CAREER:Nutrients and Energy-rich Macromolecules Recovery from Microalgae using Subcritical Water

Old Dominion University Research Foundation, Norfolk VA

Investigators

Abstract

1351413 Kumar In this CAREER research/educational project, the PI will utilize subcritical water for both extracting the energy-rich macromolecules and for recovering the minerals. The project is expected the address both of the challenges currently faced by algae biofuels. In the first step, PI will utilize flash hydrolysis (FH) to recover proteins, carbohydrates, lipids. In the second step, the PI will utilize hydrothermal mineralization (HTM) to recover inorganic nutrients for recycling. The proposed process has potential of recovering more than two-thirds of macronutrients using geo-mimetic precipitation method, while producing biofuel intermediate species. These nutrients include P, N, and inorganic solids. The FH process has the advantage of being able to disrupt algal cell walls without changing the functionality of the cell components such as lipids. The recovered nutrients will be utilized as slow-release fertilizer for algae cultivation. An array of characterization methods will be utilized for understanding the effects of algae productivity, and the efficacy of the recycled nutrients. Selective FH of algae proteins within a few seconds without the use of any added chemicals is a new concept. The project will examine FH of model proteins to derive a fundamental understanding of reaction pathways, intermediate compounds, and interactions of macromolecules under fast reaction conditions. This will extend our knowledge of conversion of organic matters in hydrothermal medium. The proposed nutrients recovery using HTM mimics natural geological process of minerals precipitation in aqueous medium. The integration of HTM with FH is a novel concept considering that no additional heating or pressurization will be required. A new knowledge will be developed by studying the mineralization and precipitation of dissolved ionic species (extracted from algae during FH) in hydrothermal medium to recover nutrients. The additional benefits include production of biofuel intermediates while reducing NOx emissions. In addition to educating graduate and undergraduate students, the project calls for K-12 and community outreach and involvement of underrepresented/minority groups. The outreach program is supplemented and enhanced by laboratory experiences. The PI also aims to introduce a freshman level class of environmental sustainability, exposing students to the importance and career possibilities in this topic area.