(632g) Nutrient Recovery and Fuel Precursor Production from Extracted Algae Residues Using Mild Oxidative Treatment

Valorization of algal biomass to fuels and chemicals frequently requires pretreatment to lyse cells and extraction of lipids, producing an aqueous lysate and an extracted solid residue as intermediates. Wet oxidation is a promising route to simultaneously convert nitrogen contained in the lysate and residues to easily-recyclable ammonia and to convert carbon in the same fractions to carboxylic acids that can be converted to biofuels by ketonization, condensation, and hydrodeoxygenation. We show that for a Scenedesmus algae under certain oxidation conditions, nearly all of the nitrogen in the residues can be converted to ammonia and recovered by cation exchange, while almost half of the carbon can be converted to carboxylic acids. At the same time, we also show that soluble phosphorus in the form of phosphate can be selectively recovered by anion exchange, leaving a clean aqueous carboxylic acid stream for upgrading to fuels.