Quantifying Extraction Via Ultrasonic Cavitation of Bioproducts from Algae

Utilizing biofuels limits carbon emissions in the short term as the world works towards transitioning to clean energy sources. Biofuels can be used in existing fossil fuel infrastructure with minimal alteration, replacing natural gas with syngas and gasoline with ethanol. A particularly promising source of biofuels is algae, which only require ponds to grow and do not compete with food crops. Current extraction methods are energy intensive and expensive, counteracting the neutral carbon footprint of biofuels. Ultrasonic cavitation, the creation of small bubbles that pop violently using ultrasonic waves, is potentially cheaper and more energy efficient. Many phenomena associated with cavitation are conducive to extraction, including shearing forces from jetting, high temperatures, creation of free radicals, and collection by bubbling. To quantify the effect of these phenomena and assess the potential of this process for extraction of algal biofuel, a rapid lipid quantification method is necessary, especially when investigating process variables on the macroscopic scale. Current methods limit data collection, and fluorescent lipid dyes present an opportunity for rapid quantification through spectrophotometry. Several combinations of dyes and solvents were tested, as well as various infiltration times. Water, algal oil, live algae, and algae washed with an established method were compared to assess the correlation between the fluorescence and lysis of algae. Establishing a relationship proved difficult thanks to the lack of literature regarding the ability of the dye to indicate lipid concentration, rather than viability of algae.