Melt-processing of Enzymes into Bio-catalytic Polymer Membranes for Carbon Dioxide Remediation

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This grant supports research that contributes to the development of advanced manufacturing methods to enable the capture of carbon dioxide from industrial waste gases. Greenhouse gases are the principal factor driving climate change and one of the most detrimental human-derived waste products is carbon dioxide. Current technologies to sequester carbon dioxide are energy intensive and inefficient. This research develops a process to manufacture carbon-capture membranes that are inexpensive, energy efficient, and scalable to meet this growing societal need. The research relies on polymer melt-processing, a plastic manufacturing technique that enables the large-scale production of most common plastic goods. The innovation is using melt-processing to integrate biochemical catalysts or enzymes into plastic membranes to sequester carbon dioxide. Enzymatic carbon dioxide capture occurs at room temperature to produce solid carbon salts which can be easily stored, thus greatly reducing the energy demand. The outcome of this research greatly benefits society, since climate change is a grand challenge in engineering, and, thus, is instrumental in securing the prosperity and security of the country. This research is multi-disciplinary and includes polymer science, chemical engineering, materials science, and biochemistry. Students conducting this research are trained at the forefront of science, which has a long-term positive impact on the nation?s technological output. The use of carbonic anhydrase as a carbon dioxide capture catalyst is promising given the enzymes rapid turnover number, minimal energy input for sequestration and ability to sequester carbon into solid salts. The limiting factor for applying carbonic anhydrase broadly is a manufacturing challenge that requires scalability and reproducibility. Current enzyme immobilization processes operate in batch mode and rely on adsorption or non-specific chemical reactions to a solid support, limiting scalability and reproducibility. This research develops continuous manufacturing methods to incorporate carbonic anhydrase into permeable polymer membranes that can be fabricated at large scale. The primary hurdle in accomplishing this goal is to develop a fundamental understanding of processing conditions under which carbonic anhydrase maintains stability and activity during melt-extrusion. This project seeks to understand the main stressors, temperature and shear, during processing and correlate these to enzyme performance. Once this relationship has been established, the results are used to scale-up polymer membrane manufacture to twin-screw extruders, similar to those used in commercial film manufacturing. These membranes are evaluated for carbon dioxide flux, sequestration, and durability in environments that mimic complex mixtures of industrial waste gases.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.