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

Abstract

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 CO₂/kg for PL and 1.00 kg CO₂/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 NH₃, electricity, steam, and CO₂ 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.Abbreviation: AMS, Ammonium sulfate; BE, Belgium; BMG, Biomass gasification; BFG, Blast furnace gas; BG, Biogas; BR, Brazil; CG, Coal gas; CN, China; CP, Cell protein; CF, Chemical factory; EP, Electrolysis by photovoltaic; EW, Electrolysis by wind turbine; FR, France; FC, Fuel cell; GFLI, Global Feed LCA Institute; GL, Granule L-lysine; GLO, Global; GT, Geothermal; GWP, Global warming potential; HC, Hard coal; HD, Hydro; ISO, International Organization of Standardization; LCA, Life cycle assessment; LCI, Life cycle inventory; LF, Liquid fertilizer; LQ, Liquefaction; MK, Market; MT, Methanol; NC, Nuclear; NG, Natural gas; PL, Powder L-lysine; PV, Photovoltaic; PO, Partial oxidation; RoW, Rest of World; SMR, Steam methane reforming; US, United States; VT, Vent; WC, Wood chips; WD, Wind.