International Program in Hazardous Substance and Environmental Management (IP-HSM), Graduate School, Chulalongkorn University, Bangkok, Thailand; Center of Excellence on Hazardous Substance Management (HSM), Chulalongkorn University, Bangkok, Thailand.
Faculty of Environment and Resource Studies, Mahidol University, Nakhon Pathom, Thailand.
Bioresour Technol. 2023 Jan;367:128237. doi: 10.1016/j.biortech.2022.128237. Epub 2022 Nov 1.
Polylactic acid (PLA) is commercialized as a compostable bio-thermoplastic. PLA degrades under industrial composting conditions where elevated temperatures are maintained for a long timeframe. However, these conditions cannot be achieved in a non-industrial compost pile. Therefore, this study aims to degrade high molecular weight PLA films by adding a PLA-degrading bacterial consortium (EAc) comprised of Nocardioides zeae EA12, Stenotrophomonas pavanii EA33, Gordonia desulfuricans EA63, and Chitinophaga jiangningensis EA02 during traditional composting. With EAc-bioaugmentation, PLA films (5-30% w/w) had complete disintegration (35 d), 77-82% molecular weight reduction (16 d), and higher CO liberation and mineralization than non-bioaugmented composting. Bacterial community analyses showed that EAc-bioaugmentation increased the relative abundance of Schlegelella, a known polymer degrader, and interacted positively with beneficial indigenous microbes like Bacillus, Schlegelella and Thermopolyspora. The bioaugmentation also decreased compost phytotoxicity. Hence, consortium EAc shows potential in PLA-waste treatment applications, such as backyard and small-scale composting.
聚乳酸（PLA）是一种商业化的可堆肥生物热塑性塑料。PLA 在工业堆肥条件下会降解，这种条件需要长时间维持高温。然而，这些条件在非工业堆肥堆中无法实现。因此，本研究旨在通过添加由解硫地杆菌（EAc）组成的 PLA 降解细菌混合物（EAc）来降解高分子量 PLA 薄膜，该混合物包含解硫地杆菌（EAc）、小单胞菌（EAc）、戈登氏菌（EAc）和沙雷氏菌（EAc）。在传统堆肥中，添加 EAc 后，PLA 薄膜（5-30%w/w）完全分解（35 天），分子量降低 77-82%（16 天），且 CO2 的释放和矿化作用高于未生物强化的堆肥。细菌群落分析表明，EAc 生物强化增加了已知聚合物降解菌 Schlegelella 的相对丰度，并与有益的土著微生物如芽孢杆菌、Schlegelella 和 Thermopolyspora 呈正相互作用。生物强化还降低了堆肥的植物毒性。因此，EAc 混合物在 PLA 废物处理应用中具有潜力，例如后院和小规模堆肥。
