Moisture displacement and simultaneous migration of surface-functionalized algae from water to an extraction solvent using ionic polyelectrolytes

Effective moisture removal and the ability of algal biomass to be compatible with lipophilic solvents are key to making the algal lipid extraction processes economically viable. Here we report a simple technique to chemically remove moisture from algal water while forcing above 95% of the algal cell mass to migrate to a (hydrophobic) lipid extraction solvent. The technique is based on functionalization of algal cell surface with a water-soluble cationic polyelectrolyte, Poly(diallyldimethylammonium chloride) (PolyDADMAC) that has hydrophobic ligands in its structure. Studies indicate that algal cells continued to displace moisture even after migrating into the solvent phase - continuing to perform the chemical drying step. The general results indicate that the technique could be extended to systems that require separation of particles with charged surfaces - by using a surface active ionic polyelectrolyte with appropriate charge and ligand combination(s).