Does enzymatic catalysis lead to more sustainable chemicals production? A life cycle sustainability assessment of isopropyl palmitate†

Abstract

In this work, a comprehensive Life Cycle Sustainability Assessment (LCSA) is performed assessing environmental, economic and social impacts of switching from chemical to enzymatic catalysis for the esterification of Isopropyl palmitate (IPP). A dedicated LCSA methodology with a common goal, system boundary and life cycle inventory is presented. A 7 to 13% reduction in environmental impacts was found due to less hazardous waste formation, lower feedstock consumption and reduced steam usage. The social medium risk hours increase by 9% due to a longer production time, however, certain social benefits which were identified by stakeholder interviews, such as improved safety for workers, are not properly captured by the social impacts database used. Despite reductions in utility and feedstock costs, the total operating costs are higher (+40%) due to the immobilized enzyme cost and higher labour costs. Nevertheless, profitability indicators show that switching to enzymatic production is likely to be profitable. To reduce costs, optimization efforts should focus on reducing the batch time and increasing enzyme reuse. From a social and environmental perspective, upstream impacts linked to palmitic acid and isopropyl alcohol production should be addressed.