Life cycle analysis of apple pomace biorefining for biofuel and pectin production

• Published in: The Science of the total environment 2024-11, Vol.951, p.175780, Article 175780
• Main Authors: Azarakhsh, Fatemeh Al-Sadat, Ziloue, Hamid, Ebrahimian, Farinaz, Khoshnevisan, Benyamin, Denayer, Joeri F.M., Karimi, Keikhosro
• Format: Article
• Language: English
• Subjects: Apple pomace; Biofuels; Biorefineries; Biorefining; Circular bioeconomy; Environment; High-value product; High-value products; Human health; Life cycle analysis; Life cycle assessment; Low impacts; Malus; Pectins; Resource conservation; Sustainability analysis
• ISSN: 0048-9697; 1879-1026; 1879-1026
• DOI: 10.1016/j.scitotenv.2024.175780

This study investigated the environmental impacts associated with converting apple pomace, a globally abundant resource, into biofuels and high-value products using a comparative consequential life cycle assessment. In three developed scenarios, an acid pretreatment method was applied and the pretreated liquid was used for ethanol and pectin production. The pretreated solids were utilized to produce different products: scenario 1 produced biogas, scenario 2 generated butanol, and scenario 3 yielded both biogas and butanol from the solids. The results demonstrated that scenario 1 exhibited the best performance compared to the other two scenarios, imposing the lowest environmental burdens across all damage categories, including human health, ecosystems, and resources. Despite the induced impacts, the benefits of avoided products, i.e., ethanol, natural gas, butanol, acetone, and pectin, compensated for these induced environmental impacts to some extent. The results also revealed that among all products generated through the biorefineries, first-generation ethanol substitution had the most significant positive environmental impacts. Overall, the biorefinery developed in scenario 1 represents the most feasible strategy for a circular bioeconomy. It performs 84.38 % and 72.98 % better than scenarios 2 and 3 in terms of human health, 85.34 % and 74.54 % better in terms of ecosystems, and more than 100 % better in terms of resources. Conversely, scenario 2 resulted in the highest net impacts across all damage categories. Furthermore, in scenario 1, the midpoint results showed 83.10 % and 71.08 % lower impacts on global warming, 85.15 % and 74.17 % lower impacts on terrestrial acidification, and 99.26 % and 98.53 % lower impacts on fossil resource scarcity compared to scenarios 2 and 3, respectively. In conclusion, the first scenario shows promise for the sustainable valorization of apple pomace. [Display omitted] •LCA of three promising apple pomace biorefineries was evaluated and compared.•Biogas (1st), ABE (2nd), both (3rd); ethanol & pectin are considered in all scenarios.•Impacts on human health, ecosystems, and resources were investigated.•Scenarios 1 and 3 had lower net impacts than scenario 2.•Electricity and heat consumption were major contributors.•Benefits of avoided products partially offset induced impacts.