Department of Chemical System Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Department of Urban Engineering, Graduate School of Engineering, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8656, Japan.
Environ Sci Technol. 2021 Mar 2;55(5):3380-3388. doi: 10.1021/acs.est.0c06612. Epub 2021 Feb 15.
Poly(3-hydroxybutyrate--3-hydroxyhexanoate), PHBH or PHBHHx, is a novel bio-based polymer that is biodegradable in both soil and marine environments. While bio-based and biodegradability are often celebrated features to mitigate environmental problems of plastics, their life cycle environmental impacts contain uncertainties that are yet to be fully understood. To develop effective introduction schemes for PHBH, this study assessed the life cycle climate change implications of PHBH. We computed the life cycle greenhouse gas emissions (GHG) and fossil resource consumption of produce bags and spoons composed of PHBH and their fossil-based alternatives based on industrial-scale data. The products were assessed against 10 end-of-life scenarios for commercial plastics. As a result, the cradle-to-gate GHG of PHBH ranged between 0.32 and 16.5 kgCOe/kg-PHBH depending on the land-use change assumed for the biomass production. The product-based comparative analysis presented that PHBH spoons have lower cradle-to-grave GHG emissions over their fossil-based alternatives but not with produce bags because PHBH spoons have a smaller GHG per functional unit than that of its fossil counterpart. The end-of-life scenario analysis conveyed that PHBH should be introduced to a region with a plastic waste management system that avoids methane generation and facilitates energy recovery.
聚（3-羟基丁酸酯-3-羟基己酸酯），PHBH 或 PHBHHx，是一种新型的生物基聚合物，在土壤和海洋环境中均可生物降解。虽然生物基和可生物降解性通常是减轻塑料环境问题的值得称赞的特点，但它们的生命周期环境影响仍存在不确定性，有待充分理解。为了开发 PHBH 的有效引入方案，本研究评估了 PHBH 的生命周期气候变化影响。我们根据工业规模数据，计算了由 PHBH 及其基于化石的替代品组成的生产袋和勺子的生命周期温室气体排放（GHG）和化石资源消耗。这些产品根据 10 种商业塑料的最终使用情景进行了评估。结果表明，PHBH 的摇篮到大门 GHG 范围在 0.32 到 16.5kgCOe/kg-PHBH 之间，具体取决于生物量生产所假设的土地利用变化。基于产品的比较分析表明，PHBH 勺子在其化石替代品的摇篮到坟墓 GHG 排放方面较低，但与生产袋不同，因为 PHBH 勺子的每个功能单位的 GHG 低于其化石对应物。最终使用情景分析表明，PHBH 应引入到具有避免甲烷生成和促进能源回收的塑料废物管理系统的地区。
