ST3-04: Screening for Freshwater Algae as a Source of Biofuels in the Southeastern US

Algae represent an attractive source for biodiesel as they contain upwards of 60% lipids/oils and grow much faster than terrestrial energy crops.  It is estimated that algae could yield as much as 300 times more biodiesel per unit area than soybean. Furthermore, algae cultivation requires lower energy inputs and readily accommodates numerous waste streams for fuel substrate production by nutrient re-use.  We surmise that algal strains endemic to a region will be competitively superior for open water cultivation than common laboratory strains, thus affording greater consistency and sustainability in fuel substrate production. The goal of this study was to broadly survey algal diversity from surface waters and to down-select potential biofuel production candidates based on growth characteristics and neutral lipid accumulation. Over 100 freshwater samples were collected throughout the Central Savannah River Area of South Carolina and microalgae were enriched in 2 growth medium formulations at 3 pH values. Approximately 500 microalgal strains were sorted by phenotypic features and representative strains were isolated to purity for sequence based identification.  This research is proceeding on 2 fronts.  First, growth studies are being systematically conducted for each of the biofuel candidate strains to define the elemental controls on growth rate; thus permitting objective comparison of strain performance.  Secondly, we are testing the responsiveness and timing of the ‘lipid trigger’ for neutral lipid over-production and accumulation.