(388d) Biomass Size Reduction of Microalgae

Microalgae derived fuels have great potential to replace fossil fuels with environmental friendly alternatives.  Microalgae are advantageous because they grow quickly, offer higher photosynthetic efficiencies, better accumulation of lipids, may offer hydrogen for fuel cells, and synthesis of energy storing starch relative to most biofuel feedstocks.  However, the high water content of microalgae restricts the optimization of biomass energy conversion.  Here, we report on a new technique to remove the water from microalgae leaving dry biomass.  This technique atomizes the micron sized algae within the droplets.  The nebulized droplets dry in a diffusion drier prior to entering a differential mobility analyzer (DMA), in which they are classified by their size-to-charge ratio.  The dry algal biomass was observed to have a dry size ranging from 50-300 nm and was approximately spherical in shape.  The same algae were sized between 10-15 microns using asymmetric field-field flow fractionation (AFFFF) in liquid form.  DMA classified algae were electrostatically deposited and compared with the unaltered algae.  Electron microscopy reveals that DMA classified algae preserved organelles yet consistently separated the biomass from water.  This technique may improve the efficiency of biomass energy conversion.