Comprehensive life cycle assessment of powder- vs. granule-form L-lysine production: Evaluating climate impact and sustainability

• Comparative life cycle assessment for powder and granule lysine was performed. • Granule lysine production lowers carbon dioxide emission by 42% compared to powder lysine. • Heat integration reduces steam consumption by 26.2% for PL and 47.7% for GL. • Raw material and energy sourcing strategy has large impact on the process sustainability . Lysine, an essential amino acid, is increasingly used as a feed additive, contributing to increased greenhouse gas emissions from livestock farming. This study aims to comprehensively assess the environmental impact of a newly proposed granule L-lysine (GL) production process in comparison to the conventional powder L-lysine (PL) process using life cycle assessment (LCA). By leveraging operational data from commercial-scale processes, this research provides insights into the potential sustainability benefits of GL production, offering strategic direction for more environmentally friendly lysine manufacturing and feed industry practices. The results revealed global warming potentials of 1.71 kg CO 2 /kg for PL and 1.00 kg CO 2 /kg for GL. By coupling LCA with heat integration, this study highlights its role in improving sustainability by reducing heating requirement up to 37 % and 45 % for PL and GL, respectively. Sensitivity analyses showed that optimizing production regions and inputs such as NH 3 , electricity, steam, and CO 2 utilization scenarios significantly enhances environmental performance. Additionally, 18 superstructure-based scenarios provided insights into regional and input-specific impacts. This study highlights the need for environmentally friendly conversion processes and systematic LCA methodologies for L-lysine production. Through a comprehensive LCA, this study identifies a promising production site and an optimal raw material production strategy for a more sustainable feed industry. These findings provide valuable insights for reducing environmental impact and guiding future improvements in lysine manufacturing.