Life cycle assessment of cleaner production measures in monosodium glutamate production: A case study in China

Abstract

Monosodium glutamate (MSG) is one of the most commonly used seasonings in daily life and food industry. This study provides an initial Life Cycle Assessment (LCA) of maize-based MSG production in 2018 to determine the life cycle environmental impact of MSG production in China. The environmental performance of several cleaner production measures in the MSG industry were also analysed and evaluated using LCA. Results show that when producing 1 t maize-based MSG without any cleaner production measures, the global warming potential, aquatic ecotoxicity, aquatic acidification, and aquatic eutrophication are 6.26 t CO2eq, 848 t TEG watereq, 83.5 kg SO2eq, and 5.04 kg PO4 P-limeq. Energy consumption, direct emission in the MSG production process, and maize production are identified as the most significant contributors to the life cycle environmental impact in MSG production. Scenario analysis of different production measures, namely cogeneration, co-production and the hybrid scenario integrating the two listed measures, showed that the hybrid scenario, which represents the mainstream cleaner production technology level of the MSG industry of China, is the optimal option for environmental impact reduction of MSG production. In the hybrid scenario, the global warming potential, aquatic ecotoxicity, aquatic acidification, and the aquatic eutrophication decreased 13.90%, 7.19%, 64.29%, and 80.00% compared with the non-cleaner production scenario. Two major directions to further improve the environmental performance of the MSG production are improving energy use efficiency (and/or using cleaner energy) and modifying the production process to maximise material use efficiency.