Highly Efficient Base-Catalyzed Valorization of Food Waste into Lactic Acid at Mild Conditions with the Pretreatment Using HCl Recovered from PVC

Lactic acid (LA) serves as a crucial platform chemical and monomer for the production of biodegradable plastic known as polylactic acid. Presently, LA is predominantly derived from the fermentation of crop syrups, a process that consumes substantial grain reserves and poses a significant threat to food security. Food waste (FW) represents a promising alternative source for LA production due to its abundant carbohydrate content. This study proposes an efficient and expeditious method for converting FW into LA at a relatively low temperature of 70 °C. The method involves the utilization of hydrochloric acid (HCl) recovered from poly(vinyl chloride) plastic (PVC) for the acid pretreatment of FW. Remarkably, this approach achieves a high LA yield of over 60% (molar yield) from simulated FW, all without the need for complex catalysts. Furthermore, the conversion process benefits from Ba2+-assisted base catalysis, demonstrating robust performance regardless of variations in the major components present in FW. This research not only offers an effective means of valorizing FW but also presents an innovative strategy to reduce the reliance of LA production on food reserves.