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生物可分解塑膠袋及容器之堆肥可行性評估計畫

中文摘要 生物可分解塑膠(biodegradable plastics)係指可以被微生物分解為水、二氧化碳及生物質的塑膠。例如聚乳酸(poly-lactic acid, PLA)就是目前最被廣泛應用的生物可分解塑膠的材料之一,聚乳酸在高溫、高濕的堆肥環境下,微生物可以快速將其分解。目前國內尚未建立這類材料實際分解速度及堆肥成效相關資訊;故本計畫目的是:1.在商業運轉的堆肥場檢測其分解效果。2.檢測堆肥成品能否符合肥料法規的規範。3.篩選能快速分解PLA的微生物。 本計畫在二家商轉的堆肥場進行試驗,透過堆肥製作過程的堆肥化來測試生物可分解塑膠的分解成效,結果顯示全部的生物可分解樣品包含容器、吸管、袋子類,都在試驗後45天開始碎裂成塊狀,最終於60天內分解達目視不可辨識的等級,這是因為商轉堆肥場在堆肥化過程中能提供高溫的環境,加速生物可分解袋及容器分解的成效。最後再將堆肥後的成品進行作物毒害試驗,結果顯示對植物的發芽與生長沒有毒害;同時堆肥中的有害成分測值也符合肥料法規上的標準。 本研究另在實驗室進行定量的分解試驗,將生物可分解塑膠添加於不同土壤基質和市售堆肥基質,並觀察分解成效。土壤基質主要目的係模擬掩埋場掩埋入土的處理方法;市售堆肥基質是因堆肥產品本身富含多種不同的微生物,又不同廠牌因原物料和製作有所差異,使微生物菌相更為多樣性,本研究目的係確認不同環境下對生物可分解塑膠的分解能力。試驗結果發現在不同土壤樣品中,塑膠袋60天內可達20-35%重量的分解率;在不同市售堆肥成品中,可達到25-60%分解率;PLA盒類產品在不同土壤樣品中分解效果皆不明顯,但試驗過程中若市售堆肥的基質在有經過類似商轉堆肥場的溫度(40-50℃維持2-4周)環境下,分解率可大幅提高到64%~87%。 本計畫從上述結果的材料中篩選具分解能力的微生物,經序列比對後確認出4株屬安全菌株 (Risk group 1) 的放線菌,分別為Agromyces mediolanus、Arthrobacter chlorophenolicus、Microbacterium barkeri、Streptomyces diastaticus;將篩選出的菌株進行PLA的分解測試,結果顯示Microbacterium barkeri對PLA的分解能力最佳,7日內PLA的分解量達到27.59%,然而未添加微生物的PLA降解量只有9.89%。
中文關鍵字 生物可分解塑膠、聚乳酸、堆肥化、微生物

基本資訊

專案計畫編號 109A356 經費年度 109 計畫經費 2666 千元
專案開始日期 2020/12/29 專案結束日期 2021/11/30 專案主持人 黃裕銘
主辦單位 回收基管會 承辦人 張儷瓊 執行單位 漢將農業生物科技股份有限公司

成果下載

類型 檔名 檔案大小 說明
期末報告 生物可分解塑膠袋及容器之堆肥可行性評估計畫成果報告.pdf 30MB

The Feasibility of Biodegradable Plastic Bags and Containers Decomposed in Commercial Composting System

英文摘要 Biodegradable plastics are plastics that can be decomposed by microbes into water, carbon dioxide, and biomass. For example, PLA (poly-lactic acid), is one of the most common material in biodegradable plastics. PLA can be decomposed in composts with high temperature, high humidity and microbes in a relatively short time span. However, the information about how fast and the effectiveness of biodegradable plastics’ decomposition in composts are still quite rare in Taiwan. Thus, the purpose of this project “The Feasibility Study about the Decomposition of Biodegradable Plastic Bags and Containers in Commercial Composting Systems” includes: 1. Testing the effectiveness of biodegradation of certificated compostable bags and containers, in commercial composting systems. 2. Examining the composting results if meet the requirements of fertilizer protocol. 3. Searching for the safe microorganisms which can accelerate PLA’s biodegradation. The result of this study shows that in the experiments of two commercial composting yards, all compostable products including bags, containers, and straws decomposed into pieces 45 days after treatment. All samples wholly decomposed visually within 60 days. This was because it would produce high temperature environment during composting. The final composts have been tested and certified that no biotoxin found in seed germination and vegetable growth experiments. Additionally, the final composts meet the requirements of fertilizer protocol under Taiwan’s regulation. In lab scale quantitative experiments, we collected various of soil samples and commercial compost products as decomposition medium. The purpose of soil medium was investigated the decomposition of biodegradable plastics in landfill. We also investigated the decomposing of biodegradable plastics in different commercial compost products’ medium which can provide variety of decomposing environment by microbial diversity. We found the compostable bags buried in soil medium, within 60 days, show decomposing by 20-35% weight-loss. In compost medium, the bags show better decomposing effect with 25-60% weight-loss. Moreover, we found the PLA containers have no significant decomposition without high temperature. Once providing 40-50℃ temperature treatment for 2-4 weeks, PLA containers decomposed increasingly to 63-87% weight-loss, within 60 days. From the various medium (soils and composts) used in this study and the final composts of the mentioned experiments in commercial composting yards, we collected microorganism samples and looked for which one can accelerate the biodegradation of PLA. After purification and species identification, we got 4 safe strains (Agromyces mediolanus, Arthrobacter chlorophenolicus, Microbacterium bakeri, and Streptomyces diastaticus) belong to Risk Group 1. From them, we found Microbacterium barkeri having the best performance, causing 27.59% weight-loss on the PLA testing sample within 7 days, much better than the blank controller, only decomposed by 9.89% weight-loss.
英文關鍵字 biodegradable plastic, poly-lactic acid, composting, microbial