Extraction of Bioproducts from Algae in Water using Cavitating Jets

One of the most promising biomass sources for fuels and other feedstocks is photosynthetic algae. Algae can produce lipids, proteins, and other compounds, and can be grown in salt water. Current production practices rely on expensive means of harvesting, concentrating, and extracting the algae. This makes the “bio-crude” produced by algae more expensive than petroleum. Recovering the cellular contents of the algae directly from the growth media would reduce production costs and improve profitability. This proposal is to develop a method for lysing the algae and recovering the bio-crude without pre-concentrating or dewatering. Hydrodynamic cavitation using submerged jets uses fluid shear flow to create high pressure fluctuations in the shear layer to cause bubbles to grow and collapse using a fraction of the energy required for ultrasonic cavitation. Cavitation has been shown to have the capability to rupture algal cell membranes and release the cell contents. Cavitating jets also create clouds of fine bubbles that can attach to lipids in the water and lift them to the surface. By controlling the creation and collection of the resulting foam the lipids can be concentrated and recovered from the growth media with minimal energy input.