Green metrics-guided redesign of cheese whey permeate upcycling via biocatalysis

Abstract

Valorizing industrial side-streams through (bio)catalysis can contribute to the transition toward circular manufacturing by implementing sustainable and effective waste-to-value processes. In this study, cheese whey permeate, an abundant effluent of the dairy industry, was upcycled into the hydrophilic headgroup 1-butyl β-D-galactopyranoside of sugar fatty acid ester surfactants via enzymatic transglycosylation. This biotransformation was systematically redesigned by using a comprehensive green metrics-guided approach to enhance process sustainability, while ensuring operational simplicity and scalability. By moving from a homogeneous ternary reaction medium to a biphasic system and replacing flash chromatography with a streamlined downstream process involving liquid-liquid extraction and a recyclable hydrophobic resin, the process was successfully scaled-up to 1.5 L yielding the product on the gram-scale. Process redesign resulted in 8-fold reduction of E(nvironmental)-factor, about 60-fold improvement of solvent eco-impact, and 27-fold decrease in global warming potential (GWP). Moreover, the redesigned process enabled closed-loop material flows facilitating the direct recovery and recycling of materials (1-BuOH and the hydrophobic resin) within the same reaction unit. Finally, the recovered sugar-enriched aqueous stream from the enzymatic transglycosylation was reused as a nutrient-rich growth medium for microbial cultivation, paving the way for a future highly integrated biomanufacturing framework.