From Conventional PLA Production to Chemical Recycling: Techno-Economic Comparison of Two Waste-PLA Recycling Pathways

This study presents a techno-economic comparison of conventional PLA production by fermentation from glucose with two chemical recycling pathways that recycle postconsumer waste PLA by enzymatic hydrolysis and alcoholysis. Process simulations in Aspen Plus show all routes achieve high material efficiency (>90%) but differ markedly in ecological and economic performance. The benchmark fermentation process requires the most auxiliary materials and energy, resulting in higher costs and environmental impact. Enzymatic hydrolysis of waste PLA (wPLA) improves material efficiency and lowers costs, but its viability depends on the purity and yield of the waste stream. Alcoholysis with methanol is the most advantageous, offering the lowest capital and operating costs, high robustness to feedstock prices, and superior material efficiency. Sensitivity analyses confirm the potential of the recycling routes under a wide range of assumptions regarding process parameters and ecological framework conditions. These findings highlight the ecological and economic benefits of transitioning from linear to circular PLA production, with alcoholysis-based recycling identified as the most promising pathway for sustainable, large-scale bioplastics manufacturing.