ASU’s DAC polymer-enhanced cyanobacterial bioproductivity (AUDACity)

ASU’s DAC polymer-enhanced cyanobacterial bioproductivity (AUDACity) project aims to demonstrate a novel, scalable method for removing carbon dioxide (CO₂) directly from ambient air and delivering it to cyanobacterial cultures to produce commodity biofuel, mid-value protein for supplements, and high value phycocyanin (PC), a natural blue colorant (Figure A). This approach uses low-cost, reusable anion exchange polymers embedded in modular mesh packets, which capture CO₂ during drying cycles when exposed to ambient air, and release concentrated CO₂ into aqueous cultivation systems. The project addresses a critical challenge in energy research needed for developing sustainable, economically viable methods of Direct Air Capture (DAC) that can be integrated with bio-based systems for fuel and chemical production. AUDACity contributes to scientific understanding by integrating materials chemistry, cyanobacterial biology, and system engineering to create a distributed CO₂ delivery platform. Key insights have emerged around the design of biocompatible sorbents, optimization of CO₂ capture-release cycles, and durability of packet-based delivery systems under outdoor conditions. Notably, the team has synthesized and tested a range of polymer sorbents, identified mechanisms of material degradation and fouling, and advanced both lab- and pilot-scale cultivation systems to evaluate performance. From a technical and economic standpoint, AUDACity shows promise for achieving cost-effective CO₂ capture and delivery into aqueous media and biofuel production. Preliminary techno-economic analysis (TEA) indicates that the DAC system based on current performance can reach $680/tonne CO₂ delivered into aqueous solution; with reasonable improvements to sorbent lifetime, sorbent capacity, reducing water uptake the approach could reach $66/tonne by avoiding the need for energy-intensive sorbent regeneration and CO<. Authors: Flory, Justin [Arizona State University; Center for Negative Carbon Emissions]; Li, Shuqin [Arizona State University; School of Life Sciences]; Taylor, Samantha [Arizona State University; Center for Negative Carbon Emissions]; Tiwari, Sunil [Arizona State University; School of Life Sciences]; Cole, Garrett [Sustainability Sciences LLC; Colorado State University]. DOE Contract: EE0009274. Subjects: 09 BIOMASS FUELS; 60 APPLIED LIFE SCIENCES; anion-exchange resins; biofouling; CO2 transport into aqueous medium; life cycle assessment; moisture swing sorption; negative emissions; outdoor microalgae cultivation; passive capture; Reactive capture and conversion; sorbent containment; techno-economic analysis