| dc.description.abstract | Plastic products have become an indispensable part of contemporary life, with global plastic production reaching up to 400 million tons annually. As environmental awareness rises, people are beginning to seek ＂biodegradable＂ plastics, with polylactic acid (PLA) being a notable example. Due to the specific conditions required for PLA degradation, incineration is currently the primary disposal method. However, incineration not only consumes energy but also releases carbon dioxide, exacerbating the greenhouse effect. To address the issue of PLA plastic waste, this study aims to use enzymes to hydrolyze PLA into lactic acid (LA). Lactic acid is non-toxic, biodegradable, and biocompatible, making it a suitable material for medical and cosmetic applications. However, when used as a drug carrier, PLA′s high crystallinity leads to slow degradation and delayed drug release. By condensing PLA with the natural organic acid L-malic acid (L-MA) to form the copolymer poly (L-lactic acid-co-L-malic acid) (PMALA), the hydrolysis efficiency is increased, and the hydrophobic properties are enhanced compared to PLA. This makes PMALA a potential carrier for anti-tumor drugs, biopharmaceuticals, and tissue regeneration, thereby enhancing the applicability and value of the product. Currently, approximately 30% of polylactic acid (PLA) products are derived from petrochemical processes. Disposing of these products through incineration or landfill is a waste of petrochemical resources. Considering the finite nature of these resources, it is imperative to recycle the raw materials. This study presents a potential solution to the plastic waste problem by using the enzyme Proteinase K to hydrolyze PLA and recover lactic acid (LA), achieving an LA recovery efficiency of 60-80% compared to the alkaline hydrolysis method used in this research. Discarded PLA was utilized as the LA source and converted into the medically valuable PMALA gel copolymer under atmospheric pressure and at 80°C. Unlike traditional copolymer production, which requires polymerization under vacuum or reduced pressure at temperatures above 110°C, this research demonstrates that PMALA can be polymerized at 80°C. This suggests the potential for synthesis using geothermal systems, enabling energy savings by operating at lower temperatures while adding value to waste PLA. This approach aligns with the 12th Sustainable Development Goal (SDG): Responsible Consumption and Production. | en_US |