Home • Scenedesmus sp. NREL 46B-D3 v1.0
Scenedesmus sp. NREL 46B-D3
Micrograph of Scenedesmus sp. NREL 46B-D3. Photo credit: Lee Elliott, National Renewable Energy Laboratory

Scenedesmus sp. NREL 46B-D3, isolated from brackish waters in Ft. Collins, Colorado, possesses a number of promising characteristics for outdoor deployment as a feedstock for renewable fuel and chemical production. The alga displays rapid, high biomass accumulation capacity, halotolerance for full strength seawater cultivation, wide temperature tolerance for seasonable deployment, and high fuel precursor flux.

Detailed growth analyses have revealed this alga sustains a level of biomass accumulation in a non-growth state nearly equivalent to the biomass accumulation rate for actively growing cells. The biomass added during this phase is almost exclusively in the form of storage carbon, and results in an expansion of cell size to greater than 10 µm to accommodate the additional intracellular carbon accumulation. Resultant composition is approximately 40% dry cell weight lipid and 40% dry cell weight carbohydrate. The capacity of this algal to continue active photosynthesis in a non-dividing state, while fixing carbon to fuel precursors offers great promise in reducing costs associated with frequent harvesting and operating costs associated with nutrient supply. The alga’s large cell size leads to natural settling in outdoor cultivation systems, offering another potentially favorable deployment characteristic for economic biomass harvesting. The strain also displays flux to carotenoids upon nutrient deprivation, offering high-value co-product potential.

The draft sequence of the Scenedesmus sp. NREL 46B-D3 genome will thus provide critical insights into the mechanisms governing carbon assimilation and partitioning in industrially-relevant algae. Comparative inter- and intra-genus analyses will provide further insight into photosynthetic mechanisms and storage carbon flux in a non-growth state, with potential implications for an array of photoautotrophic organisms.

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