Life cycle assessment of zein, ethyl lactate, and derivative nanofiltration membranes

Abstract

Agricultural biomass from corn can be upcycled into valuable biodegradable materials such as zein, ethyl lactate, and membranes, reducing depleting resource consumption, minimizing waste, and contributing to a circular bioeconomy. Zein, a protein sourced from corn, is an alternative to fossil-based polymers. Proteins are more abundant, biodegradable, nontoxic, complex, and versatile than other biopolymers. In ethyl lactate, an alternative green solvent emerging in various applications, zein can form nanofiltration membranes. Herein, we report the life cycle assessment of zein, ethyl lactate, and membranes derived from these compounds. The assessment compares different feedstock, solvents, purification techniques, and solvent management methods to identify the environmental hotspots, particularly during the extraction stage, as an aid for decision-making. Notably, although environmental impacts are not necessarily outweighed by utilizing agricultural waste, they can be reduced through high-protein-content feedstock and proper solvent management. We also show the impact of systems thinking through the production of membrane materials and close the life cycle loop via biodegradation.