Establishment of a bioenergy-focused microalgal culture collection

Abstract

A promising renewable energy scenario involves growing photosynthetic microalgae as a biofuel feedstock that can be converted into fungible, energy-dense fuels. Microalgae transform the energy in sunlight into a variety of reduced-carbon storage products, including triacylglycerols, which can be readily transformed into diesel fuel surrogates. To develop an economically viable algal biofuel industry, it is important to maximize the production and accumulation of these targeted bioenergy carriers in selected strains. In an effort to identify promising feedstock isolates we developed, evaluated and optimized contemporary high-throughput cell-sorting techniques to establish a collection of microalgae isolated from highly diverse ecosystems near geographic areas that are potential sites for large-scale algal cultivation in the Southwest United States. These efforts resulted in a culture collection containing 360 distinct microalgal strains. We report on the establishment of this collection and some preliminary qualitative screening studies to identify important biofuel phenotypes including neutral lipid accumulation and growth rates. As part of this undertaking we determined suitable cultivation media and evaluated cryopreservation techniques critical for the long-term storage of the microorganisms in this collection. This technique allows for the rapid isolation of extensive strain biodiversity that can be leveraged for the selection of promising bioenergy feedstock strains, as well as for providing fundamental advances in our understanding of fundamental algal biology.