Work

Life cycle assessment of an integrated food waste biorefinery for butyric acid production: environmental hotspots and recovery process comparison

Year: 2026

Type: article

Abstract: This study evaluated the environmental performance of a novel integrated biorefinery that converts household food waste, one of the largest urban organic waste streams, into high-purity n-butyric acid (BA). The process comprised hydrothermal pretreatment, lactic acid fermentation, and BA fermentation. Two downstream recovery strategies were compared, namely adsorptive separation using zeolite (Scenario 1) and extractive distillation (Scenario 2). A gate-to-gate life cycle assessment and hotspot analysis were conducted using ReCiPe 2016 based on Aspen Plus simulations and detailed process equipment design. Adsorptive separation demonstrated superior environmental performance compared with extractive distillation across all impact categories. At 85% recovery, Scenario 1 required 0.113 MWh/t of electricity and 0.234 MWh/t of heat, compared with 0.261 MWh/t and 3.08 MWh/t, respectively, for Scenario 2, resulting in 29-97% lower endpoint damages. Accordingly, human health, ecosystem, and resource damages associated with product recovery decreased from 3.096 × 10⁻³ to 1.346 × 10⁻³ DALY, from 14.188 × 10⁻⁶ to 10.042 × 10⁻⁶ species·yr, and from 182 to 24 USD2013, respectively. Increasing BA recovery from 85% to 99% reduced endpoint damages by 13–22% in Scenario 2, whereas the corresponding reductions in Scenario 1 were <2%. The results identified BA fermentation as the dominant contributor, accounting for 70–75% of total environmental impacts, while nutrient inputs were responsible for 95–97% of fermentation-related impacts. These findings highlight nutrient management as the primary opportunity for reducing the environmental footprint of food-waste-based BA production and improving the sustainability of urban food waste valorization systems.

Source: Sustainable Chemistry for Climate Action

DOI: 10.1016/j.scca.2026.100245

Authors: Keikhosro Karimi, Azam Aydani, Hafez Maghsoudi, Ramon Ganigué, Ángel Galán-Martín, Joeri F.M. Denayer