our results highlight the importance of employing a functional diversity approach for consortia design.